[lungfish]

Laryngospasm:
A laryngospasm is a protetive reflex that protects the airway by closing off the vocal cords in the throat preventing water from entering the lungs. When a swimmer is drowning, this is usually stimulated when the water hits the back of the throat. The spasm can last for several minutes until either the diver is recovered/rescued or he takes a "death breath" of water as the body tries a last ditch effort to save itself.

If you are supporting a diver in black out who is experiencing a laryngospasm - breathing is seen in the chest but not heard at the mouth and nostrils - then one should do two breaths of rescue breathing into the diver to break the spasm and the airway should open and spontaneous breathing begins. If it doesnt then continue rescue breathing at one breath every five seconds...