The process of drowning begins as a person struggles to keep afloat in the water, He gulps in large breaths of air as he thrases about. When he can no longer keep afloat and starts to sumberge, he tries to take and hold one more deep breath. As he does, water may enter the airway. There is a series of coughing and swallowing actions, and the vivtim involuntarily inhales and swallows more water. As water flow past the epiglottis, it triggers a reflex spasm of larynnk. This spasm seals the airway so effectively that no more than a small amount of water reaches the lungs. Unconciousness soon result from hypoxia (oxygen starvation)
About 10% of the people who drown die just from the lack of air. In the remaining victims, the person attempts a final respiratory effort and draws water into the lungs, or the spasm subside with the onset of unconciousness and water freely enters the lungs.
As a paramedic, we sould start using the term near-drowning. Obviously, if the patient is breathing and coughing up the water, he has not drawned but has nearly drowned. This is only part of what we mean by near-drowning. If patient has “drowned” in lay person’s term, he is not necessarily biologically dead. Resusciation effort may keep the patient biologically alive long enough for more advanced measures to save the patient’s life.
Only when sufficient time has passed to render resuciation useless has drowning truly taken place. Some patient in cold water can be resusciatated after 30 minutes or more in cardiac arrest. Once the water temperature falls below 70 F (21 C). biological death may be delayed. the colder the water, the better are the patient’s chance for survival, unless generalized hypotermia produces lethal complications.
Source : Bready Emergency Care, 10th Edition