2017 December;47(4)

Diving Hyperb Med. 2017 Dec;47(4):214-215. doi: 10.28920/dhm47.4.214-215.

Back to the future: occupational diver training in Australia

David Smart 

Professor David Smart, Department of Diving and Hyperbaric Medicine, Royal Hobart Hospital, PO Box 1061, Hobart, TAS 7001, Australia
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Key words

Diving at work; Diving incidents; Diving industry; Education; Safety; Standards

Abstract

(Smart D. Back to the future: diver training in Australia. Diving and Hyperbaric Medicine. 2017 December;47(4):214-215. doi10.28920/dhm47.4.214-215.) 
The Australian Diver Accreditation Scheme (ADAS) had its genesis in the 1990s in response to a need to produce occupational divers who were trained to international standards with the necessary skills to safely undertake complex work in high-risk environments. Well-trained dive teams who are 'fit-for-purpose' can be regarded as the highest level of risk control in preventing accidents and workplace morbidity. Without such training, work site risks are not detected, with potentially disastrous consequences. In September 2017, the only civilian ADAS level 3 and 4 training facility in Australia, The Underwater Centre Tasmania (TUCT), closed its doors. The reasons for TUCT closure were multifactorial. However, the loss
of higher level training capability in this country and its benefits to industry will have a future adverse impact. As industry pushes for more complex diving to improve productivity, Australian occupational diver training processes are becoming 'streamlined' and are losing parity with international benchmarks. This is a potentially fatal combination. 

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

Publication Type: Editorial


Diving Hyperb Med. 2017 Dec;47(4):214-215. doi: 10.28920/dhm47.4.216-222.


Influence of repetitive diving in saltwater on pressure equalization and Eustachian tube function in recreational scuba divers

Moritz F Meyer1, Manuela Boor1, Stefanie Jansen1, Eberhard D Pracht2, Moritz Felsch3, Heinz D Klünter1, Karl-Bernd Hüttenbrink1, Dirk Beutner1, Maria Grosheva1

1 Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Germany
2 German Centre for Neurodegenerative Diseases (DZNE), Bonn, Germany
3 Institute of Medical Statistics, Informatics and Epidemiology, University of Cologne, Germany

Corresponding author: Professor Moritz F Meyer, Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Cologne, Kerpener Straße 62, 50937 Cologne, Germany, This email address is being protected from spambots. You need JavaScript enabled to view it.

Key words

Tympanometry; Middle ear; Ear barotrauma; Recreational diving

Abstract
(Meyer MF, Boor M, Jansen S, Pracht ED, Felsch M, Klünter HD, Hüttenbrink K-B, Beutner D, Grosheva M. Influence of repetitive diving in saltwater on pressure equalization and Eustachian tube function in recreational scuba divers. Diving and Hyperbaric Medicine. 2017 December;47(4):216-222. doi10.28920/dhm47.4.216-222.)
Introduction: We investigated in a prospective, observational trial the feasibility of using the Eustachian tube function test (ETFT) to measure the effect of repetitive pressure exposure during open seawater dives on Eustachian tube function. 
Methods: The study included 28 adult divers during six consecutive days of diving in the Red Sea. Participants underwent otoscopy and ETFT before the first dive, between each dive and after the last dive. ETFT included regular tympanometry (R-tymp), tympanometry after Valsalva (V-tymp) and after swallowing (S-tymp). The R-tymp was obtained as ‘baseline’ peak pressure. After a Valsalva, the peak pressure should shift (positively), revealing a positive shift of the tympanic membrane. This pressure shift is defined here as R-VdP. The changes in compliance and peak pressure were recorded and correlated with otoscopic findings and diving experience. Middle ear barotrauma was scored using the Edmonds modified TEED scale.
Results: The 28 participants performed 437 dives. Positive shift of pressure in the middle ear was evident with significant changes from day one to day three (P < 0.0001). Divers with barotrauma showed significantly lower values of R-tymp peak pressure and significantly higher negative R-VdP, compared to divers with normal otoscopic findings (P < 0.05). Diving
experience significantly correlated with R-tymp peak pressure and prevalence of middle ear barotrauma.
Conclusion: Significant changes in middle ear pressure and pressure equalization from repeated pressure exposure in saltwater were seen using ETFT. Repetitive, multi-day diving led to significantly decreased compliance and increased R-tymp peak pressure (overpressure) in the middle ear. Most profound changes were observed in less and intermediate experienced divers.

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

Publication Type: Original Articles


Diving Hyperb Med. 2017 Dec;47(4):223-227. doi: 10.28920/dhm47.4.223-227.

Influence of repetitive diving in freshwater on pressure equalization and Eustachian tube function in recreational scuba divers

Stefanie Jansen1, Manuela Boor1, Moritz F Meyer1, Eberhard D Pracht2, Ruth Volland3, Heinz D Kluenter1, Karl-Bernd Huettenbrink1, Dirk Beutner1 , Maria Grosheva1

1 Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Medical Faculty, Germany
2 German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
3 Department of Paediatric Oncology and Haematology, University Children’s Hospital of Cologne, Cologne, Germany

Corresponding author: Professor Moritz F Meyer, Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Cologne, Kerpener Straße 62, 50937 Cologne, Germany
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Key words

Tympanometry; Middle ear; Ear barotrauma; Recreational diving

Abstract
(Jansen S, Boor M, Meyer MF, Pracht ED, Volland R, Kluenter HD, Huettenbrink K-B, Beutner D, Grosheva M. Repetitive diving in freshwater alters Eustachian tube function measured by Eustachian tube function test in recreational scuba divers. Diving and Hyperbaric Medicine. 2017 December;47(4):223-227. doi10.28920/dhm47.4.223-227.)
Introduction: We investigated the effect of repetitive pressure exposure during freshwater dives on Eustachian tube function and the middle ear, assessed by the Eustachian tube function test (ETFT).
Methods: This prospective observational cohort study included 23 divers over three consecutive days of diving in freshwater lakes in Nordhausen, Germany. Participants underwent otoscopy and ETFT before the first dive, between each dive and after the last dive. ETFT included regular tympanometry (R-tymp), tympanometry after Valsalva (V-tymp) and after
swallowing (S-tymp). The peak pressure difference between the R-tymp and the V-tymp (R-VdP) defined effectiveness of pressure equalization after Valsalva manoeuvres. We evaluated the change in compliance and peak pressure and correlated the results to the otoscopic findings and diving experience.
Results: Twenty-three divers performed 144 dives. Middle ear barotrauma was assessed using the Edmonds modification of the TEED scoring system. In the ETFT, the R-tymp peak pressure displayed a negative shift from day one to three (P = 0.001) and differed significantly between the experience groups (P = 0.01). R-VdP did not change significantly on any
of the three days of diving (all P > 0.05). Participants without MEBt showed significantly lower R-tymp values than did those with barotrauma (P = 0.019).
Conclusion: Repetitive pressure exposure during three consecutive days of freshwater diving led to a negative shift of the peak pressure in the middle ear. Less experienced divers showed significantly higher middle ear peak pressure and higher pressure differences after equalization manoeuvres. Higher middle ear peak pressure was also associated with a higher
prevalence of 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 printed and other forms.

Publication Type: Original Articles


Diving Hyperb Med. 2017 Dec;47(4):228-232. doi10.28920/dhm47.4.228-232.

Thromboelastographic assessment of the impact of mexiletine on coagulation abnormalities induced by air or normal saline intravenous injections in conscious rats

Joseph L Nates1, Davide Cattano2, Fernanda S Costa3, Jacques E Chelly4, Marie-Francoise Doursout2

1 Critical Care Department, Division of Anesthesiology and Critical Care, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
2 Department of Anesthesiology, The University of Texas Medical School at Houston, Houston, Texas, USA
3 Universidade Estácio de Sá, Rio de Janeiro, Brazil
4 Department of Anesthesiology, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA

Corresponding author: Professor Joseph L. Nates, Department of Critical Care Medicine, Division of Anesthesiology, Critical Care, and Pain Medicine, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 112, Houston, TX 77030, USA
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Key words

Thromboelastography; Air embolism; Mexiletine; Coagulation; Animal model

Abstract
(Nates JL, Cattano D, Costa FS, Chelly JE, Doursout MF. Thromboelastographic assessment of the impact of mexiletine on coagulation abnormalities induced by air or normal saline intravenous injections in conscious rats. Diving and Hyperbaric Medicine. 2017 December;47(4):228-232. doi10.28920/dhm47.4.228-232.)
Background: Thromboelastography (TEG) in venous air embolism (VAE) has been poorly studied. We induced coagulation abnormalities by VAE in a rat model, assessed by TEG with and without mexiletine, a lidocaine analogue local anesthetic. 
Methods: Twenty-three Sprague Dawley rats instrumented under isoflurane anesthesia and allowed to recover five days prior to the experiments were randomized into three experimental groups: 1) VAE (n = 6); 2) VAE and mexiletine (n = 9); and 3) normal saline (NS) alone (control group, n = 8). Blood samples were collected at baseline, one hour (h) and 24 h in all groups and analyzed by TEG to record the R, K, angle α and MA parameters. 
Results: In Group 1, VAE decreased significantly R at 1 h (31%), K at 1 h (59%) and 24 h (34%); α increased significantly at 1 h (30%) and 24 h (22%). While R returned to baseline values within 24 h, K, MA and α did not. In group-2 (Mexiletine + VAE), K and R decreased at 1 h (48% and 29%, respectively) and at 24 h the changes were non-significant. Angle α
increased at 1 h (28%) and remained increased for 24 h (25%). In group 3 (NS), only R was temporarily affected. MA increased significantly at 24 h only in the VAE alone group.
Conclusion: As expected, VAE produced a consistent and significant hypercoagulable response diagnosed/confirmed by TEG. Mexiletine prevented the MA elevation seen with VAE and corrected R and K time at 24 h, whereas angle α remained unchanged. Mexiletine seemed to attenuate the hypercoagulability associated with VAE in this experiment. These results
may have potential clinical applications and deserve further investigation.

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

Publication Type: Original Articles


Diving Hyperb Med. 2017 Dec;47(4):233-238. doi10.28920/dhm47.4.233-238.

Hyperbaric oxygen in the treatment of acute retinal artery occlusion

Mark J Elder1,2, John A Rawstron1, Michael Davis2,3

1 Ophthalmology Department, Christchurch Hospital, Christchurch, New Zealand
2 University of Otago, Christchurch
3 formerly Hyperbaric Medicine Unit, Christchurch Hospital

Corresponding author: Professor Mark Elder, Ophthalmology Department, Christchurch Hospital, Private Bag 4710, Christchurch 8140, New Zealand
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Key words

Vision disorders; Visual acuity; Outcome; Retrospective studies; Clinical audit

Abstract
(Elder MJ, Rawstron JA, Davis M. Hyperbaric oxygen in the treatment of acute retinal artery occlusion. Diving and Hyperbaric Medicine. 2017 December;47(4):233-238. doi10.28920/dhm47.4.233-238.)
Introduction: Acute retinal artery occlusion (ARAO) is a major cause of sudden, painless visual loss, often leaving no useful vision in the affected eye. Its incidence is cited at 0.85 per 100,000 persons per year but may be higher because of under-reporting. The natural history is difficult to study, but a spontaneous resolution rate of < 1–8% for acute, non-arteritic
ARAO has been cited. Occurrence in an only eye is devastating for the patient. There is currently no consensus regarding management of ARAO and little evidence to support any treatment modality. Despite only limited case series, hyperbaric oxygen treatment (HBOT) is recommended for ARAO by the Undersea and Hyperbaric Medical Society (UHMS) and by
the European Committee for Hyperbaric Medicine.
Methods: Between early 2003 and December 2012, all ARAO patients presenting to Christchurch Hospital were referred for consideration of HBOT. These 31 consecutive patients’ medical records were reviewed retrospectively. The time delay from onset of visual loss to commencing HBOT; the presenting visual acuity; various demographic data; the HBOT administered and the outcome visual acuity were documented.
Results: All 31 patients underwent at least one HBOT (median 4, range 1–7) at a pressure of 203–284 kPa for 1.5 to 2.0 h. One patient’s treatment was terminated after 60 min at their request; another declined further HBOT and one suffered middle ear barotrauma. Thirteen patients also received anticoagulants at the discretion of the referring ophthalmologist. Twentythree patients had temporarily improved vision with the first HBOT. Seven patients had permanent, good visual recovery (6/18 or better; Snellen chart); and two only modest improvement (6/60). All nine patients who improved permanently were treated within 10 hours of symptom onset.
Conclusions: Where available, HBOT is indicated for ARAO. Our protocol may not have been aggressive enough and the UHMS protocol is recommended. A multi-centre, randomised controlled trial is feasible, but would be logistically difficult and expensive and may be ethically unsupportable given the lack of alternative, effective treatments.

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

Publication Type: Original Articles


Diving Hyperb Med. 2017 Dec;47(4):239-247. doi10.28920/dhm47.4.239-247.

Lost at sea: the medicine, physiology and psychology of prolonged immersion

Heather Massey1, John Leach1, Michael Davis2, Vicki Vertongen3

1 Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
2 Formerly Medical Director, Hyperbaric Medicine Unit, Christchurch Hospital, Christchurch, New Zealand
3 Emergency Medicine Department, Wellington Hospital, Wellington, New Zealand

Corresponding author: Dr Heather Massey, Department of Sport and Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth PO1 2ER, UK
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Key words

Immersion; Hypothermia; Physiology; Psychology; Environment; Diving incidents; Review article

Abstract

(Massey H, Leach J, Davis FM, Vertongan V. Lost at sea: the medical, physiological and psychological factors of prolonged immersion. Diving and Hyperbaric Medicine. 2017 December;47(4):239-247. doi10.28920/dhm47.4.239-247.)
In most countries, immersion represents the second most common cause of accidental death in children and the third in adults. Between 2010 and 2013, 561 deaths worldwide involving recreational divers were recorded by the Divers Alert Network. Consequently, there is no room for complacency when diving. Being lost at sea is a diver’s worst nightmare.
In 2006, a diver was lost at sea off the coast of New Zealand for 75 hours. It is unprecedented that, after such a long time immersed in temperate (16−17°C) waters, he was found and survived. His case is presented and utilised to illustrate the many physiological and psychological factors involved in prolonged immersion and what might determine survival under
such circumstances. We also briefly review options for enhancing diver location at sea and a few issues related to search and rescue operations are discussed.

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

Publication Type: Review Articles


Diving Hyperb Med. 2017 Dec;47(4):248-252. doi10.28920/dhm47.4.248-252.

Personality and behavioural outcomes in diving: current status and recommendations for future research

Charles H Van Wijk

Corresponding author: Charles H Van Wijk, PO Box 494, Simon’s Town 7995, South Africa
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Key words

Psychology; Performance; Military diving; Recreational diving; Review article

Abstract

(Van Wijk CH. Personality and behavioural outcomes in diving: current status and recommendations for future research. Diving and Hyperbaric Medicine. 2017 December;47(4):248-252. doi10.28920/dhm47.4.248-252.)
This paper provides a brief overview of the shift from studies describing the personality profiles of divers to studies exploring associations between personality variables and diving performance in terms of behavioural outcomes. The personality associations that were investigated include performance during training, panic proneness, diving injuries, susceptibility
to inert gas narcosis, and the behaviour of tourist divers. The paper concludes with a number of suggested directions for further research on personality and diving that may provide tangible benefits in terms of both enhanced safety and improved performance underwater.

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

Publication Type: Review Articles


Diving Hyperb Med. 2017 Dec;47(4):248-252. doi10.28920/dhm47.4.248-252.

Diving and antidepressants

Abraham L Querido

Corresponding author:  Abraham L Querido, Praktijk Querido, Larenseweg 14, Hilversum, The Netherlands
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Key words

Medications; Fitness to dive; Diving medicine; Recreational diving; Side effects; Review article

Abstract

(Querido AL. Diving and antidepressants. Diving and Hyperbaric Medicine. 2017 December;47(4):253-256. doi10.28920/dhm47.4.253-256.)
Psychoactive drugs pose a risk to both the diver and his or her buddy. Little is known about the safety of diving with antidepressants. Amongst the potential interactions with the diving environment are: somnolence; convulsions; a bleeding tendency (potentially worsening decompression illness, DCI), alterations to glucose metabolism and psychiatric side effects. Fluoxetine may potentially reduce the inflammatory process associated with DCI. This article presents guidelines for recreational diving in combination with antidepressants. These guidelines were endorsed at a meeting of the Dutch Association for Diving Medicine in 2015 and are solely based on ‘expert’ opinion.

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

Publication Type: Review Articles


Diving Hyperb Med. 2017 Dec;47(4):257-259. doi10.28920/dhm47.4.257-259.

Delayed hyperbaric intervention in life-threatening decompression illness

Michael FM Perez, Janet V Ongkeko-Perez, April R Serrano, Maravic P Andal, Maria CC Aldover

Saint Patrick’s Hospital Medical Centre, SPHMC-HH, Philippines

Corresponding author: Dr Michael FM Perez, Saint Patrick’s Hospital Medical Centre, SPHMC-HH, Lopez Jaena Street, Batangas City, Philippines
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Key words

Cerebral arterial gas embolism (CAGE); Rebreathers/closed circuit; Hyperbaric oxygen therapy; Intensive care medicine; Persistent (patent) foramen ovale; Case report

Abstract

(Perez MFM, Ongkeko-Perez JV, Serrano AR, Andal MP, Aldover MCC. Delayed hyperbaric intervention in life-threatening decompression illness. Diving and Hyperbaric Medicine. 2017 December; 47(4):257-259. doi10.28920/dhm47.4.257-259.)
Arterial gas embolism is a catastrophic event. Bubbles in the arterial circulation may lodge in the brain and cause infarction in the affected area and/or in a coronary vessel causing acute myocardial ischaemia. There is no well-defined window of time beyond which a response to hyperbaric oxygen is not expected. Major improvement may occur if the patient is treated as soon as possible, but is less likely in divers with severe decompression illness who have delayed intervention. We report on a 51-year-old, male rebreather diver who suffered loss of consciousness and cardiovascular collapse within minutes of a 30-metre deep dive at a remote Micronesian dive site. Recompression treatment did not start for six days for reasons to be presented, during which time he remained deeply comatose, cardiovascularly unstable and intubated on ventilator support. Despite this, following aggressive hyperbaric treatment over many days he made a functional recovery. At one year post injury, he is leading a functional life but has not returned to his previous occupation as a diver and suffers from moderately severe tinnitus and impaired right ear hearing and occasional mild speech problems. He is undertaking a number of on-line courses with a view to re-employment.

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

Publication Type: Case Reports


Diving Hyperb Med. 2017 Dec;47(4):260-262. doi10.28920/dhm47.4.260-262.

Hyperbaric oxygen-associated seizure leading to stroke

Jordan M Warchol1, Jeffrey S Cooper1, Thomas S Diesing2

1 Department of Emergency Medicine, University of Nebraska Medical Centre, Omaha, Nebraska, USA
2 Department of Neurology, University of Nebraska Medical Centre, Omaha

Corresponding author: Dr Jeffrey S Cooper, 981150 NMC, University of Nebraska Medical Centre, Omaha, NE 68198-1150, USA
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Key words

Hyperoxia; Central nervous system; Toxicity; Case reports

Abstract

(Warchol JM, Cooper JS, Diesing TS. Hyperbaric oxygen-associated seizure leading to stroke. Diving and Hyperbaric Medicine. 2017 December;47(4):260-262. doi10.28920/dhm47.4.260-262.)
Oxygen toxicity seizures are a well-known complication of hyperbaric oxygen treatment (HBOT). Until now, there have not been any reported cases of an acute ischaemic event (stroke) as the result of a HBOT-associated oxygen toxicity seizure. We report an event in which a seizure and stroke occurred together and consider that the stroke may have been caused by
seizure-induced demand ischaemia. This challenges the generally held view that oxygen toxicity seizures in the clinical hyperbaric setting are benign. A discussion of the literature on the subject of seizure-induced brain injury is included. Risk factors for cerebrovascular disease should be taken into consideration in determining treatment pressures for HBOT, as
reducing pressure reduces 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 printed and other forms.

Publication Type: Case Reports


 

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