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

Abstract

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.

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

“…Together with a history of rapid ascent as registered in the dive profile, the presence of air in the systemic circulation is one of the key criteria for diagnosing PBt/AGE [ 17 , 18 , 29 ]. Although some studies have described technical modifications that demonstrate this in various organs at autopsy [ 33 ], the use of post-mortem imaging techniques should be used when available. Unfortunately, these radiological and macroscopic techniques may not be conclusive to show air existence because most autopsies are performed by pathologists who are not familiar with diving-related injuries.…”

“…Exclusion criteria for this study were included age over 65 years; PMI longer than 30 h; use of high-pressure oxygen in cardiopulmonary resuscitation (CPR) advanced manoeuvers; admission to the intensive care unit of a medical centre; and pneumological diseases showing chronic pulmonary emphysema according to medical records and standard histological results. These exclusion criteria were established in accordance with different studies published describing the presence of air secondary to age (senile lung emphysema), decomposition, CPR advanced manoeuvers and pre-existing pathologies [ 24 , 33 , 38 ].…”

Fatal systemic (paradoxical) air embolism diagnosed by postmortem funduscopy

“…Based on case reports, 100-300 ml of venous air may cause death in humans [50,56]. However, the critical volume remains unknown since death from VAE depends on the amount of air, the rate it enters the circulation, body position, the superior cerebellar, and basilar arteries before brain removal and intracardiac air assessment after filling the partially opened pericardial sac with water following ligation of the internal thoracic arteries [74]. Quantitation and collection of intravascular air or gas require specialized autopsy techniques [75][76][77].…”

“…Standard radiography can detect large volume AE, whereas postmortem CT can reveal smaller volumes of intravascular air and differentiate AE from decompositional gas in certain circumstances [25,69–73]. Suggested autopsy technique modifications facilitating detection of AE include ligation of the internal carotid, superior cerebellar, and basilar arteries before brain removal and intracardiac air assessment after filling the partially opened pericardial sac with water following ligation of the internal thoracic arteries [74]. Quantitation and collection of intravascular air or gas require specialized autopsy techniques [75–77].…”

A Review of Barotrauma from Diving: A Narrative Literature Review

“…1,2 Cases of barotrauma are often found in the community, especially in coastal areas. 3,4 This is related to the diving activities of coastal communities that do not use the equipment according to safety standards in diving. That effect is generated When exposed to very strong pressure and occurs suddenly.…”