机械通气影响健康志愿者的血流动力学研究

Effect of mechanical ventilation on hemodynamics in healthy volunteers

目的观察健康志愿者在不同无创通气模式(CPAP或BiPAP)下,压力变化对血流动力学的影响,探讨正压通气影响血流动力学的机制,为临床实施循环保护通气策略提供依据。方法连续入选30例健康志愿者,每例均先后接受CPAP(压力为0、10、15 cmH 2O)与BiPAP(IPAP 0、15、20 cmH 2O,EPAP 4 cmH 2O)模式并同步监测血流动力学指标。血流动力学监测心率(HR)、心输出量(CO)、心脏动力学指数(CPI)等大循环指标及经皮氧分压(PctO 2)、经皮二氧化碳分压(PctcO 2)等微循环指标。结果在CPAP和BiPAP两种通气模式下随压力的增加,SV、SI变化均无统计学意义(P>0.05),而HR、CI、CO及CPI降低,TPR及TPRI升高,差异有统计学意义(P<0.01);同一模式下改变通气压力PctO 2的变化无统计学意义(P1>0.05),但BiPAP模式下PctO 2较CPAP更高,差异有统计学意义(P2<0.01);两种通气模式下PctcO 2均呈降低趋势(P1<0.01),但BiPAP模式降幅更大,差异有统计学意义(P2<0.01)。结论CPAP和BiPAP均能引起健康志愿者血流动力学改变,心率、心输出量及心肌收缩力指数下降,微循环灌注增加,其中BiPAP对提高组织氧及降低组织二氧化碳的效果更明显。

Objective To observe the effect of pressure change on hemodynamics in healthy volunteers under different non-invasive ventilation modes(CPAP or BiPAP),and to explore the mechanism of ventilation mode affecting hemodynamics,so as to provide a basis for clinical implementation of circulatory protection ventilation strategy.Methods 30 healthy volunteers were enrolled consecutively,and each patient received CPAP(pressure 0,10,15 cmH 2O)and BiPAP(IPAP 0,15,20 cmH 2O,EPAP4 cmH 2O)mode ventilation and simultaneously monitored hemodynamics and microcirculation indicators.Hemodynamic indicators included heart rate(HR),cardiac output(CO)and cardiac dynamic index(CPI),while microcirculation indicators included percutaneous oxygen partial pressure(PctO 2)and percutaneous carbon dioxide partial pressure(PctcO 2).Results Under CPAP and BiPAP ventilation modes,SV and SI changes were not statistically significant with the increase of pressure(P>0.05),while HR,CI,CO and CPI decreased,and TPR and TPRI increased,the difference was statistically significant(P<0.01).There was no statistically significant change in PctO 2 before and after the two modes(P>0.05),but PctO 2 in BiPAP mode was higher than that in CPAP mode,and the difference was statistically significant(P<0.01).PctcO 2 decreased in both ventilation modes(P<0.01),but BiPAP decreased more pronounced than CPAP(P<0.01).Conclusion Both CPAP and BiPAP can cause hemodynamic changes in healthy volunteers,including decreased heart rate,cardiac output and myocardial contractility index,and increased microcirculation perfusion.Among them,BiPAP is more effective in improving tissue oxygen and reducing tissue carbon dioxide than CPAP.