2023 December;53(4)
Diving Hyperb Med. 2023 December 20;53(4):299−305. doi: 10.28920/dhm53.4.299-305. PMID: 38091588. PMCID: PMC10944666.
Risk assessment of SWEN21 a suggested new dive table for the Swedish armed forces: bubble grades by ultrasonography
Carl Hjelte1,2,3, Oskar Plogmark1,2, Mårten Silvanius2,4, Magnus Ekström1, Oskar Frånberg1,4
1 Lund University, Faculty of Medicine, Department of Clinical Sciences Lund, Respiratory Medicine and Allergology,
Lund, Sweden
2 Swedish Armed Forces Diving and Naval Medicine Center, Swedish Armed Forces, Karlskrona, Sweden
3 Sahlgrenska University Hospital, Anesthesia and Intensive Care, Gothenburg, Sweden
4 Blekinge Institute of Technology, Department of Mathematics and Natural Science, Karlskrona, Sweden
Corresponding author: Dr Carl Hjelte, Kungsladugårdsgatan 113B. 414 76, Gothenburg, Sweden
ORCiD: 0009-0009-5522-8735
carl_hjelte@hotmail
Keywords
Decompression; Decompression illness; Decompression tables; Diving; Echocardiography; Risk; Venous gas emboli
Abstract
(Hjelte C, Plogmark O, Silvanius M, Ekström M, Frånberg O. Risk assessment of SWEN21 a suggested new dive table for the Swedish armed forces: bubble grades by ultrasonography. Diving and Hyperbaric Medicine. 2023 December 20;53(4):299−305. doi: 10.28920/dhm53.4.299-305. PMID: 38091588. PMCID: PMC10944666.)
Introduction: To develop the diving capacity in the Swedish armed forces the current air decompression tables are under revision. A new decompression table named SWEN21 has been created to have a projected risk level of 1% for decompression sickness (DCS) at the no stop limits. The aim of this study was to evaluate the safety of SWEN21 through the measurement of venous gas emboli (VGE) in a dive series.
Methods: A total 154 dives were conducted by 47 divers in a hyperbaric wet chamber. As a proxy for DCS risk serial VGE measurements by echocardiography were conducted and graded according to the Eftedal-Brubakk scale. Measurements were done every 15 minutes for approximately 2 hours after each dive. Peak VGE grades for the different dive profiles were used in a Bayesian approach correlating VGE grade and risk of DCS. Symptoms of DCS were continually monitored.
Results: The median (interquartile range) peak VGE grade after limb flexion for a majority of the time-depth combinations, and of SWEN21 as a whole, was 3 (3–4) with the exception of two decompression profiles which resulted in a grade of 3.5 (3–4) and 4 (4–4) respectively. The estimated risk of DCS in the Bayesian model varied between 4.7–11.1%. Three dives (2%) resulted in DCS. All symptoms resolved with hyperbaric oxygen treatment.
Conclusions: This evaluation of the SWEN21 decompression table, using bubble formation measured with echocardiography, suggests that the risk of DCS may be higher than the projected 1%.
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
Diving Hyperb Med. 2023 December 20;53(4):306−312. doi: 10.28920/dhm53.4.306-312. PMID: 38091589. PMCID: PMC10944662.
Rapture of the deep: gas narcosis may impair decision-making in scuba divers
Pauliina A Ahti1, Jan Wikgren1
1 Centre for Interdisciplinary Brain Research, Department of Psychology, University of Jyväskylä, Finland
Corresponding author: Dr Pauliina A Ahti, Centre for Interdisciplinary Brain Research, Department of Psychology,
University of Jyväskylä, Finland
ORCiD: 000-002-6216-9616
Keywords
Cold; Deep diving; Gases; Nitrogen narcosis; Personality; Psychology; Scientific diving
Abstract
(Ahti PA, Wikgren J. Rapture of the deep: gas narcosis may impair decision-making in scuba divers. Diving and Hyperbaric Medicine. 2023 December 20;53(4):306−312. doi: 10.28920/dhm53.4.306-312. PMID: 38091589. PMCID: PMC10944662.)
Introduction: While gas narcosis is familiar to most divers conducting deep (> 30 metres) dives, its effects are often considered minuscule or subtle at 30 metres. However, previous studies have shown that narcosis may affect divers at depths usually considered safe from its influence, but little knowledge exists on the effects of gas narcosis on higher cognitive functions such as decision-making in relatively shallow water at 30 metres. Impaired decision-making could be a significant safety issue for a multitasking diver.
Methods: We conducted a study exploring the effects of gas narcosis on decision-making in divers breathing compressed air underwater. The divers (n = 22) were evenly divided into 5-metre and 30-metre groups. In the water, we used underwater tablets equipped with the Iowa Gambling Task (IGT), a well-known psychological task used to evaluate impairment in decision-making.
Results: The divers at 30 metres achieved a lower score (mean 1,584.5, standard deviation 436.7) in the IGT than the divers at 5 metres (mean 2,062.5, standard deviation 584.1). Age, body mass index, gender, or the number of previous dives did not affect performance in the IGT.
Conclusions: Our results suggest that gas narcosis may affect decision-making in scuba divers at 30 metres depth. This supports previous studies showing that gas narcosis is present at relatively shallow depths and shows that it may affect higher cognitive functions.
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
Diving Hyperb Med. 2023 December 20;53(4):313−320. doi: 10.28920/dhm53.4.313-320. PMID: 38091590. PMCID: PMC10735670.
Full-face snorkel masks increase the incidence of hypoxaemia and hypercapnia during simulated snorkelling compared to conventional snorkels
Janneke Grundemann1, Xavier CE Vrijdag1, Nicole YE Wong2, Nicholas Gant3, Simon J Mitchell1,2,4, Hanna van Waart1
1 Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
2 Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand
3 Department of Exercise Sciences, University of Auckland, New Zealand
4 Slark Hyperbaric Unit, North Shore Hospital, Auckland, New Zealand
Corresponding author: Dr Hanna van Waart, Department of Anaesthesiology, School of Medicine, University of Auckland,
Private Bag 92019, Auckland 1142, New Zealand
ORCiD: 0000-0002-6931-0168
Keywords
Diving research; Equipment; Hypercapnia; Hypoxia; Safety
Abstract
(Grundemann J, Vrijdag XCE, Wong NYE, Gant N, Mitchell SJ, van Waart H. Full-face snorkel masks increase the incidence of hypoxaemia and hypercapnia during simulated snorkelling compared to conventional snorkels. Diving and Hyperbaric Medicine. 2023 December 20;53(4):313−320. doi: 10.28920/dhm53.4.313-320. PMID: 38091590. PMCID: PMC10735670.)
Introduction: Air flow in full-face snorkel masks (FFSMs) should be unidirectional to prevent rebreathing of exhaled air. This study evaluated rebreathing and its consequences when using full-face snorkel masks compared to a conventional snorkel.
Methods: In a dry environment 20 participants wore three types of snorkel equipment in random order: Subea Easybreath FFSM; QingSong 180-degree panoramic FFSM; and a Beuchat Spy conventional snorkel (with nose clip), in three conditions: rest in a chair; light; and moderate intensity exercise on a cycle ergometer. Peripheral oxygen saturation, partial pressure of carbon dioxide (PCO2) and oxygen (PO2) in the end tidal gas and FFSM eye-pockets, respiratory rate, minute ventilation, were measured continuously. Experiments were discontinued if oxygen saturation dropped below 85%, or if end-tidal CO2 exceeded 7.0 kPa.
Results: Experimental runs with the FFSMs had to be discontinued more often after exceeding 7.0 kPa end-tidal CO2 compared to a conventional snorkel e.g., 18/40 (45%) versus 4/20 (20%) during light intensity exercise, and 9/22 (41%) versus 3/16 (19%) during moderate intensity exercise. Thirteen participants exhibited peripheral oxygen saturations below 95% (nine using FFSMs and four using the conventional snorkel) and five fell below 90% (four using FFSMs and one using the conventional snorkel). The PCO2 and PO2 in the eye-pockets of the FFSMs fluctuated and were significantly higher and
lower respectively than in inspired gas, which indicated rebreathing in all FFSM wearers.
Conclusions: Use of FFSMs may result in rebreathing due to non-unidirectional flow, leading to hypercapnia and hypoxaemia.
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
Full article available here.
Diving Hyperb Med. 2023 December 20;53(4):321−326. doi: 10.28920/dhm53.4.321-326. PMID: 38091591. PMCID: PMC10944667.
Measuring whole body inert gas wash-out
Oscar Plogmark1,2, Mårten Silvanius3, Max Olsson1, Carl Hjelte1,2, Magnus Ekström1, Oskar Frånberg1,3
1 Lund University, Faculty of Medicine, Department of Clinical Sciences Lund, Respiratory Medicine and Allergology, Lund, Sweden
2 Swedish Armed Forces Diving and Naval Medicine Center, Swedish Armed Forces, Karlskrona, Sweden
3 Blekinge Institute of Technology, Department of Mathematics and Natural Science, Karlskrona, Sweden
Corresponding author: Oscar Plogmark, Sölvegatan 19, 221 85 Lund, Sweden
ORCiD: 0009-0008-3230-8807
Keywords
Decompression sickness; Diving research; Gas kinetics; Nitrogen; Physiology; Pressure
Abstract
(Plogmark O, Silvanius M, Olsson M, Hjelte C, Ekström M, Frånberg O. Measuring whole body inert gas wash-out. Diving and Hyperbaric Medicine. 2023 December 20;53(4):321−326. doi: 10.28920/dhm53.4.321-326. PMID: 38091591. PMCID: PMC10944667.)
Introduction: Quantifying inert gas wash-out is crucial to understanding the pathophysiology of decompression sickness. In this study, we developed a portable closed-circuit device for measuring inert gas wash-out and validated its precision and accuracy both with and without human subjects.
Methods: We developed an exhalate monitor with sensors for volume, temperature, water vapor and oxygen. Inert gas volume was extrapolated from these inputs using the ideal gas law. The device’s ability to detect volume differences while connected to a breathing machine was analysed by injecting a given gas volume eight times. One hundred and seventy-two coupled before-and-after measurements were then compared with a paired t-test. Drift in measured inert gas volume during unlabored breathing was evaluated in three subjects at rest using multilevel linear regression. A quasi-experimental crossover study with the same subjects was conducted to evaluate the device’s ability to detect inert gas changes in relation to diving interventions and simulate power.
Results: The difference between the injected volume (1,996 ml) and the device’s measured volume (1,986 ml) was -10 ml. The 95% confidence interval (CI) for the measured volume was 1,969 to 2,003 ml. Mean drift during a 43 min period of unlaboured breathing was -19 ml, (95% CI, -37 to -1). Our power simulation, based on a cross-over study design, determined a sample size of two subjects to detect a true mean difference of total inert gas wash-out volume of 100 ml.
Conclusions: We present a portable device with acceptable precision and accuracy to measure inert gas wash-out differences that may be physiologically relevant in the pathophysiology of decompression sickness.
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
Diving Hyperb Med. 2023 December 20;53(4):327−332. doi: 10.28920/dhm53.4.327-332. PMID: 38091592. PMCID: PMC10735710.
Comparing the EMMA capnograph with sidestream capnography and arterial carbon dioxide pressure at 284 kPa
Xavier CE Vrijdag1, Hanna van Waart1, Chris Sames2, Jamie W Sleigh1,3, Simon J Mitchell1,2,4
1 Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
2 Slark Hyperbaric Unit, Waitemata District Health Board, Auckland, New Zealand
3 Department of Anaesthesia, Waikato Hospital, Hamilton, New Zealand
4 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
Keywords
Capnography; Hyperbaric chamber; Intensive care; Patient monitoring
Abstract
(Vrijdag XCE, van Waart H, Sames C, Sleigh JW, Mitchell SJ. Comparing the EMMA capnograph with sidestream capnography and arterial carbon dioxide pressure at 284 kPa. Diving and Hyperbaric Medicine. 2023 December 20;53(4):327−332. doi: 10.28920/dhm53.4.327-332. PMID: 38091592. PMCID: PMC10735710.)
Introduction: Capnography aids assessment of the adequacy of mechanical patient ventilation. Physical and physiological changes in hyperbaric environments create ventilation challenges which make end-tidal carbon dioxide (ETCO2) measurement particularly important. However, obtaining accurate capnography in hyperbaric environments is widely considered difficult. This study investigated the EMMA capnograph for hyperbaric use.
Methods: We compared the EMMA capnograph to sidestream capnography and the gold standard arterial carbon dioxide blood gas analysis in a hyperbaric chamber. In 12 resting subjects breathing air at 284 kPa, we recorded ETCO2 readings simultaneously derived from the EMMA and sidestream capnographs during two series of five breaths (total 24 measurements). An arterial blood gas sample was also taken simultaneously in five participants.
Results: Across all measurements there was a difference of about 0.1 kPa between the EMMA and sidestream capnographs indicating a very slight over-estimation of ETCO2 by the EMMA capnograph, but fundamentally good agreement between the two end-tidal measurement methods. Compared to arterial blood gas pressure the non-significant difference was about 0.3 and 0.4 kPa for the EMMA and sidestream capnographs respectively.
Conclusions: In this study, the EMMA capnograph performed equally to the sidestream capnograph when compared directly, and both capnography measures gave clinically acceptable estimates of arterial PCO2.
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
Full article available here.
Diving Hyperb Med. 2023 December 20;53(4):333−339. doi: 10.28920/dhm53.4.333-339. PMID: 38091593. PMCID: PMC10944664.
Within-diver variability in venous gas emboli (VGE) following repeated dives
David J Doolette1,2, F Gregory Murphy1
1 Navy Experimental Diving Unit, Panama City, Florida, USA
2 Department of Anaesthesiology, University of Auckland, New Zealand
Corresponding author: Associate Professor David J Doolette, Navy Experimental Diving Unit, Panama City, Florida, USA
ORCiD: 0000-0001-9027-3536
Keywords
Bubbles; Decompression sickness; Diving; Echocardiography; Risk
Abstract
(Doolette DJ, Murphy FG. Within-diver variability in venous gas emboli (VGE) following repeated dives. Diving and Hyperbaric Medicine. 2023 December 20;53(4):333−339. doi: 10.28920/dhm53.4.333-339. PMID: 38091593. PMCID: PMC10944664.)
Introduction: Venous gas emboli (VGE) are widely used as a surrogate endpoint instead of decompression sickness (DCS) in studies of decompression procedures. Peak post-dive VGE grades vary widely following repeated identical dives but little is known about how much of the variability in VGE grades is proportioned between-diver and within-diver.
Methods: A retrospective analysis of 834 man-dives on six dive profiles with post-dive VGE measurements were conducted under controlled laboratory conditions. Among these data, 151 divers did repeated dives on the same profile on two to nine occasions separated by at least one week (total of 693 man-dives). Data were analysed for between- and within-diver variability in peak post-dive VGE grades using mixed-effect models with diver as the random variable and associated intraclass correlation coefficients.
Results: Most divers produced a wide range of VGE grades after repeated dives on the same profile. The intraclass correlation coefficient (repeatability) was 0.33 indicating that 33% of the variability in VGE grades is between-diver variability; correspondingly, 67% of variability in VGE grades is within-diver variability. DCS cases were associated with an individual diver’s highest VGE grades and not with their lower VGE grades.
Conclusions: These data demonstrate large within-diver variability in VGE grades following repeated dives on the same dive profile and suggest there is substantial within-diver variability in susceptibility to DCS. Post-dive VGE grades are not useful for evaluating decompression practice for individual 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 electronic and other forms.
Publication Type: Original article
Diving Hyperb Med. 2023 December 20;53(4):340−344. doi: 10.28920/dhm53.4.340-344. PMID: 38091594. PMCID: PMC10944665.
Pulmonary oxygen toxicity breath markers after heliox diving to 81 metres
Feiko JM de Jong1,2, Paul Brinkman3, Thijs T Wingelaar1,2, Pieter-Jan AM van Ooij1,3, Robert A van Hulst2
1 Royal Netherlands Navy Diving and Submarine Medical Centre, 1780 CA, Den Helder, The Netherlands
2 Department of Anesthesiology, Amsterdam University Medical Center, location AMC, 1100 DD, Amsterdam, The Netherlands
3 Department of Pulmonology, Amsterdam University Medical Center, location AMC, 1100 DD, Amsterdam, The Netherlands
Corresponding author: Feiko JM de Jong, Royal Netherlands Navy Diving and Submarine Medical Centre, Rijkszee-en, Marinehaven, Postbus 10.000, 1780 CA, Den Helder, The Netherlands
ORCiD: 0009-0008-9804-8307
Keywords
Diving research; Helium; Military diving; Unit pulmonary toxic dose; Volatile organic compounds
Abstract
(de Jong FJM, Brinkman P, Wingelaar TT, van Ooij PJAM, van Hulst RA. Pulmonary oxygen toxicity breath markers after heliox diving to 81 metres. Diving and Hyperbaric Medicine. 2023 December 20;53(4):340−344. doi: 10.28920/dhm53.4.340-344. PMID: 38091594. PMCID: PMC10944665.)
Pulmonary oxygen toxicity (POT), an adverse reaction to an elevated partial pressure of oxygen in the lungs, can develop as a result of prolonged hyperbaric hyperoxic conditions. Initially starting with tracheal discomfort, it results in pulmonary symptoms and ultimately lung fibrosis. Previous studies identified several volatile organic compounds (VOCs) in exhaled breath indicative of POT after various wet and dry hyperbaric hypoxic exposures, predominantly in laboratory settings. This study examined VOCs after exposures to 81 metres of seawater by three navy divers during operational heliox diving. Univariate testing did not yield significant results. However, targeted multivariate analysis of POT-associated VOCs identified significant (P = 0.004) changes of dodecane, tetradecane, octane, methylcyclohexane, and butyl acetate during the 4 h post-dive sampling period. No airway symptoms or discomfort were reported. This study demonstrates that breath sampling can be performed in the field, and VOCs indicative of oxygen toxicity are exhaled without clinical symptoms of POT, strengthening the belief that POT develops on a subclinical-to-symptomatic spectrum. However, this study was performed during an actual diving operation and therefore various confounders were introduced, which were excluded in previous laboratory studies. Future studies could focus on optimising sampling protocols for field use to ensure uniformity and reproducibility, and on establishing dose-response relationships.
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
Diving Hyperb Med. 2023 December 20;53(4):345−350. doi: 10.28920/dhm53.4.345-350. PMID: 38091595. PMCID: PMC10944668.
Cerebral arterial gas embolism (CAGE) during open water scuba certification training whilst practising a controlled emergency swimming ascent
Neil Banham1, Elisabete da Silva1, John Lippmann2
1 Department of Hyperbaric Medicine, Fiona Stanley Hospital, Murdoch, Australia
2 Australasian Diving Safety Foundation, Melbourne, Australia
Corresponding author: Dr Neil Banham, Department of Hyperbaric Medicine, Fiona Stanley Hospital, 11 Warren Drive,
Murdoch WA 6150, Australia
Keywords
Case reports; CESA; Diving accidents; Emergency ascent; Pneumomediastinum; Pneumothorax; Pulmonary barotrauma
Abstract
(Banham N, da Silva E, Lippmann J. Cerebral arterial gas embolism (CAGE) during open water scuba certification training whilst practising a controlled emergency swimming ascent. Diving and Hyperbaric Medicine. 2023 December 20;53(4):345−350. doi: 10.28920/dhm53.4.345-350. PMID: 38091595. PMCID: PMC10944668.)
We report the case of a 23-year-old male novice diver who sustained cerebral arterial gas embolism (CAGE) during his open water certification training whilst practising a free ascent as part of the course. He developed immediate but transient neurological symptoms that had resolved on arrival to hospital. Radiological imaging of his chest showed small bilateral pneumothoraces, pneumopericardium and pneumomediastinum. In view of this he was treated with high flow normobaric oxygen rather than recompression, because of the risk of development of tension pneumothorax upon chamber decompression. There was no relapse of his neurological symptoms with this regimen. The utility and safety of free ascent training for recreational divers is discussed, as is whether a pneumothorax should be vented prior to recompression, as well as return to diving following pulmonary 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: Case report
Diving Hyperb Med. 2023 December 20;53(4):351−355. doi: 10.28920/dhm53.4.351-355. PMID: 38091596. PMCID: PMC10944663.
Hyperbaric oxygen treatment in delayed post-hypoxic encephalopathy following inhalation of liquefied petroleum gas: a case report
Kubra Canarslan Demir1, Burak Turgut1, Kubra Ozgok Kangal1, Taylan Zaman1, Kemal Şimşek1
1 Underwater and Hyperbaric Medicine, University of Health Sciences, Gulhane Training and Research Hospital, Ankara, Turkey
Corresponding author: Dr Kübra Canarslan Demir, SBÜ-Gülhane Eğitim ve Araştırma Hastanesi, Sualtı Hekimliği ve Hiperbarik Tıp Kliniği, Etlik/Ankara, Turkey
ORCiD: 0000-0001-6911-2375
Keywords
Brain; Dementia; Hyperbaric medicine; Neurology; Toxicity
Abstract
(Canarslan Demir K, Turgut B, Ozgok Kangal K, Zaman T, Şimşek K. Hyperbaric oxygen treatment in delayed posthypoxic encephalopathy following inhalation of liquefied petroleum gas: a case report. Diving and Hyperbaric Medicine. 2023 December 20;53(4):351−355. doi: 10.28920/dhm53.4.351-355. PMID: 38091596. PMCID: PMC10944663.)
Delayed post-hypoxic encephalopathy can occur after an episode of anoxia or hypoxia. Symptoms include apathy, confusion, and neurological deficits. We describe a 47-year-old male patient who inhaled gas from a kitchen stove liquid petroleum gas cylinder. He was diagnosed with hypoxic ischaemic encephalopathy 12 hours after his emergency department admission. He received six sessions of hyperbaric oxygen treatment (HBOT) and was discharged in a healthy state after six days. Fifteen days later, he experienced weakness, loss of appetite, forgetfulness, depression, balance problems, and inability to perform self-care. One week later, he developed urinary and fecal incontinence and was diagnosed with post-hypoxic encephalopathy. After 45 days from the onset of symptoms, he was referred to the Underwater and Hyperbaric Medicine Department for HBOT. The patient exhibited poor self-care and slow speech rate, as well as ataxic gait and dysdiadochokinesia. Hyperbaric oxygen was administered for twenty-four sessions, which significantly improved the patient’s neurological status with only hypoesthesia in the left hand remaining at the end of treatment. Hyperbaric oxygen has been reported as successful in treating some cases of delayed neurological sequelae following CO intoxication. It is possible that HBO therapy may also
be effective in delayed post-hypoxic encephalopathy from other causes. This may be achieved through mechanisms such as transfer of functional mitochondria to the injury site, remyelination of damaged neurons, angiogenesis and neurogenesis, production of anti-inflammatory cytokines, and balancing of inflammatory and anti-inflammatory cytokines.
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
Diving Hyperb Med. 2023 December 20;53(4):356−359. doi: 10.28920/dhm53.4.356-359. PMID: 38091597. PMCID: PMC10944661.
Hypoxic loss of consciousness in air diving: two cases of mixtures made hypoxic by oxidation of the scuba diving cylinder
Arnaud Druelle1, Lucille Daubresse1, Jean U Mullot2, Hélène Streit3, Pierre Louge4
1 Department of Hyperbaric Medicine, Military Teaching Hospital, Sainte-Anne, Toulon, France
2 Navy Laboratory for Analysis Surveillance and Expertise, 83000 Toulon, France
3 Medical Center of ATRIA, 90 000 BELFORT, France
4 Acute Medicine Department, Hyperbaric Medicine Unit, Geneva University Hospitals, rue Gabrielle-Perret-Gentil 4, 1205 Geneva, Switzerland
Corresponding author: Dr Arnaud Druelle, Department of Hyperbaric Medicine, Military Teaching Hospital, HIA Ste Anne, 2 boulevard Ste Anne, BP 600, 83800 Toulon CEDEX, France
Keywords
Case reports; Corrosion; Diving tank; Hypoxia; Oxygen consumption; Rust; Unconsciousness
Abstract
(Druelle A, Daubresse L, Mullot JU, Streit H, Louge P. Hypoxic loss of consciousness in air diving: two cases of mixtures made hypoxic by oxidation of the scuba diving cylinder. Diving and Hyperbaric Medicine. 2023 December 20;53(4):356−359. doi: 10.28920/dhm53.4.356-359. PMID: 38091597. PMCID: PMC10944661.)
Without an adequate supply of oxygen from the scuba apparatus, humans would not be able to dive. The air normally contained in a scuba tank is dry and free of toxic gases. The presence of liquid in the tank can cause corrosion and change the composition of the gas mixture. Various chemical reactions consume oxygen, making the mixture hypoxic. We report two cases of internal corrosion of a scuba cylinder rendering the respired gas profoundly hypoxic and causing immediate hypoxic loss of consciousness in 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 electronic and other forms.
Publication Type: Case report
Diving Hyperb Med. 2023 December 20;53(4):360. doi: 10.2980/dhm53.4.360. PMID: 38091598. PMCID: PMC10944660.
University of Auckland Postgraduate Diploma in Diving and Hyperbaric Medicine
Michael Davis
Corresponding address: PO Box 35, Tai Tapu 7645, New Zealand
Keywords
Diving medicine; Hyperbaric medicine; Education; Qualifications
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