Objective: To evaluate the value of intraoperative cerebral oxygen saturation in predicting postoperative neurocognitive dysfunction (PND) in elderly patients with mild cognitive impairment. Methods: A total of 210 cases of lumbar decompression, bone grafting and fusion surgery under general anesthesia were collected in the Third Central Hospital of Tianjin from June, 2019 to January, 2020, either sex, aged 65-75 year, BMI 19.5-32.5 kg/m(2), ASA physical status Ⅱ or Ⅲ, preoperative comorbidities with mild cognitive impairment. MoCA and MMSE were used to evaluate the cognitive function of patients 1 day before the operation, 7 days and 3 monthes after operation. PND group (n=38) and non-PND group (n=172) were selected according to postoperative MMSE and MoCA scale scores and the diagnostic criteria of PND. Heart rate (HR) , mean arterial pressure (MAP), pulse oxygen saturation (SpO(2)), bispectral index (BIS), cerebral tissue oxygen saturation (SctO(2), average left and right brain SctO(2) were recorded) were recorded pre-anesthetic (T(0)), ten minutes of anesthesia(T(1)), twenty minutes of anesthesia (T(2)), thirty minutes into the operation (T(3)), one hour into the operation (T(4)), end of the surgery (T(5)), and leave the PACU (T(6)). SctO(2) at time point T(0) was the base value of SctO(2), and the maximum percentage drop in SctO(2) from the base value was calculated (SctO(2max)%). Results: The incidence of PND was 18% (38/210) in 210 elderly patients undergoing surgery. The age of PND group and non-PND group was (71.0±2.1) and (67.8±2.0) years old, and the PACU time was (57±5) and (46±8) min, respectively. Compared with the non-PND group, the age of the PND group was higher (t=2.600, P<0.05) and the PACU time was longer (t=3.039, P<0.05). At the time points T(3), T(4), T(5) and T(6), SctO(2) in the PND group was (62±10) %, (60±11) %, (64±12) % and (66±10)%, respectively, lower than that in the non-PND group (67±60) %, (68±6) %, (69±5) % and (70±7)%, respectively, and the difference was statistically significant (t=3.369, 4.906, 3.787, 2.516, all P<0.05).The MoCA and MMSE scores of the PND group were (22.9±1.2) and (24.1±1.2) points, respectively, 1 day before surgery; and the MoCA and MMSE scores of the PND group were reduced to (20.8±1.2) and (21.3±0.7) points, respectively, 7 days after surgery, with statistically significant differences (t=3.523, 5.675, all P<0.05). MoCA and MMSE scores 7 days after surgery in the non-PND group were (22.4±1.3) and (23.1±1.6) points, respectively. Compared with the non-PND group, MoCA and MMSE scores 7 days after surgery in the PND group were reduced (t=2.630, 3.108, all P<0.05). The critical value of intraoperative SctO(2max)% was 13.74%, the area under the curve of PND was predicted to be 0.907 (95%CI: 0.819-0.995), sensitivity and specificity were 88.9% and 88.5%, respectively. Conclusion: SctO(2max)%>13.74% can be used as an indicator to predict PND occurrence in elderly patients with mild cognitive impairment during lumbar surgery.

目的： 评价术中脑氧饱和度对轻度认知功能障碍老年患者腰椎手术后神经认知障碍（PND）的预测价值。 方法： 收集2019年6月至2020年1月天津市第三中心医院择期行全身麻醉下腰椎减压植骨融合手术患者210例，性别不限，年龄65~75岁，体质指数（BMI） 19.5~32.5 kg/m(2)，美国麻醉医师协会（ASA）分级Ⅱ或Ⅲ级，术前并存轻度认知功能障碍。术前1 d 、术后7 d和术后3个月采用简易智力状态量表（MMSE）、蒙特利尔认知评估量表（MoCA）评估患者认知功能状态。根据术后MMSE和MoCA量表评分及PND诊断标准筛选出PND组（n=38）和非PND组（n=172)。于麻醉前（T(0)）、麻醉开始10 min（T(1)）、麻醉开始20 min（T(2)）、手术开始30 min（T(3)）、手术开始1 h（T(4)）、手术结束（T(5)）、离开麻醉恢复室（T(6)）时记录患者的心率（HR）、平均动脉压（MAP）、血氧饱和度（SpO(2)）、脑电双频指数（BIS）和脑氧饱和度（SctO(2)，以左脑和右脑SctO(2)平均值记录）。T(0)时间点SctO(2)为SctO(2)的基础值，计算各时间点SctO(2)较基础值下降的最大百分数（SctO(2max)%）。 结果： 210例老年手术患者中，PND发生率为18%（38/210）。PND组与非PND组患者年龄分别为（71.0±2.1）、（67.8±2.0）岁，麻醉恢复室（PACU）时间分别为（57±5）、（46±8）min；与非PND组比较，PND组的年龄偏高（t=2.600, P<0.05），PACU时间延长（t=3.039，P<0.05）。PND组在T(3)、T(4)、T(5)和T(6)时间点SctO(2)分别为（62±10）%、（60±11）%、（64±12）%、（66±10）%，低于非PND组的（67±6）%、（68±6）%、（69±5）%、（70±7）%，差异均有统计学意义（t=3.369、4.906、3.787、2.516，均P<0.05）。PND组术前1 d的MoCA、MMSE评分分别为（22.9±1.2）、（24.1±1.2）分，术后7 d的MoCA、MMSE评分均降低，分别为（20.8±1.2）、（21.3±0.7）分，差异均有统计学意义（t=3.523、5.675，均P<0.05）。非PND组术后7 d的MoCA、MMSE评分分别为（22.4±1.3）、（23.1±1.6）分，与非PND组比较，PND组术后7 d的MoCA、MMSE评分均降低（t=2.630、3.108，均P<0.05）。术中SctO(2max)%的临界值为13.74%，预测PND的曲线下面积为0.907（95%CI：0.819~0.995），敏感度和特异度分别为88.9%和88.5%。 结论： 轻度认知功能障碍老年患者腰椎手术术中SctO(2max)%>13.74%可以作为预测PND发生的指标。.