机械功对中重度急性呼吸窘迫综合征的诊断价值——基于MIMIC-Ⅲ数据库的资料分析

Diagnostic value of mechanical power in patients with moderate to severe acute respiratory distress syndrome:an analysis using the data from MIMIC-Ⅲ

目的基于美国重症监护医学信息数据库Ⅲv1.4(MIMIC-Ⅲv1.4)探讨机械功(MP)对中重度急性呼吸窘迫综合征(ARDS)的诊断价值。方法收集MIMIC-Ⅲv1.4数据库中2001年6月至2012年10月在美国马萨诸塞州波士顿贝丝以色列女执事医疗中心住院进行有创机械通气至少48 h的ARDS患者的相关资料。提取患者人口统计学信息、疾病严重程度评分、ARDS病因、预后指标、通气前动脉血气分析和通气48 h内呼吸力学参数等。以通气前氧合指数(PaO_(2)/FiO_(2))最低值将患者分为轻中度ARDS组(>150 mmHg,1 mmHg≈0.133 kPa)和中重度ARDS组(≤150 mmHg),比较两组间基线特征的差异。采用Logistic回归法分析与ARDS严重程度相关的独立危险因素;绘制受试者工作特征曲线(ROC曲线),计算ROC曲线下面积(AUC),评价MP对中重度ARDS的诊断价值,并用约登指数确定MP对中重度ARDS的诊断阈值。根据约登指数确定的MP最佳截点值将所有ARDS患者分为高MP组和低MP组,绘制Kaplan-Meier生存曲线,分析两组患者的28 d生存状态。结果共筛选出403例ARDS患者纳入分析,其中轻中度ARDS组107例,中重度ARDS组296例。两组患者年龄、序贯器官衰竭评分(SOFA)、通气前PaO_(2)/FiO_(2)最低值、通气前最后一次PaO_(2)/FiO_(2)、28 d病死率、重症监护病房(ICU)住院时间、机械通气时间、通气第2个24 h肺动态顺应性(Cdyn)及通气48 h内呼气末正压(PEEP)、平台压(Pplat)、驱动压(ΔP)、呼吸频率(RR)、肺静态顺应性(Cst)、MP、吸入氧浓度(FiO_(2))差异均有统计学意义。在调整了年龄、SOFA评分、通气前最后一次PaO_(2)/FiO_(2)及相关呼吸力学参数等变量后,多因素Logistic回归分析显示,更高的ΔP、PEEP、MP及更低的通气前最后一次PaO_(2)/FiO_(2)与中重度ARDS的发生独立相关〔优势比(OR)和95%可信区间(95%CI)分别为1.137(1.032~1.252)、1.333(1.139~1.561)、1.102(1.030~1.179)、0.996(0.993~0.998),均P<0.01〕。ROC曲线分析显示,MP诊断中重度ARDS的最佳截点值为18.1 J/min(敏感度为81.42%,特异度为60.75%),AUC为0.745(95%CI为0.690~0.799)。根据ROC曲线得出的MP最佳截点值将所有ARDS患者分为高MP组(>18.1 J/min)和低MP组(≤18.1 J/min);Kaplan-Meier生存曲线显示,高MP组28 d累积生存率明显低于低MP组(73.8%比85.1%;Log-Rank检验:χ^(2)=5.660,P=0.017)。结论MP是与ARDS严重程度相关的独立预测因素,可用于诊断中重度ARDS。

Objective To explore the diagnostic value of mechanical power(MP)in patients with moderate to severe acute respiratory distress syndrome(ARDS)based on the Medical Information Mart for Intensive Care-Ⅲv1.4(MIMIC-Ⅲv1.4).Methods The information of ARDS patients undergoing invasive mechanical ventilation for no less than 48 hours who were hospitalized at Beth Israel Deaconess Medical Center in Boston,Massachusetts from June 2001 to October 2012 in the MIMIC-Ⅲv1.4 were collected.The demographics of patients,disease severity scores,ARDS etiology,prognostic indicators,pre-ventilation arterial blood gas analysis and respiratory parameters within 48 hours of ventilation were extracted.According to the lowest oxygenation index(PaO_(2)/FiO_(2))before ventilation,the patients were divided into mild to moderate ARDS group(>150 mmHg,1 mmHg≈0.133 kPa)and moderate to severe ARDS group(≤150 mmHg),and the differences in baseline characteristics between the two groups were compared.The independent predictors associated with the severity of ARDS were analyzed using Logistic regression.The receiver operator characteristic curve(ROC curve)was plotted.The area under ROC curve(AUC)was calculated to evaluate the diagnostic value of MP for moderate to severe ARDS.The Youden index was used to determine the diagnostic threshold of MP for moderate to severe ARDS.According to the cut-off value of MP based on Youden index,all ARDS patients were divided into high and low MP groups.Kaplan-Meier survival curve was used to analyze the 28-day survival status of patients.Results A total of 403 ARDS patients were enrolled in the study,including 107 subjects with mild to moderate ARDS and 296 with moderate to severe ARDS.There were significant differences in age,sequential organ failure assessment(SOFA)score,the lowest PaO_(2)/FiO_(2) before ventilation,the last PaO_(2)/FiO_(2) before ventilation,28-day mortality,the length of intensive care unit(ICU)stay,duration of mechanical ventilation,lung dynamic compliance(Cdyn)in the second 24 hours of ventilation and positive end-expiratory pressure(PEEP),plateau pressure(Pplat),driving pressure(ΔP),respiratory rate(RR),lung static compliance(Cst),MP,inspired fraction of oxygen(FiO_(2))within 48 hours of ventilation between the two groups.After adjusting variables such as age,SOFA score,the last PaO_(2)/FiO_(2) before ventilation,and related respiratory mechanics parameters,multivariate Logistic regression analysis showed that higherΔP,PEEP and MP,and lower last PaO_(2)/FiO_(2) before ventilation were independently associated with moderate to severe ARDS[odds ratio(OR)and 95%confidence interval(95%CI)was 1.137(1.032-1.252),1.333(1.139-1.561),1.102(1.030-1.179),and 0.996(0.993-0.998),respectively,all P<0.01].The ROC curve analysis showed that the best cut-off value of MP for the diagnosis of moderate to severe ARDS was 18.1 J/min with sensitivity of 81.42%and specificity of 60.75%,and the AUC was 0.745(95%CI was 0.690-0.799).According to the cut-off value of MP obtained by ROC curve,all ARDS patients were divided into high MP group(>18.1 J/min)and low MP group(≤18.1 J/min).The Kaplan-Meier survival curve showed that the 28-day cumulative survival rate in the high MP group was significantly lower than that in the low MP group(73.8%vs.85.1%;Log-Rank test:χ^(2)=5.660,P=0.017).Conclusion MP is an independent predictor of the severity of ARDS,and it can be used to diagnose moderate to severe ARDS.