DROWNING - Medicine for Mountaineering and Other Wilderness Activities - page 425

Many terms are used in the drowning literature. For this chapter drowning is defined as
water submersion resulting in asphyxia and death. Individuals who have been submerged
in water and require cardiopulmonary resuscitation (CPR) have drowned.
Though not used in this chapter, the term near-drowning has been applied to situations
in which individuals survive drowning more than twenty-four hours, after which they may
dieormaysurviveinanormalorimpairedneurologicalstate.Suchterminologyisnotused
for any other medical condition. (A person who has been successfully resuscitated from a
cardiac arrest is not said to have had a near-cardiac arrest.)
A submersion incident is an event, usually unintentional or accidental, in which an in-
dividual is submersed in water and is at least at risk of drowning, may aspirate water, but
does not suffer cardiopulmonary arrest. Sophisticated medical care including hospitaliza-
tion may be needed, but CPR is unnecessary.
The terms wet drowning and dry drowning are applied to lung changes that result from
aspiration or lack of aspiration of water. Wet drowning refers to fluid in the lungs after an
individual aspirates water. Dry drowning refers to a submersion event in which spasm of
the vocal cords closes the airway and prevents the individual from aspirating water. About
10 to 15 percent of drownings are dry.
Immersion syndrome is sudden death resulting from ventricular fibrillation or cardiac
arrest immediately after sudden immersion in cold water.
Immersion hypothermia occurs as the core temperature gradually falls through surface
cooling when a person is immersed in cold water. However, even in ice-cold water death
fromhypothermiadoesnotoccurinminutes.Incapacitationbythecoldmayleadtodrown-
ing in just a few minutes, but lethal cooling requires approximately two hours.
Acute submersion hypothermia is the rapid development of hypothermia during drown-
ing due to core cooling from aspiration and absorption of cold water.
EPIDEMIOLOGY OF DROWNING
Young children are most vulnerable to drowning due to their lack of awareness of danger,
poor swimming techniques, and the size of their heads in relation to body size, which
makes them susceptible to falling into containers. Children under one year of age drown
most frequently in bathtubs, toilets, and buckets. Children aged one to four years drown
most commonly in residential swimming pools. Teen drowning is often the result of risk-
taking behaviors and lack of supervision, compounded by drug and alcohol intake. In 2005
males accounted for 80 percent of all U.S. drownings, largely due to risk-taking behavi-
ors characteristic of the adolescent male group. Beyond the toddler age group, boys have a
three times greater risk of drowning.
Although swimming programs for very young children have proliferated, no studies
demonstrate that they prevent drowning. Such programs may produce a false sense of se-