Yatsushiro Masahiko, Nakamae Takuma, Katsuyama Midori, Miyamoto Machiko, Hayashi Takahito
Department of Legal Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.
Forensic Sci Med Pathol. 2024 Dec 6. doi: 10.1007/s12024-024-00927-z.
A mixture of baking soda (sodium hydrogen carbonate) and citric acid is used for cleaning purposes, but, in recent years, this mixture has been introduced on the internet as a method for suicide. Here, we report a case in which the two agents were mixed in a bathtub to generate carbon dioxide (CO). A man in his early 60s was found dead in his clothes in a bathtub with a lid. Postmortem changes were somewhat progressed, but only pulmonary edema was observed, with no injuries or lesions that could have led to cause of death, and no drug toxicants detected. Empty containers of baking soda (789 g) and citric acid (850 g) were found at the scene. We conducted a reproduction experiment showing that CO reached a lethal concentration (~ 60%) within 12 s, but the O concentration was about 10%, which is not a lethal concentration. Therefore, it is highly likely that the man died of CO intoxication within a short period of time and before he would have suffered asphyxiation due to oxygen deficiency. Normally, this result can only be obtained with the cooperation of an investigative agency and a large-scale reproduction experiment, but we were able to diagnose the cause of his death, including a differential diagnosis of asphyxia due to oxygen deficiency, by means of a reproduction model at 1/35 scale that could easily be performed in the laboratory.
小苏打（碳酸氢钠）和柠檬酸的混合物常用于清洁，但近年来，这种混合物在互联网上被作为一种自杀方法传播。在此，我们报告一例将这两种物质在浴缸中混合产生二氧化碳（CO）的案例。一名60岁出头的男子被发现穿着衣服死在一个带盖子的浴缸里。尸体变化有一定进展，但仅观察到肺水肿，没有发现可能导致死亡的损伤或病变，也未检测到药物毒物。现场发现了空的小苏打容器（789克）和柠檬酸容器（850克）。我们进行了一项重现实验，结果显示CO在12秒内达到致死浓度（约60%），但氧气浓度约为10%，这并非致死浓度。因此，该男子很可能在短时间内死于CO中毒，且在因缺氧窒息之前。通常情况下，只有通过调查机构的合作和大规模重现实验才能得出此结果，但我们通过在实验室中易于进行的1/35比例重现模型，得以诊断其死因，包括对缺氧窒息的鉴别诊断。
