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

The effect of a single closed-circuit rebreather decompression dive in extremely cold water to cardiac function

PURPOSE

Dive-induced cardiac and hemodynamic changes are caused by various mechanisms, and they are aggravated by cold water. Therefore, aging divers with pre-existing cardiovascular conditions may be at risk of acute myocardial infarction, heart failure, or arrhythmias while diving. The aim of this study was to assess the effect of a single decompression CCR dive in arctic cold water on cardiac function in Finnish technical divers.

METHODS

Thirty-nine divers performed one identical 45 mfw CCR dive in 2-4 °C water. Hydration and cardiac functions were assessed before and after the dive. Detection of venous gas embolization was performed within 120 min after the dive.

RESULTS

The divers were affected by both cold-water-induced hemodynamic changes and immersion-related fluid loss. Both systolic and diastolic functions were impaired after the dive although the changes in cardiac functions were subtle. Venous inert gas bubbles were detected in all divers except for one. Venous gas embolism did not affect systolic or diastolic function.

CONCLUSION

A single trimix CCR dive in arctic cold water seemed to debilitate both systolic and diastolic function. Although the changes were subtle, they appeared parallel over several parameters. This indicates a real post-dive deterioration in cardiac function instead of only volume-dependent changes. These changes are without a clinical significance in healthy divers. However, in a population with pre-existing or underlying heart problems, such changes may provoke symptomatic problems during or after the dive.

Beyond drowning: Characteristics, trends, the impact of exposure on unintentional non-drowning coastal fatalities between 2012 and 22

OBJECTIVES

Drowning has been the focus of coastal safety, but a notable proportion of coastal mortality is due to other causes of death. This study describes that burden and quantifies the impact of exposure on Australian unintentional coastal fatalities not due to drowning.

METHODS

Analyses of Australian non-drowning coastal fatalities (NDCF) between July 2012 and June 2022 were conducted. Population and exposure-based rates were calculated for Australians 16+ years and compared to all-cause mortality rates. Time series analysis was performed using Joinpoint regression.

RESULTS

616 NDCFs were recorded (0.27/100,000 pop.), with a decreasing average annual percent change of -5.1% (95% CI:-9.5 to -0.4). Cardiac conditions were the primary causal factor, involved in 52% of deaths. Higher fatality rates were seen among men and for incidents occurring in rural and remote areas. Fatality rates were disproportionately high among young adults when compared to all-cause mortality.

CONCLUSIONS

Men, young adults, and those living in/visiting regional and remote areas represent high-risk populations. Proximity to emergency services and extended response times represent major determinants of NDCF.

IMPLICATIONS FOR PUBLIC HEALTH

Due to the high prevalence of NDCF, coastal safety practitioners should expand their attention beyond drowning to consider the broader range of coastal hazards and fatality types.

Conceptual definition for drowning prevention: a Delphi study

BACKGROUND

Expanding support for drowning prevention is evidenced by interlinked Resolutions at the United Nations (2021) and World Health Assembly (2023). While progress has accelerated, a universally agreed definition for drowning prevention remains absent. Here, we aim to develop a conceptual definition of drowning prevention using the Delphi method.

METHODS

First, we conducted a document review to guide our development and consensus-building process. Then, we formed an advisory group and recruited participants with diverse expertise to contribute to Delphi-method surveys. In the first round, participants selected from draft concepts to build a definition and delineate between the terms drowning prevention and water safety. In the second round, we presented a codeveloped definition, and three statements based on first-round findings. We then sought participant feedback where ≥70% support was considered consensus-based agreement.

RESULTS

Participants (n=134) were drawn from community (7.46%), policy (26.87%), research (40.30%) and technical backgrounds (25.37%), and low-income and middle-income countries (38.06%). In the first- round, half (50.74%) disagreed with the proposition that drowning prevention was synonymous to water safety, while 40.30% agreed. The second- round achieved consensus-based agreement (97.27%) for the definition: Drowning prevention is defined as a multidisciplinary approach that reduces drowning risk and builds resilience by implementing evidence-informed measures that address hazards, exposures and vulnerabilities to protect an individual, community or population against fatal and non-fatal drowning.

CONCLUSION

The Delphi method enabled the codevelopment of our conceptual definition for drowning prevention. Agreement on the definition forms the basis for strengthened multisectoral action, and partnerships with health and sustainable development agendas. Defining drowning prevention in terms of vulnerability and exposure might increase focus on social determinants and other upstream factors critical to prevention efforts.

Fatal diving accidents in Genoa (North-West Italy) from 1968 to 2021: Forensic approach and literature review

Scuba diving is one of the most common and practised water sport activities in Genoa, especially in the more recent years. Although scuba diving is generally considered a safe activity, this does not exclude the possibility of serious or fatal accidents from happening. This retrospective study investigates the case history of deaths resulting from diving accidents recorded by the Municipal Morgue of Genoa over a period of 53 years, specifically from 1968 to 2021. Of the total 52 deaths covered by the study, 48 were male with an age range of 16-71 years. In 25 of these subjects, pre-existing pathological conditions of a cardiovascular nature, not recognised at the time of death, were reported. Out of the total deaths studied, 9 subjects died following a diving accident related to free diving, while 43 subjects died from scuba or rebreather diving. Among the latter subjects, the cause of death was attributed to drowning in 17 cases, arterial gas embolism (AGE) from pulmonary over-distension in 11 cases, cardio-circulatory arrest (CA) favoured by pre-existing and non-existing heart disease known prior to the death in 10 cases, decompression sickness (DCS) in 2 cases, a combination of DCS and AGE in 2 cases and oxygen intoxication in 1 case. Twelve of the fatal accidents occurred in the marine area near the village of Arenzano, where the shipwreck of the oil tanker, the "Haven", sank in 1991 and is today the largest shipwreck explored by divers in the Mediterranean Sea. In all cases of diving deaths, a multi-disciplinary approach is important: in particular, the role of the forensic pathologist is essential in order to accurately reconstruct the dynamics of the accident, thus identifying the predisposing or triggering factors that led to death, and defining the cause of it.

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.

Routine Chest X-Rays Are Inaccurate in Detecting Relevant Intrapulmonary Anomalies During Medical Assessments of Fitness to Dive

Introduction: Intrapulmonary pathology, such as bullae or blebs, can cause pulmonary barotrauma when diving. Many diving courses require chest X-rays (CXR) or high-resolution computed tomography (HRCT) to exclude asymptomatic healthy individuals with these lesions. The ability of routine CXRs and HRCT to assess fitness to dive has never been evaluated.

Methods: Military divers who underwent yearly medical assessments at the Royal Netherlands Navy Diving Medical Center, including CXR at initial assessment, and who received a HRCT between January and June 2018, were included. The correlations of CXR and HRCT results with fitness to dive assessments were analyzed using Fisher's exact tests.

Results: This study included 101 military divers. CXR identified bullae or blebs in seven divers, but HRCT found that these anomalies were not present in three subjects and were something else in four. CXR showed no anomalies in 94 subjects, but HRCT identified coincidental findings in 23 and bullae or blebs in seven. The differences between CXR and HRCT results were statistically significant (p = 0.023). Of the 34 subjects with anomalies on HRCT, 18 (53%) were disqualified for diving.

Discussion: Routine CXR in asymptomatic military divers does not contribute to the identification of relevant pathology in fitness to dive assessments and has a high false negative rate (32%). HRCT is more diagnostic than CXR but yields unclear results, leading to disqualification for diving. Fitness to dive tests should exclude routine CXR; rather, HRCT should be performed only in subjects with clinical indications.

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.