Study of the protective effects of lower body negative pressure strategy and thigh cuff strategy on cerebral blood flow during simulated push pull maneuver
10.3760/cma.j.cn113854-20200812-00118
- VernacularTitle:下体负压与下肢局部加压对模拟推拉动作时脑血流的保护作用研究
- Author:
Changyang XING
1
;
Yuan GAO
;
Xinpei WANG
;
Yunnan LIU
;
Jiaxin ZHANG
;
Chen WANG
;
Xing ZHANG
;
Jia LI
;
Ting CHANG
;
Shu ZHANG
;
Yong LIU
;
Lijun YUAN
;
Feng GAO
Author Information
1. 空军军医大学航空航天医学系，西安 710032
- Publication Type:Journal Article
- Keywords:
Push pull maneuver;
Cerebral blood flow;
Lower body negative pressure
- From:
Chinese Journal of Aerospace Medicine
2021;32(1):1-6
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To compare the protective effects of cerebral blood flow during simulated push pull maneuver (PPM) between lower body negative pressure (LBNP) strategy and thigh cuff (TC) strategy.Methods:It was a repeated cross-over design study. Fifteen healthy young male subjects were recruited. All subjects underwent the control bout (simulated PPM without any intervention), PPM with LBNP bout, and PPM with TC bout. Such position changes as "upright to head down tilt to upright" were performed by tilting table to simulate PPM. The control bout underwent normal PPM. LBNP of -40 mmHg (1 mmHg=0.133 kP) was applied prior to and during -G z stress and released at the subsequent transition to +G z stress in LBNP bout. TC of +200 mmHg was applied at bilateral upper thighs prior to and during simulated PPM. Beat-to-beat cerebral and systemic hemodynamics of the subjects were continuously recorded. Results:During the rapid -G z to +G z transition, the mean cerebral blood flow velocity (CBFVm) was decreased by 0.7-17.3 cm/s [ΔCBFVm=(-7.5±4.5) cm/s], and the mean arterial pressure at the level of middle cerebral artery(MAP MCA) was decreased by 42-76 mmHg [ΔMAP MCA=(-61.0±10.0) mmHg] in control bout. However, the change of CBFVm was -2.4-10.2 cm/s in LBNP bout, whose average value was increased (3.3±4.1) cm/s rather than decreased. The drop of MAP MCA was 23-50 mmHg [ΔMAP MCA=(-41.0±11.0) mmHg], which was significantly reduced than that in control bout ( P<0.05). The change of CBFVm in TC bout was -7.9-1.4 cm/s [ΔCBFVm=(-3.0±4.2) cm/s], and the decrease of ΔMAP MCA was 37-59 mmHg [ΔMAP MCA=(-47.0±13.0) mmHg], both of which were significantly smaller than that in control bout ( P<0.05). There was significant difference in ΔCBFVm between LBNP and TC bouts ( P<0.05), while no significant difference was found in ΔMAP MCA. Conclusions:Both the LBNP and TC strategies can protect the cerebral blood flow during simulated PPM. LBNP strategy showed better improvement of CBFVm than TC. Both strategies demonstrated protective effect by increasing diastolic cerebral blood flow.
