Drowning is suffocation that results from being submerged in water or anotherfluid. Near-drowning is the term for surviving such suffocation.
The number of near-drownings in the United States is hard to estimate becausenot all incidents are reported, but estimates range from 15,000-70,000. Nearly half of all drownings and near-drownings involve children less than four years old, and 60-90% of drownings in this age group are in home swimming pools. Teenage boys also face a heightened risk of drowning and near-drowning, because of their tendency to behave recklessly and use drugs and alcohol (drugsand alcohol are implicated in 40-50% of teenage drownings). At all ages, males are more likely than females to drown, possibly because they are not supervised as closely.
Not all drownings and near-drownings occur because a nonswimmer accidentallyventures into deep water. Many are a result of some other event such as a heart attack that causes unconsciousness or a head or spinal injury that prevents a diver from resurfacing. Drownings can occur in shallow, as well as deep,water. Young children have drowned or almost drowned in bathtubs, toilets, large buckets, and washing machines. Bathtubs are especially dangerous for infants six months to one year old, who can sit up straight in a bathtub but maynot be able to pull themselves out of the water if they slip under the surface.
Human life depends on a constant supply of oxygen-laden air reaching the blood by way of the lungs. When drowning begins, the larynx (an air passage) closes, preventing both water and air from entering the lungs. If the larynx stays closed, the concentration of oxygen in the blood drops. This is called "drydrowning." In "wet drowning," the larynx relaxes and water enters the lungs,also resulting in a drop in oxygen concentration. All of this happens very quickly: within three minutes of submersion most people are unconscious, and within five minutes the brain begins to suffer from lack of oxygen. Other problems that often occur in near-drowning cases are abnormal heart rhythms (cardiac dysrhythmias), cardiac arrest, an increase in blood acidity (acidosis), and a severe drop in body temperature (hypothermia).
The signs and symptoms of near-drowning can differ widely from person to person. Some victims are alert but agitated, while others are comatose. Breathingmay stop, or the victim may gasp for breath. Bluish skin (cyanosis), coughing, and frothy pink sputum (material expelled from the respiratory tract by coughing) are often observed. Rapid breathing (tachypnea), a rapid heart rate (tachycardia), and a low-grade fever are common during the first few hours after rescue. Conscious victims may appear confused, lethargic, or irritable.
Treatment begins with removing the victim from the water and performing cardiopulmonary resuscitation (CPR). One purpose of CPR--which should be attemptedonly by people trained in its use--is to bring oxygen to the lungs, heart, brain, and other organs by breathing into the victim's mouth. When the victim's heart has stopped, a person administering CPR also attempts to get the heart pumping again by pressing down on the victim's chest. After CPR has been performed and emergency medical help has arrived on the scene, the victim is given oxygen and intravenous fluids and is checked for injuries.
In the emergency department, victims continue receiving oxygen until blood tests show a return to normal. Patients who have experienced hypothermia are rewarmed. Comatose patients usually do not benefit from treatment. Patients whorecover can be discharged from the emergency department after four to six hours if their blood oxygen level is normal and they have no other problems. But because lung problems can develop 12 or more hours after submersion, patients are dismissed only if the medical staff is convinced they will seek medical help if necessary. Patients who do not recover fully in the emergency department are admitted to the hospital for at least 24 hours for further observation and treatment.
Brain damage is the major long-term problem from near-drowning. However, mostpatients who are not comatose when they arrive at the hospital survive withbrain function intact. Death or permanent brain damage are very likely when patients arrive comatose. Early rescue of near-drowning victims (within 5 minutes of submersion) and prompt CPR (within less than 10 minutes of submersion)seem to be the best guarantees of a complete recovery.
Prevention of drowning and near-drowning depends on educating people about water safety. Parents should never leave young children in or near water without supervision for even a short time. Everyone should follow the rules for safe swimming and boating, and adults and teenagers should learn CPR. Anyone whohas a medical condition that can cause a seizure or otherwise threaten safety in the water should swim only with a partner. People also need to be awarethat alcohol and drug use substantially increase the chances of an accident.