择期腹部大手术后首次动脉乳酸浓度对POSSUM评分预测并发症发生率的影响

Effects of initial serum lactate level on POSSUM-expected morbidity after major elective abdominal surgery

目的:观察择期腹部大手术后首次动脉血乳酸浓度与术后并发症发生率的关系,并进一步分析对POSSUM(physiological and operative severity score for the enumeration of mortality and morbidity)评分预测并发症发生率的影响。方法:收集104例择期腹部大手术患者的一般相关资料、POSSUM评分、术后首次动脉血气指标pH、乳酸浓度、碱缺、PaO2/FiO2及术后各种并发症。ROC曲线比较酸碱血气指标预测术后并发症的价值,并确定乳酸最佳预测临界值。根据临界值将患者分为高乳酸组和正常乳酸组,比较两组术后实际与POSSUM评分预测并发症发生率的差异。结果:29例(28%)出现各种术后并发症。除乳酸外(AUC=0.661,95%CI0.562～0.751,P=0.010),其他血气指标pH、碱缺、PaO2/FiO2均无统计学意义的预测价值(均P>0.20)。乳酸预测术后并发症的最佳临界值为1.5mmol/L。两组POSSUM评分无明显差异,高乳酸组(>1.5mmol/L)并发症发生率与POSSUM评分预测率相仿(45%vs33%,P=0.136),正常乳酸组(≤1.5mmol/L)并发症发生率明显低于高乳酸组(14/71vs15/33,P=0.013),亦低于POSSUM评分预测率(20%vs31%,P=0.040)。结论:择期腹部大手术后首次动脉乳酸浓度可预测术后并发症,维持正常乳酸水平(≤1.5mmol/L)能降低术后POSSUM评分预测并发症发生率。

Objective To examine the relationships between immediate postoperative lactate and outcome after major elective abdominal surgery. Methods Arterial lactate level was measured in 104 consecutive patients immediately after major elective abdominal surgery. Receiver-operator curves （ROC） were constructed to compare abilities of lactate and other blood gas values to predict hospital morbidity, and to identify optimal cut off value of lactate （the value associated with the highest sum of sensitivity and specificity）. Patients were then divided into 2 groups ： hyperlactatemia and without hyperlactatemia, according to their lactate level. The complication rates were compared between 2 groups and with respective physiological and operative severity score for the enumeration of mortality and morbidity （POSSUM）-expected morbidity. Results 29 patients developed postoperative complications, as compared with 33 patients predicted by POSSUM （P=0.403）. No death occurred. The area under ROC of lactate to morbidity was statistically larger than 0.5 （0.661,95%CI 0.562 - 0.751, P=0.010） ,but not did that of pH, base deficit and PaO2/FiO2. The value of lactate with the best predictive ability was greater than 1.5 mmol/L. The observed postoperative complication rate in patients with hyperlactatemia （〉 1.5 mmol/L） was higher than that in patients without hypedactatemia （≤ 1.5 mmol/L） （15/33 vs 14/ 71, P=0.013 ）, and not different from POSSUM-expected morbidity （45% vs 33%, P=0.136）. However, in patients without hypedactatemia,the actual complication rate was significantly lower than POSSUM-expected morbidity （20% vs 31%,P= 0.040）. Conclusion Initial serum lactate level can predict postoperative complications, and lactate level of 1.5 mmol/L or less is significantly associated with reduced POSSUM-expected morbidity after major elective abdominal surgery.