A review of the forensic investigation of scuba diving deaths

Pulmonary barotrauma in SCUBA diving-related fatalities: a histological and histomorphometric analysis

Arterial gas embolism following pulmonary barotrauma occurs in 13-24% of cases of diving deaths. The study aimed to evaluate the usefulness of a histomorphometric digital analysis in the detection of air space over-distension due to pulmonary barotrauma. The study was performed on lung parenchyma specimens of 12 divers: six had died due to arterial gas embolism following pulmonary barotrauma (mean age at death of 54 years, range of 41-61 years), and six had drowned in saltwater without a diagnosis of pulmonary barotrauma (mean age at death of 54 years, range of 41-66 years) (positive controls). For negative controls, six cases of non-SCUBA divers (mean age of death of 42 years, range of 23-55 years) who died of intracerebral haemorrhage were evaluated. No significant differences were observed in the characteristics of the air spaces between control groups (positive and negative). However, differences were observed in the area occupied by air spaces and the percentage of air space area when we compared the case group to the controls (p < 0.01); and there was a slight difference in the maximum and minimum diameters of air space (p < 0.05). The mean area occupied by air spaces and the mean percentage of air space were the most useful for discriminating pulmonary barotrauma from other causes of death (100% sensitivity and 91.7% specificity). Based on our study, inclusion of an increased pattern of air spaces as a possible diagnostic criterion for pulmonary barotrauma would be useful in discerning the cause of diving death.

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.

Post-mortem computer tomography in ten cases of death while diving: a retrospective evaluation

INTRODUCTION

Self-contained underwater breathing apparatus (SCUBA) diving deaths have always been a challenge for forensic pathologists. Post-mortem computer tomography (PMCT) allows intracorporeal gas visualization, contributing to identify the cases in which the cause of death is arterial gas embolism (AGE). However, in the literature, it is indicated to perform the radiological examination within 24 h after death.

MATERIALS AND METHODS

In this retrospective study, 32 cases of death who had undergone PMCT 24-48 h after death/corpse finding between January 2011 and March 2021 were analyzed, including ten cases of SCUBA divers who died of AGE. All cases' radiological images were reviewed to localize the intracorporeal gas distribution alongside other findings that are usually related to SCUBA diving death. A semi-quantitative evaluation was also performed.

RESULTS

Most of the divers showed gas within the left heart and the arteries. In addition, the semi-quantitative evaluation revealed that the divers presented a higher mean amount of intraarterial gas compared to the fresh corpses. On the other hand, the putrefied corpses presented gas within the portal system and generalized subcutaneous emphysema with higher frequency and quantity than the divers and fresh corpses.

CONCLUSION

Our cases suggested that the PMCT, even when performed 24-48 h after death, remains a valuable tool to diagnose AGE in cases of SCUBA diving deaths. In addition, with the limit of the small sample size, our data showed that at least a medium quantity of intraarterial gas, when not associated with a high amount of gas within the portal system and subcutaneous emphysema, could be considered a diagnostic criterion of AGE.

Diagnosis of arterial gas embolism in SCUBA diving: modification suggestion of autopsy techniques and experience in eight cases

The purpose of this study was to suggest modifications of autopsy techniques in order to improve post-mortem diagnosis of arterial gas embolism (AGE) based on multidisciplinary investigation of SCUBA diving fatalities. Five adult human cadavers from the voluntary donation program of the Human Anatomy Laboratory, and eight judicial autopsied bodies of SCUBA divers from the Forensic Pathology Service were assessed. Before performing any autopsies, we accessed the diving plan and the divers' profiles for each case. We then introduced a new dissection procedure that included identification, isolation, and manipulation of carotid, vertebral and thoracic arterial systems. The dissected vascular structures that allowed optimall isolation of the systemic arterial circulation were identified and ligated. In three of the eight judicial cases, we had a strongly suggestive history of arterial gas embolism following pulmonary barotrauma (PBt/AGE). In these cases, the additional arterial dissection allowed us to clearly diagnose AGE in one of them. The autopsy of the rest of the cases showed other causes of death such as asphyxia by drowning and heart attack. In all cases we were able to reject decompression sickness, and in some of them we showed the presence of artefacts secondary to decomposition and resuscitation maneuvers. These results allow us to suggest a specific autopsy technique divided into four steps, aimed at confirming or excluding some evidence of dysbaric disorders according to a re-enactment of the incident. We have demonstrated the presence of large volumes of intravascular air, which is typical of PBt/AGE.

Dilemma of Natural Death While Scuba Diving

Sudden death from natural causes occurs frequently and the cause is often not discovered until the time of autopsy. Just as it occurs on land, so too do natural deaths occur in the water. However, the deaths may be inappropriately attributed to drowning simply due to their occurrence in the water, particularly in the case of scuba divers. We emphasize the importance of taking into consideration all factors when investigating these deaths, with particular emphasis on witness statements, equipment analysis, and autopsy findings in attempt to avoid the mischaracterization of sudden natural death in the water as drowning.

We present two cases of sudden death in middle-aged males while scuba diving. Upon close examination of the autopsy findings, in conjunction with the eyewitness statements regarding the circumstances of their deaths, the cause of death was ultimately determined to be due to their significant cardiac disease, rather than drowning. In cases such as these, particular importance must be given to heart weight, evidence of coronary artery disease, lung weights, and evidence of aspiration on autopsy. If the evidence suggests death due to cardiac disease, these deaths should be categorized as natural deaths and not drownings.

Scuba-diving related deaths in Okinawa, Japan, from 1982 to 2007

We reviewed the autopsies of scuba-diving related deaths (SDRDs) that were collected from April 1982 until March 2007. In the period under consideration, a total of 40 SDRDs were registered, out of which 34 were males and 6 females. Ages ranged from 19 to 65 years, with the average of 41.5 years (SD=12.9). Divers over the age of 40 accounted for 60% of all fatalities. The major cause of death was drowning (62.5%), followed by disease (28.5%). The average age for drowning and disease-related deaths was 38.6 (SD=12.8) and 48.7 years (SD=10.1), respectively. Of the 40 fatalities, 24 were beginners who had little or no experience. In this study, we compared SDRDs in the first term, from April 1982 to March 1995, and in the second term, from April 1995 to March 2007. The average age in the first and second terms was 35.4 and 45.2 years, respectively; the average age for the second term was 10 years older than the first. Of those in the first term, 13.3%, and of those in the second term, 40.0%, died from complications arising from already existing conditions. This study revealed that the onset of diseases during diving frequently causes fatal accidents, especially for older divers.

Medico-legal considerations of deaths from watersports among Caribbean tourists

Watersports are the dominant recreational sporting activity in the Caribbean islands. The economy of many of these islands is tourist-oriented and millions of tourists take part in such sports annually with some fatalities. A total of 13 watersport-related deaths observed in the Cayman Islands over a 2-year period are presented. Complete autopsies with toxicological and histological studies were carried out in each case. Preexisting cardiovascular disease such as hypertension, coronary artery disease (or relative insufficiency) and cardiomyopathies were observed to be significant risk factors and the mean age at death was 53.7 years. Sudden cardiac deaths predominate. One fatal jet skiing accident also occurred. Tourists are advised to undergo complete medical investigations (including ECG and stress tests) prior to engaging in watersports. Drugs of abuse are to be avoided for medical reasons and insurance considerations. Watersports operators must ensure that their clients complete a medical checklist. All equipment and accessories must be functioning optimally to avoid accidents contributed to by such negligence. Consideration should be given to introducing medical tests prior to signing on their clients and there must be adequate supervision. Some form of governmental regulation and enforceable supervision is necessary.