Inhaling butane gas can cause drowsiness, narcosis, asphyxia, cardiac arrhythmia and frostbite. Butane is the most commonly misused volatile solvent in the UK and caused 52% of solvent-related deaths in 2000. When butane is sprayed directly into the throat, the jet of fluid can cool rapidly to −20°C by adiabatic expansion, causing prolonged laryngospasm. Sudden sniffing death syndrome is commonly known as SSDS. Some inhalants can also indirectly cause sudden death by cardiac arrest, in a syndrome known as "sudden sniffing death".[23] The anaesthetic gases present in the inhalants appear to sensitize the user to adrenaline and, in this state, a sudden surge of adrenaline (e.g., from a frightening hallucination or run-in with aggressors), may cause fatal cardiac arrhythmia.[24]
Furthermore, the inhalation of any gas that is capable of displacing oxygen in the lungs (especially gasses heavier than oxygen) carries the risk of hypoxia as a result of the very mechanism by which breathing is triggered. Since reflexive breathing is prompted by elevated carbon dioxide levels (rather than diminished blood oxygen levels), breathing a concentrated, relatively inert gas (such as computer-duster tetrafluoroethane or nitrous oxide) that removes carbon dioxide from the blood without replacing it with oxygen will produce no outward signs of suffocation even when the brain is experiencing hypoxia. Once full symptoms of hypoxia appear, it may be too late to breathe without assistance, especially if the gas is heavy enough to lodge in the lungs for extended periods. Even completely inert gasses, such as argon, can have this effect if oxygen is largely excluded as used in suicide bags.
