nitrogen narcosis


nitrogen narcosis
a semistupor, lightheadedness, or euphoria experienced by deep-sea divers when nitrogen from air enters the blood at higher than atmospheric pressure. Also called rapture of the deep.
[1935-40]

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or nitrogen euphoria or raptures of the deep

Effects of breathing nitrogen under increased pressure.

In divers breathing compressed air, nitrogen saturates the nervous system, causing an intoxicating light-headed, numb feeling, then slowed reasoning and dexterity, and then emotional instability and irrationality. Severe cases progress to convulsions and blackout. Susceptibility varies, and severity increases with depth, but there are no aftereffects. Physical function remains normal, and divers may be unaware of the growing irrationality that can cause them to rise too fast (see decompression sickness) or let their air supply run out. Helium, which dissolves less easily in body tissues, is substituted for nitrogen for deep dives.

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also called  Nitrogen Euphoria, or Raptures Of The Deep,  

      effects produced by the gas nitrogen when it is breathed under increased pressure. nitrogen, a major constituent of air, is quite inert and passes into the fluids and tissues of the body without undergoing chemical change. Even though it is not used to sustain the bodily functions, it, nevertheless, has certain effects upon the tissues when it is present in excess of the amounts breathed at atmospheric pressures.

      As divers (underwater diving) descend in the water, the pressure upon their bodies increases proportionally to the water depth; in order for them to breathe normally, they are supplied with air at a pressure equal to that of the water. A diver situated at 30 m (100 feet) under water is breathing air that is four times more dense than at sea level; the quantity of nitrogen is, likewise, four times greater.

      Nitrogen is absorbed by the fatty tissue (lipids) much faster than by other tissues; the brain and the rest of the nervous system have a high lipid content. Consequently, when a high concentration of nitrogen is breathed, the nervous system becomes saturated with the inert gas, and normal functions are impaired. Each individual has his own threshold of susceptibility; some divers experience narcosis at 15 m, while others can go to 60 m without any apparent effects. Most often, nitrogen narcosis begins to be apparent at about 10 m of depth. As a diver goes deeper, the symptoms increase in severity. When the diver ascends, the symptoms terminate with essentially no aftereffects or permanent harm done.

      Mild cases begin as an intoxicating feeling of light-headedness, euphoria, numbness, and carefreeness. The reasoning ability and manual dexterity may next be slowed down. Emotional instability and irrationality may then ensue. Persons severely affected lapse into convulsions and unconsciousness. Divers swimming in clear, warm water seem to experience pleasant sensations, while those in dark, cold water seem to encounter panic, fear, anxiety, and depression. Unless the narcosis is severe, the victim is capable of functioning physically and may not fully realize that his rationality is being impaired. Irrationality itself, however, can cause the diver to inflict bodily harm upon himself by rising too fast or by failing to realize that his air supply has been depleted.

      Because helium dissolves less readily in body tissue than nitrogen, mixtures of helium and oxygen are used in place of the usual nitrogen-oxygen mixtures for deep dives.

      See also decompression sickness.

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Universalium. 2010.

Look at other dictionaries:

  • nitrogen narcosis — n a state of euphoria and confusion similar to that of alcohol intoxication which occurs when nitrogen in normal air enters the bloodstream at increased partial pressure (as in deepwater diving) <divers typically begin to experience the… …   Medical dictionary

  • nitrogen narcosis — n. reduction in the ability to think clearly and react quickly, caused by increased air pressure which increases the concentration of nitrogen in the body tissue and brain: a special concern of deep sea divers …   English World dictionary

  • Nitrogen narcosis — Inert gas narcosis [Nitrogen narcosis] Classification and external resources Divers breathe a mixture of oxygen, helium and nitrogen for deep dives to avoid the effects of narcosis. A cylinder label shows the maximum operating depth and mixture… …   Wikipedia

  • nitrogen narcosis — noun confused or stuporous state caused by high levels of dissolved nitrogen in the blood deep sea divers can suffer nitrogen narcosis from breathing air under high pressure • Hypernyms: ↑narcosis …   Useful english dictionary

  • nitrogen narcosis — noun Date: 1937 a state of euphoria and confusion similar to that of alcohol intoxication which occurs when nitrogen in normal air enters the bloodstream at increased pressure (as in deep water diving) called also rapture of the deep …   New Collegiate Dictionary

  • nitrogen narcosis — noun A condition of disorientation, intoxication and stupor caused by increased levels of dissolved nitrogen in the blood; occurs in divers breathing air under pressure; the rapture of the deep …   Wiktionary

  • nitrogen narcosis — ni′trogen narco sis n. pat a stupor or euphoria induced in deep sea divers when nitrogen from air enters the blood at higher than atmospheric pressure Also called rapture of the deep • Etymology: 1935–40 …   From formal English to slang

  • nitrogen narcosis — recovery of fish suddenly from deep water can case expansion of gases by rapid decompression, harming the fish. Applies to humans too …   Dictionary of ichthyology

  • nitrogen narcosis — noun Medicine a drowsy state induced by breathing air under pressure, e.g. in deep sea diving …   English new terms dictionary

  • Narcosis de nitrógeno — (narcosis de gas inerte) Clasificación y recursos externos DiseasesDB 30088 MeSH …   Wikipedia Español


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