Subjective Responses to Positive Pressure Breathing under Sustained High-G Using the Combat Edge System.

摘要

The two studies reported here were conducted during the check-out phase of an assisted positive pressure breathing system, known as COMBAT EDGE, being developed by the U.S. Air Force. Manned centrifuge tests of the regulator which controls air pressure to the oro-nasal mask and counterpressure vest provided an early opportunity to obtain subjective data concerning systems characteristics from subjects under high-G. Subjects underwent four different high-G profiles: 1) +9Gz maximum (onset rate=0.1G/sec), 2) +5Gz maximum (onset rate=0.5 G/sec), 3) +7Gz maximum (onset rate=0.5 G/sec) and 4) +9Gz maximum (onset rate=0.5 G/sec). Onset of pressure to the mask and vest occurred at +4Gz with a rate of 12 mmHg/g. Maximum pressure was 60 mmHg at +9Gz. Subjects' reports of body pain mostly concerned the elbows and arms, followed by leg, ear, buttock, facial and rib pain. Subjects also reported that the M-1 and L-1 straining maneuvers were not needed as frequently with the COMBAT EDGE system. Tensing of the leg/buttock area was sufficient to counteract the effects of high-G. (JS)