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.

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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

Diving and Hyperbaric Medicine is indexed on MEDLINE, Science Citation Index Expanded (SciSearch®) and Embase/Scopus and complies with the International Committee of Medical Journal Editors (ICMJE) Recommendation for the Conduct, Report, Editing and Publication of Scholarly Work in Medical Journals.
Articles from 2017 are deposited in PubMed Central