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Near-drowning is the term used to describe survival after suffocation from submersion in a liquid medium, usually water. One of the many causes of mental retardation includes the catastrophic event of near-drowning. Children who experience a near drowning episode may have resulting neurological damage to the extent that the criteria are met for a diagnosis of mental retardation.

Physiology of Drowning
A reduced concentration of oxygen in the blood, hypoxemia, is common to all near-drownings. In the early stages of drowning, the person may initially gasp and aspirate small amounts of water. Hyperventilation and voluntary holding of breath may follow. The aspiration of small amounts of water triggers laryngospasm during which the trachea is sealed such that neither water nor air passes through. Hypoxemia results and asphyxia leads to relaxation of the airway, allowing water to enter and fill the lungs. This is referred to as “wet drowning”. In some cases (approximately 10 – 20%), the individual does not aspirate water due to tight laryngospasms or “dry drowning”.

In either case, hypoxemia causes progressive damage to the brain, heart, lungs, and other major organs. Systemic hypoxemia eventually leads to abnormal heart rhythm, respiratory arrest, and finally cardiopulmonary arrest.

Drowning occurs very quickly. Within two to three minutes of submersion, most individuals are unconscious and within four to six minutes the brain begins to suffer from lack of oxygen.

The mammalian diving reflex may allow some individuals to survive for longer periods in the water. The diving reflex may occur in young children who are suddenly submerged in cold water. This reflex slows the heartbeat, constricts peripheral arteries thereby directing more oxygenated blood to the heart and brain, and produces immediate apnea that prevents aspiration. Respiratory and cardiac metabolism decreases, which in turn reduces the damage to organs. In some cases, children who have been submerged for extended time periods can be fully resuscitated.

Factors Affecting Survival

The critical factors affecting the chances of an individual surviving submersion without permanent injury include the following:

• duration of submersion;
• water temperature;
• age of the victim;
• speed of resuscitation; and
• presence of associated injuries.

Signs and Symptoms

Symptoms of near-drowning can range significantly from minor symptoms to near death. The person may be alert, drowsy, confused, or comatose. Some individuals may be gasping for air, coughing, wheezing, or vomiting, and some may not be breathing at all. Clear to frothy red sputum may be present. The person’s skin may be cold and appear blue or pale. Abdominal distension may be present. The person may have an abnormal heart rate or have a pulse that cannot be detected.

Treatment

Treatment begins with removing the person from the water. Immediate on-site resuscitation is crucial to increasing the rate of survival without neurological damage. Artificial respiration and cardiopulmonary resuscitation (CPR) should be provided as indicated. The person’s neck should be moved as little as possible if there is any indication of a spinal injury.

After initial resuscitation efforts and emergency personnel are on the scene, oxygen is administered. As needed, intubation may be necessary to maintain the airway. The individual is checked for injuries and fluids are given intravenously. If the person was in cold water and is hypothermic, emergency personnel will take steps to warm the individual.

Every person who is a near-drowning victim should be transported and evaluated in a hospital, even those who may have appeared to fully recover. Serious complications may have a delayed onset, such as aspiration pneumonia.

In the hospital, treatment focuses on intensive pulmonary care. Measures may range from simple administration of oxygen to continuous mechanical ventilation. Fluid and electrolyte solutions may also be administered. Treatment for cardiac dysrhythmias and hypothermia may be necessary. The person may develop Adult Respiratory Distress Syndrome.

The overall prognosis of a person experiencing near-drowning is related directly to the duration and magnitude of hypoxia. Neurological damage is the major long-term concern in treating persons experiencing near-drowning.

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