What is required to initiate surface decompression if no recompression chamber is available?

To initiate surface decompression when a recompression chamber is unavailable, the correct approach is to continue decompression on air. This process is necessary because divers need to avoid the risk of decompression sickness, which can occur if they ascend too quickly or surface directly without managing inert gas elimination.

Continuing decompression on air allows the diver to gradually off-gas nitrogen absorbed during the dive while still being at the surface. By ascending to the surface under controlled conditions and following specific decompression schedules, divers can reduce the risk of bubbles forming in their bodies, which is critical when recompression therapy can't be administered.

In contrast, utilizing a mixing chamber, making an immediate ascent to the surface, or increasing ventilation rate do not effectively address the critical need for controlled off-gassing in the absence of a recompression chamber. A mixing chamber is not commonly used for surface decompression, and ascending too quickly can lead to severe decompression sickness. Increasing the ventilation rate may provide temporary relief but does not replace the need for appropriate decompression practices.