Aix-Marseille Université, Faculté de Médecine, Laboratoire de Physiopathologie et Thérapeutique Vasculaire (L2PTV), Marseille, France.
Int J Legal Med. 2013 Jan;127(1):177-84. doi: 10.1007/s00414-011-0662-6. Epub 2011 Dec 30.
Postmortem computed tomography can easily demonstrate gas collections after diving accidents. Thus, it is often used to support the diagnosis of air embolism secondary to barotrauma. However, many other phenomenons (putrefaction, resuscitation maneuvers, and postmortem tissue offgassing) can also cause postmortem gas effusions and lead to a wrong diagnosis of barotrauma.
The aim of this study is to determine topography and time of onset of postmortem gas collections respectively due to putrefaction, resuscitation maneuvers, and tissue offgassing.
A controlled experimental study was conducted on nine pigs. Three groups of three pigs were studied postmortem by CT from H0 to H24: one control group of nonresuscitated nondivers, one group of divers exposed premortem to an absolute maximal pressure of 5 b for 16 min followed by decompression procedures, and one group of nondivers resuscitated by manual ventilation and thoracic compression for 20 min. The study of intravascular gas was conducted using CT scan and correlated with the results of the autopsy.
The CT scan reveals that, starting 3 h after death, a substantial amount of gas is observed in the venous and arterial systems in the group of divers. Arterial gas appears 24 h after death for the resuscitated group and is absent for the first 24 h for the control group. Concerning the putrefaction gas, this provokes intravenous and portal gas collections starting 6 h after death. Subcutaneous emphysema was observed in two of the three animals from the resuscitated group, corresponding to the thoracic compression areas.
In fatal scuba diving accidents, offgassing appears early (starting from the first hour after death) in the venous system then spreads to the arterial system after about 3 h. The presence of intra-arterial gas is therefore not specific to barotrauma. To affirm a death by barotrauma followed by a gas embolism, a postmortem scanner should be conducted very early. Subcutaneous emphysema should not be mistaken as diagnostic criteria of barotrauma because it can be caused by the resuscitation maneuvers.
死后计算机断层扫描可以轻松显示潜水事故后的气体积聚。因此，它通常用于支持气压伤继发于空气栓塞的诊断。然而，许多其他现象（腐败、复苏操作和死后组织放气）也会导致死后气体渗出，并导致气压伤的误诊。
本研究的目的是确定分别由于腐败、复苏操作和组织放气导致的死后气体积聚的时间和分布。
对 9 头猪进行了一项对照实验。三组各有三头猪在死后通过 CT 从 H0 到 H24 进行检查：一组未复苏的非潜水者对照组，一组生前暴露于绝对最大压力 5 b 下 16 分钟，然后进行减压程序，一组非潜水者通过手动通气和胸部压缩复苏 20 分钟。血管内气体的研究使用 CT 扫描进行，并与尸检结果相关联。
CT 扫描显示，从死亡后 3 小时开始，潜水组的静脉和动脉系统中观察到大量气体。复苏组的动脉气体在死后 24 小时出现，对照组在前 24 小时内不存在。关于腐败气体，它会引起静脉和门静脉气体积聚，从死亡后 6 小时开始。复苏组的三头猪中有两头出现皮下气肿，对应于胸部压缩区域。
在致命的水肺潜水事故中，放气现象早期出现（从死亡后第一小时开始），首先出现在静脉系统，然后在大约 3 小时后扩散到动脉系统。因此，动脉内气体的存在并不特定于气压伤。为了确认气压伤继发的气体栓塞导致的死亡，应在死后早期进行扫描。皮下气肿不应被误诊为气压伤的诊断标准，因为它可能是由复苏操作引起的。
