血浆和尿NGAL浓度预测老年患者术后谵妄的准确性

Accuracy of plasma and urine neutrophil gelatinase-associated lipocalin concentrations in predicting postoperative delirium in elderly patients

目的 评价血浆和尿中性粒细胞明胶酶脂质相关转载蛋白（NGAL）浓度预测老年患者术后谵妄的准确性.方法 选择2014年11月至2015年3月行单侧全髋或全膝关节置换术老年患者70例,年龄65 ～ 85岁,体重指数18 ～ 25 kg/m2,性别不限,ASA分级Ⅱ或Ⅲ级.分别于术后24、48和72 h时采用ICU患者意识模糊评估法评估谵妄的发生情况.根据是否发生术后谵妄将患者分为谵妄组和非谵妄组.分别于麻醉诱导前5 min、气管拔管即刻、术后24和72 h时,取中段尿样及外周静脉血样,采用免疫增强比浊法检测尿和血浆NGAL浓度.分别于麻醉诱导前5 min、术后24和48 h时,测定血清肌酐和胱抑素C的浓度,并记录术后急性肾损伤的发生情况.绘制尿和血浆NGAL浓度判断术后谵妄的ROC曲线,计算曲线下面积及其95％可信区间;根据约登指数最大值时所对应的尿和血浆NGAL浓度,计算最佳临界值及其灵敏度和特异度.结果 术后谵妄发生率为15％.与非谵妄组比较,谵妄组气管拔管即刻血浆NGAL浓度升高,气管拔管即刻和术后24 h时尿NGAL浓度升高（P＜0.01）.2组不同时点血清肌酐和胱抑素C的浓度比较差异无统计学意义（P＞0.05）.2组均未见术后急性肾损伤的发生.气管拔管即刻尿NGAL浓度预测术后谵妄的曲线下面积（95％可信区间）为0.736（0.509～ 0.946）,临界值为149.1 ng/ml,灵敏度为60％,特异度为97％,术后24 h时尿NGAL浓度预测术后谵妄的曲线下面积（95％可信区间）为0.785（0.565～0.998）,临界值为131.5ng/ml,灵敏度为60％,特异度为82％;气管拔管即刻血浆NGAL浓度预测术后谵妄的曲线下面积（95％可信区间）为0.772（0.580～0.965）,临界值为107.9 ng/ml,灵敏度为80％,特异度为79％,术后24 h时血浆NGAL浓度预测术后谵妄的曲线下面积（95％可信区间）为0.679（0.524 ～ 0.835）,临界值为153.65 ng/ml,灵敏度为70％,特异度为90％.结论 气管拔管即刻血浆和尿NGAL浓度可准确地预测老年患者术后谵妄的发生.

Objective To evaluate the accuracy of plasma and urine neutrophil gelatinase-associated lipocalin （NGAL） concentrations in predicting postoperative delirium in elderly patients.Methods From November 2014 to March 2015,70 patients of either sex who underwent total unilateral hip or knee replacement,aged 65-85 yr,with body mass index of 18-25 kg/m2,of American Society of Anesthesiologists physical status Ⅱ or Ⅲ,were selected.The Confusion Assessment Method for the Intensive Care Unit was used to assess the development of postoperative delirium at 24,48 and 72 h after operation.The patients were divided into either delirium group or non-delirium group according to whether or not postoperative delirium occurred.At 5 min before anesthesia induction,immediately after extubation,and at 24 and 72 h after operation,the midstream urine samples and peripheral venous blood samples were collected for determination of the urine and plasma NGAL concentrations by immuno-enhanced turbidimetry.At 5 min before anesthesia induction,and 24 and 48 h after operation,the serum creatinine and cystatin C concentrations were detected,and the development of postoperative acute kidney injury was recorded.The receiver operating characteristic curve for urine and plasma NGAL concentrations in diagnosing postoperative delirium was plotted,and the area under the curve and 95% confidence interval were calculated.The critical value and sensitivity and specificity were calculated according to the corresponding concentrations of NGAL in urine and plasma when Youden index reached the maximal value.Results The incidence of postoperative delirium was 15%.Compared with non-delirium group,the plasma NGAL concentrations were significantly increased immediately after extubation,and the urine NGAL concentrations were significantly increased immediately after extubation and at 24 h after operation in delirium group （P〈0.01）.There was no significant difference in the serum creatinine and cystatin C concentrations between the two groups （P〉0.05）.Postoperative acute kidney injury was not found in the two groups.The area under the curve （95% confidence interval） for urine NGAL concentrations measured immediately after extubation in predicting postoperative delirium was 0.736 （0.509-0.946）,the critical value was 149.1 ng/ml,the sensitivity 60%,and the specificity 97%.The area under the curve （95% confidence interval） for urine NGAL concentrations measured at 24 h after operation in predicting postoperative delirium was 0.785 （0.565-0.998）,the critical value was 131.5 ng/ml,the sensitivity 60%,and the specificity 82%.The area under the curve （95% confidence interval） for plasma NGAL concentrations measured immediately after extubation in predicting postoperative delirium was 0.772 （0.580-0.965）,the critical value was 107.9 ng/ml,the sensitivity 80%,and the specificity 79%.The area under the curve （95% confidence interval） for plasma NGAL concentrations at 24 h after operation in predicting postoperative delirium was 0.679 （0.524-0.835）,the critical value was 153.65 ng/ml,the sensitivity 70%,and the specificity 90%.Conclusion The plasma and urine NGAL concentrations measured immediately after extubation can accurately predict the development of postoperative delirium in elderly patients.