Suicidal deaths due to helium inhalation

Forensic Toxicology https://doi.org/10.1007/s11419-019-00473-2 REVIEW ARTICLE Suicidal deaths due to helium inhalation Karolina Nowak1,2 · Paweł Szpot1,2 · Marcin Zawadzki1,2 Received: 26 January 2019 / Accepted: 5 April 2019 © The Author(s) 2019 Abstract Purpose The authors reviewed the literature paying attention to helium suicide rates, autopsy findings in people exposed to helium, methods of collecting biological material for toxicological tests, and analytical methods used for detection and quantification of helium in the collected specimens. Methods All reviewed information was gathered through a detailed search of Scopus, PubMed and the World-Wide Web using relevant keywords, e.g., helium, asphyxia, and suicide. Results The use of helium for suicidal purposes is becoming an increasingly common phenomenon around the world. This is undoubtedly influenced by the Internet, which explains in detail the technical aspects of the suicidal use of helium and describes the dying process. Exposure to helium does not lead to poisoning; instead, death is caused by asphyxia. Conclusions Deaths due to helium asphyxiation are still a problem for modern forensic toxicology. Most current methods for collecting biological specimens and identifying the gas seem to be insufficient to give definite opinions in cases of helium asphyxiation. More attempts should be made to modify these methods in order to improve and facilitate detection and quantitative determination of helium and other inert gases. Keywords Helium · Suicide · Asphyxia · Detection and quantification · Sampling procedure · GC–MS Introduction Suicides still account for a considerable percentage of all deaths. There were 5276 documented suicides on the territory of Poland in 2017. Although most such deaths are the result of hanging, suicides due to poisoning by fumes or gases are not uncommon. In 2017 alone, there were 29 such deaths recorded in Poland [1]. For comparison, there were 21 documented cases in 2016, 37 cases in 2015, 18 cases in 2014, and 15 cases in 2013 [2]. Helium suicides are becoming more popular. Within 1 year, the local Forensic Medicine Department carried out five medicolegal autopsies of victims who had died due to inhalation of this gas (unpublished data). In the literature, there are reports on similar cases from other parts of this country [3–6]. * Marcin Zawadzki 1 Department of Forensic Medicine, Wroclaw Medical University, 4 J. Mikulicza‑Radeckiego Street, 50‑345 Wrocław, Poland 2 Institute of Toxicology Research, 45 Kasztanowa Street, 55‑093 Borowa, Poland Also, the observed trend in helium suicides is not limited to Poland. In the years 2001–2011, there were 2495 suicides committed with gas (5.2% of the total number of suicides during the study period) in England and Wales [7]. Helium suicides accounted for 183 deaths, with a noticeable upward trend from 2 cases in 2001 to 53 cases in 2011 [7]. An analysis of 1333 cases of suicide committed in the territories of Amsterdam-Amstelland and Zaanstreek-Waterland in the period from 2005 to 2014 found 83 cases of suicide by asphyxia with a plastic bag [8]. Among them, helium contributed to death in 16 cases from 2005 to 2012 and in 13 cases from 2013 to 2014 [8]. The literature also described cases reported in other European countries: Austria (three cases recorded in Vienna within 3 months) [9], Germany [10], Switzerland [11], and Norway [12]. Numerous scientific reports confirm a global upward trend in this type of death. An analysis of suicides by Forensic Science South Australia [13] over a period of 15 years (from January 2003 to December 2017) showed 33 cases of death caused by helium inhalation and 56 cases of combined nitrogen and helium poisoning. Most cases were recorded in recent years covered by the study (from 2013 to 2017). In particular, there were 15 deaths caused by helium inhalation and 13 Vol.:(0123456789) Forensic Toxicology 31 combined deaths [13]. It should be added that in the period from 1985 to 1999, no suicides due to helium inhalation were recorded in the territory of South Australia [14]. A review [15] of suicide cases in the USA in the years 2005–2012 showed that helium was used in 665 cases of a total of 80,715 suicides registered in the National Violent Death Reporting System (NVDRS). There were a total 3242 cases of suicidal deaths by gas asphyxiation, 73% of which were caused by carbon monoxide (CO), followed by helium (21%) [15]. Similar results were obtained by a retrospective analysis of suicides in San Diego County between 2000 and 2012. Among 4537 suicides committed over a period of 13 years, 103 cases involved CO and 65 cases involved helium [16]. Also, in Hong Kong in the period from 2005 to 2013, there were 15 recorded cases of helium poisoning among a total of 8445 suicides [17]. It is worth noting an upward trend in the use of helium for suicidal purposes because 11 out of 15 cases took place in the last year covered by the study, and in the years 2005–2010, Hong Kong recorded no suicides by helium asphyxiation [17]. In the years 2000–2008, there were 10 suicides with the use of helium in North Carolina [18]. Gilson et al. [19] from the Forensic Science Center (Tucson, AZ, USA) presented cases of death due to helium asphyxiation that had occurred over a period of 18 months. Of the seven described cases, there were two collective suicides (a common-law couple and a married couple). Asphyxiation by helium can also be used for murder. Cuypers et al. [20] presented a case of attempted extended suicide, where the mother had killed three of her children (2, 4, and 6 years old), while leaving two older offspring alive (an 11-year-old boy and a second child of unknown age). In the children’s room, there were six helium cylinders connected by tubes to plastic bags. In addition to homeopathic medicines, an empty doxylamine blister pack was found at the scene. The woman was found unconscious in the bedroom. Next to her, there was a bloody syringe and empty lidocaine packaging. Before connecting the helium cylinder, the woman had given the above pharmaceuticals to the children. Toxicological tests were used to determine doxylamine in blood and urine samples for all three children. The blood concentrations of the drug in all three cases exceeded 7000 ng/mL, which were lethal concentrations. Also, helium was detected from all lung specimens. The ultimate cause of death was found to be poisoning with sedatives and asphyxiation due to helium inhalation [20]. Influence of mass media on helium inhalation The Internet plays a huge role in disseminating advice on effective suicide methods. Among others, detailed how-to instructions and instructional videos are widely available. 13 In a study conducted in 2014, Biddle et al. [21] showed a threefold increase in the number of “pro-suicide” websites as compared to 2007. By contrast, the number of prevention and support websites declined by half during the same (...truncated)