目的 研究不同体外循环温度复合右美托咪定对体外循环下心脏手术患者氧化应激及术后谵妄（POD）的影响。 方法 选取于2021年6月至2024年6月择期行体外循环下心脏手术240例患者，最终纳入220例患者，年龄50 ~ 75岁，且无严重肝肾功能不全。术前1 d采用MMSE量表对患者的基础认知功能进行评估。患者常规建立体外循环。采用随机数字表法将患者随机分为四组（n = 55）：低温+生理盐水组（L0）组、低温+右美托咪定组（L1）组、高温+生理盐水组（H0）组和高温+右美托咪定组（H1）组。低温组转流期间维持鼻咽温为（30±1）℃，高温组转流期间维持鼻咽温为（33±1）℃，L1、H1组麻醉诱导前10 min内静脉输注右美托咪定注射液1 μg/kg，之后以0.5 μg/（kg·h）速率持续泵注至手术结束。L0、H0组输入等容量的生理盐水至手术结束。于麻醉开始前（T1）、手术结束时（T2）、术后24 h（T3）、48 h（T4）采集患者中心静脉血5 mL，采用ELISA法检测血清神经元特异性烯醇化酶（NSE）、白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）水平，采用黄嘌呤氧化酶法检测血清超氧化物歧化酶（SOD）水平，采用硫代巴比妥酸法检测丙二醛（MDA）浓度。术后12 h至术后3 d采用重症监护室混淆评估法（CAM-ICU）对患者进行是否发生POD的评估。根据是否发生POD，将患者分为术后谵妄组（POD组）和未发生术后谵妄组（NPOD组）。 结果 220例患者中发生POD 81例，发生率约为36.8%，其中L0组POD发生率约为30.9%、L1组POD发生率约为12.7%、H0组POD发生率约为58.2%和 H1组POD发生率约为45.5%。与NPOD组相比，POD组患者NSE、IL-6、TNF-ɑ、MDA浓度升高，SOD浓度降低。与L0组比较，L1组T2 ~ T4患者血清NSE、IL-6、TNF-α、MDA浓度降低，SOD浓度升高，与H0组比较，H1组T2 ~ T4患者血清NSE、IL-6、TNF-α、MDA浓度降低，SOD浓度升高。与L0组比较，H0组T2 ~ T4患者血清NSE、IL-6、TNF-α、MDA浓度升高，SOD浓度降低。与L1组比较，H1组T2 ~ T4患者血清NSE、IL-6、TNF-α、MDA浓度升高，SOD浓度降低。 结论 体外循环下心脏手术期间低温复合右美托咪定可以降低患者的氧化应激反应，从而降低POD的发生。

Objective To study the effects of different extracorporeal circulation temperature combined with dexmedetomidine on oxidative stress in patients undergoing cardiac surgery under cardiopulmonary bypass. Methods 240 patients who underwent cardiac surgery under cardiopulmonary bypass were selected from June 2021 to June 2024. The patients were 50 to 75 years old and did not have severe hepatic or renal insufficiency. The Mini-Mental State Examination was completed 1 day before the operation. Patients were routinely established for cardiopulmonary bypass. Patients were randomly divided into four groups （n = 55）： hypothermia + normal saline group （L0）， hypothermia + dexmedetomidine group （L1）， hyperthermia + normal saline group （H0） and hyperthermia + dexmedetomidine group （H1）. The nasopharyngeal temperature was maintained at （30 ± 1）℃ in the hypothermia group and （33 ± 1）℃ in the high-temperature group during the reflux period. Dexmedetomidine injection was intravenously injected at 1 μg/kg 10 minutes before anesthesia in L1 and H1 groups， and pumped continuously at a rate of 0.5 μg/（kg·h） until the end of surgery. L0 and H0 groups were given equal volume of normal saline until the end of operation. 5 mL of central venous blood was collected before the beginning of anesthesia （T1）， at the end of surgery （T2）， 24 h （T3） and 48 h（T4） after surgery， and serum neuron specific enolase （NSE）， interleukin-6 （IL-6） and tumor necrosis factor -α（TNF-α） levels were detected by ELISA. The levels of superoxide dismutase （SOD） and malondialdehyde （MDA） in serum were determined by xanthine oxidase method and thiobarbituric acid method. The Confusion Assessment Method-ICU was used to evaluate the occurrence of POD. Results 220 patients were finally enrolled， including 81 patients in POD group， with an incidence of 36.8%. Compared with NPOD group， the concentrations of NSE， IL-6， TNF-ɑ and MDA in POD group were increased， while the concentration of SOD was decreased.Compared with L0 group， the concentrations of NSE， IL-6， TNF-ɑ and MDA were decreased and the concentration of SOD increased in L1 group.Compared with H0 group， NSE， IL-6， TNF-ɑ and MDA concentrations in H1 group were decreased， while SOD concentration was increased.Compared with L0 group， concentration of NSE， IL-6， TNF-ɑ and MDA increased， while the concentration of SOD decreased in H0 group. Compared with L1 group， concentration of NSE， IL-6， TNF-ɑ and MDA increased， while the concentration of SOD decreased in H1 group. Conclusion Hypothermia combined with dexmedetomidine during cardiopulmonary bypass can reduce oxidative stress response and POD in patients.