<unk>  results from breathing gases under elevated pressure, and may be classified by the principal gas involved. The noble gases, except helium and probably neon, as well as<unk> , oxygen and hydrogen cause a decrement in mental function, but their effect on psychomotor function (processes affecting the coordination of sensory or cognitive processes and motor activity) varies widely. The effect of carbon dioxide is a consistent diminution of mental and psychomotor function. The noble gases argon, krypton, and xenon are more narcotic than<unk>  at a given pressure, and xenon has so much anesthetic activity that it is a usable anesthetic at 80% concentration and normal atmospheric pressure. Xenon has historically been too expensive to be used very much in practice, but it has been successfully used for surgical operations, and xenon anesthesia systems are still being proposed and designed.
Nitrogen narcosis
Malignant hyperthermia
Anoxia
Barbiturate overdose
Histotoxic hypoxia
Pseudohypoxia
Hypoxia 
Hypothermia