目的 探讨全麻胸腔镜手术患者应用右美托咪定（0.5、1.0、2.0 μg/kg）复合罗哌卡因超声引导下胸椎旁神经阻滞（TPVB）对生命体征、应激反应等指标的影响，为临床优化麻醉方案提供参考。 方法 选取全麻胸腔镜手术患者99例，按照随机数字表法将患者分为低、中、高剂量组，各为33例。麻醉诱导结束后，低、中、高剂量组分别给予右美托咪定0.5、1.0、2.0 μg/kg复合0.375%罗哌卡因超声引导下TPVB，三组均观察至术后3 d。比较各组围手术期指标，苏醒质量，术后2、6、12、24 h的疼痛程度，麻醉前（T1）、气管拔管时（T2）、气管拔管5 min时（T3）的生命体征，术前、术后3 d的免疫功能、应激反应及观察时间内的不良反应。 结果 较低剂量组，瑞芬太尼、丙泊酚用量在中、高剂量组中更低，术后自控镇痛次数更少（P < 0.05）。苏醒、气管拔管及恢复室停留时间在低、中、高剂量组之间延长（P < 0.05）。视觉模拟评分法（VAS）评分在三组术后2、6、12、24 h逐渐降低（P < 0.05），较低剂量组，中、高剂量组VAS评分在术后2、6、12 h更低（P < 0.05）。较T1时，三组心率（HR）、平均动脉压（MAP）在T2、T3时均升高，T2、T3时的HR、MAP在低、中、高剂量组之间升高（P < 0.05）；与T2时比较，三组T3时的HR、MAP均降低（P < 0.05）。较术前，三组全血CD8⁺、血清皮质醇（Cor）、C反应蛋白（CRP）、去甲肾上腺素（NE）、肾上腺素（E）水平在术后3 d升高，术后3 d上述指标在低、中、高剂量组之间升高（P < 0.05）；三组全血CD3⁺、CD4⁺、CD4⁺/CD8⁺水平在术后3 d降低，术后3 d上述指标在低、中、高剂量组之间降低（P < 0.05）。三组安全性比较差异无统计学意义（P > 0.05）。 结论 1.0 μg/kg右美托咪定复合罗哌卡因超声引导下TPVB在减轻全麻胸腔镜手术患者疼痛程度，减少瑞芬太尼、丙泊酚用量及术后自控镇痛次数方面具有一定的优势，而0.5 μg/kg右美托咪定复合罗哌卡因超声引导下TPVB在改善患者生命体征，减轻免疫抑制、应激反应及促进麻醉后苏醒方面具有一定的优势，临床可根据患者实际情况合理选择麻醉方案。

Objective To investigate the effects of dexmedetomidine （0.5， 1.0， 2.0 μg/kg） combined with ropivacaine ultrasound guided thoracic paravertebral nerve block （TPVB） in patients undergoing thoracoscopic surgery under general anesthesia on the vital signs， stress response and other indexes， and to provide reference for the optimization of anesthesia regimen in the clinic. Methods A total of 99 cases of patients undergoing thoracoscopic surgery under general anesthesia were selected， and the patients were divided into the low， medium， and high-dose groups of 33 cases each according to the method of randomized numerical table. At the end of anesthesia induction， dexmedetomidine 0.5， 1.0， and 2.0 μg/kg compounded with 0.375% ropivacaine ultrasound-guided TPVB was administered to the low， medium， and high-dose groups， respectively， and all three groups were observed until 3 d postoperatively. Perioperative indicators， quality of awakening， degree of pain at 2， 6， 12， and 24 h postoperatively， vital signs before anesthesia （T1）， at tracheal extubation （T2）， and at 5 min of tracheal extubation （T3）， and immune function， stress response， and adverse reactions during the observation time were compared between the groups. Results Compared with the low-dose group， remifentanil and propofol dosages were lower in the medium- and high-dose groups， and the number of postoperative self-controlled analgesia was lower （P < 0.05）. Awakening， tracheal extubation， and recovery room stay were prolonged between the low， medium， and high dose groups （P < 0.05）. Scores of visual analog scale （VAS） were progressively lower in the three groups at 2， 6， 12， and 24 h postoperatively （P < 0.05）， and compared with the low-dose group， scores of VAS were lower in the medium and high-dose groups at 2， 6， and 12 h postoperatively （P < 0.05）. Compared with T1， heart rate （HR）， mean arterial pressure （MAP） were higher in all three groups at T2， T3， and HR， MAP at T2， T3 were higher between the low， medium， and high dose groups （P < 0.05）； compared with T2， HR， MAP were lower in all three groups at T3 （P < 0.05）. Compared with the preoperative period， levels of whole blood CD8⁺， serum cortisol （Cor）， C-reactive protein （CRP）， norepinephrine （NE）， and epinephrine （E） were increased in the three groups at 3 d postoperatively， and the above indexes were elevated between the low， medium， and high dosage groups at 3 d postoperatively （P < 0.05）； levels of whole blood CD3⁺， CD4⁺， CD4⁺/CD8⁺ were decreased in the three groups at 3 d postoperatively， and the above indexes were elevated between the low， medium， and high dosage groups at 3 d postoperatively （P < 0.05）. There was no statistically significant difference in the safety comparison among the three groups （P > 0.05）. Conclusions 1.0 μg/kg dexmedetomidine combined with ropivacaine ultrasound guided TPVB had certain advantages in reducing the degree of pain of general anesthesia thoracoscopic surgery patients， reducing the dosage of remifentanil and propofol and the number of postoperative self-controlled analgesia， while 0.5 μg/kg dexmedetomidine combined with ropivacaine ultrasound guided TPVB had certain advantages in improving patients' vital signs， reducing immunosuppression， stress reaction and promoting post-anesthesia awakening. Clinical anesthesia protocols could be rationally selected according to the actual situation of patients.