超声膈肌增厚分数联合最大吸气压测定对机械通气患者撤机的预测价值

The predictive value of ultrasonic measurement of the diaphragmatic thickening fraction combined with the maximal inspiratory pressure in mechanical ventilation patients

目的探讨膈肌增厚分数与最大吸气压对机械通气患者撤机的预测价值。方法选择2018年6月至2019年4月入住皖南医学院弋矶山医院重症医学科机械通气>24 h患者为研究对象,在患者符合临床撤机筛查条件后应用低水平PSV法进行自主呼吸试验(SBT)30 min,对符合临床撤机标准者进行撤机。撤机前测量患者最大吸气压(MIP),使用超声测量右侧膈肌位移(DE)、吸气末和呼气末膈肌厚度,计算膈肌增厚分数(DTF)。统计分析DTF、膈肌位移和MIP与撤机结果之间的关系,采用AUCROC分别评价DTF、膈肌位移和MIP对撤机成功的预测价值。结果共73例患者纳入本研究,其中撤机成功57例,撤机失败16例。撤机成功组的DTF(35%±8%)明显高于撤机失败组的DTF(25%±5%),差异有统计学意义(t=6.401,P<0.01)。撤机成功组的MIP[(34±9)cmH2O,1 cmH2O=0.098 kPa]明显高于撤机失败组的MIP[(23±3)cmH2O],差异有统计学意义(t=7.186,P<0.01)。DTF、MIP和膈肌位移的受试者工作特征曲线(ROC)分别是0.907、0.896和0.749。以DTF≥27.78%为标准预测撤机成功,敏感度92.98%,特异度81.25%,ROC曲线下面积为0.907(95%CI:0.816~0.963)。以MIP>26.5 cmH2O为标准预测撤机成功,敏感度80.7%,特异度93.75%,ROC曲线下面积为0.896(95%CI:0.803~0.955)。以DTF≥27.78%且MIP≥26.5 cmH2O为标准预测撤机成功,其ROC曲线下面积为0.920(95%CI:0.832~0.971),特异度提高到87.7%,但敏感度略降低到87.5%。结论DTF及MIP对机械通气患者撤机时机选择和撤机结果预测具有指导作用,与DTF及MIP相比,DTF结合MIP提高了对成功撤机的预测价值。

Objective To evaluate the value of the diaphragmatic thickening fraction(DTF)combined with the maximum inspiratory pressure(MIP)for the prediction of weaning success in mechanically ventilated patients.Methods Patients admitted to the intensive care unit(ICU)of Yijishan Hospital of Wannan Medical College and on mechanical ventilation for 24 hours from June 2018 to April 2019 were selected as the study subjects.A low-level pressure support ventilation(PSV)method was applied to conduct a spontaneous breathing test(SBT)for 30 minutes after the patients met the screening conditions for clinical weaning;and the patients were weaned when they met the clinical weaning criteria.Before weaning,the patient′s MIP was measured.The right hemidiaphragmatic excursion(DE)and the thickness of the diaphragm at the end of inspiration and at the end of exhalation were measured by ultrasound,and the DTF was calculated.The statistical relationship between the DTF,DE and MIP was analyzed.The predictive value for the success of weaning was calculated with the DTF,DE and MIP and was evaluated by the area under the receiver operating characteristic curve(AUC).Results A total of 73 patients were included in this study,including 57 patients who were successfully weaned,and 16 patients who experienced failure.The DTF of the successful weaning group(35%,8%)was significantly higher than that of the failed weaning group(25%±5%),and the difference was statistically significant(t=6.401,P<0.01).The MIP(34±9 cmH2O)in the successful weaning group was significantly higher than that in the failed weaning group(23±3 cmH2O),and the difference was statistically significant(t=7.186,P<0.01).The ROCs for the DTF,MIP,and diaphragmatic displacement were 0.907,0.896,and 0.749,respectively.A DTF≥27.78%,with a sensitivity of 92.98%,a specificity of 81.25%,and an AUC of 0.907(95%CI:0.816-0.963),was used as the standard to predict the success of weaning.An MIP>26.5 cmH2O,with a sensitivity of 80.7%,a specificity of 93.75%,and an AUC of 0.896(95%CI:0.803-0.955),was used as the standard to predict the success of weaning.The AUC of DTF≥27.78%and MIP≥26.5 cmH2O was 0.920(95%CI:0.832-0.971),and the specificity increased to 87.7%,but the sensitivity was slightly reduced to 87.5%.Conclusions The DTF and MIP play a crucial role in determining the appropriate time and predicting the outcome of weaning of mechanical ventilation patients.Compared with the DTF and MIP alone,the DTF combined with MIP greatly improved the accuracy of predicting successful weaning.