Oxygen Toxicity
Oxygen toxicity is rarely seen in sports diving. It refers to the mental and physical impairment that a diver may experience when exposed to elevated levels of respired oxygen for a prolonged period of time. One might experience toxicity under water or in a decompression chamber (highly concentrated oxygen is often used to treat acute decompression illness in a chamber). Symptoms may include abnormal sensations, impaired muscular function of the arms and legs, pallor (a whitening of the skin), twitching of the facial muscles, nausea, dizziness, and/or convulsions (seizure activity). Remember, a blue unconscious diver is oxygen starved and a white (pallor) unconscious diver may have been over-exposed to oxygen. Pallor may also be associated with states of poor blood flow (shock) or hypothermia.
If the lungs are over-exposed to pressurized oxygen for a prolonged period of time they too may suffer from the ill effects of oxygen toxicity. Oxygen toxicity of the lungs may cause the collapse of breathing units and flooding of the lungs with fluid. Symptoms may include a scratchy sensation of the throat, shortness of breath, chest congestion, unremitting cough, and/or chest pain. Symptoms typically abate when the partial pressure of oxygen (the concentration) is reduced.
Factors that increase the risk of oxygen toxicity include:
- Using high percentage oxygen supplies such as Nitrox.
- Prolonged exposure to oxygen on deep dives.
- Using pure oxygen rebreathers.
- Using pure oxygen in decompression chambers.
Because oxygen toxicity is rarely seen in sport diving we felt that a lengthy discussion of recognition and treatment would be unnecessary for the scope of this guide. If more information is needed please discuss the topic with your dive master or dive physician or refer to Professional Association of Diving Instructors (PADI) or Diver’s Alert Network (DAN) for more information.
