比例辅助通气对慢性阻塞性肺疾病呼吸衰竭患者呼吸力学的影响

目的　观察比例辅助通气 (PAV)不同辅助比例对慢性阻塞性肺疾病 (COPD)合并呼吸衰竭患者呼吸力学的影响。方法　 15例COPD合并呼吸衰竭的患者 ,予以常规药物治疗同时进行经面罩双水平气道正压通气(BiPAP)与PAV辅助通气 ,并按不同辅助比例 80 %、6 0 %、4 0 %和 2 0 %分别通气 30min后采集数据。监测患者在不同通气模式时气道峰压 (PIP)、呼吸频率 (RR)、潮气量 (VT)、每分钟通气量 (MV)和吸气 /呼吸周期时间比 (Ti/Ttotal)的变化 ,并计算平均吸气流速 (VT/Ti)。结果　在EPAP/CPAP相同情况下 ,PAV通气时的PIP和VT/Ti与BiPAP(S)相比有显著降低 (P <0 0 5 ) ,Ti/Ttotal与BiPAP(S)相比显著升高 (P <0 0 5 ) ,而MV无明显变化 (P >0 0 5 )。PAV辅助比例为 2 0 %时的VT明显低于BiPAP(S)时的VT(P <0 0 5 ) ,同时低于辅助比例为 4 0 %时的VT(P <0 0 5 )。当PAV辅助比例≥ 4 0 %时 ,所有患者的VT在不同辅助比例时均无明显变化 ,且与BiPAP(S)时VT相比差异也无显著性 ( P >0 0 5 ) ;同样在辅助比例≥ 4 0 %时 ,所有患者的RR、MV、Ti/Ttotal和VT/Ti变化差异也无显著性 (P >0 0 5 )。结论　PAV不同辅助比例与BiPAP(S)相比 ,PIP显著降低。PAV适宜的辅助比例在 4 0 %～80 %。

Effects of proportinal assist ventilation on respiratory dynamics in COPD with respiratory failure

Objective To investigate the effects of proportional assist ventilation (PAV) with different assist proportions on respiratory dynamics in COPD patients with respiratory failure.Methods Fifteen COPD patients with respiratory failure received conventional medical therapy plus BiPAP(S) and PAV.Different assist proportions of PAV (80%,60%,40% and 20%,respectively) were used in the patients for 30 min,and peak inspiratory pressure(PIP),respiratory rate, tidal volume(V T ),minute ventilation(MV),inspiratory duty cycle(Ti/Ttotal) and mean inspiratory flow(V T /Ti)were measured.Results Compared with BiPAP(S) mode under the similar EPAP/CPAP,PIP and Vt/Ti were significantly low (P<0 05) while Ti/Ttotal was significantly high (P<0 05) during different assist proportions of PAV,but MV had no significant difference(p>0 05).Compared with PAV 20%,V T in BiPAP(S) and PAV 40% all decreased while RR increased (P<0 05).During PAV 80%,60% and 40%,V T had no significant differentce (P>0 05).Compared with BiPAP(S) mode,V T was significantly higher during PAV 80%,60% and 40% (P<0 05),but RR,MV,Ti/Ttotal and V T /Ti had no significant difference (P>0 05).Conclusion Different assist proportions of PAV (assist 80%,60%,40% and 20%,respectively) significantly lower PIP than BiPAP(S) does.The appropriate assist proportion of PAV is 40%-80%.