ABSTRACT
Inert gas narcosis (IGN) refers to a clinical syndrome characterized by impairment of intellectual and neuromuscular performance and changes in mood and behaviour. It is produced by an increased partial pressure of inert gas. In compressed-air exposure, these changes, which have been observed for over 100 years, are now known to be largely due to nitrogen. The effects are progressive with increasing depth, but not with increasing time at the same depth. The word 'inert' indicates that these gases exert their effect without undergoing metabolic change in the body, rather than inert gas in the biophysical sense.
