Cerebral arterial gas embolism (CAGE) during open water scuba certification training whilst practising a controlled emergency swimming ascent.

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.

Snorkelling and breath-hold diving fatalities in Australian waters, 2014 to 2018.

Introduction: This study investigated snorkelling and breath-hold diving deaths in Australia from 2014-2018 and compared these to those from 2001-2013 to identify ongoing problems and assess the effectiveness of countermeasures. Methods: Media reports and the National Coronial Information System were searched to identify snorkelling/breath-hold diving deaths for 2014-2018, inclusive. Data were extracted from witness and police reports, medical histories, and autopsies. An Excel® database was created and a chain of events analysis conducted. Comparisons were made with the earlier report. Results: Ninety-one fatalities (78 males, 13 females, median age 48 years [range 16-80]) were identified with one third likely doing some breath-hold diving. Fifty-two of 77 with known body mass index were overweight or obese. Approximately two thirds were inexperienced snorkellers and 64 were alone. Fifty-one were tourists. Planning shortcomings, such as solo diving and diving in adverse conditions, as well as pre-existing health conditions and inexperience predisposed to many incidents. Primary drowning was the likely disabling condition in 39% of cases with drowning recorded as the cause of death (COD) in two thirds. Cardiac events were the likely disabling conditions in 31% although recorded as the COD in 21% of cases. Conclusions: Increasing age, obesity and associated cardiac disease have become increasingly prevalent in snorkelling deaths and there is a need for improved health surveillance and risk management. Closer supervision of inexperienced snorkellers is indicated. Apnoeic hypoxia from extended breath-holding and poor supervision remain a problem. The increased risk of harvesting seafood in areas frequented by large marine predators needs to be appreciated and managed appropriately.

Compressed gas diving fatalities in Australian waters 2014 to 2018.

INTRODUCTION: This study aimed to investigate compressed gas diving deaths in Australia from 2014-2018 and make comparison to those from 2001-2013 to identify ongoing problems and assess countermeasures. METHODS: Media reports and the National Coronial Information System were searched to identify scuba diving deaths for 2014-2018, inclusive. Data were extracted from the witness and police reports, medical histories, and autopsies. An Excel® database was created and a chain of events analysis conducted. Comparisons were made with the earlier report. RESULTS: Forty-two fatalities were identified, 38 using scuba and four using surface-supplied breathing apparatus involving 30 males and 12 females. The mean age of victims was 49.7 years, six years higher than the previous cohort. Fifty-four percent were obese. Six victims were unqualified, three were under instruction and at least 28 were experienced divers, significantly more than in the previous cohort. Health-related predisposing factors, predominantly obesity and cardiac-related, were identified as likely contributory to 26 incidents, and planning shortcomings to at least 22 deaths. One-third of the disabling conditions were primary drowning and one-quarter were cardiac. Three divers died subsequent to carbon monoxide poisoning and three likely from immersion pulmonary oedema. CONCLUSIONS: Advancing age, obesity and the associated cardiac disease have become increasingly prevalent in diving fatalities and the need for appropriate assessment of fitness to dive is evident.

Determining best practice for technical assessment of hookah surface supply diving equipment during diving fatality investigation.

INTRODUCTION: This study aimed to develop a standard process and checklist for technical investigation of hookah diving equipment and apply it to Tasmanian hookah fatality investigations from the last 25 years. METHODS: A literature search was undertaken to identify technical reports and equipment investigations associated with diving accidents. The information was assimilated to create a process and checklist for specifically assessing the hookah apparatus. The checklist was then applied in a gap analysis of Tasmanian hookah diving fatality technical reports from 1995 to 2019. RESULTS: As no papers specifically describing technical evaluation of hookah equipment were identified, references evaluating scuba equipment were used to create a hookah technical assessment process incorporating unique features of the hookah. Features included: owner responsibility for air quality; maintenance, function; exhaust proximity to air intake; reservoir volume; output non-return valves; line pressure; sufficiency of supply; entanglement; hose severance risk; gas supply failure and hosing attachment to the diver. Seven hookah diving deaths occurred in Tasmania (1995-2019) of which three had documented technical assessment. Gap analysis identified inconsistent structure between reports with variability in the case descriptors. Missing technical data included: overview of the hookah systems; accessories; weights; how the apparatus was worn by the diver; compressor suitability; assessment of hookah function; breathing gas output and exhaust position relative to air intake. CONCLUSIONS: The study demonstrated a need to standardise technical reporting of hookah equipment after diving accidents. The checklist generated may serve as a resource for future hookah assessments and inform strategies for preventing future hookah accidents.

Severe carbon monoxide poisonings in scuba divers: Asia-Pacific cases and causation.

Aim: Reports of fatal incidents in recreational scuba divers from carbon monoxide (CO) poisoning are rare. This study aimed to identify scuba fatalities in the Asia-Pacific region caused by breathing-gas contamination to better understand the likely sources of contamination and reduce such preventable deaths. Methods: A hand search of Project Stickybeak reports, subsequent Australian fatality series reports, and of published New Zealand diving fatality reports and associated data was conducted, as well as key word searches of the National Coronial Information System for scuba fatalities in Australia and New Zealand. Cases identified were matched with the Australasian Diving Safety Foundation diving fatality database. Available reports were examined. Results: Four scuba deaths resulting from CO poisoning were identified from 645 scuba fatalities, including one report from each of Australia, New Zealand, Singapore, and the Maldives. A near-fatal incident was also identified in Indonesia. Two of the fatal incidents and the near-fatal incident involved internal combustion engine exhaust gases from the compressor system or elsewhere entering the air intake. Two deaths likely resulted from combustion within compressor systems. Conclusions: Scuba fatalities from CO poisoning are uncommon, albeit likely under-reported. Sources of CO include exhaust gases entering the compressor and CO production by pyrolysis or gasification within the compressor or its filter system. Preventive measures include proper installation (including positioning of the air intake relative to combustion exhaust), appropriate maintenance, fitting of pressure-maintaining valves and avoidance of overheating. Formal training of compressor operators, improved diver education, mandatory requirements for installation compliance assessments, safety inspections, and the use of carbon monoxide alarms are recommended.

A review of snorkelling and scuba diving fatalities in Queensland, Australia, 2000 to 2019.

INTRODUCTION: This study examined all known diving-related fatalities in Queensland, Australia, from 2000 to 2019 to determine likely causes and potential countermeasures. METHODS: Data were extracted from the Australasian Diving Safety Foundation fatality database, including previously published reports. The National Coronial Information System was searched to identify diving-related deaths in Queensland for 2014-2019 and data were extracted, analysed, and combined with previously published data covering the period 2000-2013. Descriptive statistics and parametric and non-parametric tests were used to analyse these data. RESULTS: There were 166 snorkelling and 41 scuba victims identified with median ages of 59 and 49 years respectively, and 83% of snorkel and 64% of scuba victims were males. One quarter of snorkel and 40% of scuba victims were obese. Two-thirds of the snorkellers and three quarters of scuba divers were overseas tourists. Contributory predisposing health conditions were identified in 61% of snorkel and 50% of scuba victims. Nine scuba victims died on their first dive. CONCLUSIONS: The increase in snorkelling deaths likely reflects increased participation, higher age, and poorer health. The main disabling condition in both cohorts was cardiac-related. Pre-existing health conditions, poor skills, inexperience, poor planning, supervision shortcomings and lack of effective buddy systems featured in both cohorts, and apnoeic hypoxia in breath-hold divers. Suggested countermeasures include improved education on the importance of health and fitness for safe diving and snorkelling, increased emphasis on an honest and accurate pre-activity health declaration and subsequent implementation of appropriate risk mitigation strategies, improved supervision, better buddy pairing, and on-going education on the hazards of extended apnoea.

Scuba diving-related fatalities in New Zealand, 2007 to 2016.

INTRODUCTION: New Zealand (NZ) diving-related fatalities have been reported since the 1960s. The aim is to identify contributing risk factors, including medical, and to inform appropriate preventative strategies. METHODS: NZ scuba diving fatalities from 2007 to 2016 were searched from multiple sources - the National Coronial Information System (NCIS); the NZ Chief Coroner's office; Water Safety NZ Drownbase™ and the NZ Police National Dive Squad records. For inclusion, a victim must have been wearing a scuba set (which may include a rebreather). A key word search of the NCIS was made and the results matched to the other databases. An Excel® database was created and a chain of events analysis (CEA) conducted. RESULTS: Forty-eight scuba diving fatalities were identified, 40 men and eight women, average age 47 years (range 17-68), 20 of Maori ethnicity. Thirty-five were classified as overweight (14) or obese (21). Pre-existing medical risk factors were identified, either pre dive or at autopsy, in 37 divers, the commonest being ischaemic heart disease (IHD, 20), left ventricular hypertrophy (LVH, 18) and hypertension (seven). IHD, LVH and obesity were variously associated with each other. The likely commonest disabling conditions, identified in 32 cases, were asphyxia (15), cardiac (nine) and pulmonary barotrauma/cerebral arterial gas embolism (five). Multiple environmental and diving practice breaches and poor planning were identified in the CEA, similar to those seen in other studies. Thirty-eight divers had not released their weight belt. Information on resuscitation was limited. CONCLUSIONS: Obesity and cardiovascular disease were common and Maori appear to be over-represented, both as previously reported.

Regular medication use by active scuba divers with a declared comorbid medical condition and victims of scuba and snorkelling-related fatalities.

INTRODUCTION: The aim of this study was to describe the nature of regular medications taken by active comorbid scuba divers (having a declared medical comorbidity) and scuba divers and snorkellers who died following a diving incident. METHODS: We undertook a retrospective, observational study from July to October, 2020. Data on 268 active comorbid divers were obtained through a 2013 survey of Divers Alert Network Asia-Pacific members. Data on 126 deceased scuba divers and 175 deceased snorkellers were obtained predominantly from 2001-2013 reports to Australian State Coronial Services. RESULTS: The active comorbid divers were significantly older, less likely to be male, and more likely to be taking one or more medications than the two deceased subject groups (P < 0.001). Cardiovascular, endocrine and psychotropic medications accounted for 53.4%, 9.9% and 6.4% of all medications taken, respectively. Almost one tenth of the deceased divers took at least one psychotropic medication, a proportion significantly greater than the other groups (P = 0.01). CONCLUSIONS: Medication use among active comorbid divers is common which likely reflects their declared medical condition. Nevertheless, they appear to be diving relatively safely, often with conditions once thought to be absolute contradictions to scuba diving. The deceased divers took significantly more psychotropic medications. It is possible that their underlying psychological/psychiatric conditions rendered them more at risk of a diving incident. Increased vigilance for psychological conditions may need to be considered during diving medical examinations.

An underappreciated cause of ocean-related fatalities: A systematic review on the epidemiology, risk factors, and treatment of snorkelling-related drowning.

AIM: Snorkelling is a popular aquatic activity which may result in fatal and non-fatal drowning. However, little is known about the scale of injury, factors impacting risk and strategies for prevention. This review assesses the current literature on snorkelling-related drowning with the aim of assessing available data, improving safety recommendations and reducing the global mortality burden. METHODS: A systematic review of peer-reviewed literature in English, Spanish and Portuguese language published between 1 January 1980 and 31 October 2020 was conducted using the PRISMA guidelines. CINAHL Complete, Embase, Medline (Ovid), PubMed, SafetyLit, SportDiscus and grey literature were searched to identify studies reporting the incidence of fatal and non-fatal snorkelling-related drowning, or associated risk factors, prevention strategies, treatments or casualty characteristics. Quality was assessed using the NIH Quality Assessment Tool. RESULTS: Forty-three studies were included (26 reporting population data, 17 case series), of which 27 (62.8%) studies reported data from Australia. Incidence was reported as about 8% of total ocean-related drownings. Case series documented 144 fatalities over 17 years. Frequent casualty characteristics include male (82.6%), pre-existing heart disease (59.4%), tourists (73%) who were inexperienced (71.0%), and lack of a buddy system (89.6%). Two at-risk profiles identified were older adult tourists with pre-existing medical conditions and local, experienced spearfishers. Twenty-two expert recommendations were developed to improve the safety of snorkellers related to individuals, tourism companies, government agencies and diving organisations. CONCLUSION: Snorkelling-related drownings are not infrequent, and there are many opportunities to improve the safety of this activity based on available data.

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

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

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

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

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

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

Scuba diving fatalities in Australia 2001 to 2013: Chain of events.

INTRODUCTION: We aimed to identify the possible chain of events leading to fatal scuba diving incidents in Australia from 2001-2013 to inform appropriate countermeasures. METHODS: The National Coronial Information System was searched to identify scuba diving-related deaths from 2001-2013, inclusive. Coronial findings, witness and police reports, medical histories and autopsies, toxicology and equipment reports were scrutinised. These were analysed for predisposing factors, triggers, disabling agents, disabling injuries and causes of death using a validated template. RESULTS: There were 126 known scuba diving fatalities and 189 predisposing factors were identified, the major being health conditions (59; 47%), organisational/training/experience/skills issues (46; 37%), planning shortcomings (29; 23%) and equipment inadequacies (24; 19%). The 138 suspected triggers included environmental (68; 54%), exertion (23; 18%) and gas supply problems (15; 12%) among others. The 121 identified disabling agents included medical-related (48; 38%), ascent-related (21; 17%), poor buoyancy control (18; 14%), gas supply (17; 13%), environmental (13; 10%) and equipment (4; 3%). The main disabling injuries were asphyxia (37%), cardiac (25%) and cerebral arterial gas embolism/pulmonary barotrauma (15%). CONCLUSIONS: Chronic medical conditions, predominantly cardiac-related, are a major contributor to diving incidents. Divers with such conditions and/or older divers should undergo thorough fitness-to-dive assessments. Appropriate local knowledge, planning and monitoring are important to minimise the potential for incidents triggered by adverse environmental conditions, most of which involve inexperienced divers. Chain of events analysis should increase understanding of diving incidents and has the potential to reduce morbidity and mortality in divers.

Medical conditions in scuba diving fatality victims in Australia, 2001 to 2013.

INTRODUCTION: This study identified pre-existing medical conditions among scuba diving fatalities in Australia from 2001 to 2013, inclusive, and assessed whether these conditions likely contributed to the deaths. METHODS: The National Coronial Information System (NCIS) was searched for scuba diving-related cases during 2001-2013, inclusive. Coronial findings, witness and police reports, medical histories, and autopsy and toxicology reports were scrutinised for pre-existing medical conditions and autopsy findings. Predisposing factors, triggers, disabling agents, disabling injuries and causes of death were analysed using a validated template. RESULTS: There were 126 scuba diving-related fatalities identified during the study period. Forty-six (37%) divers were identified as having a significant medical condition which may have contributed to their incident. The most common condition was ischaemic heart disease (IHD) which had been diagnosed in 15 of the divers. Thirty-two (25%) deaths were attributed to cardiac disabling injuries (DI) such as ischaemic heart disease and arrhythmias, although a cardiac DI was thought likely in another six. Respiratory conditions were implicated in eight (6%) deaths, at least four associated with cerebral arterial gas embolism. At least 14 (11%) divers who had contributory pre-existing medical conditions had been cleared to dive by a medical practitioner within the year prior. CONCLUSIONS: Chronic health-related factors played a major role in almost half of these deaths; primarily cardiac conditions such as IHD and cardiac arrhythmias. Although fitness-to-dive (FTD) assessments have limitations, the high incidence of cardiac-related deaths indicates a need for 'older' divers to be medically assessed for FTD.

Scuba diving fatalities in Australia, 2001 to 2013: Diver demographics and characteristics.

INTRODUCTION: This study identified characteristics of victims of fatal scuba diving incidents to determine contributing factors and inform appropriate countermeasures. METHODS: The National Coronial Information System (NCIS) was searched to identify scuba diving deaths for 2001-2013, inclusive. Data were extracted from witness and police reports, medical histories and autopsies. Descriptive statistics were used to analyse these data. RESULTS: There were 126 scuba diving-related fatalities identified during the study period. The mean age was 44 years, 99 (79%) victims were male and 83 (77%) were either overweight or obese. Most deaths occurred in New South Wales and Queensland, often in a commercial setting. Twenty-three (79%) Queensland victims were overseas tourists. At least 52 (41%) were novices and 17 (13%) died during training or an introductory scuba experience. Only 35 (28%) were with a buddy when the incident occurred and at least 81 (64%) were still wearing weights when recovered. CONCLUSIONS: The age of these victims may reflect an older cohort of participants and the associated higher prevalence of chronic medical conditions. The high prevalence of obesity suggests that this may be a risk factor. The high proportion of deaths in overseas tourists highlights an on-going need for appropriate screening and monitoring in what may be a higher risk cohort. The number of deaths that occurred under instruction highlights the importance of careful assessment of the site, prevailing conditions, an appropriate instructor-student ratio and close supervision.

Rescue and resuscitation factors in scuba diving and snorkeling fatalities in Australia, 2001-2013.

Aim: The aim of this study was to examine first aid measures applied in a large series of Australian dive-related fatalities to better determine where improvements can be made. Methods: The National Coronial Information System was searched to identify scuba diving and snorkeling-related cases reported to various Australian Coroners for the years 2001-2013 inclusive. Coronial documents examined included witness statements, police reports and ambulance and medical reports where available. Information relating to the recovery, rescue and/or resuscitation of the victims was extracted, compiled and analyzed. Results: 126 scuba diving and 175 snorkeling-related fatalities were identified during the study period, with airway management complications reported in one-third. Cardiopulmonary resuscitation was performed in three-quarters of the incidents. An automated external defibrillator was attached to 40 victims as a first aid measure, and shocks were indicated and delivered in five cases. Although three-quarters of the reports included no information about whether supplemental oxygen was provided, it was confirmed in 19% of both the scuba diving and snorkeling incidents. Conclusion: There were often considerable delays in the recognition, rescue and/or recovery of an unconscious snorkeler or diver and, consequently, the time to commencement of basic life support. Such delays can affect chances of survival and need to be minimized. Delivery of supplemental oxygen during resuscitation appears to be relatively infrequent and sometimes suboptimal; improvement appears necessary. Some measures that would have improved availability and/or better use in these cases include the selection of appropriate equipment compatible with likely circumstances and operator skills; improved training and ongoing skills practice; and regular checking and maintenance of equipment. Improved data collection and recording by official on-site investigators, preferably with knowledge of diving, would better inform potential or necessary improvements.

Fatal air embolism in a breath-hold diver.

Cerebral arterial gas embolism (CAGE) from breath-holding or inadequate exhalation during ascent is a well-recognised complication of scuba diving. It does not usually occur with breath-hold (BH) diving in those with normal lungs, as the volume of gas in the lungs on surfacing cannot exceed what it was on leaving the surface. However, a BH diver who breathes from a compressed gas supply at depth essentially becomes a scuba diver and is at risk of pulmonary barotrauma (PBt) and CAGE on ascent. In this case, a 26-year-old male experienced BH diver breathed from a scuba set at approximately 10 metres' sea water depth and ascended, sustaining massive PBt and CAGE with a fatal outcome. BH and scuba divers, especially those with less experience, need to be well-informed about this potential risk.

Immersion pulmonary edema: case reports from Oceania.

INTRODUCTION: We aimed to document identified cases of immersion pulmonary edema (IPE) in divers from Oceania (the Indo-Pacific region) from January 2002 to May 2018, inclusive. METHOD: Cases were identified using various sources, including searches of the Divers Alert Network Asia-Pacific (DAN AP) Fatality Database, published case reports, and interviews with survivors who had reported their incident to DAN AP. Where available, investigations, pathology and autopsy results were obtained. Only incidents diagnosed as IPE by diving physicians or pathologists with experience in the investigation of diving accidents were included. Individual case histories and outcomes, together with brief individual summaries of the associations and possible contributing factors were recorded. RESULTS: Thirty-one IPE incidents in divers from Oceania were documented. There were two surface snorkelers, 22 scuba air divers and seven nitrox divers which included three closed-circuit rebreathers (CCR). The mean (SD) age was 53 (12) years, 58% of victims were females, and the average dive profile was to a maximum depth of 19 meters of seawater for 25 minutes. Six victims (19%) had previous episodes of IPE. There were nine recorded fatalities. Cardiac anomalies dominated the associated or possible contributing factors. These included valvular disease in 29%, transient cardiomyopathies in 26% and dysrhythmias in 16%. CONCLUSIONS: Previously reported associations of IPE such as exertion, stress, cold exposure, negative inspiratory pressure, hypertension, overhydration, ascent or surfacing, tight wetsuit, aspiration and certain medications were identified. Cardiac conditions were frequent and included chronic disorders (valvular pathology, coronary artery disease) and transient disorders (dysrhythmias, transient myocardial dysfunction, takotsubo or stress cardiomyopathy). It is likely that the chronic cardiac disorders may have contributed to the IPE, whereas the transient cases could be either sequelae, contributors or coincidental to the IPE.

Immersion pulmonary edema: an analysis of 31 cases from Oceania.

AIM: To review incidents of immersion pulmonary edema (IPE) from Oceania, to determine the demographics, diving parameters, and comorbidities that may be related to this disorder. METHOD: Incidents of IPE, most of which were documented by Divers Alert Network Asia-Pacific (DAN AP) or reported in our medical literature, were analyzed. They included interviews with the survivors and a review of available medical records. Only incidents diagnosed as IPE by specialist diving physicians or pathologists with experience in the investigation of diving accidents were included. RESULTS: Thirty-one IPE incidents in divers from Oceania were documented. There were two surface snorkelers, 22 scuba air divers and seven nitrox divers, which included three closed-circuit rebreathers (CCR). The mean (SD) age was 53 (12) years, 58% of victims were females, and the average dive profile was to a maximum depth of 19 msw for 25 minutes. Six victims (19%) had previous episodes of IPE. There were nine recorded fatalities in this cohort. Medical comorbidities were recorded in 68%, with 42% being cardiac. The latter included valvular disease in 29%, transient cardiomyopathies in 26% and dysrhythmias in 16%. CONCLUSION: IPE was more likely in middle-aged females, in experienced divers, and during ascent or after surfacing. Commonly reported associations such as exertion, stress, cold exposure, negative inspiratory pressure, hypertension, overhydration, tight wetsuit, aspiration and certain medications were identified. This series supports the hypothesis that the elderly IPE subjects are likely to have comorbidities and be susceptible to IPE recurrences and fatalities unless the contributing factors can be identified and addressed.

Snorkelling and breath-hold diving fatalities in Australia, 2001 to 2013. Demographics, characteristics and chain of events.

INTRODUCTION: The aim of this study was to identify characteristics of victims of fatal snorkelling and breath-hold diving accidents in Australia from 2001-2013, inclusive, to determine underlying factors and risks associated with such activities and inform appropriate countermeasures. METHODS: The National Coronial Information System (NCIS) was searched to identify snorkelling and breath-hold diving-related cases reported to Australian coroners for the years 2001-2013, inclusive. Coronial data in the form of findings, witness and police reports, medical histories and autopsies were collected and collated, and descriptive statistics were used to analyse these data. A chain of events analysis was used to determine the likely sequence of events. RESULTS: There were 175 identified snorkelling-related fatalities during the study period. Most victims were middle-aged males (mean age 49 years). Pre-existing health conditions were possible contributors to 41% of the deaths, the main being ischaemic heart disease. The majority of deaths occurred in Queensland in inexperienced snorkellers, often in commercial settings. The victim's plight often went unnoticed as they were alone, or poorly supervised, when the incident occurred. Apnoeic hypoxia appeared to have been associated with at least 12.5% of the deaths. The main disabling injuries were asphyxia (40%) and cardiac incidents (35%). CONCLUSION: Human factors, such as chronic health conditions, poor skills and inexperience and poor planning can play a substantial role throughout the chain of events leading to a snorkelling fatality. It is important to educate the community, doctors and dive industry professionals about potential problems associated with the interaction between certain health-related conditions, especially cardiovascular conditions, and snorkelling. Close supervision is strongly recommended for inexperienced snorkellers due to their likely poor skills, as well as for experienced breath-hold divers due to the potential for apnoeic hypoxia.