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Comprehensive
information
about diving and undersea medicine for the
non-medical diver, the non-diving physician and the specialist.
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Comprehensive
information
about diving and undersea medicine for the
non-medical diver, the non-diving physician and the specialist.
|
|
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.
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
http://snipurl.com/3s5x
[Involvement
of adrenergic mechanisms in developing the nervous syndrome of high
pressure
and nitrogen narcosis] (Sledkov AI; Aviakosm Ekolog Med, 1996)|1
http://snipurl.com/3s5v
Nitrogen
narcosis attenuates shivering thermogenesis. (Mekjavi´c IB; J
Appl
Physiol, 1995 Jun)|1
http://snipurl.com/3s5u
Dissociation
of the behavioral and subjective components of nitrogen narcosis and
diver
adaptation. (Hamilton K; Undersea Hyperb Med, 1995 Mar)|1
http://snipurl.com/3s5t
Perception
of thermal comfort during narcosis. Undersea Hyperb Med. 1994 Mar;
21(1):
9-19.
http://snipurl.com/3s5s
Effect
of brief, repeated hyperbaric exposures on susceptibility to nitrogen
narcosis.
Undersea
Biomed Res. 1989 May; 16(3): 227-232.
http://snipurl.com/3s5r
The
effects of hyperbaric air in combination with ethyl alcohol and
dextroamphetamine
on serial choice-reaction time. Ergonomics. 1989 Apr; 32(4): 409-422.
http://snipurl.com/3s5o
Nitrogen
narcosis and ethyl alcohol increase the gain of the vestibular ocular
reflex.
Undersea Biomed Res. 1989 Mar; 16(2): 129-137.
http://snipurl.com/3s5k
Lithium
effects: protection against nitrogen narcosis, potentiation of HPNS.
Undersea
Biomed Res. 1980 Mar; 7(1): 11-16.
http://snipurl.com/3s5h
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Ernest Campbell, MD, FACS All Rights Reserved. |
