1706, "stoppage of pulse," from Mod.L., from Gk. asphyxia "stopping of the pulse," from a- "not" + sphyzein "to throb." The current sense of "suffocation" is from 1778, but it is a "curious infelicity of etymology" [OED] since victims of suffocation have a pulse for some time after breathing has stopped.
(ās-fĭk'sē-ə) A condition characterized by an extreme decrease in the amount of oxygen in the body accompanied by an increase of carbon dioxide, caused by an an inability to breathe. Asphyxia usually results in loss of consciousness and sometimes death.