评价膈肌功能指导慢性阻塞性肺疾病患者撤机的可行性研究

A pilot study of diaphragmatic function evaluated as predictors of weaning in chronic obstructive pulmonary disease patients

目的 探讨神经机械耦联指数（NMC）和神经通气耦联指数（NVC）对慢性阻塞性肺疾病（COPD）患者撤机的指导价值.方法 以2008年12月至2009年12月入住东南大学附属中大医院重症医学科行机械通气超过24 h,且考虑撤机的COPD患者为研究对象.根据患者撤机成功与否分为撤机成功组与撤机失败组.具备撤机条件后行自主呼吸试验（SBT）30 min,监测SBT0、5、30 min时膈肌电活动（Edi）、NMC、NVC、NVC × NMC、呼吸浅快指数（f/Vt）及口腔闭合压（P0.1）.结果 16例患者纳入本研究,其中撤机成功组6例,撤机失败组10例.（1）Edi对撤机失败的预测价值：SBT30 min时,撤机失败组Edi明显高于撤机成功组,其预测撤机失败的接受者操作特征（ROC）曲线下面积（AUC）为0.817（P＜0.05）.（2）NVC、NMC对撤机的判断：SBT 5、30 min时撤机成功组NVC、NMC均高于撤机失败组.SBT 30 min时,NVC预测撤机失败的AUC为0.850（P＜0.05）,NMC预测撤机失败的AUC为0.800（P＞0.05）.（3）NVC×NMC对撤机失败的预测：SBT 30 min时预测撤机失败的AUC为0.850（P＜0.05）,以NVC×NMC＜39 em H2O·ml·μV-2（1 em H2O=0.098 kPa）为临界值时,其灵敏度为100.0%,特异度为83.3%.（4）f/Vt、f/Vt×P0.1对撤机的预测：SBT 时,f/Vt、f/Vt×P0.1均不能预测撤机失败.结论 Edi、NVC、NVC×NMC对COPD患者撤机具有良好的预测价值.

Objective To evaluate the predictive performance of neuro-mechanical coupling （NMC） and neuro-ventilatory coupling （NVC） in the weaning outcome in patients with chronic obstructive pulmonary disease （COPD）. Methods Sixteen patients were enrolled when the criteria for their first spontaneous breathing trial （SBT） was met. A 30-minute SBT was attempted, with the measurement of electrical activity of the diaphragm （Edi） , NMC, NVC, NVC ×NMC, index of rapid shallow breathing （f/Vt） , airway occlusion pressure （P0.1） and f/Vt ×P0.1 at 0, 5 and 30 min. The receiver operating characteristic （ROC） curve was calculated to evaluate the predictive performance of each index. Results Successful weaning（S group） was observed in 6 patients while weaning failure（F group） in 10 patients. （1）The predictive capacity of Edi： at 30 min of SBT, Edi showed higher values in the F group （P ＜ 0. 05）, the area under the ROC curves（AUC） was 0. 817（P ＜0. 05）. （2） The predictive capacity of NVC and NMC：at 5, 30 min of SBT, NVC and NMC showed higher values in the S group （P ＜0. 05）; at 30 min of SBT NVC presented the largest AUC than any other time of SBT （0. 822, P ＜ 0. 05）, while the AUC of NMC was 0. 800 （P ＞ 0. 05）. （3） The predictive capacity of NVC × NMC： at 30 min of SBT, the AUC of NVC × NMC was larger than NVC （0. 864, P ＜ 0. 05） , showing greater sensitivity （100. 0%） and specificity （83. 3%） .（4） The predictive capacity of f/Vt and P0.1： f/Vt and f/Vt × P0.1 presented poor predictive performance in the failed patients. Conclusions Edi, NVC and NVC × NMC were good predictor for the weaning outcome in patients with COPD.