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.

Muertes en el buceo: un modelo de investigación multidisciplinar / Diving deaths: A multidisciplinary research model

El buceo es una de las actividades subacuáticas más practicadas en el litoral español. Los sistemas más comunes utilizados son el buceo con escafandra autónoma con circuito abierto, cerrado o semicerrado. Aunque hoy en día el buceo con escafandra autónoma se considera una práctica segura, cada año se describen nuevas muertes relacionadas con esta actividad. El ahogamiento es la principal causa de muerte, pero se han descrito otras, como la embolia gaseosa arterial, la enfermedad por descompresión, la enfermedad natural asociada y los traumatismos. Las autopsias de muertes relacionadas con el buceo son un gran desafío para cualquier patólogo forense, y es aconsejable poseer conocimientos sobre fisiopatología del buceo y experiencia en la práctica de técnicas de autopsia específicas. Colaborar con un equipo multidisciplinar proporciona información, evidencias y hallazgos patológicos suficientes para una investigación altamente calificada de los casos y poder resolver las principales cuestiones médico-legales

Diving is one of the most practiced underwater activities on the Spanish coast. The most common methods used in diving activities are SCUBA (self-contained underwater breathing apparatus), CCR (closed circuit rebreather) and SCR (semi-closed circuit rebreather). Although recreational diving is safe overall, diving accidents are potentially serious and even fatal. Despite all the precautions taken by divers, fatalities related to this activity are reported every year. Drowning is the main cause of death, but others have been described, such as arterial gas embolism, decompression sickness, natural pathology, and trauma. Autopsies of SCUBA diving-related deaths are a big challenge for any forensic pathologist. It is advisable to have some knowledge about diving physiopathology and experience in the practice of special autopsy techniques. Collaboration with a multidisciplinary team provides enough information, evidence and pathological findings for highly-qualified investigation of the incidents to be able to prevent similar incidents in the future

Diving-related fatalities: multidisciplinary, experience-based investigation.

To describe the technical characteristics of fatal diving mishaps and to elucidate the causes of death using a sequence analysis and a multidisciplinary investigation of diving-related fatalities. All cases of diving deaths recorded on the coast of Girona (Spain) between January 2009 and May 2018 were analyzed. Most data were obtained from the police technical reports and the forensic pathology service. Each accident was analyzed in order to identify the trigger, disabling agent, disabling injury, and cause of death. During the study period 25 diving-related fatalities were recorded. Most of the victims were males aged 50-69 years, and 11 were experienced divers. Almost all victims were using open-circuit SCUBA to breathe with compressed air as their sole gas supply. None of the victims were diving alone. The most common identified triggers included exertion, panic, buoyancy problems, disorientation and confusion. The main factors identified as disabling agents were rapid ascent, a cardiac incident, panic and entrapment. Asphyxia, lung over expansion, and myocardial ischemia were the most frequent disabling injuries. Finally, drowning represented the main cause of death, followed by arterial gas embolism and natural causes or internal diseases. A differential diagnosis, performed in the setting of a multidisciplinary investigation, is essential for elucidating the cause of death in diving-related fatalities. The proposed sequence analysis allows to clarify underlying problems in these cases and to identify risk factors and unsafe behaviors in diving.

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.