The most common reason an unconscious diver stops breathing is the obstruction of the respiratory tract.
An unconscious diver in a vertical position does not necessarily have obstructed airways just by being in that position. The obstruction of the airways can occur for various reasons, such as the presence of a foreign body, swelling due to allergic reactions, or the relaxation of the throat muscles that can occur in an unconscious state.
In commercial diving rescue operations that involve the use of a harness, it is crucial to position the head properly to ensure unobstructed breathing. At times, it might be necessary to use an airway alignment device, provided that the rescue team has the necessary training and the conditions allow for it.
The orientation of the body and the position of the head are critical in keeping the airways open. An unfavorable angle of the head or neck, exacerbated by the weight of the diving gear, could potentially close or compress the airways, increasing the risk of asphyxiation.
