Confusion in divers can be a sign of which of the following?

• A. Hypoxia
• B. Hypercapnia
• C. Oxygen toxicity
• D. All of the above

Answer: (D)

Confusion in divers signals that brain function is being compromised by gas-related problems. The brain needs a steady supply of oxygen, so hypoxia—too little oxygen reaching tissues—can quickly impair judgment and cause disorientation. Hypercapnia, or excessive carbon dioxide, also disrupts brain activity and can produce confusion, headaches, and dizziness when ventilation is inadequate or gas flow is mismatched. Oxygen toxicity, specifically CNS oxygen toxicity from breathing gas with too high a partial pressure of oxygen at depth, can manifest as confusion, visual disturbances, and seizures as the oxygen level becomes unsafe for the brain. Because confusion can arise from any of these scenarios, recognizing it as a possible sign of multiple serious issues is why “All of the above” is the best choice. In practice, a diver who becomes confused should be treated as an emergency situation: stop the dive, assess the gas supply and ventilation, and follow rescue and ascent procedures as appropriate.