Food-choking and drowning deaths prevented by external subdiaphragmatic compression. Physiological basis.

Applying subdiaphragmatic compression has been successful in saving victims of food-choking and drowning by expelling the asphyxiating bolus or aspirated water. Sudden elevation of the diaphragm compresses the lungs, which explosively forces air out through the trachea, ejecting the obstructing object. The flow rate, pressure, and volume of air expelled were determined in 10 subjects and found to be substantial, providing confirmation of the effectiveness of the procedure.