If your buddy becomes unconscious about two minutes after surfacing, what should be suspected?

When a buddy becomes unconscious shortly after surfacing, air embolism is a serious concern due to the potential for gas bubbles forming in the bloodstream. This condition typically occurs when a diver ascends too rapidly or holds their breath during ascent, causing air to expand and form bubbles that can block blood vessels. The fact that the buddy becomes unconscious only two minutes after surfacing indicates that a rapid ascent may be involved, allowing little time for any other causes to present symptoms.

In contrast, shallow water blackout would occur during or immediately after a dive due to hypoxia, typically from hyperventilating before diving, but it would not present as an unconsciousness two minutes post-surface. Nitrogen narcosis is associated with deeper depths and affects divers while they are still submerged, rather than after surfacing. Decompression sickness might cause symptoms such as fatigue or joint pain and usually takes longer than two minutes to manifest after surfacing. Thus, air embolism is the condition most closely linked to the scenario described and warrants immediate attention.