Drowning and Cold-Water Immersion
Drowning: respiratory impairment from submersion or immersion in liquid
Fatal drowning: drowning that results in death
Nonfatal drowning: drowning injury that does not result in death (avoid historical terms such as near drowning and wet or dry drowning)
Immersion: body entry into a liquid medium
Submersion: entry into a liquid medium where the body—particularly the head—is below the surface
Cold-Water Immersion
1. The cold shock response is the most common cause of drowning in cold water.
2. Immediately on immersion, uncontrollable gasping lasts 1 to 3 minutes, which results in aspiration of water unless the head is kept above surface.
3. Sudden skin cooling results in increased peripheral vascular resistance of superficial blood vessels.
4. Heart rate and cardiac output increase; outpouring of catecholamines may lead to fatal dysrhythmias.
5. Cooling of the periphery decreases nerve conduction, and muscle control becomes difficult, making self-rescue virtually impossible.
6. Priority for self-rescue is to maintain the head above water, assuming the heat escape lessening position (HELP) (Fig. 50-1) if possible.
7. If two or more persons are in the water, the huddle position (Fig. 50-2) is recommended to lessen total body heat loss.
FIGURE 50-2 Huddle technique. (Courtesy Alan Steinman, MD.)
8. Because children become hypothermic much more quickly than do adults, they should be placed in the middle of the huddle.
9. Drawstrings should be tightened in clothing to decrease the flow of cold water within clothing layers.
10. In cold water a person may consider whether to stay in place to conserve heat or swim to safety. Note that at 45 to 90 minutes, swim failure may occur as a result of continued reduction of core body temperature causing loss of gross motor function. The average person can swim approximately 800 m (2625 feet) in 10° C (50° F) water while wearing a personal flotation device before swim failure and death occur.
On-Scene Rescue and Patient Management
1. Safety devices should be used to tow the patient, or life preservers should be thrown to people in trouble in the water before a human responder enters the water.
2. Anticipate cervical spine fracture or a significant head injury if trauma (for example, diving or fall) is suspected.
3. Evaluate for hypoglycemia (with or without diabetes), seizure disorder, and acute myocardial infarction as potential causes of drowning.
4. Initiate resuscitation (see later).
5. If rapid extrication from water is not feasible, institute in-water rescue breathing and maintain the patient in a vertical position to minimize the potential for vomiting and further aspiration of water and emesis (Fig. 50-3).
