重力应激下自发性压力感受器-心率反射反应性的评定

Assessment of Responsiveness of Spontaneous Baroreceptor-Heart Rate Reflex under Gravitational Stress.

为探讨重力应激下自发性压力感受器 -心率反射反应性的评定方法 ,观察了 1 0人+65°头高位倾斜 (HUT)与 8人 -6.67kPa下体负压 (LBNP)作用下 ,以及 1 5人 1 6d-6°头低位卧床期间BRS的变化。结果表明 ,在HUT与LBNP作用期间 ,尽管血压反应有所不同 ,但自发性BRS值均显著减小 (P <0 .0 1 ) ,卧床第 1 6d时平均自发性BRS值也显著减小 (P <0 .0 5)。说明该方法可用于评定重力应激下压力感受器 -心率反射反应性的变化。

Beat by beat arterial blood pressure was measured using Finapres 2300 monitor. Sequences of 3 or more beats with systolic pressure and next beat interval changed in the same direction were identified as baroreflex sequences from 6-min data segments. A linear regression was applied to each sequence and the slope ( correlation coefficient≥ 0.85 ) was taken as a measure of the baroreflex response slope( BRS ). The changes in mean BRS during +65°head-up tilt ( HUT ), -6.67 kPa lower body negative pressure ( LBNP ) and 16 days -6°head-down tilt ( HDT ) bed rest were observed. The results showed that there was a significant decrease in the mean BRS during LBNP or HUT as compared with that of the supine control,though the blood pressure responses differed. The mean BRS was also significantly decreased during bed rest. It suggests that the responsiveness of spontaneous baroreceptor-heart rate reflex can be evaluated in humans under gravitational stress.