What is the procedure for conducting a controlled emergency ascent?

The procedure for conducting a controlled emergency ascent involves ascending slowly while exhaling continuously. This technique is critical because it helps to prevent barotrauma to the lungs, which can occur if a diver ascends too quickly while holding their breath. When a diver ascends, the pressure around them decreases, causing any trapped air in the lungs to expand. If a diver fails to exhale during the ascent, this expanding air can lead to serious injuries such as an air embolism.

By exhaling constantly throughout the ascent, divers ensure that the pressure in their lungs and the external water pressure remain balanced, significantly lowering the risk of lung overexpansion injuries. The recommended ascent rate is typically no faster than 30 feet per minute, allowing for safe decompression and giving any residual nitrogen in the body ample time to off-gas safely.

While stopping at regular intervals for rest, ascending with a buddy while sharing air, or ascending rapidly could seem practical in certain situations, these approaches carry significant risks. Maintaining a controlled ascent with continuous exhalation is the safest and most effective method.