摘要
为了阐明M-3动作的G防护原理，在＋1GZ条件下研究了其呼吸循环效应并与M-1和L－1动作进行了对比。实验中，测量了12名航空医学生实施上述三种抗G动作时的胸内压、每搏输出量、心水平收缩压、呼吸流率及呼吸压力等参量。结果显示，M-3、M－1动作呼气相及L-1动作屏气期胸内压分别为8．1、8．7及8．8kPa，三种动作每搏输出量分别减少16．4％、19．9％及23．2％。M－3动作胸内压升高值、每搏输出量减少值、心水平收缩压及呼吸频率与M－1动作无显著性差异（P＞0．05），而与L-1动作有显著性差异（P＜0．05）。M－3动作的平均吸气流率、平均呼气流率及呼（吸）气量显著高于M－1动作（P＜0．05）。M－3动作的声门关闭度和声门呼气阻力小于M－1动作。实施抗G动作时，为了减轻每搏输出量的降低程度，应该采取措施，增加回心血量。
To explore the protective machanism of M-3 maneuver, its effects on respiration andcirculation were studied and compared with M-1 and L-1 maneuvers under + 1 Gz. Subjects were 12aviation medical students. Intrapleural pressure, stroke volume (SV), respiratory flow, respiratory pressure,heart-level systolic pressure were measured during these anti-G maneuvers. The results showedthat intrapleural pressure during expiratory phase of M-3 and M-1 and holding breath phase of L-1 were8. 1, 8- 7, and 8. 8 kPa respectively,while SV decreased 16. 4%, 19. 9%,and 23. 2% respectively in M-3,M-1and L-1 maneuvres. During M-3 maneuver, the increased value of intraplueral pressure, decreasedvalue of SV,heart-level systolic pressure and respiratory frequency compared with the M-1 maneuverhad no significant difference (P＜0.05 );compared with those of L-1 maneuver,the difference was significant (P＜0.05). Mean inspiratory flow,mean expiratory flow and expiratory (inspiratory) volume during M-3 maneuver were higher than those of M-1 maneuver (P＜0.05). The closing degree of glottisand expiratory resistance of glottis during M-3 maneuver are less than those of M-1 maneuver. Measuresfor enhancing return of blood to heart should be adopt in order to alleviate reduction of the SV duringanti-G maneuver.
关键词
对抗动作
抗荷
M-3抗荷动作
呼吸循环效应
Anti-G maneuver Intraplueral pressure Stroke volume Respiratory flow
