危重病患儿入院时血乳酸水平对院内死亡率的预测价值

The predictive value of blood lactic acid level for the in-hospital mortality in critically ill children

目的评估危重病患儿入院时血乳酸水平的预测价值以及危重病患儿院内死亡率的截止预测值。方法纳入2008年7月至2010年12月本院儿科重症监护病房收治的1109例危重病患儿,收集患儿收入儿科重症监护病房的最初2小时内动脉血标本,测定乳酸水平,并计算入院后24小时内第三代小儿死亡危险评分（PRISMⅢ）。结果 1109例危重病患儿中,115例（10.4%）于住院期间死亡。危重病患儿血乳酸水平中位数（四分位距）为3.2 mmol/L（2.2～4.8 mmol/L）;859例（77.5%）血乳酸水平〉2.0 mmol/L。调整年龄、性别和PRISMⅢ评分后（OR=1.27;P〈0.001）,入院时血乳酸水平与患儿死亡率显著相关（OR=1.38;95%CI：1.30～1.46;P〈0.001）。多元回归分析显示,高血乳酸水平（OR=1.17;95%CI：1.07～1.29;P=0.001）,高PRISMⅢ评分（OR=1.15;95%CI：1.11～1.20;P〈0.001）以及低血清清蛋白（OR=0.92;95%CI：0.88～0.96;P〈0.001）均是影响危重病患儿院内死亡率的独立危险因素。血乳酸水平对于预测死亡率的意义占曲线下面积（AUC）的0.79（P〈0.001）,与PRISMⅢ评分所占面积（AUC=0.82;P〈0.001）相似,二者AUC比较,P=0.318。血乳酸水平最佳截止值为5.55 mmol/L时,其预测院内死亡率的敏感性为61%,特异性为86%,且积极和消极的似然比分别为4.5和0.45。结论对于危重病患儿,入院时较高的血乳酸水平是预测院内死亡的独立危险因素。

Objective To evaluate the predictive value of blood lactic acid levels at admission and determined the cut-off values for predicting in-hospital mortality in critically ill children.Method We enrolled 1109 critically ill children who were admitted to a pediatric intensive care unit from July 2008 to December 2010.Arterial blood samples were collected in the first 2 hours after admission,and the blood lactic acid levels were determined.The Pediatric Risk of Mortality Ⅲ（PRISM Ⅲ） scores were calculated during the first 24 hours after admission.Result In the 1109 cases of critically ill children,115 cases（10.4%） died in the hospital.The median（inter quartile range） blood lactic acid level in critically ill children was 3.2 mmol/L（2.2 ～ 4.8 mmol/L）.Among the children,859 cases（77.5%） had a lactate concentration 〉2.0 mmol/L.The blood lactic acid level upon admission was significantly associated with mortality（OR = 1.38;95% CI：1.30 ～ 1.46;P〈0.001）,even after adjustment for age,gender and PRISM Ⅲ（ OR = 1.27;P〈0.001）.Multivariate regression analysis showed that high blood lactic acid level（OR = 1.17;95% CI：1.07 ～ 1.29;P = 0.001）,high PRISM Ⅲ score（OR = 1.15;95% CI：1.11 ～ 1.20;P〈0.001）,and low serum albumin（OR = 0.92;95% CI：0.88 ～ 0.96;P〈0.001） were independent risk factors for mortality in critically ill children.Blood lactic acid level achieved an area under-the-receiver-operating-characteristic curve（AUC） of 0.79（P〈0.001） for predicting mortality that was similar to PRISM Ⅲ（AUC = 0.82;P〈0.001）.The P-value for a comparison of both AUC was 0.318.Blood lactic acid level displayed a sensitivity of 61% anda specificity of 86% in predicting mortality at the optimal cut-off value of 5.55 mmol/L,and the positive and negative likelihood ratios were 4.5 and 0.45,respectively.Conclusion A high blood lactic acid level at admission is independently associated with and predictive of in-hospital mortality in the general population of critically ill children.