不同剂量右美托咪定辅助硬膜外麻醉对老年直肠癌患者术后认知功能的影响

目的 观察不同剂量右美托咪定辅助硬模外麻醉对老年直肠癌开腹手术患者术后认知功能的影响.方法 选择60例70岁以上直肠癌手术患者,应用右美托咪定诱导剂量0.8 μg/（kg·min）泵注10 min,按维持剂量完全随机分为右美托咪定Ⅰ组0.4 μg/（kg·h）、Ⅱ组0.6 μg/（kg·h）、Ⅲ组0.8 μg/（kg·h）,每组20例.观察并记录3组患者入室时（T0）、用药后10 min（T1）、用药后20 min（T2）、停药即刻（T3）、停药后10 min（T4）以及手术完毕时（T5）的平均动脉压（MAP）、心率、脑电双频指数（BIS）以及镇静评分（Ramsay评分）.比较术前1 d、术后即刻、术后24 h 3组患者血浆中白细胞介素6（IL-6）、肿瘤坏死因子α（TNF-α）水平,比较3组患者术前1 d、术后1、3、7 d的简易智力状况检查法评分（MMSE）.结果 3组患者在T0时血压、心率、BIS值,镇静评分（Rammsy评分）差异均无统计学意义（P〉0.05）,T2、T3时MAP和HR均较基础值显著降低.随着右美托咪定的用量的增大,窦性心动过缓的发生率也增加,与Ⅰ、Ⅱ组相比,Ⅲ组患者T3时心率明显下降,差异有统计学意义（54.8±6.8） 次/min 比（70.2±2.5）、（69.7±2.4） 次/min]（P〈0.05）.Ⅱ、Ⅲ组患者术中BIS值维持在60～75之间,可以满足术中的镇静要求.Ⅲ组患者术中BIS值下降,Ⅰ组共有8例出现术后认知功能障碍（POCD）,发生率为40.0%,Ⅱ组有2例出现POCD,发生率为10.0%,Ⅲ组共有5例出现POCD,发生率25.0%.Ⅰ组与Ⅱ组比较,其差异有统计学意义（χ2=4.5,P〈0.05）.与I组相比,术后即刻、术后24 hⅡ、Ⅲ组IL-6、TNF-α水平差异有统计学意义术后即刻IL-6（3.6±0.4）、（3.6±0.4）ng/L比（5.7±0.4）ng/L,TNF-α（6.2±0.4）、（6.1±0.5）ng/L比（7.1±0.4）ng/L;术后24 h IL-6（3.4±0.4）、（3.4±0.4）ng/L比（6.8±0.4）ng/L,TNF-α（6.±0.5）、（6.1±0.5）ng/L比（7.1±0.4）ng/L]（P〈0.05）.结论 老年患者以0.8 μg/kg的剂量泵注右美托咪定10 min,后以0.6 μg/（kg·h）右美托咪定泵注复合硬膜外麻醉安全有效,可改善老年直肠癌患者围术期认知功能.

Effect of different doses of dexmedetomidine as an adjunct to epidural anaesthesia on cognitive function in elderly colorectal cancer patients

Objective To observe the effect of the different doses of dexmedetomidine infusion under epidural anesthesia on cognitive functions in elderly patients with colorectal cancer. Methods Totally 60 cases of colorectal cancer surgery over 70 years old were randomly divided into group I of dexmedetomidine 0.4 μg/（kg·h）, group Ⅱof 0.6 μg/（kg·h）and group III of 0.8 μg/（kg·h）.Three groups of patients were observed and recorded at different time points. Mean arterial pressure, heart rate（HR）, bispectral Index（BIS） and sedation score （ramsay score） were analyzed. The plasma Interleukin（IL）-6, tumor necrosis factor（TNF）-α levels were compared among three groups of patients before surgery 1 d, postoperative 1 d, postoperative 3 d and 7 d after the mini-mental state examination （MMSE）. Results All 3 groups of patients had no significant difference regarding T0 blood pressure, HR, BIS values, sedation score （rammsy score） （P〉0.05）. T2, T3 MAP and HR when compared with baseline values decreased significantly. With the increase of dexmedetomidine, the incidence of sinus bradycardia also increased.Compared with group Ⅰ, Ⅱ, Ⅲ patients when T3 heart rate decreased, and the difference was statistically significant（54.8±6.8）beats/min vs （70.2±2.5）, （69.7±2.4）beats/min]（P〈0.05）. Ⅱ, Ⅲ group of patients undergoing BIS value maintained between 60 to 75, could meet the requirements of intraoperative sedation. Patients in group Ⅲ BIS value dropped in groupⅠ a total of eight cases,had postoperative cognitive function disorder （POCD）, the incidence was 40.0%, 2 patients in groupⅡ had POCD, the incidence was 10.0%, a total of five cases had POCD in groupⅢ, the incidence was 25.0%. The difference was statistically significant in group Ⅰand group Ⅱ （χ2 = 4.5, P〈0.05）. Compared with group I, at immediate postoperative and 24 hours postoperative group Ⅱ, Ⅲ IL-6, TNF-α levels were significantlyimmediate postoperative IL-6（3.6±0.4）, （3.6±0.4）ng/L vs （5.7±0.4）ng/L; TNF-α （6.2±0.4）, （6.1±0.5）ng/L vs （7.1±0.4）ng/L; 24 hours postoperative IL-6（3.4±0.4）, （3.4±0.4）ng/L vs （6.8±0.4）ng/L; TNF-α （6.1±0.5）, （6.1±0.5）ng/L vs （7.1±0.4）ng/L] （P〈0.05）. Conclusion Elderly patients with 0.8 μg/kg dose of dexmedetomidine infusion set 10 minute, after to 0.6 μg/（kg·h） dexmedetomidine infusion during epidural anesthesia is safe and effective, can improve colorectal cancer in elderly patients perioperative cognitive function.