头低位-30°对肺功能的影响

Effects of -30° Head Down Tilt on Lung Function.

目的研究短时间模拟失重对健康人肺功能的影响。方法采用头低位 - 30°模拟短期 ( 4 5min)失重 ,用体描箱对 1 2名健康男性分别于坐位、平卧位、头低位 1 0～ 1 5min ,头低位 45min测量了肺功能的各项指标 ,同时用彩超测量了肺动脉血流和右心功能。并进行了对比分析。结果随着体位由坐位、平卧位到头低位 ,肺通气量 (FVC ,FEV1 ,FEV1 % ,MVV)、肺容量 (VA ,IVC)逐渐减少 ,其中以MVV变化显著 (P <0 .0 0 0 )。而同时随体位变化肺弥散显著增加 ,DLCO(P <0 .0 0 1 ) ,KCO(P <0 .0 0 0 )。结论 -30°、45min头低位时 ,肺通气量、肺容量显著减少。肺弥散量明显增加 ,其中以肺血容量增加 ,肺血流的均匀分布为主要影响因素。

Objective To investigate the effects of short-term simulated weightlessness on lung function in healthy males. Method -30° head down tilt for 45 min was used to simulate short-period weightlessness. Lung function of 12 health males, aged 18～21, were studied with plethysmography during seating, supine and head down tilt positions. At the same time, blood flow in pulmonary artery and function of right ventricle were measured with Doppler Echo-Cardiography. Comparative analysis was done. Result As body position changed from seating or supine into head down tilt, FVC, FEV1, FEV1%, MVV, VA and IVC decreased. The change of MVV was the most prominent (P<0.000). As the position changed, pulmonary diffusion increased dramatically(DL CO P<0.001, K CO P<0.000). Conclusion HDT may lead to a decrease of pulmonary ventilation and lung capacity. The increased pulmonary diffusion might be related to uniform distribution of pulmonary blood flow and increased effective pulmonary vascular bed.