摘要目的 观察人体在头高、头低反复体位改变试验刺激膛心血管参数的变化特征. 方法 在电动立位旋转床上对18名健康男性进行头高、头低反复体位改变试验,实时监测心电图(ECG)、血压(BP)、心率(HR)、每搏量(stroke volume,SV)、心输出量(cardial out,CO)、总外周阻力(total peripheral resistance,TPR)等指标,取试验前平卧位数据为对照,选取每个体位第20秒和第60秒的数据进行分析. 结果 试验中有6名受试者心电图出现了室上性期前收缩、阵发性室上性心动过速、房室传导阻滞等节律改变；18名受试者心血管参数均随着体位改变而变化,其中CO呈现出逐渐下降的趋势,而TPR呈现出逐渐升高的趋势；经过10次头高、头低体位改变后,受试者在-15°/+50°立位应激时SBP、MBP、SV、CO下降幅度有所增加. 结论 头高、头低反复体位改变试验中人体心血管参数呈现出明显的规律性变化；该模式的反复体位改变对人体立位耐力有不利影响.

abstractsObjective To observe the characteristics of cardiovascular response to the consecutive body posture change-the alternation of head up and down. Methods Eighteen healthy male subjects were exposed to the consecutive body posture change.Electrocardiogram (ECG),bloodpressure (BP),heart rate (HR),cardiac out (CO),stroke volume (SV) and total peripheral resistance (TPR) were recorded continuously. The parameters at supine posture before test were taken as the control value.We collected the cardiovascular parameters at 20 s and 60 s in each body posture for analyzing. Results There were 6 subjects of 18 had arrhythmia during the test,such as supraventricular premature beat,paroxysmal supraventricular tachycardia and atrioventricular block.The cardiovascular indexes of 18 subjects varied with posture change,eg. CO expressed decrease tendency while TPR tended to increase.There was a more profound fall on SBP,MBP,SV and CO under the 10th 15°/+50° orthostatic stress than the first -15°/+50° orthostatic stress. Conclusion The cardiovascular parameters show significant regular changes during consecutive body posture change. The pattern of cousecutive body posture change has an adverse impact on orthostatic tolerance.