中心静动脉血CO_2分压差及乳酸清除率对感染性休克患者的预后评估价值

Prognostic value of Pv-a CO_2 and LCR in patients with septic shock

目的探讨中心静动脉血二氧化碳分压差(central venous-to-arterial carbon dioxide difference,Pv-a CO_2)及乳酸清除率(lactate clearance rate,LCR)对感染性休克患者预后的评估价值。方法选取2014年1月-2017年3月本院收治的感染性休克患者156例,根据6 h Pv-a CO_2和6 h LCR分为低Pv-a CO_2组(Pv-a CO_2<6 mm Hg)(1 mm Hg=0.133 k Pa)和高Pv-a CO_2组(Pv-a CO_2≥6 mm Hg),低LCR组(LCR≤10%)和高LCR组(LCR>10%),比较各组Pv-a CO_2、LCR、急性生理学与慢性健康状况评分系统Ⅱ(acute physiology and chronic health evaluation scoring system,APACHEⅡ)评分、序贯器官衰竭评分(sequential organ failure assessment,SOFA)及病死率。应用受试者工作特征(receiver operating characteristic,ROC)曲线分析各时间点Pv-a CO_2及LCR对感染性休克患者的预后评估价值。Pearson相关分析Pv-a CO_2与LCR的相关性。结果高Pva CO_2组APACHEⅡ、SOFA评分及病死率均明显高于低Pv-a CO_2组(24.16±7.50 vs 19.38±6.72,8.96±3.18 vs 6.92±2.70,62.2%vs 17.6%,P均<0.05),而高Pv-a CO_2组6 h LCR及6 h早期目标导向治疗(early goal-directed therapy,EGDT)达标率明显低于低Pv-a CO_2组(17.28%±6.92%vs 26.53%±10.26%,52.4%vs 85.1%,P均<0.05)。低LCR组APACHEⅡ、SOFA评分、6 h Pv-a CO_2及病死率均明显高于高LCR组[23.72±7.41 vs 19.75±6.63,9.05±3.16 vs 6.83±2.74,(7.48±3.70)mm Hg vs(4.92±2.25)mm Hg(1 mm Hg=0.133 k Pa),66.1%vs 24.5%,P均<0.05],而低LCR组6 h EGDT达标率明显低于高LCR组(48.4%vs 80.9%,P<0.05)。ROC曲线显示,12 h Pv-a CO_2及12 h LCR评估感染性休克患者预后的最佳截断值分别为7.25 mm Hg和12.45%,敏感度和特异度均较好,分别为80.6%和90.4%,85.2%和92.7%。相关分析显示,感染性休克患者6 h、12 h及24 h Pv-a CO_2与6 h、12 h及24 h LCR均呈负相关(r=-0.648,P<0.01;r=-0.706,P<0.01;r=-0.591,P<0.01)。结论Pv-a CO_2及LCR变化与感染性休克患者的病情严重程度及预后相关,12 h Pv-a CO_2高于7.25 mm Hg及12 h LCR低于12.45%的患者预后较差。

Objective To investigate the prognostic value of central venous-to-arterial carbon dioxide difference （Pv-aCO2） and lactate clearance rate （LCR） in patients with septic shock. Methods One hundred and fifty-six patients with septic shock admitted to our hospital from January 2014 to March 2017 were enrolled in our study. According to the 6 h Pv-aCO2 and the 6 h LCR level, patients were divided into the low Pv-aCO2 group （Pv-aCO2 ＜ 6 mmHg） versus high Pv-aCO2 group （Pv-aCO2 ≥ 6 mmHg）, and low LCR group （LCR ≤ 10%） versus high LCR group （LCR ＞ 10%）. Pv-aCO2, LCR, APACHE Ⅱ , SOFA score and mortality in patients of two groups were compared. The receiver operating characteristic （ROC） curve was used to analyze the prognostic value of Pv-aCO2 and LCR at different time points in patients with septic shock. Pearson correlation analysis was used to analyze the correlation between Pv-aCO2 and LCR. Results The APACHE Ⅱ , SOFA score and mortality in the high Pv-aCO2 group were significantly higher than those in the low Pv-aCO2 group[（24.16±7.50） vs （19.38±6.72）, （8.96±3.18） vs （6.92±2.70）, 62.2% vs 17.6%, all P ＜ 0.05], while the 6-hour LCR and success rate of achieving 6-hour early goal-directed therapy （EGDT） in high Pv-aCO2 group were significantly lower than those in the low Pv-aCO2 group [（17.28%±6.92%） vs （26.53%±10.26%）, 52.4% vs 85.1%, all P ＜ 0.05]. APACHE Ⅱ , SOFA score, 6-hour Pv-aCO2 and mortality of low LCR group were significantly higher than those in high LCR group [（23.72±7.41） vs （19.75±6.63）, （9.05±3.16） vs （6.83±2.74）, （7.48±3.70） mmHg vs （4.92±2.25） mmHg, 66.1% vs 24.5%, all P ＜ 0.05], while the success rate of achieving 6-hour EGDT of low LCR group was significantly lower than those in high LCR group （48.4% vs 80.9%, P ＜ 0.05）. The ROC curve showed that the optimal cut-off values of 12-hour Pv-aCO2 and LCR for evaluating prognosis of septic shock patients were 7.25 mmHg and 12.45%, and the sensitivity and specificity were 80.6% and 90.4% for Pv-aCO2, 85.2% and 92.7% for LCR. Correlation analysis showed that Pv-aCO2 was negatively correlated with LCR at 6, 12 and 24 hour in patients with septic shock （r=-0.648, P ＜ 0.01; r=-0.706, P ＜ 0.01; r=-0.591, P ＜ 0.01）. Conclusion Changes in PvaCO2 and LCR are associated with the severity and prognosis of patients with septic shock, and patients with 12 h Pv-aCO2 ＞ 7.25 mmHg and 12 h LCR ＜ 12.45% are more likely to have poor prognosis.