Drowning Physiology—After the Rescue

by Paul Daniels, M. S.
Madison, Wisconsin School—Community Recreation

In America drowning is the third largest cause of accidental death, involving over 7,000 victims annually. Many of these fatalities could be prevented with proper rescue and follow-up life support procedures. It is important that recreation professionals and other persons responsible for aquatics programs understand the basic physiological threats present during and following drowning situations.

Not all drowning victims literally inhale water into their lungs. The extreme sensitivity of upper airway passages often causes a laryngeal spasm, sealing off and preventing water from entering the lungs. These spasms lead to dry drowning. Victims of dry drowning often respond to artificial ventilation without further complications if the symptoms are identified and reached soon enough, generally within one to two minutes of submersion.

Wet drowning occurs when water is inhaled past the larynx into the lungs, severely complicating rescue and life support procedures. This situation has been reported to occur in 90% of all drownings, although results of related research vary to a great degree.

When water enters the lungs the victim's blood chemistry is rapidly altered, often leading to heart failure. In fresh water drownings inhaled water is immediately absorbed into the blood causing hemodilution. The diluted blood quickly leads to heart failure due to ventricular fibrillation, a condition simply described as shivering of the heart, or anoxia (oxygen starvation). Sea or salt water creates the opposite effect. Water is drawn from the blood into the lungs. This process causes the blood to become more concentrated, leading to an increased load on the heart and heart failure. Older drowning victims may experience immediate heart failure as a result of the initial trauma of drowning, particularly in extremely cold water.

In any type of drowning situation, it is critical for the rescuer and responding rescue squad to be thoroughly trained in both artificial resuscitation and cardio-pulmonary resuscitation techniques. Artificial resuscitation alone is only adequate in some dry drowning situations, when the victim is reached before heart failure occurs. If heart failure occurs before or after the rescue, cardiopulmonary resuscitation (CPR) is required. When necessary, CPR should be initiated, even after a victim's prolonged submersion, and continued indefinitely. Successful treatment without further complications has been documented after more than 40 minutes of submersion and after hours of applied CPR.

The physiological effect of drowning, differs according to the type of water. However, immediate emergency procedures are the same.

Victims of prolonged submersion are most likely to be revived after submersion in cold water, due to a physiological phenomenon called "diver's reflex". The diver's reflex condition basically causes oxygenated blood to be shunted from one's extremities and concentrated in vital areas including the heart, lungs and brain. Other physiological processes are also "slowed down," further prolonging adequate oxygenation of vital areas. Therefore, CPR should always be initiated regardless of elapsed time in cold water drownings.

In the event a drowning victim is revived, or water is suspected to have entered the lungs, immediate hospitalization is necessary. Damage to the lungs, although often initially undetectable, can result in "delayed death subsequent to near-drowning," commonly referred to as "secondary drowning."

Secondary drowning is a sudden, rapidly deteriorating condition generally occurring without clear warning between one and forty-eight hours after initial rescue procedures. For practical purposes, it represents rapid "pneumonia-like" flooding of the lungs with pulmonary fluids. All near-drowning victims should be rapidly transported to the hospital and admitted as potential medical emergencies. Continuous observation. X-ray procedures, oxygen, intravenous treatment, plasma and advanced life support procedures may be necessary. However, if the victim is kept alive for 24 hours a complete recovery is likely.

Professionals with responsibilities in the area of aquatics, or community members involved in aquatic activities need to understand factors that contribute to death by drowning. It is essential that persons responsible for directly supervising aquatic activities be required to have current certification and regular training in advanced lifesaving as well as cardio-pulmonary resuscitation, which includes artificial resuscitation and procedures for dealing with choking.

Mr. Daniels is aquatics supervisor for the Madison School—Community Recreation Department, a position he has held for two years. He holds bachelor's and master's degrees from SIU-C and has a professional background in university intramural sports and elementary education.

Illinois Parks and Recreation 32 July/August 1982