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Gas Toxicity During Diving
Carbon dioxide poisoning
Carbon dioxide toxicity may be caused by any of the following: Inadequate respiratory effort (hypoventilation) due to high breathing resistance (eg, from regulator malfunction, tight wetsuit) Overexertion Deep diving Air supply contamination by exhaled gases (as occurs with a carbon dioxide scrubber failure in a rebreather air supply) Hypoventilation can increase blood carbon dioxide levels and cause shortness of breath and sedation. Severe carbon dioxide poisoning can cause nausea, vomiting, dizziness, headache, rapid breathing, flushing, confusion, seizures, and loss of consciousness. Mild carbon dioxide poisoning is suspected if divers frequently have dive-related headaches or low air-use rates. Carbon dioxide intoxication usually resolves during ascent; thus, arterial blood gas (ABG) testing after a dive typically does not detect any increase in carbon dioxide levels. Treatment is gradual ascent and termination of the diving exercise or correction of the precipitating cause. 