Near-Drowning Health Article

Definition

Near-drowning is the term used for survival after suffocation caused by submersion in water or other fluid or liquid.

Description

An estimated 15,000–70,000 near-drownings occur in the United States each year; insufficient reporting prevents a more precise estimate. A typical person experiencing near-drowning is young and male. Nearly half of all drownings and near-drownings involve children less than four years old. Because home swimming pools are the sites for 60–90% of drownings in the 0–4 age group, they pose the greatest risk for children. Teenage boys are also at heightened risk for drowning and near-drowning; drugs and alcohol are implicated in 40–50% of teenage drownings. Overall, roughly four out of five drowning victims are males.

Causes and symptoms

On many occasions, near-drownings are secondary to an event such as a heart attack that causes unconsciousness or a head or spinal injury that prevents a diver from resurfacing. Near-drownings, moreover, can occur in shallow as well as deep water. Small children have drowned or almost drowned in bathtubs, toilets, industrial-size cleaning buckets, and washing machines. Bathtubs are especially dangerous for infants between six months and one year of age, who can sit up straight in a bathtub but may lack the ability to pull themselves out of the water if they slip under the surface.

A reduced concentration of oxygen in the blood (hypoxemia) is common to all near-drownings. When drowning begins, the larynx (air passage) closes involuntarily, preventing both air and water from entering the lungs. In 10–15% of cases, hypoxemia results because the larynx stays closed; this is called dry drowning. Hypoxemia also occurs in wet drownings, the 85–90% of cases where the larynx relaxes and water enters the lungs. Only a small amount of either freshwater or saltwater is needed to damage the lungs and interfere with the body's oxygen intake. Within three minutes of submersion, most people are unconscious. Within five minutes, the brain begins to suffer from lack of oxygen. Abnormal heart rhythms (cardiac dysrhythmias) often occur in near-drowning cases, and the heart may stop pumping (cardiac arrest). An increase in blood acidity (acidosis) is another consequence of near-drowning and, under some circumstances,

KEY TERMS

Acidosis—An increase in acid content of the blood manifested by a decrease in blood pH below 7.40.

Cardiac arrest—Cessation of heartbeats.

Cardiac dysrhythmias—Abnormal heart rhythms.

Cyanosis—A blue color of the skin caused by inadequate oxygen in the blood.

Dry drowning—Hypoxemia due to closure of the larynx.

Endotracheal intubation—Inserting a tube in the trachea to maintain an open airway.

Hypothermia—A decrease in the internal temperature of the body to a core temperature below 96°F (35.6°C).

Hypoxemia—A reduced concentration of oxygen in the blood.

Tachycardia—Rapid heart rate.

Tachypnea—Rapid breathing.

Trachea—Windpipe.

Wet drowning—Water entering the lungs due to relaxation of the larynx.

near-drowning can cause a substantial increase or decrease in the volume of circulating blood. Many individuals experience a severe drop in body temperature (hypothermia).

The signs and symptoms of near-drowning can differ widely from person to person. Some people are alert but agitated, while others are comatose. Breathing may have stopped in one person, while another may be gasping 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. People who have experienced near-drowning but remain conscious may appear confused, lethargic, or irritable.

Diagnosis

Diagnosis relies on a physical examination and on a wide range of tests and other procedures. Blood is taken to measure oxygen levels. Pulseoximetry is another way of assessing oxygen levels. An electrocardiograph is used to monitor heart activity. X rays, computed tomography (CT) scans, or magnetic resonance imaging (MRI) scans can detect head and neck injuries and excess tissue fluid (edema) in the lungs.