A diver that loses consciousness due to air entering the bloodstream has which condition?

• A. Air Embolism
• B. Decompression Illness
• C. Nitrogen Narcosis
• D. Oxygen Toxicity

Answer: (A)

Air embolism. When air bubbles enter the bloodstream, they can travel to and obstruct vessels in the brain, causing sudden loss of consciousness. In divers, this most often happens if a breath is held during ascent or after a lung over-expansion injury, allowing air to escape into the pulmonary veins and circulate systemically. This intravascular air blockage explains the acute unconsciousness.

Decompression illness involves nitrogen bubbles forming in tissues and blood from rapid decompression and typically presents with joint pain, numbness, or skin changes before any clear intravascular air issue. Nitrogen narcosis is a CNS effect from dissolved nitrogen at depth, not air entering the bloodstream. Oxygen toxicity stems from excessive oxygen levels causing CNS or lung toxicity, not from air emboli.