摘要目的 探讨早期乳酸清除率对体外膜氧合(ECMO)治疗后的重症急性呼吸衰竭患者预后的评估作用.方法 选取2007年1月至2013年1月南京医科大学附属无锡市人民医院ICU收治的因重症急性呼吸衰竭而接受静脉-静脉(v-v) ECMO治疗的患者共43例.分别在治疗前Oh和治疗后6h测定动脉血乳酸,计算早期(6 h)乳酸清除率,并在治疗当天进行APACHEⅡ评分.以治疗后90 d为研究终点,将患者分为存活组(24例)和病死组(19例),比较两组患者治疗前动脉血乳酸值、早期乳酸清除率及APACHEⅡ评分.采用受试者工作特征(ROC)曲线分析0h动脉血乳酸、早期乳酸清除率及APACHEⅡ评分对患者预后的评估价值.运用Kaplan-Meier法绘制患者的生存曲线,Log-rank法分析患者生存情况.多因素Logistic回归分析影响患者预后的危险因素.结果 (1)存活组0h动脉血乳酸[(3.8±2.1)mmol/L]和APACHEⅡ评分(18±7)低于病死组[分别为(5.9±2.3) mmol/L和(25±7),t值分别为7.924和8.446,均P＜0.05],但早期乳酸清除率高于病死组[分别为(35.7±20.4)％和(10.7±18.2)％,t=8.607,P＜0.05].(2)0h动脉血乳酸、早期乳酸清除率及APACHEⅡ评分预测患者90 d死亡的ROC曲线下面积分别为0.699±0.083(95％ CI为0.567～0.892,P ＜0.05)、0.871 ±0.119(95％ CI为0.724～0.980,P ＜0.05)和0.836±0.063(95％ CI为0.713 ～0.958,P＜0.05).以早期乳酸清除率≥17.5％作为评估预后的最佳界值点,敏感度和特异度分别为87.5％和84.2％.(3)Kaplan-Meier生存曲线分析结果显示,高乳酸清除率患者(≥17.5％)和低乳酸清除率患者(＜ 17.5％)90 d生存率分别为78.3％和30％(x2=10.103,P＜0.05).(4)多因素Logistic回归分析显示0h血乳酸(OR=1.318,95％ CI为1.159 ～6.882,P＜0.05)、6h乳酸清除率(OR=6.921,95％ CI为4.469 ～ 15.036,P＜0.05)和APACHEⅡ评分(OR=4.417,95％ CI为3.058 ～ 10.356,P＜0.05)均是患者死亡的独立危险因素.结论 早期乳酸清除率可作为判断ECMO治疗后重症急性呼吸衰竭患者预后的重要指标.

abstractsObjective To investigate the prognostic significance of early lactate clearance rate for severe acute respiratory failure patients on extracorporeal membrane oxygenation(ECMO).Methods Fortythree patients with severe acute respiratory failure supported by venous-venous (r-y) ECMO were enrolled from January 2007 to January 2013.Arterial blood lactate at pre-ECMO support(0 h) and at post-ECMO 6 hours (6 h) were measured and then 6 h lactate clearance rate was calculated.The acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score was evaluated on the first day of ECMO support.Survival at 90 d after admission was the study endpoint.Patients were divided into the survival group (n =24) and the death group (n =19).The 0 h blood lactate,6 h lactate clearance rate and APACHE Ⅱ score were compared between groups.The value of 0 h blood lactate,6 h lactate clearance rate and APACHE Ⅱ score for predicting death was evaluated by receiver operating characteristic (ROC) curves.The surviving curve was drawn using the Kaplan-Meier method,and the survival of the patients was analyzed by the Log-rank test.Factors influencing the prognosis were analyzed by the multiple logistic regression analysis.Results (1) The 0 h blood lactate and APACHE Ⅱ score were lower in survivors than in nonsurvivors [(3.8 ± 2.1) mmol/Lvs.(5.9 ±2.3)mmol/L,(18 ±7) vs.(25 ±7),t =7.924,8.446,respectively,both P＜0.05],while the 6 h lactate clearance rate was higher in survivors than in nonsurvivors [(35.7 ± 20.4) ％ vs.(10.7 ± 18.2)％,t =8.607,P ＜0.05].(2)The areas under the ROC curve of 0 h blood lactate,6 h lactate clearance rate and APACHE lⅡ score for predicting death were 0.699 ± 0.083 (95％ CI:0.567 ～ 0.892,P ＜0.05),0.871 ± 0.119 (95％ CI:0.724 ～ 0.980,P ＜ 0.05) and 0.836 ± 0.063 (95％ CI:0.713 ～0.958,P ＜0.05).The best cutoff point was 17.5％ for 6 h lactate clearance with a sensitivity of 87.5％ and specificity of 84.2％.(3) Kaplan-Meier survival analysis showed that 90 d survival rate of the high lactate clearance rate group and the low lactate clearance rate group were 78.3％ and 30％,with significant difference between the two groups (x2 =10.103,P ＜0.05).(4)Multivariate logistic regression analysis showed that 0 h blood lactate (OR =1.318,95％ CI:1.159 ～ 6.882,P ＜ 0.05),6 h lactate clearance rate (OR =6.921,95％ CI:4.469 ～ 15.036,P ＜ 0.05) and APACHE lⅡ score (OR =4.417,95％ CI:3.058～ 10.356,P ＜0.05) were independent risk factors associated with mortality of patients on ECMO.Conclusion Early lactate clearance rate could be used as an important variable for evaluating the prognosis of severe acute respiratory failure patients on ECMO.