Shen X Y, Meng J R, Wu B, Li J J, Dong Q, Xiang Q L
Institute of Space Medico-Engineering, Beijing, China.
Space Med Med Eng (Beijing). 2001 Feb;14(1):36-40.
To understand the change of the cardiovascular function and to evaluate the usefulness of sphygmography and heart rate variability (HRV) spectrum techniques on estimating cardiovascular function during HUP + LBNP.
Blood pressure, ECG, cerebral oxygen saturation and sphygmogram of 16 subjects were studied during 75 degrees head up tilt plus lower body negative pressure (HUP + LBNP).
(1) During HUP + LBNP, heart rate, blood pressure, normalized low frequency component (LFn), LFn/HFn increased significantly, the cerebral blood oxygen saturation, T wave (ECG), HFn decreased significantly; (2) Blood pressure, heart rate and cerebral blood oxygen saturation decreased significantly in presyncopal state; (3) The heart rate in low tolerance group was higher than that in high tolerance group during the initial stage of HUT + LBNP; (4) The shape of pulse wave changed enormously during HUP + LBNP, so that no analysis could be made.
HUP + LBNP was an effective approach to examine the regulatory function of cardiovascular system, and the sphygmogram could not be used in studying the regulatory function of cardiovascular system during HUP + LBNP.
了解心血管功能变化，评估脉搏波描记术和心率变异性（HRV）频谱技术在头高位倾斜（HUP）+下体负压（LBNP）期间评估心血管功能的有用性。
对16名受试者在75度头高位倾斜加下体负压（HUP + LBNP）期间的血压、心电图、脑氧饱和度和脉搏波图进行研究。
（1）在HUP + LBNP期间，心率、血压、归一化低频成分（LFn）、LFn/HFn显著增加，脑血氧饱和度、T波（心电图）、HFn显著降低；（2）在接近晕厥状态时血压、心率和脑血氧饱和度显著下降；（3）在HUT + LBNP初始阶段，低耐受组心率高于高耐受组；（4）在HUP + LBNP期间脉搏波形状变化极大，无法进行分析。
HUP + LBNP是检测心血管系统调节功能的有效方法，脉搏波图不能用于研究HUP + LBNP期间心血管系统的调节功能。
