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Nitrogen Narcosis

("Raptures of the Deep")

Nitrogen is an inert gas existing in largest quantity in the atmosphere, 79% in air. It is inert, meaning that it does not take part in energy transformations. It is the gas that causes nitrogen narcosis through the effect of Dalton's law and it is the gas that causes decompression sickness on ascent from depth with reduction of pressure, (Boyle's Law). Nitrogen is the gas that determines decompression schedules.

Nitrogen narcosis occurs when divers go below 100 FSW, due to the laws of partial pressures. Complex reasoning decreases 33% and manual dexterity decreases 7.3%. The condition causes loss of motor function and decision-making ability and can be more clearly defined as causing one to become "drunk", as with alcoholic beverages. The comparison to having had "three Martinis" is apt, and it has been stated that one should consider the narcotic effect of one Martini for every 50 feet of sea water.

Dalton's Law states that the total pressure exerted by a mixture of gases is equal to the sum of the pressure of each of the different gases making up the mixture-each gas acting as if it alone was present and occupying the total volume. This same law causes oxygen toxicity and enhances the role of contaminant gases such as carbon monoxide and hydrocarbons.

The law is stated as:

p ATA=pO2 + pN2 + p other gases

thus: pN2= fN2 x ATA

There is a critical volume hypothesis that states there to be an increased volume of nitrogen in the membranes and this relates to solubility. This explains the pressure reversal of anesthetics. Nitrogen narcosis is potentiated by increased CO2 levels.

Certain factors increase the possibility of nitrogen narcosis:

Treatment of nitrogen narcosis is immediate controlled ascent to the surface, with the buddy or divemaster observing the diver for unusual behavior, administration of O2 and temporary cessation of diving. Prevention should be the best treatment, with no further diving below 100 feet.

Medline  References
Comparison between subjective feelings to alcohol and nitrogen narcosis: a pilot study. (Monteiro MG; Alcohol, 1996 Jan-Feb)|1

[Involvement of adrenergic mechanisms in developing the nervous syndrome of high pressure and nitrogen narcosis] (Sledkov AI; Aviakosm Ekolog Med, 1996)|1

Nitrogen narcosis attenuates shivering thermogenesis. (Mekjavi´c IB; J Appl Physiol, 1995 Jun)|1

Dissociation of the behavioral and subjective components of nitrogen narcosis and diver adaptation. (Hamilton K; Undersea Hyperb Med, 1995 Mar)|1

Perception of thermal comfort during narcosis. Undersea Hyperb Med. 1994 Mar; 21(1): 9-19.

Effect of brief, repeated hyperbaric exposures on susceptibility to nitrogen narcosis.
Undersea Biomed Res. 1989 May; 16(3): 227-232.

The effects of hyperbaric air in combination with ethyl alcohol and dextroamphetamine on serial choice-reaction time. Ergonomics. 1989 Apr; 32(4): 409-422.

Nitrogen narcosis and ethyl alcohol increase the gain of the vestibular ocular reflex. Undersea Biomed Res. 1989 Mar; 16(2): 129-137.

Lithium effects: protection against nitrogen narcosis, potentiation of HPNS. Undersea Biomed Res. 1980 Mar; 7(1): 11-16.

Diving experience and emotional factors related to the psychomotor effects of nitrogen narcosis.
Aviat Space Environ Med. 1978 Aug; 49(8): 959-962.

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 Ernest Campbell, MD, FACS All Rights Reserved.

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