Elevation of Inert Gas Partial Pressure
Elevation of the partial pressure of the inert gas (usually nitrogen)
present in a breathing mixture is associated with a narcotic effect, predictable
by the Meyer-Overton hypothesis. Based on its olive oil solubility, N2
has approximately 0.03 to 0.05 times the narcotic potency of nitrous oxide. At 3
ATA (breathing air), most people experience mild euphoria. At 6 ATA, there may be
memory loss and poor judgment. At 10 ATA, some individuals lapse into unconsciousness.
Nitrogen narcosis has been compared with alcoholic intoxication, with an increase
in ambient pressure of 1.5 ATA resulting in an effect that is said to be similar
to drinking one martini. Argon and, to a lesser degree, hydrogen are narcotic, whereas
helium has minimal, if any narcotic effect.
