Venting vs. Ventilation: A Danger of Manual Resuscitation Bags.

Hirschman AM, Kravath RE Chest 1982 Vol. 82 Pages 369-370

The authors note that hand-operated resuscitator bags are frequently used either with masks or endotracheal tubes. They are available in a variety of shapes and sizes compatible with prematurity through adulthood. Many models have a pressure relief valve available as an optional safety feature designed to limit the maximum pressure that can be provided, thus reducing the risk of overinflation and the production of pneumothorax, especially at the hands of an operator inexperienced in gauging the feel] of bagged ventilation. In the case reviewed, a pressure relief valve prevented the bag from developing sufficient pressure for ventilation during resuscitation of a patient. Many conditions for which cardiopulmonary resuscitation is needed require ventilation pressures higher than the pressure relief valve setting. Despite this, the venting of the safety valve is often unrecognized. Knowledge of this problem and of simple methods for overriding the valve need to be disseminated and the equipment designed for safer use. Anyone using a resuscitation bag should be aware that inadequate ventilation, despite vigorous squeezing of the bag, may be due to inappropriate venting of the pressure relief valve. This can be recognized by the sound made when the valve vents to the air; occluding the relief valve while bagging may be life-saving.