2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):318–324. doi: 10.28920/dhm50.4.318–324. PMID: 33325010.

Effects of inspiratory muscle training versus high intensity interval training on the recovery capacity after a maximal dynamic apnoea in breath-hold divers. A randomised crossover trial

Francisco de Asís-Fernández1,2, Tamara del Corral1,2, Ibai López-de-Uralde-Villanueva3

1 Departamento de Fisioterapia, Facultad de Ciencias de la Salud. Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, Spain
2 Breatherapy Research Group, Instituto de Neurociencias y Ciencias del Movimiento (INCIMOV), Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, Spain
3 Department of Radiology, Rehabilitation and Physiotherapy, Faculty of Nursing, Physiotherapy and Podiatry, Complutense University of Madrid, Spain

Corresponding author: Professor Tamara del Corral, Departamento de Fisioterapia, Facultad de Ciencias de la Salud. Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, Spain
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Key words
Breath-hold diving; Apnea; Exercise; Pulmonary function; Performance; Metabolism

Abstract
(de Asís-Fernández F, del Corral T, López-de-Uralde-Villanueva I. Effects of inspiratory muscle training versus high intensity interval training on the recovery capacity after a maximal dynamic apnoea in breath-hold divers. A randomised crossover trial. Diving and Hyperbaric Medicine. 2020 December 20;50(4):318–324. doi: 10.28920/dhm50.4.318-324. PMID: 33325010.)
Introduction: After a maximal apnoea, breath-hold divers must restore O2 levels and clear CO2 and lactic acid produced. High intensity interval training (HIIT) and inspiratory muscle training (IMT) could be employed with the aim of increasing recovery capacity. This study aimed to evaluate the relative effects of IMT versus HIIT on recovery of peripheral oxygen saturation (SpO2), and also on pulmonary function, inspiratory muscle strength, lactate and heart rate recovery after a maximal dynamic apnoea in breath-hold divers.
Methods: Fifteen breath-hold divers performed two training interventions (IMT and HIIT) for 20 min, three days per week over four weeks in randomised order with a two week washout period.
Results: IMT produced a > 3 s reduction in SpO2 recovery time compared to HIIT. The forced expiratory volume in the first second (FEV1) and maximum inspiratory pressure (MIP) were significantly increased in the IMT group compared to HIIT. The magnitude of these differences in favour of IMT was large in both cases. Neither training intervention was superior to the other for heart rate recovery time, nor in peak- and recovery- lactate.
Conclusions: IMT produced a reduction in SpO2 recovery time compared to HIIT after maximal dynamic apnoea. Even a 3 s improvement in recovery could be important in scenarios like underwater hockey where repetitive apnoeas during high levels of exercise are separated by only seconds. IMT also improved FEV1 and MIP, but no differences in lactate and heart rate recovery were found post-apnoea between HIIT and IMT.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):325–331. doi: 10.28920/dhm50.4.325–331. PMID: 33325011.

Acute spontaneous spinal cord infarction: Utilisation of hyperbaric oxygen treatment, cerebrospinal fluid drainage and pentoxifylline

Catherine Ashton1, Neil Banham2, Merrilee Needham1,3,4,5

1 Neurology Department, Fiona Stanley Hospital, Murdoch, Australia
2 Department of Hyperbaric Medicine, Fiona Stanley Hospital, Murdoch, Australia
3 Institute for Immunology and Infectious Diseases, Murdoch University, Murdoch, Australia
4 Perron Institute for Neurological and Translational Science, Nedlands, Australia
5 University of Notre Dame, Fremantle, Australia

Corresponding author: Dr Catherine Ashton, Neurology Department, Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch, WA 6150, Australia
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Key words
Central nervous system; Hyperbaric oxygen treatment; Infarction; Outcome; Spinal cord; Stroke; Treatment

Abstract
(Ashton C, Banham N, Needham M. Acute spontaneous spinal cord infarction: Utilisation of hyperbaric oxygen treatment, cerebrospinal fluid drainage and pentoxifylline. Diving and Hyperbaric Medicine. 2020 December 20;50(4):325–331. doi: 10.28920/dhm50.4.325-331. PMID: 33325011.)
Introduction: Spinal cord infarction (SCI) is a potentially devastating disorder presenting with an acute anterior spinal artery syndrome, accounting for an estimated 1% of stroke presentations. Aetiologies include aortic surgical complications, systemic hypotension, fibrocartilaginous embolism and vascular malformations. Diagnosis is clinical combined with restriction on diffusion-weighted magnetic resonance imaging (MRI). There are no treatment guidelines for non-perioperative cases although there is limited literature regarding potential therapies, including hyperbaric oxygen treatment (HBOT) and cerebrospinal fluid (CSF) drainage. We describe 13 cases of acute SCI, five receiving HBOT, and three also receiving pentoxifylline and drainage of lumbar CSF.
Methods: Data for all patients with MRI-proven SCI at Fiona Stanley Hospital from 2014–2019 were reviewed.
Results: Thirteen patients, median age 57 years (31–74), 54% female, were identified. Aetiologies: two fibrocartilaginous emboli; seven likely atherosclerotic; two thromboembolic; two cryptogenic. All presented with flaccid paraplegia except one with Brown-Sequard syndrome. Levels ranged from C4 to T11. Five patients received HBOT within a median time of 40 hours from symptom onset, with an average 15 treatments (10−20). Three of these received triple therapy (HBOT, pentoxifylline, CSF drainage) and had median Medical Research Council manual muscle testing power of 5, median modified Rankin Score (mRS) of 1 and American Spinal Injury Association (ASIA) score of D on discharge, compared with 2 power, mRS 3.5 and ASIA B in those who did not.
Conclusions: SCI can be severely disabling. Triple therapy with pentoxifylline, CSF drainage and HBOT may reduce disability and further prospective trials are required.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):332–337. doi: 10.28920/dhm50.4.332-337. PMID: 33325012.

Reduction of bacterial load with the addition of ultraviolet-C disinfection inside the hyperbaric chamber

Katrina Browne1, Danielle Wood2, Kate Clezy3, Jan Lehm2, William R Walsh1

1 Surgical and Orthopaedic Research Laboratory, University of New South Wales, Prince of Wales Hospital, Sydney, Australia
2 Hyperbaric Medicine Unit, Prince of Wales Hospital, Sydney, Australia
3 Infectious Diseases Department, Prince of Wales Hospital, Sydney Australia

Corresponding author: Dr Danielle Wood, Hyperbaric Medicine Unit, Prince of Wales Hospital, Nurses Dr, Randwick, NSW 2031, Australia
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Key words
Hyperbaric research; Hyperbaric facilities; Infectious disease; Bacteriology; Fire; Surveillance; Infection prevention

Abstract
(Browne K, Wood D, Clezy K, Lehm J, Walsh WR. Reduction of bacterial load with the addition of ultraviolet-C disinfection inside the hyperbaric chamber. Diving and Hyperbaric Medicine. 2020 December 20;50(4):332–337. doi: 10.28920/dhm50.4.332-337. PMID: 33325012.)
Introduction: Healthcare acquired infections (HAIs) are associated with increased mortality, morbidity and prolonged hospital stays. Microbiological contamination of the hospital environment directly contributes to HAIs. Optimising environmental cleaning reduces transmission of HAIs. The hyperbaric chamber poses a specific challenge for infection control as certain disinfectants and alcohol-based hand sanitisers are prohibited due to fire risk. Patients often possess multiple risk factors for HAIs. This study compared the bacteria remaining on a surface (bioburden) after a standard clean and after adjunctive disinfection with an ultraviolet-C (UV-C) robot.
Methods: Internal hyperbaric chamber surfaces were first manually cleaned with Clinell® universal wipes and the floor was mopped with Whiteley neutral detergent. Allocated surfaces were swabbed using sterile cotton swabs and processed using a standard microbial culture and a bacteria-specific rapid metabolic assay. Bacterial contamination was also measured by direct contact plating on flat surfaces. The plexiglass ports were covered to protect from potential UV-C mediated damage and used as a negative control. A UV-C disinfection robot was then used to disinfect the chamber for 30 min, whereafter surfaces were swabbed again.
Results: There was a significantly greater mean reduction in bioburden following adjunctive UV-C disinfection than with standard cleaning alone. The surfaces not routinely manually cleaned (e.g., bench, phone) showed greatest reduction in bacterial load following UV-C cleaning.
Conclusions: There was a significant reduction in the bacterial load in the chamber following an adjunctive UV-C clean compared with that of a standard clean. Adjunctive cleaning of the hyperbaric chamber environment with a non-touch UV-C device shows promise as a method to reduce HAIs.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):338–342. doi: 10.28920/dhm50.4.338-342. PMID: 33325013.

Effect of antiplatelet and/or anticoagulation medication on the risk of tympanic barotrauma in hyperbaric oxygen treatment patients, and development of a predictive model

Adam E Howard1, Peter Buzzacott2, Ian C Gawthrope1,3, Neil D Banham1

1 Department of Hyperbaric Medicine, Fiona Stanley Hospital, Western Australia
2 Pre-Hospital, Resuscitation and Emergency Care Research Unit, School of Nursing, Midwifery and Paramedicine, Curtin University, Western Australia
3 University of Notre Dame, Fremantle, Western Australia

Corresponding author: Dr Adam Howard, Department of Hyperbaric Medicine, Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch, WA 6150, Australia
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Key words
Middle ear; Risk factors; Haematology; Women; Age; Data

Abstract
(Howard AE, Buzzacott P, Gawthrope IC, Banham ND. Effect of antiplatelet and/or anticoagulation medication on the risk of tympanic barotrauma in hyperbaric oxygen therapy patients, and development of a predictive model. Diving and Hyperbaric Medicine. 2020 December 20;50(4):338–342. doi: 10.28920/dhm50.4.338-342. PMID: 33325013.)
Introduction: Middle ear barotrauma (MEBt) is a common side effect of hyperbaric oxygen treatment (HBOT) and can result in pain, hearing loss, tinnitus and otorrhagia. The use of antiplatelet/anticoagulant drugs is thought to increase the risk and severity of MEBt during HBOT.
Methods: Single centre, retrospective observational cohort study of all patients treated with HBOT over a 4-year period (between 01 January 2015 to 31 December 2018) looking at the incidence of MEBt and the concurrent use of antiplatelet and/or anticoagulant drugs. MEBt was assessed by direct otoscopy of the tympanic membrane post-HBOT and scored using the modified Teed classification. Multivariate modelling assessed the relationship between antiplatelet and/or anticoagulation drug use, age, sex, and MEBt during HBOT.
Results: There was no evidence that antiplatelet and/or anticoagulation drugs increase the risk of tympanic barotrauma in HBOT patients. The prevalence of MEBt was higher in female patients than in males (χ2 P = 0.004), and increased with age (χ2 P = 0.048). No MEBt was recorded in patients undergoing recompression therapy for decompression sickness or cerebral arterial gas embolism.
Conclusions: In this retrospective single-centre study, antiplatelet and/or anticoagulation drugs did not affect the risk of MEBt, but both age and sex did, with greater prevalence of MEBt among older patients and females compared with younger patients and males. A predictive model, requiring further validation, may be helpful in assessing the likelihood of MEBt in patients undergoing HBOT.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):343-349. doi: 10.28920/dhm50.4.343-349. PMID: 33325014.

Xuebijing attenuates decompression-induced lung injuries

Wen-tao Meng1,2, Long Qing3, Quan Zhou1, Wei-gang Xu1

1 Department of Diving and Hyperbaric Medicine, Naval Special Medicine Center, Naval Medical University, Shanghai, China
2 Discipline of Military and Special Medicine, The 92493 Military Hospital of PLA, Huludao, China
3 Naval Diving Medical Discipline, Naval Special Medicine Center, Naval Medical University, Shanghai, China

Corresponding author: Professor Wei-gang Xu, Department of Diving and Hyperbaric Medicine, Naval Special Medicine Center, Naval Medical University, Shanghai, China
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Key words
Decompression sickness; Decompression illness; Inflammation; Pulmonary oedema

Abstract
(Meng W, Qing L, Zhou Q, Xu W. Xuebijing attenuates decompression-induced lung injuries. Diving and Hyperbaric Medicine. 2020 December 20;50(4):343–349. doi: 10.28920/dhm50.4.343-349. PMID: 33325014.)
Introduction: The lung is among the primary organs involved in decompression sickness (DCS). Xuebijing (XBJ), a traditional Chinese medicine, has been widely used in the treatment of various acute lung diseases. This study aimed to explore potential benefit of XBJ on lung injuries induced by DCS in a rabbit model.
Methods: Twenty-four male New Zealand white rabbits underwent a simulated air dive to 50 meters’ sea water for 60 min with 2.5 min decompression, and received an intravenous injection of XBJ (5 ml·kg-1) or an equal volume of saline immediately following decompression. DCS signs were monitored for 24 h, and blood was sampled before simulated diving and at 6 h and 12 h following decompression for determination of inflammatory indices. Lung tissues were sampled after euthanasia for histology analysis and lung water content, as well as tumour necrosis factor-α level. Another six rabbits were used as control.
Results: XBJ significantly ameliorated lung injuries (lung wet/dry ratio and total protein content in bronchoalveolar lavage fluid), and notably inhibited systemic (serum level of interleukin-1β) and local (tumour necrosis factor-α in bronchoalveolar lavage fluid) inflammation responses.
Conclusions: The results strongly suggest the benefits of XBJ on ameliorating DCS lung injuries, which is possibly via inhibiting systemic and local inflammation. XBJ may be a potential candidate for the treatment of decompression-induced lung injuries.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):350–355. doi: 10.28920/dhm50.4.350-355. PMID: 33325015.

Effects of freediving on middle ear and eustachian tube function

Moritz F Meyer1,2, Kristijana Knezic1, Stefanie Jansen1, Heinz D Klünter1, Eberhard D Pracht3, Maria Grosheva1

1 Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Germany
2 Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany
3 German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany

Corresponding author: Dr Moritz F Meyer, Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine, University Hospital of Essen, Hufelandstraße 55, 45122 Essen, Germany
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Key words
Tympanometry; Repetitive diving; Ear barotrauma; ENT; Risk factors; Valsalva manoeuvre

Abstract
(Meyer MF, Knezic K, Jansen S, Klünter HD, Pracht ED, Grosheva M. Effects of freediving on middle ear and eustachian tube function. Diving and Hyperbaric Medicine. 2020 December 20;50(4):350–355. doi: 10.28920/dhm50.4.350-355. PMID: 33325015.)
Introduction: During descent in freediving there is exposure to rapidly increasing pressure. Inability to quickly equalise middle ear pressure may cause trauma to the ear. This study aimed to evaluate the occurrence of pressure-related damage to the middle ear and the Eustachian tube during freediving and to identify possible risk factors.
Methods: Sixteen free divers performed diving sessions in an indoor pool 20 metres’ freshwater (mfw) deep. During each session, each diver performed four own free dives and up to four safety dives. Naso- and oto-endoscopy and Eustachian tube function tests were performed on the right and left ears before diving, between each session and after the last session. The otoscopic findings were classified according to the Teed classification (0 = normal tympanic membrane to 4 = perforation). Additionally, ENT-related complaints were assessed using a questionnaire.
Results: Participants performed 317 dives (on average 20 dives per diver, six per session). The average depth was 13.3 mfw. Pressure-related changes (Teed 1 and 2) were detected in 48 % of ears. Teed level increased significantly with an increasing number of completed sessions (P < 0.0001). Higher pressure-related damage (Teed 2) occurred in less experienced divers, was associated with significantly lower peak pressures in the middle ear and led to more ear-related symptoms. A preference for the Frenzel technique for middle ear pressure equalisation during freediving was shown.
Conclusions: Pressure exposure during freediving had a cumulative effect on the middle ear. Factors such as diving depth, diving experience and number of diving sessions correlated with the occurrence of higher Teed levels.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):356–362. doi: 10.28920/dhm50.4.356-362. PMID: 33325016.

Safety proposals for freediving time limits should consider the metabolic-rate dependence of oxygen stores depletion

Charlotte Sadler1, Kaighley Brett1, Aaron Heerboth1, Austin R Swisher2, Nader Mehregani2, Ross Touriel1, Daniel T Cannon2

1 Department of Emergency Medicine, University of California, San Diego, USA
2 School of Exercise and Nutritional Sciences, San Diego State University, San Diego, USA

Corresponding author: Dr Charlotte Sadler, Department of Emergency Medicine, University of California, San Diego, USA
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Key words
Hypoxia; Breath-hold diving; Diving research; Hyperventilation; Metabolism; Apnoea; Apnea

Abstract
(Sadler C, Brett K, Heerboth A, Swisher AR, Mehregani N, Touriel R, Cannon DT. Safety proposals for freediving time limits should consider the metabolic-rate dependence of oxygen stores depletion. Diving and Hyperbaric Medicine. 2020 December 20;50(4):356–362. doi: 10.28920/dhm50.4.356-362. PMID: 33325016.)
Introduction: There is no required training for breath-hold diving, making dissemination of safety protocols difficult. A recommended breath-hold dive time limit of 60 s was proposed for amateur divers. However, this does not consider the metabolic-rate dependence of oxygen stores depletion. We aimed to measure the effect of apnoea time and metabolic rate on arterial and tissue oxygenation.
Methods: Fifty healthy participants (23 (SD 3) y, 22 women) completed four periods of apnoea for 60 s (or to tolerable limit) during rest and cycle ergometry at 20, 40, and 60 W. Apnoea was initiated after hyperventilation to achieve PETCO2 of approximately 25 mmHg. Pulse oximetry, frontal lobe oxygenation, and pulmonary gas exchange were measured throughout. We defined hypoxia as SpO2 < 88%.
Results: Static and exercise (20, 40, 60 W) breath-hold break times were 57 (SD 7), 50 (11), 48 (11), and 46 (11) s (F [2.432, 119.2] = 32.0, P < 0.01). The rise in PETCO2 from initiation to breaking of apnoea was dependent on metabolic rate (time × metabolic rate interaction; F [3,147] = 38.6, P < 0.0001). The same was true for the fall in SpO2 (F [3,147] = 2.9, P = 0.03). SpO2 fell to < 88% on 14 occasions in eight participants, all of whom were asymptomatic.
Conclusions: Independent of the added complexities of a fall in ambient pressure on ascent, the effect of apnoea time on hypoxia depends on the metabolic rate and is highly variable among individuals. Therefore, we contend that a universally recommended time limit for breath-hold diving or swimming is not useful to guarantee safety.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):363–369. doi: 10.28920/dhm50.4.363-369. PMID: 33325017.

A review of diving practices and outcomes following the diagnosis of a persistent (patent) foramen ovale in compressed air divers with a documented episode of decompression sickness

Christopher W Scarff1, John Lippmann2,3, Andrew W Fock1,3

1 Department of Intensive Care and Hyperbaric Medicine, Alfred Hospital, Melbourne, Australia
2 Australasian Diving Safety Foundation, Melbourne, Australia
3 Department of Public Health and Preventive Medicine, Monash University, Melbourne, Australia

Corresponding author: Dr Christopher W Scarff, The Alfred, PO Box 315, Prahran 3181, VIC, Australia
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Key words
Decompression illness; Persistent (patent) foramen ovale (PFO); Safety; Education; Diving research

Abstract
(Scarff CW, Lippmann J, Fock AW. A review of diving practices and outcomes following the diagnosis of a persistent (patent) foramen ovale in compressed air divers with a documented episode of decompression sickness. Diving and Hyperbaric Medicine. 2020 December 20;50(4):363–369. doi: 10.28920/dhm50.4.363-369. PMID: 33325017.)
Introduction: The presence of a persistent (patent) foramen ovale (PFO) increases the risk of decompression sickness (DCS) whilst diving with pressurised air. After the diagnosis of a PFO, divers will be offered a number of options for risk mitigation. The aim of this study was to review the management choices and modifications to diving practices following PFO diagnosis in the era preceding the 2015 joint position statement (JPS) on PFO and diving.
Methods: A retrospective study was conducted of divers sourced from both the Alfred Hospital, Melbourne and the Divers Alert Network Asia-Pacific during the period 2005–2015. Divers were contacted via a combination of phone, text, mail and email. Data collected included: diving habits (years, style and depths); DCS symptoms, signs and treatment; return to diving and modifications of dive practices; history of migraine and echocardiography (ECHO) pre- and post-intervention; ECHO technique(s) used, and success or failure of PFO closure (PFOC). Analyses were performed to compare the incidence of DCS pre- and post-PFO diagnosis.
Results: Seventy-three divers were interviewed. Sixty-eight of these returned to diving following the diagnosis of PFO. Thirty-eight underwent PFOC and chose to adopt conservative diving practices (CDPs); 15 chose PFOC with no modification to practices; 15 adopted CDPs alone; and five have discontinued diving. The incidence of DCS decreased significantly following PFOC and/or adoption of conservative diving practices. Of interest, migraine with aura resolved in almost all those who underwent PFOC.
Conclusions: Many divers had already adopted practices consistent with the 2015 JPS permitting the resumption of scuba diving with a lowering of the incidence of DCS to that of the general diving population. These results support the recommendations of the JPS.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):370–376. doi: 10.28920/dhm50.4.370-376. PMID: 33325018.

Decompression illness treated at the Geneva hyperbaric facility 2010–2016: A retrospective analysis of local cases

Julian Thaler1, Rodrigue Pignel2, Marie-Anne Magnan2, Michel Pellegrini2, Pierre Louge2

1 Department of Intensive Care Medicine, Valais Hospital, Sion, Switzerland
2 Hyperbaric Medicine, Geneva University Hospitals, Geneva, Switzerland

Corresponding author: Dr Julian Thaler, Department of Intensive Care Medicine, Valais Hospital, Avenue du Grand-Champsec 80, 1951 Sion, Switzerland
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Key words
Diving; Decompression illness; Arterial gas embolism; Epidemiology; Scuba; Recompression

Abstract
(Thaler J, Pignel R, Magnan M-A, Pellegrini M, Louge P. Decompression illness treated at the Geneva hyperbaric facility 2010–2016: A retrospective analysis of local cases. Diving and Hyperbaric Medicine. 2020 December 20;50(4):370–376. doi: 10.28920/dhm50.4.370-376. PMID: 33325018.)
Introduction: The Geneva hyperbaric chamber is the main treatment centre for decompression illness (DCI) in Switzerland. The characteristics, symptomatology, treatment and short-term outcome of divers treated at this chamber have not previously been investigated.
Methods: This was a retrospective study of patients treated with hyperbaric oxygen (HBO) for DCI from 2010 to 2016. Data were analysed to provide a description of the cases and statistical analysis for possible factors associated with an unfavourable outcome.
Results: One hundred and thirty-five patients were treated for DCI. Ninety-two were included in the study. Sixty-four presented with neurological and 28 with mild DCI. One hundred and thirty-five patients were treated for DCI. Ninety-two were included in the study. Sixty-four presented with neurological and 28 with mild DCI. Patients with mild DCI mainly had musculoskeletal symptoms (79%). Patients with neurological DCI mainly had spinal (55%), followed by vestibular (36%) symptoms. Arterial gas embolism was diagnosed in 30% of cases. Diving depths ranged between 15 and 142 metres, and dive times between two and 241 min. Median time to treatment was 6 h. Patients with neurological DCI had a high rate (25%) of persisting deficits after treatment. Older age was associated with an unfavourable outcome in univariate but not in multivariate analysis. No adverse effects of HBO were observed. For spinal DCI, a high Boussuges score was associated with persisting deficits after treatment.
Conclusions: Our findings are consistent with other series. Severe DCI was associated with a high rate of persisting deficits. No single factor was associated with a negative outcome. A Boussuges score > 7 had sensitivity of 90% and positive predictive value 53% for predicting an unfavourable outcome in spinal DCI.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):377–385. doi: 10.28920/dhm50.4.377-385. PMID: 33325019.

Investigating critical flicker fusion frequency for monitoring gas narcosis in divers

Xavier CE Vrijdag1,2, Hanna van Waart1, Jamie W Sleigh1,3, Costantino Balestra4, Simon J Mitchell1,5

1 Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
2 Deep Dive Dubai, Dubai, United Arab Emirates
3 Department of Anaesthesia, Waikato Hospital, Hamilton, New Zealand
4 Environmental, Occupational and Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
5 Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand

Corresponding author: Xavier Vrijdag, Department of Anaesthesiology, School of Medicine, University of Auckland, Private bag 92019, Auckland 1142, New Zealand
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Key words
CFFF; Diving research; Narcosis; Nitrogen; Oxygen; Physiology

Abstract
(Vrijdag XCE, van Waart H, Sleigh JW, Balestra C, Mitchell SJ. Investigating critical flicker fusion frequency for monitoring gas narcosis in divers. Diving and Hyperbaric Medicine. 2020 December 20;50(4):377–385. doi: 10.28920/dhm50.4.377-385. PMID: 33325019.)
Introduction: Critical flicker fusion frequency (CFFF) has been used in various studies to measure the cognitive effects of gas mixtures at depth, sometimes with conflicting or apparently paradoxical results. This study aimed to evaluate a novel automatic CFFF method and investigate whether CFFF can be used to monitor gas-induced narcosis in divers.
Methods: Three hyperbaric chamber experiments were performed: 1) Automated and manual CFFF measurements during air breathing at 608 kPa (n = 16 subjects); 2) Manual CFFF measurements during air and heliox breathing at sea level (101.3 kPa) and 608 kPa (n = 12); 3) Manual CFFF measurements during oxygen breathing at sea level, 142 and 284 kPa (n = 10). All results were compared to breathing air at sea level.
Results: Only breathing oxygen at sea level, and at 284 kPa, caused a significant decrease in CFFF (2.5% and 2.6% respectively compared to breathing air at sea level. None of the other conditions showed a difference with sea level air breathing.
Conclusions: CFFF did not significantly change in our experiments when breathing air at 608 kPa compared to air breathing at sea level pressure using both devices. Based on our results CFFF does not seem to be a sensitive tool for measuring gas narcosis in divers in our laboratory setting.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):386–390. doi: 10.28920/dhm50.4.386-390. PMID: 33325020.

Hyperbaric oxygen but not hyperbaric air increases insulin sensitivity in men with type 2 diabetes mellitus

David C Wilkinson1,2, Ian M Chapman2, Leonie K Heilbronn2

1 Hyperbaric Medicine Unit, Royal Adelaide Hospital, Adelaide, Australia
2 Adelaide Medical School, The University of Adelaide, Adelaide, Australia

Corresponding author: Dr David Wilkinson, Hyperbaric Medicine Unit, Royal Adelaide Hospital, Port Road, Adelaide SA 5000, Australia
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Key words
Blood sugar level; Diabetes; Endocrinology; Hyperbaric research; Metabolism

Abstract
(Wilkinson DC, Chapman IM, Heilbronn LK. Hyperbaric oxygen but not hyperbaric air increases insulin sensitivity in men with type 2 diabetes mellitus. Diving and Hyperbaric Medicine. 2020 December 20;50(4):386–390. doi: 10.28920/dhm50.4.386-390. PMID: 33325020.)
Introduction: We have previously shown that hyperbaric oxygen treatment (HBOT) increased insulin sensitivity in men who were obese or overweight, both with and without type 2 diabetes. The aim of this study was to test whether this insulin-sensitising effect is seen in hyperbaric air (HA).
Methods: Men with type 2 diabetes who were obese or overweight were randomised to two groups: HBOT (n = 13) or HA (n = 11). A hyperinsulinaemic euglycaemic glucose clamp (80 mU·m-2·min-1) was performed at baseline and during hyperbaric intervention. Both groups were compressed to 203 kPa (two atmospheres absolute) for 90 minutes followed by a linear 30-minute decompression. The HBOT group breathed oxygen via a hood while the HA group breathed chamber air. Insulin sensitivity was assessed from the glucose infusion rate (GIR) during the last 30 minutes in the hyperbaric chamber (SS1) and the first 30 minutes after exit (SS2). Data were analysed for within-group effect by paired student t-test and between-group effect by one-way ANOVA.
Results: HBOT increased GIR by a mean 26% at SS1 (P = 0.04) and 23% at SS2 (P = 0.018). There was no significant change in GIR during or after HA. A between-group effect was evident for the change in GIR at SS1 in HBOT vs HA (P = 0.036).
Conclusions: The pathway by which insulin sensitivity is increased in men with type 2 diabetes requires the high oxygen partial pressures of HBOT and should be further investigated. Insulin sensitivity was not changed in hyperbaric air.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):391–398. doi: 10.28920/dhm50.4.391-398. PMID: 33325021.

Dysbaric osteonecrosis (DON) among the artisanal diving fishermen of Yucatán, Mexico

Daniel Popa1,2, Anthony Medak2, Walter Chin3, Oswaldo Huchim-Lara4, Evelyne Fliszar5, Tudor Hughes5, Ian Grover2

1 Rush University Department of Emergency Medicine, Chicago IL, USA
2 UCSD Department of Emergency Medicine, Division of Hyperbaric and Undersea Medicine, San Diego, USA
3 Winship Cancer Institute of Emory University, Atlanta GA, USA
4 La Universidad Marista de Mérida School of Medicine, Mérida, Yucátan, Mexico
5 UCSD Department of Radiology, San Diego CA, USA

Corresponding author: Dr Daniel Popa, Rush University Department of Emergency Medicine, 1750 W. Harrison St., Kellogg Suite 108, Chicago, IL 60612, USA
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Key words
Bone necrosis; Decompression sickness; Diving at work; Indigenous divers; Surface supplied diving

Abstract
Popa D, Medak A, Chin W, Huchim-Lara O, Fliszar E, Hughes T, Grover I. Dysbaric osteonecrosis (DON) among the artisanal diving fishermen of Yucatán, Mexico. Diving and Hyperbaric Medicine. 2020 December 20;50(4):391–398. doi: 10.28920/dhm50.4.391-398. PMID: 33325021.)
Introduction: Artisanal diving fishermen in Yucatán, Mexico have high rates of decompression sickness as a result of frequently unsafe diving practices with surface supplied compressed air. In this study, we investigated the prevalence of dysbaric osteonecrosis (DON), a type of avascular necrosis, in the most susceptible joints in a cohort of these fishermen.
Methods: We performed radiographs of bilateral shoulders, hips, and knees of 39 fishermen in Mexico and surveyed them about their medical and diving histories. We performed pairwise correlations to examine if the fishermen’s diving behaviours affected the numbers of joints with DON.
Results: The radiographs revealed Grade II or higher DON in 30/39 (76.9%) of the fishermen. Twenty-two of 39 fishermen (56.4%) had at least two affected joints. The number of joints with DON positively correlates with the lifetime maximum diving depth and average bottom time.
Conclusions: These findings represent among the highest prevalence rates of DON in divers and reflect the wide-spread scale of decompression sickness among these fishermen. Through this work, we hope to further educate the fishermen on the sequelae of their diving with the aim of improving their diving safety.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2020 December;50(4)

Diving Hyperb Med. 2020 December  20;50(4):399–404. doi: 10.28920/dhm50.4.399-404. PMID: 33325022.

Children and diving, a guideline

Mattijn Buwalda1, Abraham L Querido2, Robert A van Hulst3

1 Medical and Educational Services, De Meent 51A, Odijk, The Netherlands
2 Praktijk Querido, Larenseweg 14, Hilversum, The Netherlands
3 Department of Anaesthesiology and Hyperbaric Medicine, Academic Medical Center, Amsterdam, The Netherlands

Corresponding author: Dr Mattijn Buwalda, Medical and Educational Services, De Meent 51A, Odijk, The Netherlands
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Key words
Recreational diving; Children; Physiology; Psychology; Diving incidents; Review article

Abstract

(Buwalda M, Querido AL, van Hulst RA. Children and diving, a guideline. Diving and Hyperbaric Medicine. 2020 December 20;50(4):399–404. doi: 10.28920/dhm50.4.399-404. PMID: 33325022.)
Scuba diving is an increasingly popular recreational activity in children and adolescents. During the dive medical examination aspects of human physiology, anatomy, and psychology, that differ between adults and children, deserve our special attention. For example, lack of mental maturity, diminished Eustachian tube function and heat loss can pose problems during diving. It is important that children who wish to take up scuba diving are seen by a dive physician, with extra attention to Eustachian tube function. In children, asthma, bronchial hyperreactivity, pulmonary hypertension, and right-to-left shunts are contra-indications for scuba diving. Attention deficit hyperactivity disorder is a relative contra-indication. This article provides a review of the current literature and presents recommendations for recreational diving in children and adolescents. These recommendations are based solely on ‘expert’ opinion and were accepted by the Dutch Society of Diving and Hyperbaric Medicine in 2020.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Guideline


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):405–412. doi: 10.28920/dhm50.4.405-412. PMID: 33325023.

First impressions: Use of the Azoth Systems O’Dive subclavian bubble monitor on a liveaboard dive vessel

Peter Germonpré1,2,3, Paul Van der Eecken4, Elke Van Renterghem2,5, Faye-Lisa Germonpré6, Costantino Balestra3,7

1 Centre for Hyperbaric Oxygen Therapy, Military Hospital Brussels, Belgium
2 Medyssea EVR, Expedition and Diving Medicine, Ghent, Belgium
3 Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
4 ENT Department, St Lucas Hospital, Ghent, Belgium
5 Emergency Department, St Lucas Hospital, Ghent, Belgium
6 Medical Student, Ghent University, Ghent, Belgium
7 DAN Europe Research Department, Brussels, Belgium and Roseto, Italy

Corresponding author: Dr Peter Germonpré, Centre for Hyperbaric Oxygen Therapy, Military Hospital Brussels, Belgium
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Key words
Bubble detection; Bubbles; Decompression; Recreational diving; Risk assessment; Surveillance

Abstract
(Germonpré P, Van der Eecken P, Van Renterghem E, Germonpré F-L, Balestra C. First impressions: Use of the Azoth Systems O’Dive subclavian bubble monitor on a liveaboard dive vessel. Diving and Hyperbaric Medicine. 2020 December 20;50(4):405–412. doi: 10.28920/dhm50.4.405-412. PMID: 33325023.)
Introduction: The Azoth Systems O’Dive bubble monitor is marketed at recreational and professional divers as a tool to improve personal diving decompression safety. We report the use of this tool during a 12-day dive trip aboard a liveaboard vessel.
Methods: Six divers were consistently monitored according to the user manual of the O’Dive system. Data were synchronised with the Azoth server whenever possible (depending on cell phone data signal). Information regarding ease of use, diver acceptance and influence on dive behaviour were recorded.
Results: In total, 157 dives were completely monitored over 11 diving days. Formal evaluations were only available after six days because of internet connection problems. Sixty-one dives resulted in the detection of bubbles, mostly in one diver, none of which produced any symptoms of decompression illness.
Conclusions: The O’Dive system may contribute to increasing dive safety by making divers immediately aware of the potential consequences of certain types of diving behaviour. It was noted that bubble monitoring either reinforced divers in their safe diving habits or incited them to modify their dive planning. Whether this is a lasting effect is not known.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Technical report


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):413–416. doi: 10.28920/dhm50.4.413-416. PMID: 33325024.

Considerations for scuba and breath-hold divers during the COVID-19 pandemic: A call for awareness

Antonis Elia1, Mikael Gennser1

1 Division of Environmental Physiology, School of Chemistry, Bioengineering and Health, KTH Royal Institute of Technology, Stockholm, Sweden

Corresponding author: Dr Antonis Elia, Division of Environmental Physiology, School of Chemistry, Bioengineering and Health, KTH Royal Institute of Technology, Stockholm, Sweden
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Key words
Apnoea; Breath-hold diving; COVID-19; Hypoxaemia; Scuba diving; SARS-CoV-2; Lungs

Abstract

(Elia A, Gennser M. Considerations for scuba and breath-hold divers during the COVID-19 pandemic: A call for awareness. Diving and Hyperbaric Medicine. 2020 December 20;50(4):413–416. doi: 10.28920/dhm50.4.413-416. PMID: 33325024.)
In late 2019, a highly pathogenic novel coronavirus (CoV), severe acute respiratory syndrome (SARS)-CoV-2 emerged from Wuhan, China and led to a global pandemic. SARS-CoV-2 has a predilection for the pulmonary system and can result in serious pneumonia necessitating hospitalisation. Computed tomography (CT) chest scans of patients with severe symptoms, show signs of multifocal bilateral ground or ground-glass opacities (GGO) associated with consolidation areas with patchy distribution. However, it is less well known that both asymptomatic and mild symptomatic patients may exhibit similar lung changes. Presumably, the various pathological changes in the lungs may increase the risk of adverse events during diving (e.g., lung barotrauma, pulmonary oedema, etc.), thus these lung manifestations need to be considered prior to allowing resumption of diving. Presently, it is not known how the structural changes in the lungs develop and to what extent they resolve, in particular in asymptomatic carriers and patients with mild disease. However, current evidence indicates that a month of recovery may be too short an interval to guarantee complete pulmonary restitution even after COVID-19 infections not demanding hospital care.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Short communication


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):417–420. doi: 10.28920/dhm50.4.417-420. PMID: 33325025.

Common mental health conditions among navy divers: A brief report

Charles H Van Wijk1, Jarred H Martin2, Nazneen Firfirey1

1 Institute for Maritime Medicine, Simon’s Town, South Africa
2 Department of Psychology, University of Pretoria, South Africa

Corresponding author: Dr Charles H Van Wijk, Institute for Maritime Medicine, PO Box 494, Simon’s Town 7995, South Africa
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Key words
Anxiety; Depression; Health surveillance; Psychology

Abstract
(Van Wijk CH, Martin JH, Firfirey N. Common mental health conditions among navy divers: A brief report. Diving and Hyperbaric Medicine. 2020 December 20;50(4):417–420. doi: 10.28920/dhm50.4.417-420. PMID: 33325025.)
Introduction: A recent article reported on common mental health conditions among recreational scuba divers, and observed that the prevalence mirrored national population figures. This raised the question of the extent to which this might also be the case among professional divers. No data on commercial divers could be located; this paper presents the situation among navy divers.
Methods: Mental health survey data from 132 South African Navy divers were reviewed to describe the 12-month prevalence of common mood, anxiety, and alcohol misuse disorders.
Results: Prevalence of common mood and anxiety conditions appeared to reflect local general population estimates, and the occurrence of alcohol misuse was higher than local population figures, although the usefulness of the population data could be challenged.
Conclusions: It appeared that common mental health conditions in both sport and navy divers may generally conform to their respective local general population estimates. If this were to be the case in the broader professional diving environment as well, the inclusion of some form of formal mental health screening during commercial diving medical examinations may be beneficial.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Short communication


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):421–423. doi: 10.28920/dhm50.4.421-423. PMID: 33325026.

Impaired consciousness when scuba diving associated with vasovagal syncope

Peter Wilmshurst1, Margaret Clamp2

1 Royal Stoke University Hospital, Stoke-on-Trent, United Kingdom
2 MC Occupational Health, Colwick, Nottingham, United Kingdom

Corresponding author: Dr Peter Wilmshurst, Consultant Cardiologist, Royal Stoke University Hospital, Stoke-on-Trent, ST4 6QG, United Kingdom
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Key words
Vasovagal syncope; Neurocardiogenic syncope; Faints; Micturition syncope; Scuba diving

Abstract
(Wilmshurst P, Clamp M. Impaired consciousness when scuba diving associated with vasovagal syncope. Diving and Hyperbaric Medicine. 2020 December 20;50(4):421–423. doi: 10.28920/dhm50.4.421-423. PMID: 33325026.)
Introduction: Drowning is likely to result from impairment of consciousness when scuba diving. Causes include toxic effects of breathing gas, including nitrogen narcosis and oxygen toxicity, and arterial gas embolism.
Methods: Review of the medical records of scuba divers who had impaired consciousness underwater that could not be attributed to toxic effects of breathing gas or arterial gas embolism.
Results: Four scuba divers had episodes of impaired consciousness when at shallow depths (8−18 m) underwater. The descriptions of the episodes were very similar. Three had histories of recurrent episodes of vasovagal syncope on land.
Conclusions: Absence of other causes for their impaired consciousness underwater leads to the conclusion that the probable cause was vasovagal syncope.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Short communication


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):424–430. doi: 10.28920/dhm50.4.424-430. PMID: 33325027.

Persistent extravascular bubbles on radiologic imaging after recompression treatment for decompression sickness: A case report

Juan C Dapena1, Corine A Lansdorp2, Simon J Mitchell3,4

1 Navy Medicine Operational Training Center, Hyperbaric Medicine Department, Pensacola (FL), USA
2 Amsterdam University Medical Centre, location AMC, Department of Anaesthesiology/Hyperbaric Medicine, Amsterdam, The Netherlands
3 Department of Anaesthesiology, School of Medicine, University of Auckland, New Zealand
4 Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand

Corresponding author: Dr Juan C Dapena, Navy Medicine Operational Training Center, Hyperbaric Medicine Department, 220 Hovey Rd, Pensacola, Florida, 32508, USA
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Key words
Decompression illness; Computed tomography; Hyperbaric oxygen; Residual symptoms; Bubbles; Nitrogen

Abstract

(Dapena JC, Lansdorp CA, Mitchell SJ. Persistent extravascular bubbles on radiologic imaging after recompression treatment for decompression sickness: A case report. Diving and Hyperbaric Medicine. 2020 December 20;50(4):424–430. doi: 10.28920/dhm50.4.424-430. PMID: 33325027.)
Decompression sickness (DCS) is a condition arising when dissolved inert gas in tissue forms extravascular and/or intravascular bubbles during or after depressurisation. Patients are primarily treated with 100% oxygen and recompression, which is often assumed to lead to resolution of bubbles. After this, repeated hyperbaric exposures can be provided in case of persistent symptoms, with oxygen delivery to ischaemic tissues, anti-inflammatory properties and reduction of oedema considered the main mechanisms of action. In this case report we present the history and imaging of a diver diagnosed with DCS that was treated with two US Navy Treatment Table 6 recompressions, but who still had multiple extravascular bubbles apparent on CT-imaging after these hyperbaric treatments. Based on these findings we hypothesise that, contrary to general belief, it is possible that large extravascular bubbles can persist after definitive treatment for DCS.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2020 December;50(4)

Diving Hyperb Med. 2020 December 20;50(4):431–436. doi: 10.28920/dhm50.4.431-436. PMID: 33325028.

Hyperbaric oxygen treatment of central retinal vein occlusion with cilioretinal artery occlusion secondary to hormonal treatment: Case report and review

Asma Khallouli1, Khaled Khelifi1, Rahma Saidane1, Racem Choura1, Afef Maalej1, Raja Ben Sassi2

1 Department of Ophthalmology, Military Hospital of Tunis, Tunisia
2 Department of Hyperbaric Oxygen Therapy, Military Hospital of Tunis, Tunisia

Corresponding author: Dr Racem Choura, Department of Ophthalmology, Military Hospital of Tunis, Mont Fleury- 1008, Tunisia
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Key words
Cilioretinal artery occlusion; Retinal vein occlusion; Fertility agents; Female

Abstract
(Khallouli A, Khelifi K, Saidane R, Choura R, Maalej A, Ben Sassi R. Hyperbaric oxygen treatment of central retinal vein occlusion with cilioretinal artery occlusion secondary to hormonal treatment: Case report and review. Diving and Hyperbaric Medicine. 2020 December 20;50(4):431–436. doi: 10.28920/dhm50.4.431-436. PMID: 33325028.)
Introduction: This report describes a case of central retinal vein occlusion (CRVO) and cilioretinal artery occlusion (CLRAO) after hormonal treatment for induction of ovulation that was successfully treated with hyperbaric oxygen.
Case report: A 48 year-old woman was admitted to our department for sudden blurred vision in her left eye. The patient had a history of 3-months hormonal treatment for induction of ovulation. The best corrected visual acuity was 7/10 (20/32) in the left eye and 10/10 (20/20) in the right eye. Fundus examination of the left eye revealed flame-shaped haemorrhages, whitening of the retina along the distribution of cilioretinal artery and tortuous retinal veins. Fluorescein angiography confirmed the combination of a non-ischaemic CRVO with CLRAO. The patient was treated with a 2 h session of hyperbaric oxygen at 253 kPa (2.5 atmospheres absolute) once daily for a total of 30 sessions. Best corrected visual acuity improved to 10/10 (20/20) in the left eye.
Conclusions: CRVO and CLRAO are both occlusive disorders. HBOT is a safe low-cost treatment modality that can be beneficial in some ocular pathologies. It can maintain oxygenation of the retina through the choroidal blood supply, decrease oedema and preserve compromised tissue adjacent to the ischaemic area.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.


Publication Type: Case report

2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):2–9. doi: 10.28920/dhm51.1.2-9. PMID: 33761535.

Hyperbaric oxygen treatment for mastectomy flap ischaemia: A case series of 50 breasts

Nicole E Spruijt1, Lisette T Hoekstra1,2, Johan Wilmink3, Maarten M Hoogbergen1,4

1 Da Vinci Clinic, Geldrop, the Netherlands
2 Department of Plastic, Reconstructive and Hand Surgery, Maastricht UMC+, the Netherlands
3 Department of Plastic, Reconstructive and Hand Surgery, Maxima Medical Center Eindhoven, the Netherlands
4 Department of Plastic, Reconstructive and Hand Surgery, Catharina Hospital, Eindhoven, the Netherlands

Corresponding author: Dr Nicole E Spruijt, Da Vinci Clinic, Nieuwendijk 49, 5664HB Geldrop, the Netherlands
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Key words
Necrosis; Nipple; Outcome; Radiotherapy; Skin; Surgery

Abstract
(Spruijt NE, Hoekstra LT, Wilmink J, Hoogbergen MH. Hyperbaric oxygen treatment for mastectomy flap ischaemia: a case series of 50 breasts. Diving and Hyperbaric Medicine. 2021 March 31;51(1):2–9. doi: 10.28920/dhm51.1.2-9. PMID: 33761535.)
Introduction: Hyperbaric oxygen treatment (HBOT) has been suggested as an effective intervention to limit necrosis of ischaemic skin flaps after mastectomy. The purpose of this study was to evaluate outcomes of HBOT in the largest series of patients to date with mastectomy flap ischaemia.
Methods: A retrospective analysis was performed of 50 breasts requiring HBOT for mastectomy flap ischaemia. The severity of the ischaemia or necrosis was evaluated by four independent observers using the skin ischaemia necrosis (SKIN) score. Multivariate logistic regression analyses were used to assess associations between risk factors and re-operation.
Results: HBOT was started a median of 3 days (range 1–23) after surgery and continued for a median of 12 sessions (range 6–22). The breast SKIN surface area scores (n = 175 observations by the independent observers) improved in 34% (of observations) and the depth scores deteriorated in 42% (both P < 0.01). Both the surface area and depth scores were associated with the need for re-operation: higher scores, reflecting more severe necrosis of the mastectomy flap, were associated with increased need for re-operation. Twenty-nine breasts (58%) recovered without additional operation. Pre-operative radiotherapy (OR 7.2, 95% CI 1.4–37.3) and postoperative infection (OR 15.4, 95% CI 2.6–89.7) were risk factors for re-operation in multivariate analyses.
Conclusions: In this case series, the surface area of the breast affected by ischaemia decreased during HBOT, and most breasts (58%) did not undergo an additional operation. A randomised control trial is needed to confirm or refute the possibility that HBOT improves outcome in patients with mastectomy flap ischaemia.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):10–17. doi: 10.28920/dhm51.1.10-17. PMID: 33761536.

An insight to tympanic membrane perforation pressure through morphometry: A cadaver study

Derya Ümit Talas1, Orhan Beger2, Ülkü Çömelekoğlu3, Salim Çakır4, Pourya Taghipour4, Yusuf Vayisoğlu1

1 Mersin University Faculty of Medicine, Department of Otorhinolaryngology, Mersin, Turkey
2 Mersin University Faculty of Medicine, Department of Anatomy, Mersin, Turkey
3 Mersin University Faculty of Medicine, Department of Biophysics, Mersin, Turkey
4 Mersin University Faculty of Medicine, Mersin, Turkey

Corresponding author: Orhan Beger, Mersin University Faculty of Medicine, Department of Anatomy, Ciftlikkoy Campus, 33343, Mersin, Turkey
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Key words
Bursting pressure, Cadaver, Ear barotrauma; Eardrum; Diving; Transducer

Abstract
(Talas DÜ, Beger O, Çömelekoğlu Ü, Çakır S, Taghipour P, Vayisoğlu Y. An insight to tympanic membrane perforation pressure through morphometry: A cadaver study. Diving and Hyperbaric Medicine. 2021 March 31;51(1):10–17. doi: 10.28920/dhm51.1.10-17. PMID: 33761536.)
Introduction: A cadaveric experimental investigation aimed to show the rupture pressure of the tympanic membrane (TM) for otologists to evaluate its tensile strength.
Methods: Twenty adult ears in 10 fresh frozen whole cadaveric heads (four males, six females) mean age 72.8 (SD 13.8) years (range 40–86) were studied. The tensile strength of the TM was evaluated with bursting pressure of the membrane. The dimensions of the membranes and perforations were measured with digital imaging software.
Results: The mean bursting pressure of the TM was 97.71 (SD 36.20) kPa. The mean area, vertical and horizontal diameters of the TM were 57.46 (16.23) mm2, 9.54 (1.27) mm, 7.99 (1.08) mm respectively. The mean area, length and width of the perforations were 0.55 (0.25) mm2, 1.37 (0.50) mm, and 0.52 (0.22) mm, respectively. Comparisons of TM dimension, bursting pressure, and perforation size by laterality and gender showed no significant differences. The bursting pressure did not correlate (positively or negatively) with the TM or perforation sizes.
Conclusions: The TM can rupture during activities such as freediving or scuba diving, potentially leading to serious problems including brain injuries. Studying such events via cadaveric studies and data from case studies is of fundamental importance. The minimum experimental bursting pressures might better be taken into consideration rather than average values as the danger threshold for prevention of TM damage (and complications thereof) by barotrauma.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):18–24. doi: 10.28920/dhm51.1.18-24. PMID: 33761537.

A survey on the health status of Dutch scuba diving instructors

Prashant Komdeur1, Thijs T Wingelaar2,3, Rob A van Hulst3

1 Sports Medical Center Papendal, Hengstdal 3, 6574 NA Ubbergen, the Netherlands
2 Diving Medical Center, Royal Netherlands Navy, Den Helder, the Netherlands
3 Department of Anaesthesiology, University Medical Center, Amsterdam, the Netherlands

Corresponding author: Dr Prashant Komdeur, Sports Medical Center Papendal, Hengstdal 3, 6574 NA Ubbergen, the Netherlands
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Key words
Age; Drugs; Fitness to dive; Health surveys; Medications; Medical conditions and problems; Risk factors

Abstract
(Komdeur P, Wingelaar TT, van Hulst RA. A survey on the health status of Dutch scuba diving instructors. Diving and Hyperbaric Medicine. 2021 March 31;51(1):18–24. doi: 10.28920/dhm51.1.18-24. PMID: 33761537.)
Introduction: As the diving population is ageing, so are the diving instructors. Health issues and the use of prescribed medications are more common when ageing. The death of two diving instructors during one weekend in 2017 in the Netherlands, most likely due to cardiovascular disease, motivated investigation of the prevalence of relevant comorbidities in Dutch diving instructors.
Methods: All Dutch Underwater Federation diving instructors were invited to complete an online questionnaire. Questions addressed diving experience and current and past medical history including the use of medications.
Results: A response rate of 27% yielded 497 questionnaires (87% male, average age 57.3 years [SD 8.5]). Older instructors were over-represented among responders (82% of males and 75% of females > 50 years versus 66% of males and 51% of females among the invited cohort). Forty-six percent of respondents reported no current medical condition. Hypertension was the most commonly reported condition followed by hay fever and problems equalising ears and sinuses. Thirty-two percent reported no past medical condition. Problems of equalising ears and sinuses was the most common past medical condition, followed by hypertension, joint problems or surgery, and hay fever. Fifty-nine percent used non-prescription medication; predominantly analgesics and nose or ear drops. Forty-nine percent used prescription medicine, mostly cardiovascular and respiratory drugs. Body mass index (BMI) was > 25 kg·m-2 in 66% of males and 38% of females. All instructors with any type of cardiovascular disease were overweight.
Conclusions: Nineteen percent of responding diving instructors suffered from cardiovascular disease with above-normal BMI and almost 60% used prescribed or non-prescribed medication. Some dived while suffering from medical issues or taking medications, which could lead to medical problems during emergency situations with their students.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):25–33. doi: 10.28920/dhm51.1.25-33. PMID: 33761538.

Snorkelling and breath-hold diving fatalities in New Zealand, 2007 to 2016

John Lippmann1,2, Chris Lawrence3,4, Michael Davis5

1 Australasian Diving Safety Foundation, Ashburton, Victoria, Australia
2 Department of Public Health and Preventive Medicine, Monash University, Victoria, Australia
3 Department of Pathology, Christchurch Hospital, Christchurch, New Zealand
4 Statewide Forensic Medical Services, Royal Hobart Hospital, Tasmania, Australia
5 Honorary Senior Lecturer, Department of Anaesthesiology, School of Medicine and Health Sciences, The University of Auckland, Auckland, New Zealand

Corresponding author: Dr John Lippmann, Australasian Diving Safety Foundation, PO Box 478, Canterbury, VIC 3126, Australia
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Key words
Apnoeic hypoxia; Cardiovascular; Diving deaths; Diving incidents; Drowning; Obesity; Pulmonary oedema

Abstract
(Lippmann J, Lawrence C, Davis M. Snorkelling and breath-hold diving fatalities in New Zealand, 2007 to 2016. Diving and Hyperbaric Medicine. 2021 March 31;51(1):25–33. doi: 10.28920/dhm51.1.25-33. PMID: 33761538.)
Introduction: New Zealand’s (NZ) long coastline offers a diverse underwater environment with abundant opportunities for harvesting seafood and for recreation. Fatalities from snorkelling/breath-hold diving have been reported from the 1960s through to 2006. Those from 2007 to 2016 are reported here.
Methods: The National Coronial Information System, the Australasian Diving Safety Foundation diving fatality database, and the Water Safety NZ “Drownbase” were searched and additional coronial data provided by the NZ Ministry of Justice. An anonymised database was created and analysed for multiple factors. A chain of events analysis was performed for each case.
Results: There were 38 snorkelling or breath-hold-related deaths in NZ, 33 men and five women. Twenty-nine were breath-hold divers involved in gathering seafood, and six ‘surface snorkellers’, predominantly sightseeing. Two-thirds were diving alone and/or were not being observed by anyone out of the water. Twenty-eight victims were classified as overweight or obese and 19/38 were Māori. Pre-existing health factors that may have or definitely contributed to the fatality were present in 30 cases. The most common of these were cardiac (18/38). Two divers had insulin-dependent diabetes mellitus, one each epilepsy and asthma whilst cannabis and/or alcohol were possible factors in seven deaths. Five (possibly six) deaths resulted from apnoeic hypoxia.
Conclusions: Overall, death from snorkelling/breath-hold diving was an uncommon event (38 in 10 years). Poor judgement was a common feature. Middle-aged Māori men with pre-existing disease feature strongly. This suggests an on-going need for appropriate water safety education within and beyond the Māori community.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):34–43. doi: 10.28920/dhm51.1.34-43. PMID: 33761539.

Adjunctive hyperbaric oxygen treatment for necrotising soft-tissue infections: A systematic review and meta-analysis

Morten Hedetoft1,2, Michael H Bennett2, Ole Hyldegaard1

1 Department of Anaesthesia, Centre of Head and Orthopaedics, Rigshospitalet, University of Copenhagen, Denmark
2 Department of Anaesthesia and Hyperbaric Medicine, Prince of Wales Hospital, Sydney, Australia

Corresponding author: Dr Morten Hedetoft, Department of Anaesthesia, Rigshospitalet, University of Copenhagen, Blegdamsvej 8, 2100 Copenhagen, Denmark
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Key words
Evidence; Necrotizing infections; Systematic review

Abstract
(Hedetoft M, Bennett MH, Hyldegaard O. Adjunctive hyperbaric oxygen treatment for necrotising soft-tissue infections: A systematic review and meta-analysis. Diving and Hyperbaric Medicine. 2021 March 31;51(1):34–43. doi: 10.28920/dhm51.1.34-43. PMID: 33761539.)
Introduction: Surgical intervention, broad-spectrum antibiotics and intensive care support are the standard of care in the treatment of necrotising soft-tissue infections (NSTI). Hyperbaric oxygen treatment (HBOT) may be a useful adjunctive treatment and has been used for almost 60 years, but its efficacy remains unknown and has not been systematically appraised. The aim was to systematically review and synthesise the highest level of clinical evidence available to support or refute the use of HBOT in the treatment of NSTI.
Methods: The review was prospectively registered (PROSPERO; CRD42020148706). MEDLINE, EMBASE, CENTRAL and CINAHL were searched for eligible studies that reported outcomes in both HBOT treated and non-HBOT treated individuals with NSTI. In-hospital mortality was the primary outcome. Odds ratio (ORs) were pooled using random-effects models.
Results: The search identified 486 papers of which 31 were included in the qualitative synthesis and 21 in the meta-analyses. Meta-analysis on 48,744 patients with NSTI (1,237 (2.5%) HBOT versus 47,507 (97.5%) non-HBOT) showed in-hospital mortality was 4,770 of 48,744 patients overall (9.8%) and the pooled OR was 0.44 (95% CI 0.33–0.58) in favour of HBOT. For major amputation the pooled OR was 0.60 (95% CI 0.28–1.28) in favour of HBOT. The dose of oxygen in these studies was incompletely reported.
Conclusions: Meta-analysis of the non-random comparative data indicates patients with NSTI treated with HBOT have reduced odds of dying during the sentinel event and may be less likely to require a major amputation. The most effective dose of oxygen remains unclear.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):44–52. doi: 10.28920/dhm51.1.44-52. PMID: 33761540.

Middle ear barotrauma in diving

Oskari H Lindfors1, Anne K Räisänen-Sokolowski2,3, Jari Suvilehto4, Saku T Sinkkonen1

1 Department of Otorhinolaryngology – Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
2 Department of Pathology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
3 Centre for Military Medicine, Finnish Defence Forces, Helsinki, Finland
4 Mehiläinen Oy, Helsinki, Finland

Corresponding author: Oskari H Lindfors, Department of Otorhinolaryngology – Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital, P.O. Box 263, FI-00029 HUH, Helsinki, Finland
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Key words
ENT; Epidemiology; Eustachian tube; Eustachian tube dysfunction; Health surveys; Survey; Valsalva manoeuvre

Abstract
(Lindfors OH, Räisänen-Sokolowski AK, Suvilehto J, Sinkkonen ST. Middle ear barotraumas in diving. Diving and Hyperbaric Medicine. 2021 March 31;51(1):44–52. doi: 10.28920/dhm51.1.44-52. PMID: 33761540.)
Introduction: Middle ear barotrauma (MEBt) is the most common medical complication in diving, posing a serious risk to dive safety. Given this prevalence and the continuing growth of the diving industry, a comprehensive overview of the condition is warranted.
Methods: This was a survey study. An anonymous, electronic questionnaire was distributed to 7,060 recipients: professional divers of the Finnish Border Guard, the Finnish Rescue Services, and the Finnish Heritage agency; and recreational divers registered as members of the Finnish Divers’ Association reachable by e-mail (roughly two-thirds of all members and recreational divers in Finland). Primary outcomes were self-reported prevalence, clinical characteristics, and health effects of MEBt while diving. Secondary outcomes were adjusted odds ratios (OR) for frequency of MEBt with respect to possible risk factors.
Results: A total of 1,881 respondents participated in the study (response rate 27%). In total, 81% of the respondents had experienced MEBt while diving. Of those affected, 38% had used medications and 1% had undergone otorhinolaryngology-related surgical procedures due to MEBt. Factors most associated with MEBt were poor subjective success in Valsalva (‘occasionally’ versus ‘always’ successful: OR 11.56; 95% CI 7.24–18.47) and Toynbee (‘occasionally’ versus ‘always’ successful: OR 3.51; 95% CI 1.95–6.30) manoeuvres.
Conclusions: MEBt is common in both recreational and professional divers, having affected 81% of the respondents. The main possible risk factors include poor success in pressure equalisation manoeuvres.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):53–62. doi: 10.28920/dhm51.1.53-62. PMID: 33761541.

Fatalities involving divers using surface-supplied breathing apparatus in Australia, 1965 to 2019

John Lippmann1,2

1 Australasian Diving Safety Foundation, Canterbury, Victoria, Australia
2 Department of Public Health and Preventive Medicine, Monash University, Victoria, Australia

Corresponding author: Dr John Lippmann, Australasian Diving Safety Foundation, P.O. Box 478 Canterbury, VIC 3126, Australia
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Key words
Carbon monoxide; Chain of events analysis; Diving compressors; Diving deaths; Fitness to dive; Occupational diving

Abstract
(Lippmann J. Fatalities involving divers using surface-supplied breathing apparatus in Australia, 1965 to 2019. Diving and Hyperbaric Medicine. 2021 March 31;51(1):53–62. doi: 10.28920/dhm51.1.53-62. PMID: 33761541.)
Introduction: This study identified characteristics and diving practices of victims of fatal surface supplied breathing apparatus (SSBA) incidents in Australia from 1965–2019 to determine underlying factors and risks associated with these activities, better educate the diving community and prevent such deaths.
Methods: A hand search was made of ‘Project Stickybeak’ reports from 1965–2000 and SSBA fatality data were compared to the Australasian Diving Safety Foundation fatality database. The National Coronial Information System was searched to identify SSBA diving deaths for 2001–2019. Extracted data were collated and analysed using descriptive statistics and Poisson Regression. A chain of events analysis was used to determine the likely sequence of events.
Results: There were 84 identified SSBA-related deaths during the study period. Most victims were relatively young, healthy males (median age 33 years). At least 50% of victims were undertaking work-related diving, and 37% were recreational diving. Equipment issues, mainly compressor-related, were the main contributor, identified as a predisposing factor in 48% of incidents and as triggers in 24%.
Conclusions: Preventable surface-supplied diving deaths still occur in both occupational and recreational diving, often from poor equipment maintenance and oversight. Incorrect configuration of the SSBA and lack of training remain on-going problems in recreational users. These could be addressed by improved education, and, failing this, regulatory oversight. The increase in health-related incidents in older participants may be controlled to some extent by greater medical oversight, especially in recreational and non-certified occupational divers who should be encouraged to undergo regular diving medical assessments.

Copyright: This article is the copyright of the author who grants Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):63–67. doi: 10.28920/dhm51.1.63-67. PMID: 33761542.

Does persistent (patent) foramen ovale closure reduce the risk of recurrent decompression sickness in scuba divers?

Björn Edvinsson1, Ulf Thilén1, Niels Erik Nielsen2, Christina Christersson3, Mikael Dellborg4, Peter Eriksson4, Joanna Hlebowicz1

1 Department of Cardiology, Department of Clinical Science, Skåne University Hospital, Lund University, Lund, Sweden
2 Department of Cardiology, Department of Clinical Science, University Hospital Linköping, Linköping University, Linköping, Sweden
3 Department of Medical Sciences, Cardiology Uppsala University, Uppsala, Sweden
4 Department of Cardiology, Department of Clinical Science, Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden

Corresponding author: Dr Joanna Hlebowicz, Department of Cardiology, Skåne University Hospital, Lund University, SE-221, 85 Lund, Sweden
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Key words
Decompression illness; Right-to-left shunt; Risk; Scuba diving; Trimix;Venous gas embolism

Abstract
(Edvinsson B, Thilén U, Nielsen NE, Christersson C, Dellborg M, Eriksson P, Hlebowicz J. Does patent foramen ovale closure reduce the risk of recurrent decompression sickness in scuba divers? Diving and Hyperbaric Medicine. 2021 March 31;51(1):63–67. doi: 10.28920/dhm51.1.63-67. PMID: 33761542.)
Introduction: Interatrial communication is associated with an increased risk of decompression sickness (DCS) in scuba diving. It has been proposed that there would be a decreased risk of DCS after closure of the interatrial communication, i.e., persistent (patent) foramen ovale (PFO). However, the clinical evidence supporting this is limited.
Methods: Medical records were reviewed to identify Swedish scuba divers with a history of DCS and catheter closure of an interatrial communication. Thereafter, phone interviews were conducted with questions regarding diving and DCS. All Swedish divers who had had catheter-based PFO-closure because of DCS were followed up, assessing post-closure diving habits and recurrent DCS.
Results: Nine divers, all with a PFO, were included. Eight were diving post-closure. These divers had performed 6,835 dives (median 410, range 140–2,200) before closure, and 4,708 dives (median 413, range 11–2,000) after closure. Seven cases with mild and 10 with serious DCS symptoms were reported before the PFO closure. One diver with a small residual shunt suffered serious DCS post-closure; however, that dive was performed with a provocative diving profile.
Conclusion: Divers with PFO and DCS continue to dive after PFO closure and this seems to be fairly safe. Our study suggests a conservative diving profile when there is a residual shunt after PFO closure, to prevent recurrent DCS events.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


 

2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):68–71. doi: 10.28920/dhm51.1.68-71. PMID: 33761543.

Hyperbaric oxygen for sudden hearing loss: Influence of international guidelines on practice in Australia and New Zealand

Susannah Sherlock1,2, Sharon Kelly3, Michael H Bennett4,5

1 Hyperbaric Medicine, Royal Brisbane and Women’s Hospital, Brisbane, Australia
2 Senior Clinical Lecturer, University of Queensland, Brisbane, Australia
3 Department of Ear Nose and Throat Surgery, Royal Brisbane and Women’s Hospital, Brisbane, Australia
4 Department of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney Australia
5 Prince of Wales Clinical School, University of New South Wales, Sydney, Australia

Corresponding author: Dr Susannah Sherlock, Royal Brisbane and Women’s Hospital, Butterfield St, Herston QLD 4029, Brisbane, Australia
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Key words
ENT; General interest; Hearing loss, sudden; Hyperbaric facilities; Hyperbaric oxygen therapy; Medical society

Abstract
(Sherlock S, Kelly S, Bennett MH. Hyperbaric oxygen for sudden hearing loss: Influence of international guidelines on practice in Australia and New Zealand. Diving and Hyperbaric Medicine. 2021 March 31;51(1):68–71. doi: 10.28920/dhm51.1.68-71. PMID: 33761543.)
Introduction: Idiopathic sudden sensorineural hearing loss (ISSHL) is an otolaryngologic emergency. The Undersea and Hyperbaric Medicine Society (UHMS) revised practice guidelines in 2014 adding ISSHL to approved indications. This study investigated whether the UHMS guidelines influenced referral and practice in Australia and New Zealand.
Methods: Retrospective review of 319 patient referrals in two time periods (five years prior to addition of ISSHL to indications (T-PRE) and three years post (T-POST)).
Results: Seven of eight participating hyperbaric facilities provided data down to the level of the indication for HBOT for analysis. In T-PRE 136 patients were treated with HBOT for ISSHL, representing between 0% and 18% of the total cases to each facility. In the T-POST period 183 patients were treated for ISSHL, representing from 0.35% to 24.8% of the total patients in each facility. Comparison between the two periods shows the proportion of patients treated with ISSHL among all indications increased from 3.2% to 12.1% (P < 0.0009). One facility accounted for 74% (101/136) of ISSHL patients receiving HBOT in T-PRE and 63% (116/183) in T-POST. ISSHL case load at that facility increased from 18% to 24.8% (P = 0.009) after the UHMS guideline publication. Three of the seven units had a significant increase in referrals after the guideline change.
Conclusion: There remains equipoise regarding HBOT in the management of ISSHL. Only three out of seven units had a significant increase in ISSHL patients after the UHMS guidelines publication. Without well controlled RCTs to develop guidelines based on good evidence this is unlikely to change and practice variation will continue.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):72–77. doi: 10.28920/dhm51.1.72-77. PMID: 33761544.

Patient knowledge and experience of hyperbaric oxygen treatment

Louise MacInnes1, Carol Baines1, Alexandra Bishop2, Karen Ford3

1 Department of Diving and Hyperbaric Medicine, Royal Hobart Hospital, Hobart, Tasmania, Australia
2 DDRC Healthcare, Hyperbaric Medical Centre, Plymouth, Devon, UK
3 Tasmanian Health Service South, Tasmania and University of Tasmania, Hobart, Tasmania, Australia

Corresponding author: Dr Carol Baines, Department of Diving and Hyperbaric Medicine, Royal Hobart Hospital, Tasmania 7000, Australia
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Key words
Communication; Panic; Patient monitoring; Questionnaire; Stress

Abstract
(MacInnes L, Baines C, Bishop A, Ford K. Patient knowledge and experience of hyperbaric oxygen treatment. Diving and Hyperbaric Medicine. 2021 March 31;51(1):72–77. doi: 10.28920/dhm51.1.72-77. PMID: 33761544.)
Introduction: This paper presents a quantitative and qualitative study exploring patients’ knowledge and experience of hyperbaric oxygen treatment (HBOT).
Methods: Participants included 29 patients with appropriate indications who were undertaking HBOT at facilities in two different locations: Hobart, Australia, and Plymouth, United Kingdom. Participants completed surveys prior to commencing HBOT, after five sessions, and on completion of HBOT. Semi-structured one-to-one interviews were conducted with each individual on conclusion of their course. Data were analysed using descriptive statistics and interpretive description.
Results: Prior to referral, 15/29 (52%) of participants knew HBOT was used to treat divers, and of these, 9/15 (60%) were familiar with its use for non-divers. Only one third sought additional information about the process between referral for HBOT and attending their medical assessment. Anxiety was a pre-treatment concern amongst participants. However, when re-measured after five sessions and upon completion of the HBOT course, anxiety was reduced. The interview data revealed themes based around the physical, emotional and social aspects of HBOT: (1) anxiety within self; (2) naivety to normalisation; (3) enjoyment being a ‘diver’; and (4) burdens of HBOT.
Conclusions: Many patients experienced anxiety prior to commencing HBOT but, with support, quickly adjusted to treatment, transitioning from a state of naivety to normalisation in their experience of the hyperbaric chamber. They enjoyed feeling like a ‘diver’ and considered aspects of the burdens of treatment, such as finances or logistics, a minor inconvenience. These results highlight the need for psychosocial support during treatment by identifying gaps in patient preparation for HBOT.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):78–81. doi: 10.28920/dhm51.1.78-81. PMID: 33761545.

Provision of emergency hyperbaric oxygen treatment for a patient during the COVID-19 pandemic

Michelle L Lim1, Soo J Kim2, Meng K Tan2, Kim H Lim2, Hooi G See2

1 Department of Surgical Intensive Care, Division of Anaesthesiology and Perioperative Medicine, Singapore General Hospital, Singapore
2 Hyperbaric and Diving Medicine Centre, Singapore General Hospital, Singapore

Corresponding author: Dr Michelle Lim, Department of Surgical Intensive Care, Division of Anaesthesiology and Perioperative Medicine, Singapore General Hospital, 1 Outram Road Singapore 169608, Singapore
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Key words
Carbon monoxide; Infectious diseases; Intensive care medicine; Logistics

Abstract

(Lim ML, Kim SJ, Tan MK, Lim KH, See HG. Provision of emergency hyperbaric oxygen treatment for a patient during the COVID-19 pandemic. Diving and Hyperbaric Medicine. 2021 March 31;51(1):78–81. doi: 10.28920/dhm51.1.78-81. PMID: 33761545.)
The experience of managing a critically ill severe carbon monoxide poisoning patient suspected of possibly also suffering COVID-19 and requiring emergency hyperbaric oxygen treatment is described. Strategies used to minimise infection risk, modifications to practice and lessons learnt are described. All aerosol generating procedures such as endotracheal tube manipulation and suctioning should be undertaken in a negative pressure room. In the absence of in-chamber aerosol generating procedures, an intubated patient presents less risk than that of a non-intubated, symptomatically coughing patient. Strict infection control practices, contact precautions, hospital workflows and teamwork are required for the successful HBOT administration to an intubated COVID-19 suspect patient.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Short communication


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):82–85. doi: 10.28920/dhm51.1.82-85. PMID: 33761546.

Investigation of a cluster of decompression sickness cases following a high-altitude chamber flight

Nazim Ata1, Erkan Karaca1

1 Aeromedical Research and Training Center, Eskisehir, Turkey

Corresponding author: Dr Nazim Ata, Ucucu Sagliği Arastirma ve Egitim Merkezi, Eski Hava Hastanesi, Eskisehir, Turkey 26010
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Key words
Ascent; Aviation; Barometric pressure; Case reports; Hyperbaric oxygen; Hypoxia training

Abstract

(Ata N, Karaca E. Investigation of a cluster of decompression sickness cases following a high-altitude chamber flight. Diving and Hyperbaric Medicine. 2021 March 31;51(1):82–85. doi: 10.28920/dhm51.1.82-85. PMID: 33761546.)
Although relatively safe, hypoxia exposure is a mandatory training requirement for aircrew that carries the risk of decompression sickness (DCS). Usually DCS affects only one individual at a time. Here, a cluster of three simultaneous cases is reported. Since these numbers were well in excess of the usually encountered incidence rate, the purpose of this work was to identify the most likely reasons using the epidemic DCS investigation framework which involves four main considerations: time; place; population; and environment. Based on time and place observations, this cluster clearly falls into the individual-based classification, where the environment is a primary concern. Indeed, equipment analysis allowed us to identify the most likely reason for two out of three cases (perforations in the oro-nasal oxygen masks worn during training). It led to replacement of damaged equipment and modification of teaching to prevent such damage. It is recommended that this investigative template may be used for any future occurrences of DCS in clusters.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):86–93. doi: 10.28920/dhm51.1.86-93. PMID: 33761547.

Hyperbaric oxygen treatment: Results in seven patients with severe bacterial postoperative central nervous system infections and refractory mucormycosis

Pedro Valente Aguiar1,2, Bruno Carvalho1,2, Pedro Monteiro1,2, Paulo Linhares1,2,3, Óscar Camacho4, Rui Vaz1,2,3

1 Neurosurgery Department, Centro Hospitalar Universitário São João, Oporto, Portugal
2 Faculty of Medicine, Oporto University, Oporto, Portugal
3 Neurosciences Centre, Hospital CUF, Oporto, Portugal
4 Hyperbaric Medical Unit, Unidade Local de Saúde de Matosinhos, Portugal

Corresponding author: Dr Pedro D Valente Aguiar, Department of Neurosurgery, Centro Hospitalar Universitário São João, Alameda Professor Hernâni Monteiro, 4200-319, Porto, Portugal
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Key words
Brain; Mucormycosis; Neurosurgery; Refractory infections; Spine

Abstract
(Valente Aguiar P, Carvalho B, Monteiro P, Linhares P, Camacho Ó, Vaz R. Hyperbaric oxygen treatment: Results in seven patients with refractory central nervous system infections. Diving and Hyperbaric Medicine. 2021 March 31;51(1):86–93. doi: 10.28920/dhm51.1.86-93. PMID: 33761547.)
Introduction: Resistant bacterial infections following brain and spine surgery and spontaneous mucormycosis with central nervous system (CNS) involvement represent a serious treatment challenge and more efficient therapeutic approaches ought to be considered. Hyperbaric oxygen treatment (HBOT) has shown promise as a complementary therapy. This case series evaluated whether HBOT contributed to infection resolution in seven patients with refractory CNS infectious conditions.
Methods: Clinical results for seven patients referred for HBOT between 2010 to 2018 to treat refractory postoperative brain and spine infections or spontaneously developing mucormycosis were retrospectively analysed. The patients’ clinical files and follow-up consultations were reviewed to assess evolution and outcome.
Results: Seven patients were referred with a median age of 56 years. The median follow-up was 20 months. Four patients had postoperative infections and three had rhino-orbital-cerebral mucormycosis (ROCM). HBOT was used as an adjunctive treatment to antimicrobial therapy in all patients. Prior to HBOT, all patients had undergone an average of four operations due to infection refractoriness and had completed an average of five months of antimicrobial therapy. After HBOT, infection resolution was obtained in six patients without additional operations, while one patient with ROCM stopped HBOT after the third session due to intolerance. Three patients stopped antimicrobial therapy while four were maintained on prophylactic treatment.
Conclusions: Infection resolution was reached in the six patients that completed HBOT as prescribed. HBOT may serve as an effective complementary treatment in CNS refractory postoperative and spontaneous infections.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):94–97. doi: 10.28920/dhm51.1.94-97. PMID: 33761548.

Saturation diver fatality due to hydrogen sulphide while working on a subsea pipe line

Ajit C Kulkarni1

1 Hyperbaric Solutions, Mumbai, India

Corresponding author: Dr Ajit C Kulkarni, Hyperbaric Solutions, 3 A, Siddhivinayak Chambers, Bandra East, Mumbai 400051, India
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Key words
Gas solubility; Hydrogen sulphide; Hyperbaric oxygen; Pulmonary oedema; Saturation diving

Abstract

(Kulkarni AC. Saturation diver fatality due to hydrogen sulphide while working on a subsea pipe line. Diving and Hyperbaric Medicine. 2021 March 31;51(1):94–97. doi: 10.28920/dhm51.1.94-97. PMID: 33761548.)
In the offshore oil industry, Multipurpose Support Vessels with extensive diving capability are used for inspection, maintenance and repair of subsea pipelines. The diving industry has developed systemic safety checks and strict regulatory control after a number of fatal accidents in early years. However, accidents do continue to occur and, when involving divers in the water, are often fatal. Hydrogen sulphide (H2S), called ‘sour gas’ in an oil field, is produced by the action of anaerobic bacteria on sulphate containing organic matter. A highly toxic gas, it remains a constant danger for offshore oil industry workers who must remain vigilant. Crude oil and gas produced in these oilfields is called ‘sour crude’ and pipelines carry this crude with varying content of dissolved H2S to shore for processing. Divers are routinely called to attend to leaking pipelines and come in contact with this crude. Their hot water suits and umbilical lines are often covered with crude containing dissolved H2S. There is always a possibility that these may enter and contaminate the bell environment. Such a case leading to fatality is reported here.

Copyright: This article is the copyright of the author who grants Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):98–102. doi: 10.28920/dhm51.1.98-102. PMID: 33761549.

Echocardiography – techniques and pitfalls whilst diagnosing persistent (patent) foramen ovale as a risk factor in divers with a history of decompression sickness

Charles P Azzopardi1, Kurt Magri1, Alex Borg2, Jake Schembri3, Jonathan Sammut3

1 Baromedicine Department, Hyperbaric Unit, Mater Dei Hospital, Malta
2 Cardiology Department, Mater Dei Hospital, Malta
3 Mater Dei Hospital, Malta

Corresponding author: Dr Charles P Azzopardi, Baromedicine Department, Hyperbaric Unit, Mater Dei Hospital, Triq id-Donaturi tad-Demm, Tal-Qroqq, Msida, Malta
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Key words
Bubbles; Decompression illness; Right-to-left shunt

Abstract

(Azzopardi CP, Magri K, Borg A, Schembri J, Sammut J. Echocardiography – techniques and pitfalls whilst diagnosing persistent (patent) foramen ovale as a risk factor in divers with a history of decompression sickness. Diving and Hyperbaric Medicine. 2021 March 31;51(1):98–102. doi: 10.28920/dhm51.1.98-102. PMID: 33761549.)
The case of a diver with a history of decompression sickness (DCS) after recreational scuba diving is presented. Cutis marmorata, a subtype of cutaneous DCS, has been consistently associated with the presence of a persistent (patent) foramen ovale (PFO) as a risk factor. Diagnostic uncertainty arose when transthoracic echocardiography with antecubital injection of agitated saline bubbles (ASBs) did not show any significant shunt, but the presence of a large Eustachian valve was counteracted by intra-femoral injection of ASBs, showing a large PFO with spontaneous shunting. The importance of proper echocardiography techniques prior to resorting to intra-femoral injection of ASBs to counteract the haemodynamic effects of the Eustachian valve is emphasised.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):103–106. doi: 10.28920/dhm51.1.103-106. PMID: 33761550.

Spinal cord decompression sickness in an inside attendant after a standard hyperbaric oxygen treatment session

Jacek Kot1,2, Ewa Lenkiewicz2, Edward Lizak2, Piotr Góralczyk2, Urszula Chreptowicz2

1 National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine in Gdynia, Medical University of Gdansk, Poland
2 Department of Hyperbaric Medicine and Sea Rescue, University Centre for Maritime and Tropical Medicine in Gdynia, Poland

Corresponding author: Associate Professor Jacek Kot, National Centre for Hyperbaric Medicine , Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Powstania Styczniowego 9B, 81-519 Gdynia, Poland
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Key words
Decompression illness; Hyperbaric facilities; Occupational health; Working in compressed air

Abstract

(Kot J, Lenkiewicz E, Lizak E, Góralczyk P, Chreptowicz U. Spinal cord decompression sickness in an inside attendant after a standard hyperbaric oxygen treatment session. Diving and Hyperbaric Medicine. 2021 March 31;51(1):103–106. doi: 10.28920/dhm51.1.103-106. PMID: 33761550.)
Medical personnel in hyperbaric treatment centres are at occupational risk for decompression sickness (DCS) while attending patients inside the multiplace hyperbaric chamber (MHC). A 51-year-old male hyperbaric physician, also an experienced diver, was working as an inside attendant during a standard hyperbaric oxygen therapy (HBOT) session (70 minutes at 253.3 kPa [2.5 atmospheres absolute, 15 metres’ seawater equivalent]) in a large walk-in MHC. Within 10 minutes after the end of the session, symptoms of spinal DCS occurred. Recompression started within 90 minutes with an infusion of lignocaine and hydration. All neurological symptoms resolved within 10 minutes breathing 100% oxygen at 283.6 kPa (2.8 atmospheres absolute) and a standard US Navy Treatment Table 6 was completed. He returned to regular hyperbaric work after four weeks of avoiding hyperbaric exposures. Transoesophageal echocardiography with a bubble study was performed 18 months after the event without any sign of a persistent (patent) foramen ovale. Any hyperbaric exposure, even within no-decompression limits, is an essential occupational risk for decompression sickness in internal hyperbaric attendants, especially considering the additional risk factors typical for medical personnel (age, dehydration, tiredness, non-optimal physical capabilities and frequent problems with the lower back).

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Publication Type: Case report


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):107–110. doi: 10.28920/dhm51.1.107-110. PMID: 33761551.

Hyperbaric oxygen treatment in recurrent development of complex regional pain syndrome: A case report

Michal Hájek1,2, Dittmar Chmelař2,3, Jakub Tlapák4,5, František Novomeský6, Veronika Rybárová6, Miloslav Klugar7

1 Centre of Hyperbaric Medicine, Ostrava City Hospital, Ostrava, Czech Republic
2 Department of Biomedical Sciences, Institute of Microbiology and Immunology, Faculty of Medicine, University of Ostrava, Ostrava, Czech Republic
3 Czech Anaerobic Bacteria Reference Laboratory, Faculty of Medicine, University of Ostrava, Ostrava, Czech Republic
4 The Institute of Aviation Medicine, Prague, Czech Republic
5 Department of Military Surgery, Faculty of Military Health Sciences, University of Defence, Hradec Králové, Czech Republic
6 Department of Forensic Medicine and Medicolegal Expertises, Jessenius Faculty of Medicine, Comenius University, University Hospital, Martin, Slovak Republic
7 Czech National Centre for Evidence-Based Healthcare and Knowledge Translation (Cochrane Czech Republic, Czech EBHC; JBI Centre of Excellence, Masaryk University GRADE Centre), Institute of Biostatistics and Analyses, Faculty of Medicine, Masaryk University, Brno, Czech Republic

Corresponding author: Dr Michal Hajek, Center of Hyperbaric Medicine, Ostrava City Hospital, Nemocnicni 20, 728 80 Ostrava, Czech Republic
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Key words
Case reports; CRPS; Hyperbaric oxygen therapy; Pain; Risk factors

Abstract

(Hájek M, Chmelař D, Tlapák J, Novomeský F, Rybárová V, Klugar M. Hyperbaric oxygen treatment in recurrent development of complex regional pain syndrome: A case report. Diving and Hyperbaric Medicine. 2021 March 31;51(1):107–110. doi: 10.28920/dhm51.1.107-110. PMID: 33761551.)
A broad spectrum of conditions including neuropathic pain, complex regional pain syndrome (CRPS) and fibromyalgia, have been implicated as causes of chronic pain. There is a need for new and effective treatments that patients can tolerate without significant adverse effects. One potential intervention is hyperbaric oxygen treatment (HBOT). The case reported here is unique in describing repeated HBOT in a patient who developed recurrent post-traumatic CRPS of the lower as well as the upper limbs. In the first event, two months after distortion and abruption of the external right ankle, the patient suffered leg pain, oedema formation, mild hyperaemia, limited mobility of the ankle and CRPS Type 1. In the second event, the same patient suffered fracture-dislocation of the distal radius 1.5 years after the first injury. After the plaster cast was removed the patient developed pain, warmth, colour changes, oedema formation and limited wrist mobility with CRPS Type 1. Pharmacological treatment as well as HBOT were used with significant improvement of functional outcome in both cases. Some studies suggest that patients with a history of CRPS are more likely to develop secondary CRPS compared to the rates reported in the literature among the general population. Patients with a history of CRPS should be counselled that they may be at risk for developing secondary CRPS if they undergo surgery or sustain trauma to another extremity.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):111–115. doi: 10.28920/dhm51.1.111-115. PMID: 33761552.

Decompression sickness after a highly conservative dive in a diver with known persistent foramen ovale: Case report

William Brampton1, Martin DJ Sayer2,3

1 Hyperbaric Medicine Unit. Aberdeen Royal Infirmary, Aberdeen, Scotland
2 Tritonia Scientific Ltd., Oban, Scotland
3 West Scotland Centre for Diving and Hyperbaric Medicine, Oban, Scotland

Corresponding author: Dr William Brampton, Hyperbaric Medical Unit, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, AB25 2ZN, Scotland, UK
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Key words
Decompression illness; Diving; Patent foramen ovale; SPUMS; UKSDMC

Abstract

(Brampton W, Sayer MDJ. Decompression sickness after a highly conservative dive in a diver with known persistent foramen ovale: Case report. Diving and Hyperbaric Medicine. 2021 March 31;51(1):111–115. doi: 10.28920/dhm51.1.111-115. PMID: 33761552.)
A diver returned to diving, 15 months after an episode of neuro-spinal decompression sickness (DCS) with relapse, after which she had been found to have a moderate to large provoked shunt across a persistent (patent) foramen ovale (PFO), which was not closed. She performed a single highly conservative dive in line with the recommendations contained in the 2015 position statement on PFO and diving published jointly by the South Pacific Underwater Medicine Society and the United Kingdom Sports Diving Medical Committee. An accidental Valsalva manoeuvre shortly after surfacing may have provoked initial symptoms which later progressed to DCS. Her symptoms and signs were milder but closely mirrored her previous episode of DCS and she required multiple hyperbaric oxygen treatments over several days, with residua on discharge. Although guidance in the joint statement was mostly followed, the outcome from this case indicates that there may be a subgroup of divers with an unclosed PFO, who have had a previous episode of serious DCS, who may not be safe to dive, even within conservative limits.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):116–118. doi: 10.28920/dhm51.1.116-118. PMID: 33761553.

Hyperbaric oxygen treatment for late low colorectal anastomosis ischaemia: Case report

Marcello Sanzi1, Alberto Aiolfi1, Jacopo Nicolò Marin1, Abd El Hakim Darawsh2, Davide Bona1

1 Department of Biomedical Science for Health, Division of General Surgery, University of Milan, Istitituto Clinico Sant’Ambrogio, Milan, Italy
2 Istituto Lombardo di Medicina Iperbarica, Milan, Italy

Corresponding author: Dr Marcello Sanzi, Istituto Clinico Sant’Ambrogio, Via Luigi Giuseppe Faravelli, 16, 20149 Milan, Italy
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Key words
Gastro-intestinal tract; Surgery; Anastomosis; Wounds

Abstract
Sanzi M, Aiolfi A, Marin JN, Darawsh AEH, Bona D. Hyperbaric oxygen treatment for late low colorectal anastomosis ischaemia: Case report. Diving and Hyperbaric Medicine. 2021 March 31;51(1):116–118. doi: 10.28920/dhm51.1.116-118. PMID: 33761553.)
Introduction: This report describes the use of hyperbaric oxygen treatment (HBOT) to treat a case of colorectal anastomosis ischaemia following colorectal surgery.
Case report: A 47-year-old man developed post-operative colorectal anastomosis ischaemia with leak after laparoscopic low anterior resection for T3N0 adenocarcinoma of the rectum. The leak with concomitant ischaemia presented 17 days after surgery. HBOT was administrated in 11 sessions over three weeks and the patient followed endoscopically and radiologically for two months. At two months the anastomosis showed both endoscopic and radiological healing; therefore the ileostomy was closed. Anal function was satisfactory with no incontinence or evidence of sepsis.
Conclusions: Intra-operative or late leak with concomitant ischaemia of a colorectal anastomosis is a challenging event in colorectal surgery. HBOT may be beneficial in promoting healing in selected patients. Further studies are needed to evaluate conservative treatments and the role of HBOT.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):119–123. doi: 10.28920/dhm51.1.119-123. PMID: 33761554.

Pneumomediastinum and the use of hyperbaric oxygen treatment

Stephanie M Price1,2, Will D Price1,3, Mickaila J Johnston1,2,4

1 Naval Hospital Guam, Agana Heights, Guam
2 USS FRANK CABLE, Santa Rita, Guam
3 USS EMORY S LAND, Santa Rita, Guam
4 Naval Medical Readiness Training Unit, Silverdale, WA, USA

Corresponding author: Dr Stephanie M Price, LT, MC, USN – USS FRANK CABLE, Unit 100105 Box 211, FPO, AP 96657, USA
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Key words
Pulmonary barotrauma; Pulmonary overinflation syndrome; Diving barotrauma

Abstract

(Price SM, Price WD, Johnston MJ. Pneumomediastinum and the use of hyperbaric oxygen treatment. Diving and Hyperbaric Medicine. 2021 March 31;51(1):119–123. doi: 10.28920/dhm51.1.119-123. PMID: 33761554.)
Pulmonary barotrauma may occur in diving and can result in a spectrum of injuries referred to as pulmonary over-inflation syndrome (POIS). Pneumomediastinum is a part of the POIS spectrum and only rarely results in respiratory symptoms. We present a case of a civilian diver who developed pneumomediastinum with respiratory symptoms which did not respond to normobaric 100% oxygen. After investigation for pneumothorax, he underwent hyperbaric oxygen treatment which resulted in significant alleviation of his symptoms. This is a novel case example of this treatment algorithm.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):124. doi: 10.28920/dhm51.1.124. PMID: 33761555.

Commentary on “Fatal air embolism in a breath-hold diver” and the implied dangers of technical freediving

Derek Covington, Chris Giordano

Address for correspondence: Department of Anesthesiology, University of Florida College of Medicine, Gainesville FL, USA
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Key words
Barotrauma; Breath-hold diving; Cerebral arterial gas embolism; Diving deaths; Sputum

 

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Letter to the Editor


2021 March;51(1)

Diving Hyperb Med. 2021 March 31;51(1):125. doi: 10.28920/dhm51.1.125. PMID: 33761556.

Acute central nervous system oxygen toxicity at normobaric pressure

F Michael Davis

Address for correspondence: Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
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Key words
Oxygen; Toxicity; Central nervous system; Pressure; Case reports

Copyright: This article is the copyright of the author who grants Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Letter to the Editor

Click to download each article. This will download a PDF that is password protected from any changes, these individual article PDFs are not for public distribution and for society members personal use. 

Copyright: These articles are the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Editorial
Mitchell SJ. Diving and hyperbaric medicine in the SARS-CoV-2 pandemic. 2020 June;50(2):90-91. doi: 10.28920/dhm50.2.90-91. PMID: 32557408.
Original articles
Kojima Y, Kojima A, Niizeki Y, Yagishita K. Recreational diving-related injury insurance claims among Divers Alert Network Japan members: Retrospective analysis of 321 cases from 2010 to 2014. Diving and Hyperbaric Medicine. 2020 June 30;50(2):92–97. doi: 10.28920/dhm50.2.92-97. PMID: 32557409.
Lippmann J, Taylor D McD. Medical conditions in scuba diving fatality victims in Australia, 2001 to 2013. Diving and Hyperbaric Medicine. 2020 June 30;50(2):98–104. doi: 10.28920/dhm50.2.98-104. PMID: 32557410.
Lippmann J, Stevenson C, Taylor D McD. Scuba diving fatalities in Australia, 2001 to 2013: Diver demographics and characteristics. Diving and Hyperbaric Medicine. 2020 June 30;50(2):105–114. doi: 10.28920/dhm50.2.105-114. PMID: 32557411.
Vrijdag XCE, van Waart H, Sleigh JW, Mitchell SJ. Pupillometry is not sensitive to gas narcosis in divers breathing hyperbaric air or normobaric nitrous oxide. Diving and Hyperbaric Medicine. 2020 June 30;50(2):115–120. doi: 10.28920/dhm50.2.115-120. PMID: 32557412.
van Waart H, Harris RJ, Gant N, Vrijdag XCE, Challen CJ, Lawthaweesawat C, Mitchell SJ. Deep anaesthesia: The Thailand cave rescue and its implications for management of the unconscious diver underwater. Diving and Hyperbaric Medicine. 2020 June 30;50(2):121–129. doi: 10.28920/dhm50.2.121-129. PMID: 32557413.
Tsai F-H, Wu W-L, Liang J-M, Hsu H-T, Chen T-Y. Anxiety impact on scuba performance and underwater cognitive processing ability. Diving and Hyperbaric Medicine. 2020 June 30;50(2):130–134. doi: 10.28920/dhm50.2.130-134. PMID: 32557414.
Review articles
Jendle JH, Adolfsson P, Pollock NW. Recreational diving in persons with type 1 and type 2 diabetes: Advancing capabilities and recommendations. Diving and Hyperbaric Medicine. 2020 June 30;50(2):135–143. doi: 10.28920/dhm50.2.135-143. PMID: 32557415.
 Technical report
Baines CR, Cooper PD, O’Rourke GA, Miller C. Evaluation of the Abbot FreeStyle Optium Neo H blood glucose meter in the hyperbaric oxygen environment. Diving and Hyperbaric Medicine. 2020 June 30;50(2):144–151. doi: 10.28920/dhm50.2.144-151. PMID: 32557416.
Short communication
Rozloznik M, Lochmanova A, Chmelar D, Hajek M, Korytkova K, Cisarikova M. Experimental use of flow cytometry to detect bacteria viability after hyperbaric oxygen exposure: Work in progress report. Diving and Hyperbaric Medicine. 2020 June 30;50(2):152–156. doi: 10.28920/dhm50.2.152-156. PMID: 32557417.
Zenske A, Koch A, Kähler W, Oellrich K, Pepper C, Muth T, Schipke JD. Assessment of a dive incident using heart rate variability. Diving and Hyperbaric Medicine. 2020 June 30;50(2):157–163. doi: 10.28920/dhm50.2.157-163. PMID: 32557418.
Van Wijk CH, Meintjes WAJ. Adult attention-deficit/hyperactivity disorder prevalence among commercial divers in South Africa. Diving and Hyperbaric Medicine. 2020 June 30;50(2):164–167. doi: 10.28920/dhm50.2.164-167. PMID: 32557419.
 Case reports
Mirasoglu B, Kirmizi S, Aktas S. Sphenoid sinus mucocele as an unusual differential diagnosis in diving injuries. Diving and Hyperbaric Medicine. 2020 June 30;50(2):168–172. doi: 10.28920/dhm50.2.168-172. PMID: 32557420.
García E, Mitchell SJ. Bubbles in the skin microcirculation underlying cutis marmorata in decompression sickness: Preliminary observations. Diving and Hyperbaric Medicine. 2020 June 30;50(2):173–177. doi: 10.28920/dhm50.2.173-177. PMID: 32557421.
Summers M, Gawthrope IC. Diaphragmatic injury a hidden issue for divers following trauma: Case report. Diving and Hyperbaric Medicine. 2020 June 30;50(2):178–180. doi: 10.28920/dhm50.2.178-180. PMID: 32557422.
Blatteau J-E, Morin J, Roffi R, Druelle A, Sbardella F, Castagna O. Clinical problem solving: Mental confusion and hypoxaemia after scuba diving. Diving and Hyperbaric Medicine. 2020 June 30;50(2):181–184. doi: 10.28920/dhm50.2.181-184. PMID: 32557423.
Lalieu RC, Bol Raap RD, Dubois EFL, van Hulst RA. Sudden death after oxygen toxicity seizure during hyperbaric oxygen treatment: A case report. Diving and Hyperbaric Medicine. 2020 June 30;50(2):185–188. doi: 10.28920/dhm50.2.185-188. PMID: 32557424.

2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):134–139. doi: 10.28920/dhm51.2.134-139. PMID: 34157727.

Necrostatin-1 prolongs latency to convulsion in mice exposed to high oxygen partial pressure

Zhen-Biao Guan1,* Yan-Yan Zhou2,* Yi Cen3, Han-De Feng3, Wen-Wu Liu4, Hong-Jie Yi5, Hui Chen3

1 Department of Respiratory and Critical Illness, Changhai Hospital, the Naval Military Medical University, People’s Liberation Army, Shanghai, 200433, China
2 Department of Orthopedic Surgery, Changzheng Hospital, the Naval Military Medical University, People’s Liberation Army, Shanghai, 200003, China
3 Department of Anesthesiology and Perioperative Medicine, Shanghai Fourth People's Hospital, Tongji University School of Medicine, Shanghai, China
4 Department of Diving and Hyperbaric Medicine, the Naval Military Medical University, People’s Liberation Army, Shanghai, 200433, China
5 Department of Hyperbaric Oxygen, Changhai Hospital, the Naval Military Medical University, People’s Liberation Army, Shanghai, 200433, China
* Both Zhen-Biao Guan and Yan-Yan Zhou contributed to this article equally

Corresponding author: Dr Hui Chen, Department of Anesthesiology and Perioperative Medicine, Shanghai Fourth People's Hospital, Tongji University School of Medicine, No 1279, Sanmen Road, 200434, Shanghai, China
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Key words
Animal model; Central nervous system; Inflammation; Necroptosis; Oxidative stress; Oxygen toxicity

Abstract
(Guan ZB, Zhou YY, Cen Y, Feng HD, Liu WW, Yi HJ, Chen H. Necrostatin-1 prolongs latency to convulsion in mice exposed to high oxygen partial pressure. Diving and Hyperbaric Medicine. 2021 June 30;51(2):134–139. doi: 10.28920/dhm51.2.134-139. PMID: 34157727.)
Introduction: Exposure to very high oxygen partial pressure may cause central nervous system oxygen toxicity (CNS-OT). The role of necroptosis in the pathogenesis of CNS-OT is still unclear.
Methods: In experiment one, male C57BL/6 mice in the oxygen toxicity (OT) group (n = 5) and necrostatin-1 (Nec-1; a necroptosis inhibitor) (1.5 mg·kg-1, intraperitoneal) group (n = 5) were exposed to pure oxygen at 600 kPa, and the latency to tonic-clonic seizure was recorded. In experiment two, mice were divided into three groups: control group (n = 11), OT group (n = 12) and Nec-1 group (n = 12). Nec-1 was intraperitoneally administered 30 min before oxygen exposure. Mice in the OT group and Nec-1 group were exposed to pure oxygen at 400 kPa for 30 min, and then sacrificed; the brain was harvested for the assessment of inflammation, oxidative stress and necroptosis.
Results: Experiment one. Nec-1 pre-treatment significantly prolonged the latency to seizure (245 [SD 18] seconds in the OT group versus 336 (34) seconds in the Nec-1 group). Experiment two. Nec-1 pre-treatment markedly reduced inflammatory cytokines and inhibited cerebral necroptosis, but failed to significantly suppress cerebral oxidative stress.
Conclusions: These findings indicate necroptosis is involved in the pathogenesis of CNS-OT, and inhibition of necroptosis may prolong seizure latency, but the specific mechanisms should be investigated further.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):140–146. doi: 10.28920/dhm51.2.140-146. PMID: 34157728.

The impact of different gas mixtures on inflammatory responses in advanced recreational divers

Monica Rocco1, Luigi Maggi2, Chiara Loffredo1, Massimiliano Pelli1, Pia Di Benedetto2, Silvia Fiorelli1, Maurizio Simmaco3, Roberto Alberto De Blasi

1 Department of Surgical and Medical Science and Translation Medicine, Sapienza University, Rome, Italy
2 Department of Anesthesia, Sant’Andrea Hospital, Rome, Italy
3 Department of Neuroscience, Mental Health and Sensory Organs, Sapienza University, Rome, Italy

Corresponding author: Dr Luigi Maggi, Department of Anesthesia, Sant’Andrea Hospital, Rome, Italy
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Key words
Air; Decompression sickness; Deep diving; Diving research; Inflammation; Trimix

Abstract
(Rocco M, Maggi L, Loffredo C, Pelli M, Di Benedetto P, Fiorelli S, Simmaco M, De Blasi RA. The impact of different gas mixtures on inflammatory responses in advanced recreational divers. Diving and Hyperbaric Medicine. 2021 June 30;51(2):140–146. doi: 10.28920/dhm51.2.140-146. PMID: 34157728.)
Introduction: Decompression sickness (DCS) is considered a ‘bubble disease’. Intravascular bubbles activate inflammatory responses associated with endothelial dysfunction. Breathing gas has been proposed as a potential risk factor but this is inadequately studied. Different gases are used in scuba diving. Helium-containing 'trimix' could theoretically mitigate inflammation and therefore reduce DCS risk. This study determined the effect of air and trimix on the inflammatory response following dives to 50 metres of sea water, and evaluated the differences between them in advanced recreational divers.
Methods: Thirty-three divers were enrolled in this observational study and were divided in two groups: 17 subjects were included in the air group, and 16 different subjects were included in the trimix (21% oxygen, 35% helium, 44% nitrogen) group. Each subject conducted a single dive, and both groups used a similar diving profile of identical duration. A venous blood sample was taken 30 min before diving and 2 h after surfacing to evaluate changes in interleukins (IL) IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, tumour necrosis factor α (TNFα), vascular endothelial growth factor (VEGF), Interferon γ (IFN-γ), monocyte chemoattractant protein 1 (MCP-1) and epithelial growth factor (EGF) after diving.
Results: No differences were observed between groups in demographic data or diving experience. Following the dive, IL-6 values showed a slight increase, while IL-8 and EGF decreased in both groups, without significant variation between the groups.
Conclusions: In physically fit divers, trimix and air gas mixture during deep diving did not cause relevant changes in the inflammatory markers tested.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):147–151. doi: 10.28920/dhm51.2.147-151. PMID: 34157729.

Mortality rate during professionally guided scuba diving experiences for uncertified divers, 1992–2019

Peter Buzzacott1, Al Hornsby2, Karl Shreeves2

1 Prehospital, Resuscitation and Emergency Care Research Unit, School of Nursing, Curtin University, Western Australia
2 Professional Association of Diving Instructors (PADI Worldwide Corp), Rancho Santa Margarita, CA, USA

Corresponding author: Dr Peter Buzzacott, Prehospital, Resuscitation and Emergency Care Research Unit, School of Nursing, Curtin University, Western Australia
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Key words
Diving deaths; Diving industry; Epidemiology; PADI; Recreational diving; Risk; Training

Abstract
(Buzzacott P, Hornsby A, Shreeves K. Mortality rate during professionally guided scuba diving experiences for uncertified divers, 1992–2019. Diving and Hyperbaric Medicine. 2021 June 30;51(2):147–151. doi: 10.28920/dhm51.2.147-151. PMID: 34157729.)
Introduction: The aim of this study was to re-examine the mortality rate among participants in the Professional Association of Diving Instructors’ (PADI)’s Discover Scuba Diving (DSD) programme.
Methods: Fatalities reported to PADI as having occurred during DSD scuba dives were counted for each year between 1992 and 2019. DSD participant registrations were also counted for each year. The data were conveniently divided into two equal 14-year periods, 1992−2005 (‘early’) and 2006−2019 (‘late’). To smooth out the year-to-year variation in raw rates, Monte Carlo simulations were performed on the mean rate per 100,000 participants per year during each period.
Results: There were a total of 7,118,731 DSD participant registrations and 79 fatalities during the study period. The estimated overall mean mortality rate in the early period was 2.55 per 100,000 DSD registrations whereas the estimated rate of 0.87 per 100,000 DSD registrations was significantly lower in the late period (P < 0.0001).
Conclusions: PADI’s contemporary Discover Scuba Diving introductory scuba experiences, at 0.87 fatalities per 100,000 participants, have a calculated mortality rate that is less than half that calculated for 1992−2008. The late period’s rate improvement appears due either to significant under-registration in the early period, or to significant safety-performance improvement in the late period or, more likely, some combination of the two.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):152–160. doi: 10.28920/dhm51.2.152-160. PMID: 34157730.

Retrospective review of enquiries to the Québec diving medicine call centre: 2004 through 2018

David PM Monnot1,2, Jocelyn Boisvert2, Dominique Buteau2,3, Neal W Pollock1,2

1 Department of Kinesiology, Université Laval, Québec, QC, Canada
2 CISSS Chaudière-Appalaches (CHAU-Hôtel-Dieu de Lévis), Hyperbaric Medicine Unit, Emergency Department, Lévis, QC, Canada
3 Family Medicine and Emergency Medicine Department, Université Laval, Québec, QC, Canada

Corresponding author: Dr David Monnot, Service de médecine hyperbare, Centre de médecine de plongée du Québec, Hôtel-Dieu de Lévis, 143 rue Wolfe, Lévis, QC, G6V 3Z1, Canada
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Key words
Diver emergency service; Diving incidents; Epidemiology; Hyperbaric facilities; Medical database; Telemedicine

Abstract
(Monnot DPM, Boisvert J, Buteau D, Pollock NW. Retrospective review of enquiries to the Québec diving medicine call centre: 2004 through 2018. Diving and Hyperbaric Medicine. 2021 June 30;51(2):152–160. doi: 10.28920/dhm51.2.152-160. PMID: 34157730.)
Introduction: The Centre de Médecine de Plongée du Québec (CMPQ) established a bilingual 24-hour dive emergency call line and diving medicine information service in 2004. The toll-free number (888-835-7121) works throughout Canada. Calls and emails (This email address is being protected from spambots. You need JavaScript enabled to view it.) are answered by a CMPQ coordinator or on-call hyperbaric physicians and other consultants as needed. We reviewed 15 years of activity.
Methods: Details of phone calls and email enquiries to the centre were reviewed individually and compiled into a database. Data were analysed to characterise contact volume and issues addressed. Contacts were categorised into five groups: information only (INF); medical opinion required (MOP); medical issue after the critical period of urgency had passed (PUR); current urgent but not immediate life-threatening issue (NLT); and immediate life- or health-threatening issue (ILT). Data presented as mean (standard deviation) or percentage.
Results: A total of 3,232 contacts were made from May 2004 through December 2018: 19 (SD 8) per month [215 (70) per year]. Primary issues of concern were: emergency planning (20%); technical (not medical/physiology) questions (16%); otorhinolaryngological (12%); and decompression sickness-related (7%). Categorisation was 52% INF, 28% MOP, 13% PUR, 7% NLT, and 0.1% ILT, with 0.2% lacking sufficient detail to categorise. The nature of the diving activity of interest was determined in 67% of cases: 48% (n = 1,039) professional; 46% (n = 1,008) recreational; and 1% (n = 11) breath-hold.
Conclusions: The call centre serves as a resource to the community, providing information on health and safety for diving in addition to being available to assist with emergent needs.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):161–166. doi: 10.28920/dhm51.2.161-166. PMID: 34157731.

Oxygen toxicity seizure mimics

Kevin Foley1, Neil Banham1, Samantha Bonnington1, Ian Gawthrope1

1 Department of Hyperbaric Medicine, Fiona Stanley Hospital, Perth, Australia

Corresponding author: Dr Neil Banham, Department of Hyperbaric Medicine, Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch WA 6150, Australia
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Key words
Hyperbaric oxygen treatment; Recompression; Neurology; Brain; Risk factors; Hyperbaric research; Clinical audit

Abstract
(Foley K, Banham N, Bonnington S, Gawthrope I. Oxygen toxicity seizure mimics. Diving and Hyperbaric Medicine. 2021 June 30;51(2):161–166. doi: 10.28920/dhm51.2.161-166. PMID: 34157731.)
Introduction: Oxygen toxicity seizures (OTS) are a well-recognised complication of hyperbaric oxygen treatment (HBOT). As such, seizure-like activity during HBOT is usually presumed to be a result of central nervous system oxygen toxicity (CNS-OT). Four cases are reported here where causes other than CNS-OT were determined as being the likely cause of the seizure; causes we have labelled ‘OTS mimics’. Through review of the current literature, and our hyperbaric medicine unit’s experience to date, we aimed to highlight the relevance of these OTS mimics, as the potential for significant morbidity and mortality exists with incorrect diagnoses.
Methods: A retrospective review of the medical records of all patients treated at the Fiona Stanley Hospital and Fremantle Hospital hyperbaric medicine units who had a seizure during HBOT between November 1989 and June 2020. These events were reviewed to determine whether causes for seizures other than oxygen toxicity were evident.
Results: Four OTS mimics were identified: posterior reversible encephalopathy syndrome, pethidine toxicity, previous subarachnoid haemorrhage with resultant epilepsy, and severe hypoglycaemia.
Conclusions: This case series highlights the need for caution when diagnosing an apparent OTS. Multiple conditions may mimic the signs and symptoms of oxygen toxicity. This creates scope for misdiagnosis, with potential for consequent morbidity and mortality. A pragmatic approach is necessary to any patient exhibiting seizure-like activity during HBOT, with suspicion for other underlying pathologies.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):167–172. doi: 10.28920/dhm51.2.167-172. PMID: 34157732.

Oxygen toxicity seizures during United States Navy Treatment Table 6: An acceptable risk in monoplace chambers?

Samantha Bonnington1, Neil Banham1, Kevin Foley1, Ian Gawthrope1

1 Department of Hyperbaric Medicine, Fiona Stanley Hospital, Murdoch, Western Australia

Corresponding author: Dr Neil Banham, Department of Hyperbaric Medicine, Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch, WA 6150, Australia
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Key words
Cerebral arterial gas embolism; Decompression illness; Diving medicine; Diving research; Hyperbaric oxygen treatment; Pressure chambers; Recompression

Abstract
(Bonnington S, Banham N, Foley K, Gawthrope I. Oxygen toxicity seizures during United States Navy Treatment Table 6: An acceptable risk in monoplace chambers? Diving and Hyperbaric Medicine. 2021 June 30;51(2):167–172. doi: 10.28920/dhm51.2.167-172. PMID: 34157732.)
Introduction: Hyperbaric oxygen treatment (HBOT) may be complicated by oxygen toxicity seizures, which typically occur with hyperbaric partial pressures of oxygen exceeding 203 kPa (2 atmospheres absolute). All other hyperbaric units in Australia exclusively use a multiplace chamber when treating with United States Navy Treatment Table 6 (USN TT6) due to this perceived risk. The purpose of this study was to determine the safety of a monoplace chamber when treating decompression illness (DCI) with USN TT6.
Methods: A retrospective review of the medical records of all patients treated at Fiona Stanley Hospital Hyperbaric Medicine Unit with USN TT6 between November 2014 and June 2020 was undertaken. These data were combined with previous results from studies performed at our hyperbaric unit at Fremantle Hospital from 1989 to 2014, creating a data set covering a 30-year period.
Results: One thousand treatments with USN TT6 were performed between 1989 and 2020; 331 in a monoplace chamber and 669 in a multiplace chamber. Four seizures occurred: a rate of 0.59% (1/167) in a multiplace chamber; and none in a monoplace chamber, indicating no statistically significant difference between seizures in a monoplace versus multiplace chamber
(P = 0.31).
Conclusions: The rate of oxygen toxicity seizures in a monoplace chamber is not significantly higher than for treatment in the multiplace chamber. We conclude that using the monoplace chamber for USN TT6 in selected patients poses an acceptably low seizure risk.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):173–181. doi: 10.28920/dhm51.2.173-181. PMID: 34157733.

The usefulness of the RSTC medical questionnaire in pre-participation health risk assessment of recreational scuba divers in Hong Kong

Tsz-Ki Cheung1,2, Willem AJ Meintjes1

1 Department of Global Health, Stellenbosch University, Cape Town, South Africa
2 Family Medicine and Primary Healthcare Division, The Chinese University of Hong Kong, Hong Kong

Corresponding author: Dr Cheung Tsz Ki, Family Medicine and Primary Health Care Division, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong
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Key words
Fitness to dive; Medicals-diving; Recreational diving; Risk assessment

Abstract
(Cheung TK, Meintjes WAJ. The usefulness of the RSTC medical questionnaire in pre-participation health risk assessment of recreational scuba divers in Hong Kong. Diving and Hyperbaric Medicine. 2021 June 30;51(2):173–181. doi: 10.28920/dhm51.2.173-181. PMID: 34157733.)
Introduction: The current practice in Hong Kong is to have potential recreational divers complete a Recreational Scuba Training Council self-declared medical statement (RSTC form) prior to participation in diving. There are no reports in the literature on the usefulness of the Chinese version of the form.
Methods: The Professional Association of Diving Instructors (PADI) RSTC form (Chinese version) was completed by 117 research participants who were then individually interviewed (without examination) to establish whether relevant information was not captured by the form. Any discrepancies or problems identified were recorded for further analysis.
Results: Among participants, 15.4% expressed difficulty in completing the RSTC form. Less than one-third (28.2%) replied ‘all negative’ to the questions. Some health conditions that could impose diving risks were not elicited by the questionnaire alone. Nevertheless, there was good sensitivity, specificity, positive predictive value and negative predictive value with the exception of a few questions. However, significant discrepancies were identified when comparing the English and Chinese versions. There was also uncertainty with aspects of implementation, including attitudes of the user and provider, reliability of self-declaration answers and the handling of completed questionnaires.
Conclusions: Health screening with a questionnaire for recreational divers remains practical and acceptable. Full revision of the RSTC form in Chinese is recommended in view of problems with the construct validity and translation. People should be informed about the non-prescriptive approach of health assessment for recreational divers. Further research on the implementation of the form may help to improve the screening strategy in the future.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):182–189. doi: 10.28920/dhm51.2.182-189. PMID: 34157734.

Sinus barotrauma in diving

Oskari H Lindfors1, Anne K Räisänen-Sokolowski2,3, Jari Suvilehto4, Saku T Sinkkonen1

1 Department of Otorhinolaryngology – Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
2 Department of Pathology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
3 Centre for Military Medicine, Finnish Defence Forces, Helsinki, Finland
4 Mehiläinen Oy, Helsinki, Finland

Corresponding author: Dr Oskari H Lindfors, Department of Otorhinolaryngology – Head and Neck Surgery, Head and Neck Center, Helsinki University Hospital, P.O.Box 263, FI-00029 HUH, Helsinki, Finland
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Key words
Allergy; ENT; Epidemiology; Health surveys; Infectious diseases; Nasal decongestants; Smoking; Survey

Abstract
(Lindfors OH, Räisänen-Sokolowski AK, Suvilehto J, Sinkkonen ST. Sinus barotrauma in diving. Diving and Hyperbaric Medicine. 2021 June 30;51(2):182–189. doi: 10.28920/dhm51.2.182-189. PMID: 34157734.)
Introduction: Sinus barotrauma is a common occurrence in diving and subaquatic medicine, potentially compromising dive safety. To gain a more thorough understanding of the condition, an in-depth investigation is justified.
Methods: This was a survey study. An anonymous, electronic questionnaire was distributed to 7,060 recipients: professional divers of the Finnish Border Guard, the Finnish Rescue Services, and the Finnish Heritage agency, as well as recreational divers registered as members of the Finnish Divers’ Association reachable by email (roughly two-thirds of all members and recreational divers in Finland). Primary outcomes were self-reported prevalence, clinical characteristics, and health effects of sinus barotrauma while diving. Secondary outcomes were adjusted odds ratios (OR) for frequency of sinus barotrauma with respect to possible risk factors.
Results: In total, 1,881 respondents participated in the study (response rate 27%). A total of 49% of the respondents had experienced sinus barotrauma while diving and of those affected, 32% had used medications to alleviate their symptoms. The factors associated with sinus barotrauma were pollen allergies (OR 1.59; 95% CI 1.10–2.29), regular smoking
(OR 2.04; 95% CI 1.07–3.91) and a high number of upper respiratory tract infections per year (≥ 3 vs. < 3 infections per year: OR 2.76; 95% CI 1.79–4.24).
Conclusions: Sinus barotrauma is the second most common condition encountered in diving medicine, having affected 49% of the respondents. Possible risk factors include allergies to pollen, regular smoking, and a high number of URTIs per year.

 

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):190–198. doi: 10.28920/dhm51.2.190-198. PMID: 34157735.

Incidence of cardiac arrhythmias and left ventricular hypertrophy in recreational scuba divers

Peter Buzzacott1,2, George Anderson1,3, Frauke Tillmans1, James W Grier4, Petar J Denoble1

1 Divers Alert Network, Durham, North Carolina, USA
2 Prehospital, Resuscitation and Emergency Care Research Unit, School of Nursing Curtin University, Western Australia
3 Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
4 Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, USA

Corresponding author: Dr Peter Buzzacott, Prehospital, Resuscitation and Emergency Care Research Unit, School of Nursing, Curtin University, Western Australia
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Key words
Cardiovascular; Diving research; Echocardiography; Health status; Risk factors; Scuba; Sudden cardiac death

Abstract
(Buzzacott P, Anderson G, Tillmans F, Grier JW, Denoble PJ. Incidence of cardiac arrhythmias and left ventricular hypertrophy in recreational scuba divers. Diving and Hyperbaric Medicine. 2021 June 30;51(2):190–198. doi: 10.28920/dhm51.2.190-198. PMID: 34157735.)
Introduction: The aims of this study were to investigate the potential impact of age, sex and body mass index (BMI) upon the incidence of arrhythmias pre- and post- diving, and to identify the prevalence of left ventricular hypertrophy (LVH) in older recreational divers.
Methods: Divers aged ≥ 40 years participating in group dive trips had ECG rhythm and echocardiograph recordings before and after diving. Arrhythmias were confirmed by an experienced human reader. LVH was identified by two-dimensional echocardiography. Weighted (0.5 fractional) values were used to account for participation by seven divers in 14 trips.
Results: Seventy-seven divers undertook 84 dive trips and recorded 677 dives. Among divers with no pre-trip arrhythmias (n = 55), we observed that 6.5 (12%) recorded post-trip arrhythmias and the median increase was 1.0 arrhythmia. In divers with pre-trip arrhythmias, 14.5 had a median of 1.0 fewer post-trip arrhythmias, 2.0 had no change and 5.5 had a median of 16.0 greater. Age, but neither sex nor BMI, was associated with change in the number of arrhythmias before and after dive trips (P = 0.02). The relative risk for experiencing a change in the frequency of arrhythmias after a diver trip, was 2.1 for each additional 10 years of age (95% CI 1.1, 4.0). Of the 60 divers with imaging of their heart, five had left ventricular hypertrophy.
Conclusions: We observed a higher than expected prevalence of arrhythmias. Divers with pre-trip arrhythmias tended to be older than divers without pre-trip arrhythmias (P = 0.02). The prevalence of LVH in our cohort was one quarter of that found post-mortem in scuba fatalities.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):199–206. doi: 10.28920/dhm51.2.199-206. PMID: 34157736.

Diving-related disorders in commercial breath-hold divers (Ama) of Japan

Kiyotaka Kohshi1,2, Hideki Tamaki2,3, Frédéric Lemaître4,5, Yoshitaka Morimatsu2, Petar J Denoble6, Tatsuya Ishitake2

1 Division of Neurosurgery, Nishinihon Hospital, Kumamoto, Japan
2 Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan
3 Division of Surgery and General Medicine, Tamaki Hospital, Yamaguchi, Japan
4 Faculty of Sport Sciences, University of Rouen, Mont-Saint-Aignan, France
5 CRIOBE USR 3278, CNRS-EPHE-UPVD, PSL, France
6 Divers Alert Network, Durham NC, USA

Corresponding author: Dr Kiyotaka Kohshi, Division of Neurosurgery, Nishinihon Hospital, 3-20-1 Hattanda, Kumamoto-higashi, Kumamoto 861-8034, Japan
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Key words
Breath-hold diving; Decompression illness; Diving profiles; Indigenous divers; Prevention; Stroke

Abstract

(Kohshi K, Tamaki H, Lemaître F, Morimatsu Y, Denoble PJ, Ishitake T. Diving-related disorders in commercial breath-hold divers (Ama) of Japan. Diving and Hyperbaric Medicine. 2021 June 30;51(2):199–206. doi: 10.28920/dhm51.2.199-206. PMID: 34157736.)
Decompression illness (DCI) is well known in compressed-air diving but has been considered anecdotal in breath-hold divers. Nonetheless, reported cases and field studies of the Japanese Ama, commercial or professional breath-hold divers, support DCI as a clinical entity. Clinical characteristics of DCI in Ama divers mainly suggest neurological involvement, especially stroke-like cerebral events with sparing of the spinal cord. Female Ama divers achieving deep depths have rarely experienced a panic-like neurosis from anxiety disorders. Neuroradiological studies of Ama divers have shown symptomatic and/or asymptomatic ischaemic lesions situated in the basal ganglia, brainstem, and deep and superficial cerebral white matter, suggesting arterial insufficiency. The underlying mechanism(s) of brain damage in breath-hold diving remain to be elucidated; one of the plausible mechanisms is arterialization of venous nitrogen bubbles passing through right to left shunts in the heart or lungs. Although the treatment for DCI in Ama divers has not been specifically established, oxygen breathing should be given as soon as possible for injured divers. The strategy for prevention of diving-related disorders includes reducing extreme diving schedules, prolonging surface intervals and avoiding long periods of repetitive diving. This review discusses the clinical manifestations of diving-related disorders in Ama divers and the controversial mechanisms.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Review article


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):207–209. doi: 10.28920/dhm51.2.207-209. PMID: 34157737.

Results of hyperbaric oxygen treatment in an at-risk nasal flap following trauma

Sinem Kara1, Ender İnci1, E Deniz Gözen1,2, K Cenk Gülgün3, H Murat Yener1,2

1 ENT Department, Istanbul University – Cerrahpasa, Istanbul, Turkey
2 Istanbul University – Cerrahpasa, Istanbul, Turkey
3 Oksimer Hyperbaric Oxygen Center, Istanbul, Turkey

Corresponding author: Dr Sinem Kara, Istanbul University – Cerrahpasa, Medical Faculty, ENT Department Cerrahpasa Mh. Kocamustafapasa Cd. No: 53, 34096 Fatih/Istanbul, Turkey
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Key words
Injuries; Hyperbaric medicine; Outcome; Skin; Surgery

Abstract

(Kara S, İnci1 E, Gözen ED, Gülgün KC, Yener HM. Results of hyperbaric oxygen treatment in an at-risk nasal flap following trauma. Diving and Hyperbaric Medicine. 2021 June 30;51(2):207–209. doi: 10.28920/dhm51.2.207-209. PMID: 34157737.)
Hyperbaric oxygen treatment (HBOT) is widely used in otorhinolaryngology for various purposes. A 20-year-old male patient was admitted following a traumatic nasal wound which occurred several hours prior. He had a nasal glass cut from the radix to the supratip area which was primarily closed by non-absorbable suture. The following day, there was a haematoma and necrosis of the skin. The haematoma was drained under local anaesthesia. Blood supply to the nasal skin was severely compromised and only the columellar artery remaining intact, by definition designating this a difficult to heal wound with the risk of overall healing failure. Necrosis of the skin had developed within the first 24 hours. Accordingly, the patient underwent 30 HBOT sessions (two hours at 253.3 kPa) twice daily for four days and daily thereafter. Antibiotic cover and conservative wound management were also used. Complete healing was achieved without the need for additional surgical intervention. We conclude that timely use of HBOT may be a valuable adjunct to conservative wound management in a case of sharp nasal trauma.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):210–215. doi: 10.28920/dhm51.2.210-215. PMID: 34157738.

Prolonged syncope with multifactorial pulmonary oedema related to dry apnoea training: Safety concerns in unsupervised dry static apnoea

Juan M Valdivia-Valdivia1,2, Anne Räisänen-Sokolowski3,4, Peter Lindholm5

1 Neurosurgery Department, St. Joseph’s Hospital, Tampa FL, USA
2 International Association for Development of Apnea (AIDA International) – Medical and Science Committee, Zurich, Switzerland
3 Pathology, Helsinki University and Helsinki University Hospital, Helsinki, Finland
4 The Centre for Military Medicine, The Finnish Defense Forces, Helsinki, Finland
5 Department of Emergency Medicine, University of California San Diego, San Diego CA, USA

Corresponding author: Professor Peter Lindholm, Department of Emergency Medicine, University of California San Diego, San Diego CA, USA
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Key words
Breath-hold diving; Case reports; Hypoxia; Imaging; Lung; Pulmonary oedema; Unconsciousness

Abstract

(Valdivia-Valdivia JM, Räisänen-Sokolowski A, Lindholm P. Prolonged syncope with multifactorial pulmonary oedema related to dry apnoea training: Safety concerns in unsupervised dry static apnoea. Diving and Hyperbaric Medicine. 2021 June 30;51(2):210–215. doi: 10.28920/dhm51.2.210-215. PMID: 34157738.)
Many competitive breath-hold divers use dry apnoea routines to improve their tolerance to hypoxia and hypercapnia, varying the amount of prior hyperventilation and lung volume. When hyperventilating and exhaling to residual volume prior to starting a breath-hold, hypoxia is reached quickly and without too much discomfort from respiratory drive. Cerebral hypoxia with loss of consciousness (LOC) can easily result. Here, we report on a case where an unsupervised diver used a nose clip that is thought to have interfered with his resumption of breathing after LOC. Consequently, he suffered an extended period of severe hypoxia, with poor ventilation and recovery. He also held his breath on empty lungs; thus, trying to inhale created an intrathoracic sub-atmospheric pressure. Upon imaging at the hospital, severe intralobular pulmonary oedema was noted, with similarities to images presented in divers suffering from pulmonary barotrauma of descent (squeeze, immersion pulmonary oedema). Describing the physiological phenomena observed in this case highlights the risks associated with unsupervised exhalatory breath-holding after hyperventilation as a training practice in competitive freediving.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):216–219. doi: 10.28920/dhm51.2.216-219. PMID: 34157739.

Hyperbaric oxygen treatment for toxic epidermal necrolysis: A case report

Selin Gamze Sümen1, Sezer Yakupoğlu2, Tuna Gümüş3, Nur Benzonana4

1 University of Health Sciences, Hamidiye Medical Faculty, Department of Underwater and Hyperbaric Medicine, Istanbul, Turkey
2 University of Health Sciences, Kartal Dr Lütfi Kirdar City Hospital, Department of Anesthesiology and Reanimation, Istanbul, Turkey
3 University of Health Sciences, Kartal Dr Lütfi Kirdar City Hospital, Department of Underwater and Hyperbaric Medicine, Istanbul, Turkey
4 University of Health Sciences, Kartal Dr Lütfi Kirdar City Hospital, Department of Infectious Diseases and Clinical Microbiology, Istanbul, Turkey

Corresponding author: Dr Selin Gamze Sümen, Sağlık Bilimleri Üniversitesi, Hamidiye Tıp Fakültesi, Sultan 2. Abdulhamid Han Eğitim ve Araştırma Hastanesi, Selimiye Mh., Tıbbiye Cd., 34668, Üsküdar/Istanbul, Turkey
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Key words
Case reports; Drugs; Hyperbaric medicine; Outcome; Side effects; Skin; Toxicity

Abstract

Sümen SG, Yakupoğlu S, Gümüş T, Benzonana N. Hyperbaric oxygen treatment for toxic epidermal necrolysis: A case report. Diving and Hyperbaric Medicine. 2021 June 30;51(2):216–219. doi: 10.28920/dhm51.2.216-219. PMID: 34157739.)
Toxic epidermal necrolysis (TEN) is a potentially life-threatening muco-cutaneous disease, largely caused by an idiosyncratic reaction to medication or infectious disease, and is characterised by acute necrosis of the epidermis. No definitive consensus regarding the treatment of TEN has been agreed. A 60-year-old woman, diagnosed with multiple myeloma three months prior, was admitted with signs of TEN to the intensive care burns unit. She had been given ciprofloxacin to treat a urinary tract infection. She complained of malaise and pain, with maculopapular and bullous eruptions over her whole body on the third day of ciprofloxacin administration. Her supportive cares included intravenous immunoglobulins, pain control with analgesics, wound care, nutrition, and fluid support. Hyperbaric oxygen treatment (HBOT) was added on the second day of admission. The patient underwent 5 sessions of HBOT at 243.1 kPa (2.4 atmospheres absolute). Desquamation was noted to stop after the first session of HBOT and re-epithelisation commenced rapidly. The patient was discharged from the burn unit after 14 days of hospital admission. Improvement in this case was temporally related to the initiation of HBOT.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):220–223. doi: 10.28920/dhm51.2.220-223. PMID: 34157740.

Hyperbaric oxygen treatment for intrauterine limb ischaemia: A newborn in the chamber

Bengusu Mirasoglu1, Hande Cetin1, Sevgi Ozdemir Akgun2, Samil Aktas1

1 Istanbul Faculty of Medicine, Underwater and Hyperbaric Medicine Department, Istanbul, Turkey
2 Istanbul Faculty of Medicine, Pediatrics Department, Istanbul, Turkey

Corresponding author: Dr Bengusu Mirasoglu, Istanbul Tip Fakultesi, Sualti Hekimligi ve Hiperbarik Tip Anabilim Dali, 34093 Fatih, Istanbul, Turkey
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Key words
Case reports; Limb salvage; Neonatal thromboembolism; Neonatal gangrene; Safety

Abstract

(Mirasoglu B, Cetin H, Ozdemir Akgun S, Aktas S. Hyperbaric oxygen treatment for intrauterine limb ischaemia: A newborn in the chamber. Diving and Hyperbaric Medicine. 2021 June 30;51(2):220–223. doi: 10.28920/dhm51.2.220-223. PMID: 34157740.)
Intrauterine limb ischaemia is a rare condition that may have devastating results. Various treatments are reported in the literature; however, results are not always promising and amputations may be required for some patients. Post-natal hyperbaric oxygen treatment (HBOT) may be a useful treatment option for the salvage of affected limbs. A patient who was born with total brachial artery occlusion and severe limb ischaemia was referred for HBOT. The patient underwent the first HBOT session at her 48th hour of life. A total of 47 HBOT sessions were completed (243.1 kPa [2.4 atmospheres absolute], duration 115 minutes being: 15 minutes of compression; three 25-minute oxygen periods separated by five-minute air breaks; and 15 minutes of decompression), four in the first 24 hours. Full recovery was achieved with this intense HBOT schedule combined with anticoagulation, fasciotomy and supportive care. The new-born tolerated HBOT well and no complications or side effects occurred. To the best of our knowledge, our patient is one of the youngest patients reported to undergo HBOT.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):224–226. doi: 10.28920/dhm51.2.224-226. PMID: 34157741.

Pulmonary barotrauma with cerebral arterial gas embolism from a depth of 0.75−1.2 metres of fresh water or less: A case report

Ulrika Lindblom1, Carl Tosterud1,2

1 Swedish Armed Forces, Diving And Naval Medicine Centre, Karlskrona, Sweden
2 Capio Saint Goran Hospital, Stockholm, Sweden

Corresponding author: Dr Ulrika Lindblom, SSS FM DNC, Box 527, SE-371 23 Karlskrona, Sweden
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Key words
Diving medicine; Decompression illness; Hyperbaric oxygen therapy; Military diving; Underwater escape training

Abstract

(Lindblom U, Tosterud C. Pulmonary barotrauma with cerebral arterial gas embolism from a depth of 0.75−1.2 metres of fresh water or less: A case report. Diving and Hyperbaric Medicine. 2021 June 30;51(2):224–226. doi: 10.28920/dhm51.2.224-226. PMID: 34157741.)
During underwater vehicle escape training with compressed air, a fit 26-year-old soldier suffered pulmonary barotrauma with cerebral arterial gas embolism after surfacing from a depth of 0.75–1.2 metres of freshwater or less. She presented with an altered level of consciousness. Rapid neurological examination noted slurred speech, a sensory deficit and right hemiparesis. Eleven hours after the accident, hyperbaric oxygen treatment was initiated using US Navy Treatment
Table 6. The soldier almost completely recovered after repeated hyperbaric oxygen treatment. Given the very shallow depth this is an unusual case with only two similar case reports published previously.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):227–228. doi: 10.28920/dhm51.2.227-228. PMID: 34157742.

Commentary on using critical flicker fusion frequency to measure gas narcosis

Jacek Kot1, Pawel J Winklewski2

1 National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine in Gdynia, Medical University of Gdansk, Poland
2 Department of Human Physiology, Medical University of Gdansk, Poland

Address for correspondence: Jacek Kot, National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine in Gdynia, Medical University of Gdansk, Poland
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Key words
Diving; Narcosis; Nitrogen; Oxygen; Performance, Letters (to the Editor)

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Letter to the Editor


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):228–229. doi: 10.28920/dhm51.2.228-229. PMID: 34157743.

Reply: Commentary on using critical flicker fusion frequency to measure gas narcosis

Xavier CE Vrijdag1, Hanna van Waart1, Jamie W Sleigh1,2, Simon J Mitchell1,3

1 Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
2 Department of Anaesthesia, Waikato Hospital, Hamilton, New Zealand
3 Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand

Address for correspondence: Xavier CE Vrijdag, Department of Anaesthesiology, School of Medicine, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Letter to the Editor


2021 June;51(2)

Diving Hyperb Med. 2021 June 30;51(2):230. doi: 10.28920/dhm51.2.230. PMID: 34157744.

Science and Statistics

Jochen D Schipke

Research Group, Experimental Surgery, University Hospital Dusseldorf, Germany
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Key words
Effect size; P-value; Scientific reasoning; Statistic; Letters (to the Editor)

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Letter to the Editor

2019 December;49(4)

Diving Hyperb Med. 2019 December 20;49(4):245–252. doi: 10.28920/dhm49.4.245-252. PMID: 31828742.

The myopic shift associated with hyperbaric oxygen administration is reduced when using a mask delivery system compared to a hood – a randomised controlled trial

Michael H Bennett1,2, Cheng FB Hui1,2, Hooi G See3, Kwan L Au-Yeung4, Christopher Tan5, Stephanie Watson1,6

1 Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
2 Department of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney, Australia
3 Division of Anaesthesiology and Perioperative Medicine, Singapore General Hospital, Singapore
4 Department of Emergency Medicine, Princess Elizabeth Hospital, Hong Kong
5 Department of Anaesthesia, The Wollongong Hospital, Wollongong, Australia
6 Save Sight Institute, Discipline of Ophthalmology, The University of Sydney, Sydney, Australia

Corresponding author: Professor MH Bennett, Prince of Wales Clinical School and Academic Director, Wales Anaesthesia,
Ground Floor, East Wing Edmund Blackett Building, Prince of Wales Hospital, Barker Street, Randwick, NSW 2031, Australia
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Key words
Side effects; Hyperbaric oxygen; Ophthalmology; Myopia; Vision

Abstract
(Bennett MH, Hui CF, See HG, Au-Yeung KL, Tan C, Watson S. The myopic shift associated with hyperbaric oxygen administration is reduced when using a mask delivery system compared to a hood – a randomised controlled trial. Diving and Hyperbaric Medicine. 2019 December 20;49(4):245–252. doi: 10.28920/dhm49.4.245-252. PMID: 31828742.)
Introduction: A temporary myopic shift is a well-recognized complication of hyperbaric oxygen treatment (HBOT). Oxidation of proteins in the crystalline lens is the likely cause. Direct exposure of the eye to hyperbaric oxygen may exacerbate the effect. Our aim was to measure the magnitude of the myopic shift over a course of HBOT when using two different methods of oxygen delivery.
Methods: We conducted a randomised trial of oxygen delivery via hood versus oronasal mask during a course of 20 and 30 HBOT sessions. Subjective refraction was performed at baseline and after 20 and 30 sessions. We repeated these measurements at four and 12 weeks after completion of the course in those available for assessment.
Results: We enrolled 120 patients (mean age 57.6 (SD 11.2) years; 81% male). The myopic shift was significantly greater after both 20 and 30 sessions in those patients using the hood. At 20 treatments: refractory change was -0.92 D with hood versus -0.52 D with mask, difference 0.40 D (95% CI 0.22 to 0.57, P < 0.0001); at 30 treatments: -1.25 D with hood versus -0.63 with mask, difference 0.62 D (95% CI 0.39 to 0.84, P < 0.0001). Recovery was slower and less complete in the hood group at both four and 12 weeks.
Conclusions: Myopic shift is common following HBOT and more pronounced using a hood system than an oronasal mask. Recovery may be slower and less complete using a hood. Our data support the use of an oronasal mask in an air environment when possible.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2019 December;49(4)

Diving Hyperb Med. 2019 December 20;49(4):253–258. doi: 10.28920/dhm49.4.253-258. PMID: 31828743.

Protective effect of hyperbaric oxygen treatment on rat intestinal mucosa after mesenteric ischaemia and reperfusion

Kurtuluş Açiksari1, Seracettin Eğin2, Gülçin Hepgül3, Bengüsu Mirasoğlu4, Gamze Tanriverdi5, Devrim S Kanber6, Sibel Demirci5, Halil Doğan7, Doğaç N Özüçelik8, Akın S Toklu4, İsmail Seçkin5, Hakan T Yanar9

1 Department of Emergency Medicine, Faculty of Medicine, Istanbul Medeniyet University, Istanbul, Turkey
2 Department of General Surgery, MoH Okmeydanı Training and Research Hospital, Istanbul, Turkey
3 Department of General Surgery, Bagcilar Training and Research Hospital, Istanbul, Turkey
4 Department of Underwater and Hyperbaric Medicine, Faculty of Medicine, Istanbul University, Istanbul, Turkey
5 Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Istanbul, Turkey
6 Department of Biophysics, Cerrahpasa Faculty of Medicine, Istanbul University, Istanbul, Turkey
7 Department of Emergency Medicine, MoH Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey
8 Health Sciences Faculty, Istanbul University, Istanbul, Turkey
9 Department of General Surgery, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey

Corresponding author: Assistant Professor Kurtuluş Açiksari, Department of Emergency Medicine, Faculty of Medicine,
Istanbul Medeniyet University, Istanbul, Turkey
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Key words
Mesenteric ischaemia; Ischaemia-reperfusion injury; Histology; Experimental study

Abstract

(Açiksari K, Eğin S, Hepgül G, Mirasoğlu B, Tanriverdi G, Kanber DS, Demirci S, Doğan H, Özüçelik DN, Toklu AS, Seçkin I, Yanar HT. Protective effect of hyperbaric oxygen therapy on rat intestinal mucosa after mesenteric ischaemia and reperfusion. Diving and Hyperbaric Medicine. 2019 December 20;49(4):253–258. doi: 10.28920/dhm49.4.253-258. PMID: 31828743.)
Introduction: Mesenteric ischaemia results from a lack of adequate blood flow to and oxygenation of the mesentery and intestines. The aim of the present study was to evaluate the effect of hyperbaric oxygen treatment (HBOT) on the healing process in intestinal mucosa of rats undergoing mesenteric ischaemia and reperfusion.
Methods: Thirty-two Wistar-Albino rats were divided into four groups of eight: 1) ischaemia/reperfusion (I/R); 2) sham operation; 3) I/R+HBOT started 6 hours after reperfusion; 4) I/R+HBOT started 12 hours after reperfusion. In the I/R groups, a vascular clamp was placed across the superior mesenteric artery to occlude arterial circulation for 60 minutes, followed by reperfusion. A dose of HBOT consisted of 100% oxygen breathing for 90 minutes at 2.5 atmospheres absolute pressure. Thirteen doses of HBOT were administered after ischaemia. The rats were sacrificed on the eighth day, and their intestinal tissues were harvested for histopathologic analysis. The tissue levels of catalase, malondialdehyde, and glutathione were determined.
Results: The histopathological scores (HSCORE) were consistent with macroscopic examinations. The scores were significantly higher (worse) in Group 1 compared to Group 2, Group 3, and Group 4 (for all comparisons, P < 0.05). Group 4’s HSCORE was significantly higher than those of Group 2 and Group 3 (for both comparisons P < 0.05). Group 3’s HSCOREs were only marginally higher than Group 2. Group 3 exhibited higher glutathione levels than Group 1 (P < 0.05). There were no significant differences across the groups with respect to malondialdehyde and catalase levels.
Conclusion: A beneficial effect of HBOT was observed on oxidative stress and inflammation in acute mesenteric ischaemiareperfusion.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2019 December;49(4)

Diving Hyperb Med. 2019 December 20;49(4):259–265. doi: 10.28920/dhm49.4.259-265. PMID: 31828744.

Decompression illness (DCI) in Finland 1999–2018: Special emphasis on technical diving

Richard V Lundell1,2, Olli Arola3, Jari Suvilehto4, Juha Kuokkanen4, Mika Valtonen3, Anne K Räisänen-Sokolowski2,4,5

1 Diving Medical Centre, Centre for Military Medicine, Finnish Defence Forces, Helsinki, Finland
2 Helsinki University, Helsinki, Finland
3 National Hyperbaric Oxygen Therapy Center, Intensive Care Unit, Turku University Hospital, Turku, Finland
4 Hyperbaric Center Medioxygen, Helsinki, Finland
5 Department of Pathology, HUSLAB, Helsinki University Hospital, Helsinki, Finland

Corresponding author: Dr Richard Lundell, Sähkölaitoksentie 4, 00860 Helsinki, Finland
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Key words
Decompression sickness; Diving; Arctic diving; Hyperbaric oxygen treatment; First aid oxygen; Epidemiology

Abstract
(Lundell RV, Arola O, Suvilehto J, Kuokkanen J, Valtonen M, Räisänen-Sokolowski AK. Decompression illness (DCI) in Finland 1999–2018: Special emphasis on technical diving. Diving and Hyperbaric Medicine. 2019 December 20;49(4):259–265. doi: 10.28920/dhm49.4.259-265. PMID: 31828744.)
Introduction: This is the first published study on decompression illness (DCI) and its treatment in Finland. Diving conditions are demanding, as even in the summer the water temperature below 20 meters’ sea/fresh water (msw/mfw) is 4–10°C. Technical diving has become more popular over the years, so the emphasis of this study was to describe DCI in technical divers and compare it with non-technical recreational divers.
Methods: This study includes by estimation over 95% of all hyperbaric oxygen-treated DCI patients during the years 1999–2018 (n = 571). The cases were divided into technical divers (n = 200) and non-technical divers (n = 371). We focused on the differences between these two groups. Technical diving was defined as the usage of mixed breathing gases, closed circuit rebreather diving or planned decompression diving.
Results: The mean annual number of treated DCI cases in Finland was 29 (range 16–38). The number of divers treated possibly indicate a shift towards technical diving. Technical dives were deeper and longer and were mainly performed in cold water or an overhead environment. Technical divers were more likely to utilize first aid 100% oxygen (FAO2) and sought medical attention earlier than non-technical divers. Symptom profiles were similar in both groups. Recompression was performed using USN Treatment Table Six in the majority of the cases and resulted in good final outcome. Eighty two percent were asymptomatic on completion of all recompression treatment(s).
Conclusion: This 20-year observational study indicates a shift towards technical diving, and hence a more demanding and challenging style of diving among Finnish divers, with a surprisingly constant number of DCI cases over the years. There is still need for improvement in divers’ education in use of FAO2 for DCI symptoms. Fortunately, the outcome after recompression therapy is generally successful.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2019 December;49(4)

Diving Hyperb Med.  2019 December 20;49(4):266–275. doi: 10.28920/dhm49.4.266-275. PMID: 31828745.

Evaluating the thermal protection provided by a 2‒3 mm wet suit during fin diving in shallow water with a temperature of 16‒20°C

Dror Ofir1, Yoav Yanir2, Mirit Eynan1, Yehuda Arieli1

1 Israel Naval Medical Institute, Haifa, Israel
2 Department of Otolaryngology – Head and Neck Surgery, Carmel Medical Centre, Haifa, Israel

Corresponding author: Dr Dror Ofir, The Israel Naval Medical Institute (INMI), Box 22, Rambam Health Care Campus, PO Box 9602, 3109601, Haifa, Israel
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Key words
Cold; Immersion; Military diving; Rebreathers; Closed circuit; Thermodynamics; Vasoconstriction

Abstract
(Ofir D, Yanir Y, Eynan M, Arieli Y. Evaluating the thermal protection provided by a 2–3 mm wet suit during fin diving in shallow water with a temperature of 16–20°C. Diving and Hyperbaric Medicine. 2019 December 20;49(4):266–275. doi: 10.28920/dhm49.4.266-275. PMID: 31828745.)
Introduction: The purpose of the study was to evaluate the thermal protection provided by a 2–3 mm surfing wet suit during at least two hours of fin diving in shallow water with a temperature of 16–20°C. We examined the effect of wearing the suit while diving in cold water on cognitive performance, muscle strength, and hand motor function.
Methods: Subjects were six male well-trained rebreather divers, 19–23 years old, acclimatised to cold. They attended the laboratory on three separate occasions, when we conducted the experiment at one of three temperatures, 16, 18, and 20°C. Core temperature (gastrointestinal system), skin temperature, oxygen consumption, and cold perception were evaluated during the test. Before and immediately after the dives, subjects performed a series of cognitive, manual dexterity, and muscle strength tests.
Results: Core temperature decreased by 0.35–0.81°C over the two hours at all three water temperatures. No subject reached a core temperature below 35°C. The decrease in upper body skin temperature during the two hour dive ranged between 5.97 and 8.41°C (P < 0.05). Two hours diving in 16–20°C water resulted in a significant increase in the time taken to perform the task of unlinking and reassembling four shackles (~30% longer, P < 0.05). No effect was found on the cognitive or muscle strength tests.
Conclusions: A 2–3 mm wet suit provides adequate thermal protection in trained and cold-acclimatised young males engaged in active diving in shallow water with a temperature of 16°C and above.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2019 December;49(4)

Diving Hyperb Med. 2019 December 20;49(4):276–282. doi: 10.28920/dhm49.4.276-282. PMID: 31828746.

Inhibition of NR2B-containing NMDA receptors during nitrogen narcosis

Bin Peng1, Du-Du Hao1, Xia Li1, Guo-Hua Wang1, Zong-Yu Guan1, Zheng-Lin Jiang1

1 Department of Neurophysiology and Neuropharmacology, Institute of Special Environmental Medicine and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China

Corresponding author: Dr Zheng-Lin Jiang. Department of Neurophysiology and Neuropharmacology, Institute of Special
Environmental Medicine, Nantong University, 9 Seyuan Road, Chongchuan District, Nantong, Jiangsu 226019, China
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Key words
Brain; Hippocampus; Hyperbaric medicine; Neuron; NMDA receptor

Abstract
(Peng B, Hao D-D, Li X, Wang G-H, Guan Z-Y, Jiang Z-L. Inhibition of NR2B-containing NMDA receptors during nitrogen narcosis. Diving and Hyperbaric Medicine. 2019 December 20;49(4):276–282. doi: 10.28920/dhm49.4.276-282. PMID: 31828746.)
Introduction: When humans breathe compressed air or N2-O2 mixtures at three to four atmospheres pressure, they will experience nitrogen narcosis that may possibly lead to a diving accident, but the underlying mechanisms remain unclear. 
Methods: Mice were exposed to 1.6 MPa breathing a N2-O2 mixture adjusted to deliver an inspired PO2 of 32–42 kPa. The electroencephalogram (EEG) and forced swimming test were used to evaluate the narcotic effect of nitrogen. Neuronal activity was observed via c-Fos expression in cortex and hippocampus tissue after decompressing to the surface. To further investigate underlying molecular mechanisms, we incubated cultured hippocampal neurons with various NMDA concentrations, and measured expression of NMDA receptors and its down-stream signal with or without 1.6 MPa N2-O2 exposure.
Results: Both the frequency of the EEG and the drowning time using the forced swimming test were significantly decreased during exposure to 1.6 MPa N2-O2 (P < 0.001). Additionally, in cultured hippocampal neurons, the increased levels of phosphorylated NR2B and cAMP-response element binding protein (CREB) induced by NMDA stimulation were significantly
inhibited by exposure to 1.6 MPa N2-O2.
Conclusions: Our findings indicated that NR2B-containing NMDA receptors were inhibited during nitrogen narcosis.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2019 December;49(4)

Diving Hyperb Med. 2019 December 20;49(4):283–290. doi: 10.28920/dhm49.4.283-290. PMID: 31828747.

Longitudinal screening of hearing threshold in navy divers: is diving really a hazard?

Thijs T Wingelaar1,2, Edwin L Endert1, Rigo Hoencamp3,4,5, Peter-Jan AM van Ooij1, Rob A van Hulst2

1 Diving Medical Center, Royal Netherlands Navy, Den Helder, the Netherlands
2 Department of Anesthesiology, Amsterdam University Medical Center, Amsterdam, the Netherlands
3 Department of Surgery, Alrijne Hospital, Leiderdorp, the Netherlands
4 Defense Healthcare Organisation, Ministry of Defence, Utrecht, the Netherlands
5 Leiden University Medical Center, Leiden, the Netherlands

Corresponding author: Thijs Wingelaar, Royal Netherlands Navy Diving Medical Center, Rijkszee en marinehaven. 1780 CA Den Helder, the Netherlands
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Key words
Fitness to dive; Health surveillance; Hearing loss; Audiology; Military diving

Abstract
(Wingelaar TT, Endert EL, Hoencamp R, van Ooij PJAM, van Hulst RA. Longitudinal screening of hearing threshold in navy divers: is diving really a hazard? Diving and Hyperbaric Medicine. 2019 December 20;49(4):283–290. doi: 10.28920/dhm49.4.283-290. PMID: 31828747.)
Introduction: Hearing loss (HL) is common in the adult working population. It is widely assumed that diving is a risk factor for HL. However, studies with sufficient follow-up comparing HL in divers to non-divers are limited. This study aimed to assess the hearing threshold (HT) of Royal Netherlands Navy divers who had been diving for more than 15 years and to compare it to the ISO standard 7029:2017 reference table.
Methods: In this 25-year retrospective cohort study the Royal Netherlands Navy Diving Medical Centre audited the medical records of 1,117 Navy divers. Yearly dive medical assessments were performed according to professional standards, including audiometry. HTs were compared to the ISO 7029:2017 reference table, including Z-distribution, using paired t-tests. 
Results: Thirty-five divers were included who had been diving for 15 years or longer. The HT increased significantly in nine of the 16 measured frequencies, while the Z-score decreased significantly in nine of the 16 tested frequencies (eight in both ears). In the 25-year follow-up the pattern was more obvious, with one significantly increased HT, and 10 significantly decreased Z-scores.
Discussion: The absolute HT increases after 15 years of military diving, but less than would be expected from normal age-related deterioration. Moreover, when comparing Z-scores, this sample of divers actually hear better than non-divers. We conclude that military diving is not an increased risk for HL compared to regular occupational hazards and suggest withdrawing the requirement for routine yearly audiometric evaluation as part of a dive medical examination.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


 

2019 December;49(4)

Diving Hyperb Med. 2019 December 20;49(4):291–297. doi: 10.28920/dhm49.4.291-297. PMID: 31828748.

Diving and mental health: the potential benefits and risks from a survey of recreational scuba divers

Marguerite St Leger Dowse1, Ben Whalley2, Matthew K Waterman1, Robert M Conway3, Gary R Smerdon1

1 DDRC Healthcare, Plymouth, United Kingdom
2 School of Psychology / Cognition, Plymouth University, Plymouth, United Kingdom
3 North Devon District Hospital, Barnstaple United Kingdom

Corresponding author: Marguerite St Leger Dowse, DDRC Healthcare, Hyperbaric Medical Centre, Plymouth Science Park, Research Way, Plymouth PL6 8BU, Devon, United Kingdom
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Key words
Depression; Anxiety; Medical conditions and problems; Psychology; Fitness to dive

Abstract
(St Leger Dowse M, Whalley B, Waterman MK, Conway RM, Smerdon GR. Diving and mental health: the potential benefits and risks from a survey of recreational scuba divers. Diving and Hyperbaric Medicine. 2019 December 20;49(4):291–297. doi: 10.28920/dhm49.4.291-297. PMID: 31828748.)
Introduction: Scuba diving is physically and cognitively demanding. Medical guidance regarding physical and mental health (MH) issues and related prescribed medication is often based on limited evidence. There is a paucity of data concerning diving with MH issues. This survey aimed to investigate the prevalence of MH issues and use of prescription medications among United Kingdom (UK) sport divers, and the rate of non-compliance with current guidance among divers suffering depression and anxiety. The positive effects of scuba diving on MH were also considered.
Methods: An anonymous online survey was publicised through diving exhibitions and social media. Measures included diver and diving demographics; GAD-7 Anxiety and PHQ-9 depression questionnaires; diagnosed current and/or past MH conditions; medication usage; comorbid medical conditions/treatments; disclosure of past/current MH issues; and perceived MH benefits of diving.
Results: Data from 729 respondents revealed MH issues at rates comparable with the general population. Current and/or past MH issues were reported by 111/729, with 60 having active diagnoses, and 45/60 taking prescribed psychotropic medications; 21/45 did not declare their medication on diver self-certification medical forms. The activity of diving was thought to be beneficial to MH by 119/729 respondents.
Conclusions: Divers experienced expected levels of MH issues, but did not comply with current medical guidelines on modifying or abstaining from diving activity or reporting their MH condition. Changes may be needed to diver training to encourage more accurate reporting and aid development of evidence-based protocols. Guidelines could be reconsidered in light of current diver behaviour, risks and potential MH benefits.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Original article


2019 December;49(4)

Diving Hyperb Med. 

Performance of cartridge and granular carbon dioxide absorbents in a closed-circuit diving rebreather

Nicholas Gant1, Hanna van Waart2, Edward T Ashworth1, Peter Mesley3, Simon J Mitchell2,4

1 Department of Exercise Sciences, University of Auckland, New Zealand
2 Department of Anaesthesiology, University of Auckland, New Zealand
3 Lust4Rust Diving Excursions, Auckland, New Zealand
4 Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand

Corresponding author: Associate Professor Nicholas Gant, Department of Exercise Sciences, University of Auckland,
Private Bag 92019, Auckland 1142, New Zealand
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Key words
Technical diving; Closed-circuit rebreather; Carbon dioxide; Soda lime; Scrubber; Hypercapnia

Abstract
(Gant N, van Waart H, Ashworth ET, Mesley P, Mitchell SJ. Performance of cartridge and granular carbon dioxide absorbents in a closed-circuit diving rebreather. Diving and Hyperbaric Medicine. 2019 December 20;49(4):298–303. doi: 10.28920/dhm49.4.298-303. PMID: 31828749.)
Introduction: Scrubbers in closed-circuit rebreather systems remove carbon dioxide (CO2) from the exhaled gas. In an attempt to be more user-friendly and efficient, the ExtendAir® non-granular, pre-formed scrubber cartridge has been developed. The cartridge manufacturer claims twice the absorptive capacity of granular CO2 absorbent, with less variability, lower work of breathing, and reduced exposure to caustic chemicals after a flood. To our knowledge there are no published data that support these claims.
Methods: Cartridge (ExtendAir®) and granular (Sofnolime® 797) scrubbers of equal volume and mass were tested five times in an immersed and mechanically ventilated O2ptima rebreather. Exercise protocols involving staged (90 minutes 6 MET, followed by 2 MET) and continuous (6 MET) activity were simulated. We compared: duration until breakthrough, and variability in duration, to endpoints of 1.0 kPa and 0.5 kPa inspired partial pressure of CO2; inspiratory–expiratory pressure difference in the breathing loop; and pH of eluted water after a 5 minute flood.
Results: Mean difference in scrubber endurance was 0–20 % in favour of the ExtendAir® cartridge, depending on exercise protocol and chosen CO2 endpoint. There were no meaningful differences in endpoint variability, inspiratory–expiratory pressure in the loop, or pH in the eluted water after a flood.
Conclusions: Cartridge and granular scrubbers were very similar in duration, variability, ventilation pressures, and causticity after a flood. Our findings were not consistent with claims of substantial superiority for the ExtendAir® cartridge.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Technical report


2019 December;49(4)

Diving Hyperb Med. 2019 December 20;49(4):304–305. doi: 10.28920/dhm49.4.304-305. PMID: 31828750.

Fatal air embolism in a breath-hold diver

Neil DG Banham1, John Lippmann2

1 Hyperbaric Medicine Unit, Fiona Stanley Hospital, Perth, Australia
2 Australasian Diving Safety Foundation, Melbourne, Australia

Corresponding author: Dr Neil DG Banham, Director, Hyperbaric Medicine Unit, Fiona Stanley Hospital, Perth, Australia
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Key words
Diving deaths; Barotrauma; Breath-hold diving; Scuba; Cerebral arterial gas embolism (CAGE); Pulmonary barotrauma; Case reports

Abstract

(Banham NDG, Lippmann J. Fatal air embolism in a breath-hold diver. Diving and Hyperbaric Medicine. 2019 December 20;49(4):304–305. doi: 10.28920/dhm49.4.304-305. PMID: 31828750.)
Cerebral arterial gas embolism (CAGE) from breath-holding or inadequate exhalation during ascent is a well-recognised complication of scuba diving. It does not usually occur with breath-hold (BH) diving in those with normal lungs, as the volume of gas in the lungs on surfacing cannot exceed what it was on leaving the surface. However, a BH diver who breathes from a compressed gas supply at depth essentially becomes a scuba diver and is at risk of pulmonary barotrauma (PBt) and CAGE on ascent. In this case, a 26-year-old male experienced BH diver breathed from a scuba set at approximately 10 metres' sea water depth and ascended, sustaining massive PBt and CAGE with a fatal outcome. BH and scuba divers, especially those with less experience, need to be well-informed about this potential risk.

 

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2019 December;49(4)

Diving Hyperb Med. 2019 December 20;49(4):306–310. doi: 10.28920/dhm49.4.306-310. PMID: 31828751.

A case of Löfgren’s syndrome confused with decompression sickness

Payal S Razdan1,2, Dominique Buteau3,4, Neal W Pollock1,2

1 Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
2 CISSS Chaudière-Appalaches (CHAU-Hôtel-Dieu de Lévis), Hyperbaric Medicine Unit, Lévis, Québec, Canada
3 Family Medicine and Emergency Medicine Department, Faculty of Medicine, Université Laval, Québec, Canada
4 CISSS Chaudière-Appalaches (CHAU-Hôtel-Dieu de Lévis), Hyperbaric Medicine Unit, Emergency Department, Lévis, Quebec, Canada

Corresponding author: Payal S Razdan, Rm 4807, Hôtel-Dieu de Lévis, 143 rue Wolfe, Lévis, QC, Canada, G6V 3Z1
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Key words
Hyperbaric oxygen; Differential diagnosis; Mycobacterium marinum infection; Pulmonary sarcoidosis

Abstract

(Razdan PS, Buteau D, Pollock NW. A case of Löfgren’s syndrome confused with decompression sickness. Diving and Hyperbaric Medicine. 2019 December 20;49(4):306–310. doi: 10.28920/dhm49.4.306-310. PMID: 31828751.)
A broad differential diagnosis is important to provide appropriate care. This may be challenging for conditions like decompression sickness (DCS) which can be easily confused with other conditions. In suspected DCS, treatment may be an important part of the diagnosis. An improvement in symptoms after hyperbaric oxygen treatment (HBOT) is consistent with a DCS event. However, HBOT may also impact symptoms in other conditions, including Löfgren’s syndrome (LS). LS, a poorly understood, clinically distinct phenotype of sarcoidosis, is a complex, multi-system granulomatous inflammatory condition. Like DCS, LS symptoms are heterogeneous and idiosyncratic. We report on a patient initially diagnosed with DCS who presented new symptoms suggestive of LS after HBOT.

Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Case report


2019 December;49(4)

Diving Hyperb Med. 2019 December 20;49(4):311–312. doi: 10.28920/dhm49.4.311-312. PMID: 31828752.

Gas micronuclei that underlie decompression bubbles and decompression sickness have most probably been identified – in response to the Letter to the Editor from Dr David Doolette

Ran Arieli

The Israel Naval Medical Institute, Israel Defence Forces Medical Corps, Haifa, Israel; Eliachar Research Laboratory, Western Galilee Medical Centre, Nahariya, Israel

Address for correspondence: 12 Klil-Hakhoresh, Rakefet, D.N. Misgav 2017500, Israel
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Key words
Nanobubbles; Gas micronuclei; Decompression bubbles; Hydrophobicity; Letter to the Editor

Copyright: This article is the copyright of the author who grants Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.

Publication Type: Letter to the Editor


 

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Articles from 2017 are deposited in PubMed Central