Snorkelling deaths in Australia, 1987-1996

Toward a hyperventilation detection system in freediving: a proof of concept using force sensor technology

Background and aim

Hyperventilation before breath-hold diving (freediving) is widely accepted as a risk factor for hypoxic syncope or blackout (BO), but there is no practical way to address it before dives. This study explores the feasibility of using a force sensor to predict end-tidal carbon dioxide (P ETCO2) to assess hyperventilation in freedivers.

Methods and results

Twenty-one freedivers volunteered to participate during two national competitions. The divers were instructed to breathe normally and perform three dry apneas of 1, 2, and 3-min duration at 2-min intervals in a sitting position. Before and after the apneas, P ETCO2 was recorded. The signal from the force sensor, attached to a chest belt, was used to record the frequency and amplitude of the chest movements, and the product of these values in the 60 s before the apnea was used to predict P ETCO2. The mean P ETCO2 was below 35 mmHg before all apneas. The mean amplitude of the signal from the force sensor increased from apnea 1 to apnea 3 (p < 0.001), while the respiratory rate was similar (NS). The product of the respiratory rate and amplitude from the force sensor explained 34% of the variability of the P ETCO2 in the third apnea.

Conclusion

This study shows that a force sensor can estimate hyperventilation before static apnea, providing a basis for further research. More studies are needed to confirm its effectiveness in preventing issues. Freedivers may hyperventilate without noticing it, and such a system could improve awareness of this condition. Additional underwater tests are essential to determine whether this system can enhance safety in freediving.

Effects of hyperventilation on oxygenation, apnea breaking points, diving response, and spleen contraction during serial static apneas

PURPOSE

Hyperventilation is considered a major risk factor for hypoxic blackout during breath-hold diving, as it delays the apnea breaking point. However, little is known about how it affects oxygenation, the diving response, and spleen contraction during serial breath-holding.

METHODS

18 volunteers with little or no experience in freediving performed two series of 5 apneas with cold facial immersion to maximal duration at 2-min intervals. In one series, apnea was preceded by normal breathing and in the other by 15 s of hyperventilation. End-tidal oxygen and end-tidal carbon dioxide were measured before and after every apnea, and peripheral oxygen saturation, heart rate, breathing movements, and skin blood flow were measured continuously. Spleen dimensions were measured every 15 s.

RESULTS

Apnea duration was longer after hyperventilation (133 vs 111 s). Hyperventilation reduced pre-apnea end-tidal CO2 (17.4 vs 29.0 mmHg) and post-apnea end-tidal CO2 (38.5 vs 40.3 mmHg), and delayed onset of involuntary breathing movements (112 vs 89 s). End-tidal O2 after apnea was lower in the hyperventilation trial (83.4 vs 89.4 mmHg) and so was the peripheral oxygen saturation nadir after apnea (90.6 vs 93.6%). During hyperventilation, the nadir peripheral oxygen saturation was lower in the last apnea than in the first (94.0% vs 86.7%). There were no differences in diving response or spleen volume reduction between conditions or across series.

CONCLUSIONS

Serial apneas  revealed a previously undescribed aspect of hyperventilation; a progressively increased desaturation across the series, not observed after normal breathing and could heighten the risk of a blackout.

Injuries and Fatalities Related to Freediving: A Case Report and Literature Review

This case report and literature review aim to explore the range of injuries sustained in the sport of freediving. The case report involves a 37-year-old patient who sustained a pneumothorax secondary to freediving. We conducted the literature review to analyse the injuries associated with freediving. We used the combination of search terms 'freediving", "injuries", and "breath-hold diving" on the database PubMed®. A total of 40 studies were eligible for inclusion in this review. The search revealed a wide range of ophthalmological, pulmonary, neurological, ear, nose, and throat injuries, along with several fatalities. Freediving is a sport performed in extreme environments and, if undertaken by inexperienced, untrained, or competition divers, can lead to severe injury or even death. However, the risk of damage can be reduced by performing it responsibly with the appropriate training and by using proper safety measures. Future research is warranted into the psychological, physiological, and economic benefits of freediving at both individual and community levels.

Travel-weary to travel-worry: the epidemiology of injury-related traveller deaths in Australia, 2006-2017

OBJECTIVE

To explore injury deaths in international and domestic interstate travellers, together with those newly arrived to Australia.

METHODS

A population-based cohort study of all injury-related deaths between 1January 2006 and 31 December 2017 registered with Births Death and Marriages in Australia was conducted using Australian Bureau of Statistics' (ABS) Cause of Death information. Population data on travellers were obtained from Tourism Research Australia.

RESULTS

There were 4,503 injury-related traveller deaths (domestic interstate:3,055; international:934; new arrivals:514). The average annual age-standardised mortality rates in domestic interstate travellers was 0.75 per 100,000, compared with 2.22 per 100,000 in international travellers. Leading causes of injury-related death were land transport incidents (n=1495, 33.2%), self-harm (n=786, 17.5%) and falls (n=513, 11.4%), with differences in mechanism by state/territory, traveller type and age group. Intentional self-harm was common amongst all visitor types, however, it was the primary cause of death in new arrivals Conclusion: Age-standardised mortality rates were almost three-fold higher in international than domestic travellers. New arrivals, international and domestic travellers have different injury profiles, and each require specific prevention strategies.

IMPLICATIONS FOR PUBLIC HEALTH

While COVID has restricted travel to and within Australia, this has provided an opportunity for exploration, reflection, and consideration of risk factors for travellers, and to develop targeted injury prevention strategies for visitor types, so travel experience can be optimised and the magnitude of harm can be reduced.

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.

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.

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.

Interacting Factors Associated with Adult Male Drowning in New Zealand

Objectives

i) to identify factors that contribute to the global trend of the higher incidence of male drowning relative to females, and; ii) to explore relationships between such factors from mortality data in New Zealand.

Methods

Drownings from 1983 to 2012 were examined for: Age, Ethnicity, Site, Activity, Buoyancy and Alcohol. Conditional frequency tables presented as mosaic plots were used to assess the interactions of these factors.

Results

Alcohol was involved in a high proportion of Accidental Immersion drownings (61%) and was highest for males aged 20-24 years. When alcohol was involved there were proportionally more incidences where a life jacket was Available But Not Worn and less incidences where a life jacket was Worn. Many 30-39 year old males drowned during underwater activities (e.g., snorkeling, diving). Older men (aged +55 years old) had a high incidence of drowning while boating. Different ethnicities were over-represented in different age groups (Asian men aged 25-29, and European men aged 65-74) and when involved in different activities.

Conclusions

Numerous interacting factors are responsible for male drownings. In New Zealand, drowning locations and activities differ by age and ethnicity which require targeted intervention strategies.

Snorkelling-related deaths in Australia, 1994-2006

OBJECTIVE

To examine the frequency and causes of snorkelling-related deaths in Australia.

DESIGN, SETTING AND SUBJECTS

We conducted a retrospective analysis of snorkelling-related deaths recorded in Australia from 1994 to 2006 inclusive, based on information from the Divers Alert Network Asia-Pacific database, the National Coroners Information System, coronial files from all states and territories, and annual national drowning reports.

MAIN OUTCOME MEASURES

Number and attributed causes of snorkelling-related deaths.

RESULTS

We identified 140 snorkelling-related deaths. Forensic details were available for 130 of these. Four principal cause-of-death categories were identified: deaths from cardiac or suspected cardiac causes (60), deaths from surface drowning (largely in inexperienced snorkellers) (33), deaths from drowning after prolonged breath-hold diving (largely in experienced divers) (19), and deaths from trauma (10). Eight people died of other causes.

CONCLUSIONS

In the context of the large population sampled, snorkelling-related deaths are rare. Preventive measures for such deaths could include pre-dive medical assessments for people with a history of cardiac or respiratory disease or with a family history of sudden unexpected death; improved training in how to use snorkelling equipment; better matching of skills to health, fitness and water conditions; better supervision and quality training of supervisors in rescue and resuscitation techniques; and avoidance of hyperventilation before breath-hold diving.

Predicting the postmortem submersion interval for human remains recovered from U.K. waterways

This article aims to increase accuracy in estimating the postmortem submersion interval (PMSI) for bodies recovered from rivers in the United Kingdom. Data were collected from closed case files, crime scene reports, and autopsy files concerning bodies recovered over a 15-year period from the River Clyde, Scotland, and the River Mersey and canals in northwest England. One hundred and eighty-seven cases met the study criteria and were scored by quantifying the overall amount of decomposition observed in each case. Statistical analysis showed that the duration of a body's submergence in water and the temperatures to which it was exposed, as measured in accumulated degree days (ADD), had a significant effect on the decay process. Further analysis indicated that there were no significant differences in decomposition between the waterways. By combining the data from all study samples, it was possible to produce a single linear regression model for predicting ADD from observed decomposition.

Representations and coverage of non-English-speaking immigrants and multicultural issues in three major Australian health care publications

BACKGROUND

No recent Australian studies or literature, provide evidence of the extent of coverage of multicultural health issues in Australian healthcare research. A series of systematic literature reviews in three major Australian healthcare journals were undertaken to discover the level, content, coverage and overall quality of research on multicultural health. Australian healthcare journals selected for the study were The Medical Journal of Australia (MJA), The Australian Health Review (AHR), and The Australian and New Zealand Journal of Public Health (ANZPH). Reviews were undertaken of the last twelve (12) years (1996-August 2008) of journal articles using six standard search terms: 'non-English-speaking', 'ethnic', 'migrant', 'immigrant', 'refugee' and 'multicultural'.

RESULTS

In total there were 4,146 articles published in these journals over the 12-year period. A total of 90 or 2.2% of the total articles were articles primarily based on multicultural issues. A further 62 articles contained a major or a moderate level of consideration of multicultural issues, and 107 had a minor mention.

CONCLUSIONS

The quantum and range of multicultural health research and evidence required for equity in policy, services, interventions and implementation is limited and uneven. Most of the original multicultural health research articles focused on newly arrived refugees, asylum seekers, Vietnamese or South East Asian communities. While there is some seminal research in respect of these represented groups, there are other communities and health issues that are essentially invisible or unrepresented in research. The limited coverage and representation of multicultural populations in research studies has implications for evidence-based health and human services policy.

Overseas visitors admitted to Queensland hospitals for water-related injuries

OBJECTIVE

To determine the number of overseas visitors admitted to Queensland hospitals for water-related injuries over three years, the causes of their injuries, the resulting conditions treated, and the type of hospitals to which they were admitted.

DESIGN

Retrospective analysis of admissions of overseas visitors to Queensland hospitals over the three financial years 1995/96, 1996/97 and 1997/98.

PATIENTS

296 overseas visitors admitted for water-related injuries, identified from hospital records by their usual place of residence.

MAIN OUTCOME MEASURES

Number of admissions, causes of injuries, conditions treated, and bed days occupied by these patients at different types of hospitals (metropolitan, regional and rural public hospitals, and private hospitals).

RESULTS

The 296 overseas visitors accounted for a total of 596 separate admissions, many of these the result of patients with decompression illness being admitted several times to a regional hospital hyperbaric chamber for treatment as day patients. The largest number of injuries involved the use of diving equipment. The main conditions treated were decompression illness (54.7%), fractures and dislocations (15.5%), and drowning and non-fatal submersion (14.9%). Overall, overseas visitors admitted to hospital following a water-related incident occupied 1215 bed days; 90% of these admissions were to regional hospitals.

CONCLUSIONS

The main reason for admission of overseas visitors is for decompression illness, suggesting that the prevention of injuries among scuba divers requires further coordinated efforts by health and tourism authorities.