[Cardiovascular effect of positive pressure breathing using G-suits with different bladder coverage].
OBJECTIVE
To compare cardiovascular function of subjects exposed to positive pressure breathing (PPB) while wearing G-suits with different bladder coverage.


METHODS
6 male healthy subjects (18-20 years) wearing three kinds of G-suit with bladder coverage of 45%, 65% and 90% respectively, were exposed to PPB with counterpressures of 30, 50 or 70 mmHg for up to 3 min continuously. G-suit bladder pressure value was three times as high as that of PPB counterpressure. Cardiovascular function was observed every minute. The interval between PPBs was 10 min. The equipment consists of G-suit, jerkin, helmet and mask.


RESULTS
All subjects completed the experiment successfully. Mean arterial pressure (MAP) elevated significantly, while stroke volume had no striking change, as compared with control group when wearing G-suit with 65% or 90% bladder coverage G-suit. During PPB for 3 min, cardiovascular function didn't change significantly. The mean value of MAP was proportional to the level of PPB.


CONCLUSIONS
The greater G-suit bladder coverage, the less cardiovascular function effect when PPB was conducted simultaneously.
Institute of Aviation Medicine, The Air Force, Beijing, China. hanxueping6006@sohu.arn.cn
Xue-ping
XP
Han
Qiong
Q
Wang
Li-shan
LS
Fu
Juan
J
Chen
Qiang
Q
Shi
Ru-quan
RQ
Yan
D000293:Adolescent; D000328:Adult; D000337:Aerospace Medicine; D001794:Blood Pressure / Q000502:physiology*; D002320:Cardiovascular Physiological Phenomena; D005676:Gravity Suits; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008397:Masks; D011175:Positive-Pressure Respiration; D011312:Pressure; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology