Physiological Effects of Positive Pressure Breathing with Pure Oxygen and a Low Oxygen Gas Mixture

Positive pressure breathing (PPB) is a part of the life support system for pilots, but can cause respiratory fatigue and circulatory collapse due to peripheral pooling of blood. This study examines the physiological effects of PPB with pure oxygen and a low-oxygen gas mixture. The tests were completed at ground level, simulating pure oxygen PPB at high altitude. Stroke volume and heart rate responses differed for pure oxygen and low oxygen. It is concluded that PPB has a negative effect on the cardiovascular system and performance of flying tasks.