Lung pressure injuries

Question:
Recently, a program on TV included an account of a dive accident in which a non-breathing diver was recovered from a depth of 10 metres, after having got stuck on a wreck. The diver sustained a lung pressure injury.
I have always thought that non-breathing/unconscious divers cannot sustain lung pressure injuries because they are not able to consciously hold their breath, and therefore the air expanding in their lungs during an ascent will be able to escape.
What are your views on this? And if non-breathing/unconscious divers are susceptible to lung pressure injuries, what can the rescuer do to minimize the risk?

Answer:
Lung pressure injuries can occur with hydrostatic pressure gradients as little as 1,5 meters of water, if the lung is totally inflated when leaving the bottom depth.
It is not always true that non breathing unconscious divers have a free and patent airway, for a number of reasons:

  • it takes some minutes before hypoxia induces a muscle relaxation,
  • even if this has already happened, incorrect head and neck positioning may hinder expanding air volumes air from escaping through the airway.

Minimizing the risk of a lung pressure injury should always include

  • correct positioning of the injured diver's head and neck, which may need continuous support during the ascent,
  • limiting the ascent rate as much as possible,
  • and, obviously, caring for the rescuer's safety first.

If the condition underlying the loss of consciousness and respiratory arrest also caused any form of trismus ( clenching of the jaw ) or other spasmodic muscular contractions, it may be difficult to assure an adequately patent airway anyhow, until sufficient time have elapsed to induce relaxation.