Nitrogen narcosis
Background
- A reversible alteration in consciousness that occurs while diving at depth
- Caused by the anesthetic effect of nitrogen at high pressure
- Does not usually become noticeable at depths less than 30 meters (100 ft), unless breathing non-standard air mixtures
- May cause scuba diving accidents at depth or in a hyperbaric chamber, but stops once the patient is at normal pressure
Clinical Features
- Produces a state similar alcohol intoxication (or nitrous oxide inhalation), only while at depth
- Completely reversed in a few minutes by ascending to a shallower depth, with no long-term effect
Differential Diagnosis
Diving Emergencies
- Barotrauma of descent
- Otic barotrauma
- Pulmonary barotrauma
- Sinus barotrauma
- Mask squeeze
- Barodentalgia (trapped dental air causing squeeze)
- Barotrauma of ascent
- Pulmonary barotrauma (pulmonary overpressurization syndrome)
- Decompression sickness (DCS)
- Arterial gas embolism
- Alternobaric vertigo
- Facial baroparesis (Bells Palsy)
- At depth injuries
- Oxygen toxicity
- Nitrogen narcosis
- Hypothermia
- Contaminated gas mixture (e.g. CO toxicity)
- Caustic cocktail from rebreathing circuit
Workup
- Clinical diagnosis
Management
- Ascent