Beat-to-beat cardiovascular responses to rapid, low-level LBNP in humans
Beat-to-beat cardiovascular responses to rapid, low-level LBNP in humans
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DOI：
10.1152/ajpregu.2001.281.1.r213
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发表时间：
2001-07-01
影响因子：
2.8
通讯作者：
Walloe, L
中科院分区：
文献类型：
--
作者：
Hisdal, J;Toska, K;Walloe, L
检验的假设是，即使在稳态值未检测到变化的实验情况下，在轻度下体负压（LBNP，-20 mmHg）快速发作和释放后，心血管变量也会发生显著的一过性变化。12名受试者参加了研究。在LBNP前（0-120 s）、LBNP期间（120-420 s）和LBNP后（420-600 s）连续记录心率、每搏输出量（SV）、心输出量、平均动脉压（MAP）、总外周阻力（TPR）、肢端和非肢端皮肤血流量和肱动脉血流速度。主要发现是MAP是短暂的，但受到LBNP的快速变化（小至-20 mmHg）的强烈影响。心血管对LBNP的发作和释放的反应也有特征性的不对称性，特别是SV的反应。MAP的瞬时变化表明影响TPR的神经反应不足以快速补偿LBNP的快速变化。在这种情况下，动脉压力感受器将被激活，以及感觉中心静脉压的低压压力感受器。在今后讨论黎巴嫩边界法议定书的结果时必须考虑到这一点。
The hypothesis tested was that there are significant transient changes in the cardiovascular variables after rapid onset and release of mild lower body negative pressure (LBNP, -20 mmHg), even in experimental situations where there is no detectable change in steady-state values. Twelve subjects participated in the study. Heart rate, stroke volume (SV), cardiac output, mean arterial pressure (MAP), total peripheral resistance (TPR), acral and nonacral skin blood flow, and blood flow velocity in the brachial artery were continuously recorded during the pre-LBNP period (0-120 s), during LBNP (120-420 s), and during the post-LBNP period (420-600 s). The main finding was that MAP is transiently but strongly affected by rapid changes in LBNP as small as -20 mmHg. There was also a characteristic asymmetry in cardiovascular responses to the onset and release of LBNP, particularly in the responses in SV. The transient changes in MAP indicate that the neural responses that affect TPR are not fast enough to compensate for the rapid changes in LBNP. In this case, the arterial baroreceptors will be activated as well as the low-pressure baroreceptors that sense central venous pressure. This must be taken into consideration in future discussions of the results of LBNP protocols.