血乳酸联合中心静脉-动脉血二氧化碳分压差与动脉-中心静脉血氧含量差比值预测脓毒性休克患者预后的应用价值

Prognostic value of arterial lactate combined with central venous-to-arterial carbon dioxide difference to arterial-to-central venous oxygen content difference ratio in septic shock patients

目的探讨早期液体复苏后血乳酸(Lac)联合中心静脉-动脉血二氧化碳分压差与动脉-中心静脉血氧含量差比值(Pcv-aCO2/Ca-cvO2)对脓毒性休克患者预后的预测价值。方法选择2017年1月至2019年12月兰州大学第二医院重症医学科收治的97例脓毒性休克患者。收集复苏前及复苏6 h桡动脉和上腔静脉血气分析结果,计算Pcv-aCO2/Ca-cvO2比值。根据28 d预后将患者分为死亡组和存活组,比较两组患者一般资料、急性生理学与慢性健康状况评分Ⅱ(APACHEⅡ)、序贯器官衰竭评分(SOFA)、临床治疗情况、6 h乳酸清除率(LCR)、重症监护病房(ICU)住院时间以及复苏前后血流动力学和氧代谢指标;采用多因素Cox回归法分析脓毒性休克患者28 d死亡的危险因素,通过受试者工作特征曲线(ROC)评价死亡相关危险因素对预后的预测价值。结果①与存活组比较,死亡组患者APACHEⅡ评分和SOFA评分更高〔APACHEⅡ评分(分):23.96±4.31比17.70±3.92,SOFA评分(分):12.74±2.80比9.23±2.43,均P<0.01〕,机械通气及连续性肾脏替代治疗(CRRT)比例更高〔机械通气:85.2%(23/27)比50.0%(35/70),CRRT:51.9%(14/27)比25.7%(18/70),均P<0.05〕,6 h补液量更多(L:2.92±0.24比2.63±0.25,P<0.01),6 h LCR更低〔(11.61±7.76)%比(27.67±13.71)%,P<0.01〕,ICU住院时间更短(d:6.37±2.70比7.67±2.31,P<0.05)。②与存活组比较,死亡组复苏前平均动脉压(MAP)更低〔mmHg(1 mmHg=0.133 kPa):52.63±4.35比55.74±3.01,P<0.01〕,Lac和Pcv-aCO2/Ca-cvO2比值更高〔Lac(mmol/L):7.13±1.75比5.22±1.36,Pcv-aCO2/Ca-cvO2比值:1.67±0.29比1.48±0.22,均P<0.01〕;死亡组复苏6 h MAP仍显著低于存活组(mmHg:62.59±4.80比66.71±3.91,P<0.01),而中心静脉压(CVP)、Lac、Pcv-aCO2及Pcv-aCO2/Ca-cvO2比值明显高于存活组〔CVP(mmHg):10.74±1.40比8.80±0.75,Lac(mmol/L):6.36±1.86比3.90±1.95,Pcv-aCO2(mmHg):7.59±2.02比4.34±1.37,Pcv-aCO2/Ca-cvO2比值:1.87±0.51比1.03±0.27,均P<0.01〕。③多因素Cox回归分析显示,复苏前及复苏6 h Lac和Pcv-aCO2/Ca-cvO2比值是脓毒性休克患者28 d死亡的独立危险因素〔复苏前Lac:相对危险度(RR)=1.434,95%可信区间(95%CI)为1.070~1.922,P=0.016;复苏6 h Lac:RR=1.564,95%CI为1.202~2.035,P=0.001;复苏前Pcv-aCO2/Ca-cvO2比值:RR=2.828,95%CI为1.108~4.207,P=0.038;复苏6 h Pcv-aCO2/Ca-cvO2比值:RR=4.386,95%CI为2.842~5.730,P=0.000〕。④ROC曲线分析显示,复苏6 h Lac和Pcv-aCO2/Ca-cvO2比值对脓毒性休克患者预后均有预测价值,ROC曲线下面积(AUC)分别为0.849(95%CI为0.762~0.914)和0.905(95%CI为0.828~0.955),二者联合对脓毒性休克患者预后的预测价值明显大于Lac〔AUC(95%CI):0.976(0.923~0.996)比0.849(0.762~0.914),Z=3.354,P=0.001〕,敏感度为97.14%,特异度为88.89%。结论Lac和Pcv-aCO2/Ca-cvO2比值是脓毒性休克患者28 d死亡的独立危险因素,二者联合可以更准确地评估脓毒性休克患者的预后。

Objective To evaluate the prognostic value of arterial lactate(Lac)combined with central venous-to-arterial carbon dioxide difference to arterial-to-central venous oxygen content difference ratio(Pcv-aCO2/Ca-cvO2)in patients with septic shock following early fluid resuscitation.Methods A total of 97 patients with septic shock admitted to intensive care unit(ICU)of Lanzhou University Second Hospital from January 2017 to December 2019 were enrolled.The Pcv-aCO2/Ca-cvO2 ratio was calculated from blood gas analysis of radial artery and superior vena cava which was performed before resuscitation and at 6 hours of resuscitation at the same time.The patients were divided into death group and survival group according to the 28-day prognosis.The baseline data,acute physiology and chronic health evaluationⅡ(APACHEⅡ)score,sequential organ failure score(SOFA),clinical therapy,lactate clearance rate(LCR)at 6 hours,the length of ICU stay,hemodynamics and oxygen metabolism parameters before and after resuscitation were compared between the two groups.Risk factors were analyzed by multivariate Cox regression for 28-day mortality of patients with septic shock.The receiver operating characteristic(ROC)curve was plotted to assess the prognostic values of these factors for 28-day mortality.Results①Compared with the survival group,the patients in the death group showed significantly higher levels of APACHEⅡscore(23.96±4.31 vs.17.70±3.92)and SOFA score(12.74±2.80 vs.9.23±2.43,both P<0.01),significantly higher proportions of mechanical ventilation[85.2%(23/27)vs.50.0%(35/70)]and continuous renal replacement therapy[CRRT;51.9%(14/27)vs.25.7%(18/70),both P<0.05],a significantly more fluid replacement at 6 hours(L:2.92±0.24 vs.2.63±0.25,P<0.01),a significantly lower level of LCR at 6 hours[(11.61±7.76)%vs.(27.67±13.71)%,P<0.01],and a shorter length of ICU stay(days:6.37±2.70 vs.7.67±2.31,P<0.05).②Compared with the survival group,the patients before resuscitation in the death group showed a significantly lower level of mean arterial pressure[MAP(mmHg,1 mmHg=0.133 kPa):52.63±4.35 vs.55.74±3.01,P<0.01],significantly higher levels of Lac and Pcv-aCO2/Ca-cvO2 ratio[Lac(mmol/L):7.13±1.75 vs.5.22±1.36,Pcv-aCO2/Ca-cvO2 ratio:1.67±0.29 vs.1.48±0.22,both P<0.01];and the patients at 6 hours of resuscitation in the death group showed a significantly lower level of MAP(mmHg:62.59±4.80 vs.66.71±3.91,P<0.01),significantly higher levels of central venous pressure(CVP),Lac,Pcv-aCO2 and Pcv-aCO2/Ca-cvO2 ratio[CVP(mmHg):10.74±1.40 vs.8.80±0.75,Lac(mmol/L):6.36±1.86 vs.3.90±1.95,Pcv-aCO2(mmHg):7.59±2.02 vs.4.34±1.37,Pcv-aCO2/Ca-cvO2 ratio:1.87±0.51 vs.1.03±0.27,all P<0.01].③Multivariate Cox regression analysis showed that the independent risk factors for 28-day mortality in patients with septic shock were Lac and Pcv-aCO2/Ca-cvO2 ratio whether before or at 6 hours of resuscitation[Lac before resuscitation:relative risk(RR)=1.434,95%confidence interval(95%CI)was 1.070-1.922,P=0.016;Lac at 6 hours of resuscitation:RR=1.564,95%CI was 1.202-2.035,P=0.001;Pcv-aCO2/Ca-cvO2 ratio before resuscitation:RR=2.828,95%CI was 1.108-4.207,P=0.038;Pcv-aCO2/Ca-cvO2 ratio at 6 hours of resuscitation:RR=4.386,95%CI was 2.842-5.730,P=0.000].④ROC curve analysis showed that Lac and Pcv-aCO2/Ca-cvO2 ratio at 6 hours of resuscitation had predictive value for the prognosis of patients with septic shock,the area under ROC curve(AUC)was 0.849(95%CI was 0.762-0.914)and 0.905(95%CI was 0.828-0.955),respectively.However,the predictive value of Lac combined with Pcv-aCO2/Ca-cvO2 ratio in patients with septic shock was significantly higher than Lac[AUC(95%CI):0.976(0.923-0.996)vs.0.849(0.762-0.914),Z=3.354,P=0.001],the sensitivity was 97.14%,and the specificity was 88.89%.Conclusions Lac and Pcv-aCO2/Ca-cvO2 ratio are independent risk factors for predicting 28-day mortality in patients with septic shock.Lac combined with Pcv-aCO2/Ca-cvO2 ratio can assess the prognosis of patients with septic shock more accurately.