Positive pressure breathing for acceleration protection and its role in prevention of inflight G-induced loss of consciousness.
That pressure breathing for G protection (PBG) can improve both tolerance and endurance to high sustained +Gz acceleration is now well established. It is not surprising, therefore, that the undoubted potential benefits of PBG in an operational environment have been greeted with enthusiasm by aircrew and their commanders. In some quarters, the use of positive pressure breathing (PPB) during periods of high sustained +Gz acceleration is being hailed as a potential cure for the problem of G-induced loss of consciousness (G-LOC). We believe, however, that confidence in the technique for this purpose in modern, highly agile fighter aircraft is misplaced. This article reviews PPB's background and present use as protection against +Gz acceleration, and summarizes the physiologic basis for its effectiveness, before relating it to its undoubted role in support of other anti-G strategies. From theoretical considerations supported by published evidence, we conclude that while PPB, if used correctly and when combined with other strategies, can enhance tolerance to +Gz acceleration, its principal influence on the occurrence of G-LOC will be by virtue of its ability to increase endurance by decreasing aircrew fatigue.
Harding
R M
RM
Crew Technology Division, USAF School of Aerospace Medicine, Brooks Air Force Base, San Antonio, TX 78235.
Bomar
J B
JB
D000054:Acceleration / Q000009:adverse effects*; D000328:Adult; D000401:Aircraft; D005221:Fatigue / Q000503:physiopathology / Q000517:prevention & control*; D006112:Gravitation; D006801:Humans; D011175:Positive-Pressure Respiration / Q000379:methods*; D014474:Unconsciousness / Q000503:physiopathology / Q000517:prevention & control*