Drowning Causes, Symptoms, Treatment, and Prevention on MedicineNet.com

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Drowning (cont.)

The Grief and Mourning Quiz

Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Does the type of drowning matter?

There have been a variety of theories reported regarding the potential responses of the body to different drowning situations. Most discuss dry vs. wet drowning and salt vs. fresh water drowning.

Wet vs. Dry Drowning

Most drownings are unwitnessed, and the victim is found floating. While only a small amount of aspirated water is required to cause significant problems with lung function, it is the prolonged submersion time and lack of breathing that causes morbidity due to hypoxemia.

Approximately 10%-20% of drowning victims have dry drowning, but even most wet drowning victims have less than 4cc/kg of water found in their lungs. For a 50 pound child, this amounts to less than 3 ounces.

Salt vs. Fresh Water Drowning

In the lung, the breathing tubes (trachea, bronchi, bronchioles) branch into smaller and smaller segments until they end in an air pocket called an alveolus (plural alveoli). This is the part of the lung where air and red blood cells in capillary blood vessels come near enough to allow the transfer of oxygen and carbon dioxide between the two. Alveoli are covered with a chemical called surfactant that allows the air pocket to open and close easily when breathing occurs.

When fresh water enters an alveolus, it destroys the surfactant and causes the alveoli to collapse, unable to open with breathing. A ventilation-perfusion mismatch occurs in which the body sends blood to parts of the lung that lack oxygen, resulting in a decrease in the concentration of oxygen in the blood.

Salt water doesn't destroy surfactant, rather it washes it away and damages the membrane between the alveolus and the capillary blood vessel. One again, the body sends blood flow to areas of the lung that aren't able to provide it oxygen, and hypoxemia occurs.

Regardless of the type of water, lung function is compromised, and hypoxemia occurs. In some circumstances, electrolyte abnormalities may occur with fresh water drowning.