critical care medicine
Airway and Respiratory Devices
Introduction
If no spontaneous respiration occurs after Clearing and Opening the Upper Airway and no respiratory devices are available, rescue breathing (mouth-to-mask or mouth-to-barrier device) is started; mouth-to-mouth ventilation is rarely recommended. Exhaled air contains 16 to 18% oxygen and 4 to 5% carbon dioxide, which is adequate to maintain blood oxygen and carbon dioxide values close to normal. Larger-than-necessary volumes of air may cause gastric distention with associated risk of aspiration. (See also Overview of Respiratory Arrest , 