[Cardiovascular responses to G-suits with 3 levels of positive pressure breathing using different chest counter pressures].
OBJECTIVE
To observe cardiovascular responses to positive pressure breathing (PPB) using different counter pressures.


METHODS
Cardiovascular responses of 7 male healthy subjects (aged 18-20 years) wearing two kinds of Jerkin-G-suit were observed under three levels of ground-level PPB (30, 50, 70 mmHg) for 3 min.


RESULTS
All subjects completed the experiment successfully. While during PPB at 50, 70 mmHg levels within 3 min, HR, MAP, TPR elevated significantly, while SV declined significantly. At all 3 PPB levels Q-Z time was not significantly changed. There were significant difference (P<0.05) between delta SV and delta TPR with the two Jerkin-G-suits under PPB of 70 mmHg.


CONCLUSIONS
PPB resulted in elevation of MAP, TPR, HR and decline of SV significantly using two kinds of Jerkin-G-suit. PPB had no effect on contractile function of cardiac muscle. Under PPB, SV increased significantly when chest counter pressure was equal to the mask pressure.
Han
Xue-ping
XP
Institute of Aviation Medicine, Air Force, Beijing, China. hanxueping6006@soho.com.cn
Jia
Yu-lan
YL
Yan
Ru-quan
RQ
Chen
Juan
J
Fu
Li-shan
LS
D000293:Adolescent; D000328:Adult; D000337:Aerospace Medicine; D001794:Blood Pressure / Q000502:physiology; D005676:Gravity Suits; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008397:Masks; D009206:Myocardium; D011175:Positive-Pressure Respiration; D011312:Pressure; D013318:Stroke Volume / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology