Nitrogen narcosis: Difference between revisions

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*Develops between 3-4ATM (99-132 feet)<ref name="Grover">Grover CA, Grover DH. Albert Behnke: nitrogen narcosis. J Emerg Med. 2014 Feb;46(2):225-7.</ref>
*Develops between 3-4ATM (99-132 feet)<ref name="Grover">Grover CA, Grover DH. Albert Behnke: nitrogen narcosis. J Emerg Med. 2014 Feb;46(2):225-7.</ref>
**Rare at depths less than 30 meters (100 ft) unless breathing non-standard air mixtures
**Rare at depths less than 30 meters (100 ft) unless breathing non-standard air mixtures
**Similar to alcohol, frequent divers can develop tolerance to the effects of nitrogen narcosis<ref name="Grover" />
**Similar to alcohol, frequent divers can develop subjective "tolerance" to the effects, but impairment remains<ref name="Levett">Levett DZ, Millar IL. Bubble trouble: a review of diving physiology and disease. Postgrad Med J. 2008 Nov;84(997):571-8.</ref><ref name="Grover" />
*Can be prevented by using nitrogen-free gas mixture (e.g. heliox), or mixtures with reduced nitrogen content (e.g. helium-nitrogen-oxygen)<ref name="Grover" />
*Can be prevented by using nitrogen-free gas mixture (e.g. heliox), or mixtures with reduced nitrogen content (e.g. helium-nitrogen-oxygen)<ref name="Grover" />
*Risk factors = exertion during dive, cold conditions, alcohol intoxication before dive<ref name="Grover" />
*Risk factors = exertion during dive, cold conditions, alcohol intoxication before dive<ref name="Grover" />
*Other inert gases cause similar symptoms at depth - severity based on lipid solubility of the gas<ref>Bove AA. Diving medicine. Am J Respir Crit Care Med. 2014 Jun 15;189(12):1479-86.</ref>


==Clinical Features==
==Clinical Features==
*Insidious onset of symptoms similar to alcohol intoxication (or nitrous oxide inhalation)<ref name="Grover" />
*Insidious onset of symptoms similar to alcohol intoxication (or nitrous oxide inhalation)<ref name="Grover" /><ref name="Levett" />
**Early stage: Euphoria, false sense of security, impaired judgement
**Early stage: Euphoria, false sense of security, impaired judgement
**Later stage: Impaired concentration and memory, paresthesias, hallucinations
**Later stage: Impaired concentration and memory, paresthesias, hallucinations
**Final stage: [Occurs at depths of at least 10-13ATM (333-429 feet)], lethargy and loss of consciousness
**Final stage: [Occurs at depths of at least 10-13ATM (333-429 feet)], lethargy and loss of consciousness
*Causes high risk of making bad decisions at depth (cause of up to 9% of diving deaths)<ref name="Grover" />
*Causes high risk of making bad decisions at depth (cause of up to 9% of diving deaths)<ref name="Grover" /><ref name="Levett" />


==Differential Diagnosis==
==Differential Diagnosis==

Revision as of 02:44, 6 March 2016

Background

  • Toxic effects of breathing nitrogen-containing gases while at depth
  • Called the "rapture of the deep"
  • Develops between 3-4ATM (99-132 feet)[1]
    • Rare at depths less than 30 meters (100 ft) unless breathing non-standard air mixtures
    • Similar to alcohol, frequent divers can develop subjective "tolerance" to the effects, but impairment remains[2][1]
  • Can be prevented by using nitrogen-free gas mixture (e.g. heliox), or mixtures with reduced nitrogen content (e.g. helium-nitrogen-oxygen)[1]
  • Risk factors = exertion during dive, cold conditions, alcohol intoxication before dive[1]
  • Other inert gases cause similar symptoms at depth - severity based on lipid solubility of the gas[3]

Clinical Features

  • Insidious onset of symptoms similar to alcohol intoxication (or nitrous oxide inhalation)[1][2]
    • Early stage: Euphoria, false sense of security, impaired judgement
    • Later stage: Impaired concentration and memory, paresthesias, hallucinations
    • Final stage: [Occurs at depths of at least 10-13ATM (333-429 feet)], lethargy and loss of consciousness
  • Causes high risk of making bad decisions at depth (cause of up to 9% of diving deaths)[1][2]

Differential Diagnosis

Diving Emergencies

Diagnosis

  • Clinical diagnosis

Management

  • Ascent - symptoms completely reversed within minutes by ascending to a shallower depth, with no long-term effect
    • Therefore, consider other causes in patients with continued symptoms after ascent

Disposition

  • Discharge

See Also

External Links

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Grover CA, Grover DH. Albert Behnke: nitrogen narcosis. J Emerg Med. 2014 Feb;46(2):225-7.
  2. ↑ 2.0 2.1 2.2 Levett DZ, Millar IL. Bubble trouble: a review of diving physiology and disease. Postgrad Med J. 2008 Nov;84(997):571-8.
  3. ↑ Bove AA. Diving medicine. Am J Respir Crit Care Med. 2014 Jun 15;189(12):1479-86.
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