头低位与头高位反复体位改变对人体立位耐力的影响

Effects of head-down tilt and head-up tilt mode of repeated body position changes on human orthostatic tolerance

目的探究头低位与头高位交替的反复体位改变模式(head-down and head-up tilt,HDT/HUT)对人体立位耐力的影响。方法 12名受试者进行HDT/HUT模式的反复体位改变试验,试验前、后分别进行头高位立位耐力测试,取测试时平卧位和立位第1 min(HUT 1 min)的心率(heart rate,HR)、收缩压(systolic blood pressure,SBP)、舒张压(diastolic blood pressure,DBP)、平均动脉压(mean arterial pressure,MAP)、每搏量(stroke volume,SV)、心输出量(cardiac output,CO)、总外周阻力(total peripheral resistance,TPR)数据,用于比较分析。结果反复体位改变前、后立位耐力测试相比,试验后平卧位HR、SV、CO明显降低(P<0.05、P<0.01),TPR明显升高(P<0.01);HUT 1 min时,DBP、MAP、SV、CO明显降低(P<0.05、P<0.01),TPR明显升高(P<0.01)。结论头低位与头高位反复体位改变降低了人体立位耐力。

Objective To explore the effects of the head-down and head-up tilt （HDT/HUT） mode of repeated body postural changes on human orthostatic tolerance. Methods Twelve subjects were exposed to an HDT/HUT mode of repeated body position change experiment. Before and after the experiment, the subjects were exposed to head-up tilt （HUT） to test their orthostatic tolerance. The heart rate （HR）, systolic blood pressure （SBP）, diastolic blood pressure （DBP）, mean arterial pressure （MAP）, stroke volume （SV）, cardiac output （CO）, and total peripheral resistance （TPR） of the first minute in the HUT and supine position before and after the experiment were recorded for analysis. Results After the experiment, the HR, SV and CO in the supine position decreased significantly （P〈0.05 or P〈0.01）, TPR increased significantly （P〈0.01）, DBP, MAP, SV and CO that were measured one minute into HUT decreased significantly （P〈0.05 or P〈0.01）, but TPR increased （P〈0.01）. Conclusion The head-down tilt and head-up tilt mode of repeated body position changes can cause a decrease of human orthostatic tolerance.