Suffocation by inhaled gases has been reported involving a variety of gases. We report a case of suicidal asphyxiation by forced replacement of oxygen with helium by using a complex homemade mask. In this case, a young woman researched suicide on the Internet and found an advocated method of suicide using helium. To our knowledge, there is only 1 previously reported case of suicidal asphyxia by using helium.
Suicide by asphyxiation is more commonly associated with hanging or drowning, since asphyxiating gases are not a commonly used means of suicide. 1 Deaths from smothering gases are usually the result of accidental industrial or environmental exposure; however, suicidal examples have been reported. 1,2 Toxic gases may accumulate in various conditions. Fires, for example, may deplete the environment of oxygen and liberate gases such as carbon monoxide and cyanide. 3 Carbon dioxide gas accumulates in grain silos, wells and shafts in limestone, and also in fires. 3 Nitrogen also may accumulate and replace oxygen in industrial metal chambers as the steel walls may rust, consuming environmental oxygen in producing ferric oxides. 3 These result in a reduction and/or replacement of atmospheric oxygen. In these conditions, death may result more rapidly than with pure anoxia alone. Suicidal suffocation has been reported by using propane and carbon dioxide. 1 There is 1 report of an accidental suffocation with pure helium gas. 4 Another case showed asphyxial suicide by using helium and a plastic bag. 5 Our case involves a very rare suicidal death of a young person using helium, a complex homemade mask, and instructions she discovered on the Internet to induce asphyxiation.