Original Article
Study of the protective effects of lower body negative pressure strategy and thigh cuff strategy on cerebral blood flow during simulated push pull maneuver
Xing Changyang, Gao Yuan, Wang Xinpei, Liu Yunnan, Zhang Jiaxin, Wang Chen, Zhang Xing, Li Jia, Chang Ting, Zhang Shu, Liu Yong, Yuan Lijun, Gao Feng
Published 2021-03-15
Cite as Chin J Aerospace Med, 2021, 32(1): 1-6. DOI: 10.3760/cma.j.cn113854-20200812-00118
Abstract
ObjectiveTo 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.
MethodsIt 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 -Gz stress and released at the subsequent transition to +Gz 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.
ResultsDuring the rapid -Gz to +Gz 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(MAPMCA) was decreased by 42-76 mmHg [ΔMAPMCA=(-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 MAPMCA was 23-50 mmHg [ΔMAPMCA=(-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 ΔMAPMCA was 37-59 mmHg [ΔMAPMCA=(-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 ΔMAPMCA.
ConclusionsBoth 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.
Key words:
Push pull maneuver; Cerebral blood flow; Lower body negative pressure
Contributor Information
Xing Changyang
School of Aerospace Medicine, Air Force Medical University, Xi′an 710032, China
Tangdu Hospital, Air Force Medical University, Xi′an 710038, China
Gao Yuan
School of Aerospace Medicine, Air Force Medical University, Xi′an 710032, China
Wang Xinpei
School of Aerospace Medicine, Air Force Medical University, Xi′an 710032, China
Liu Yunnan
Tangdu Hospital, Air Force Medical University, Xi′an 710038, China
Zhang Jiaxin
School of Aerospace Medicine, Air Force Medical University, Xi′an 710032, China
Wang Chen
Tangdu Hospital, Air Force Medical University, Xi′an 710038, China
Zhang Xing
School of Aerospace Medicine, Air Force Medical University, Xi′an 710032, China
Li Jia
School of Aerospace Medicine, Air Force Medical University, Xi′an 710032, China
Chang Ting
Tangdu Hospital, Air Force Medical University, Xi′an 710038, China
Zhang Shu
School of Aerospace Medicine, Air Force Medical University, Xi′an 710032, China
Liu Yong
School of Aerospace Medicine, Air Force Medical University, Xi′an 710032, China
Yuan Lijun
Tangdu Hospital, Air Force Medical University, Xi′an 710038, China
Gao Feng
School of Aerospace Medicine, Air Force Medical University, Xi′an 710032, China
