- Toxic effects of breathing nitrogen-containing gases while at depth
- Called the "rapture of the deep"
- Develops between 3-4ATM (99-132 feet)
- Can be prevented by using nitrogen-free gas mixture (e.g. heliox), or mixtures with reduced nitrogen content (e.g. helium-nitrogen-oxygen)
- Risk factors = exertion during dive, cold conditions, alcohol intoxication before dive
- Other inert gases cause similar symptoms at depth - severity based on lipid solubility of the gas
- Insidious onset of symptoms similar to alcohol intoxication (or nitrous oxide inhalation)
- Early stage: Euphoria, false sense of security, impaired judgement, diminished reaction times
- 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, i.e. impairs diver's judgment therefore leading to drowning accidents (cause of up to 9% of diving deaths)
- Barotrauma of descent
- Barotrauma of ascent
- At depth injuries
- Clinical diagnosis
- 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
- Grover CA, Grover DH. Albert Behnke: nitrogen narcosis. J Emerg Med. 2014 Feb;46(2):225-7.
- Levett DZ, Millar IL. Bubble trouble: a review of diving physiology and disease. Postgrad Med J. 2008 Nov;84(997):571-8.
- Bove AA. Diving medicine. Am J Respir Crit Care Med. 2014 Jun 15;189(12):1479-86.