De Kock M, Wiederkher P, Laghmiche A, Scholtes J L
Department of Anesthesiology, University of Louvain, St. Luc Hospital, Brussels, Belgium.
Anesthesiology. 1997 Feb;86(2):285-92. doi: 10.1097/00000542-199702000-00003.
Many studies have shown the beneficial effect of epidural clonidine in postoperative pain management. In these studies, the patients received local anesthetics, opioids, or both in combination with clonidine. Due to the interactive potentiation of those drugs, the importance of the intrinsic analgesic properties of the alpha 2-adrenoceptor agonist is difficult to establish. The authors investigated the analgesic potency of epidural clonidine when used as the sole analgesic agent during and after major abdominal surgery.
Fifty young adult patients undergoing intestinal surgery under general anesthesia with propofol were studied. At induction, the patients received epidurally either an initial dose of 2 micrograms/kg clonidine followed by an infusion of 0.5 microgram.kg-1.h-1 (group 1, n = 10) or 4 micrograms/kg followed by 1 microgram.kg-1.h-1 (group 2, n = 20) or 8 micrograms.kg-1.h-1 followed by an infusion of 2 micrograms.kg-1.h-1 (group 3, n = 20). During the operation, increases in arterial blood pressure or heart rate that did not respond to a propofol bolus (0.5 mg/kg) were treated with a bolus of intravenous lidocaine (1 mg/kg). Three successive injections were allowed. When baseline values were not restored, opioids were added and the patient was removed from the study. After operation, the clonidine infusions were maintained for 12 h. During this period and at every 30 min, sedation scores and visual analog scale values at rest and at cough were noted. In case of subjective scores up to 5 cm at rest or up to 8 cm at cough, the patients were given access to a patient-controlled analgesia device that delivered epidural bupivacaine. The end point of the study was reached once the patient activated the analgesic delivery button.
During surgery, 60% of patients in group 1 compared with 33% of patients in group 2 and only 5% of patients in group 3 were removed from the study protocol because of inadequate anesthesia (P < 0.05). After operation, epidural clonidine provided complete analgesia lasting 30 +/- 21 min in group 1 compared with 251 +/- 237 min in group 2 or 369 +/- 256 min in group 3 (P < 0.05 for group 1 vs. groups 2 and 3 and group 2 vs. group 3).
Epidural clonidine used as the sole analgesic agent provided dose-dependent control of the hemodynamic changes associated with surgical stimulation. It also produced dose-dependent postoperative analgesia without major side effects.
许多研究已表明硬膜外可乐定在术后疼痛管理中具有有益作用。在这些研究中，患者接受局部麻醉药、阿片类药物或两者与可乐定联合使用。由于这些药物的相互增效作用，α2肾上腺素能受体激动剂的内在镇痛特性的重要性难以确定。作者研究了硬膜外可乐定在腹部大手术期间及术后用作单一镇痛剂时的镇痛效力。
研究了50例接受丙泊酚全身麻醉下肠道手术的年轻成年患者。诱导时，患者硬膜外给予初始剂量2微克/千克可乐定，随后以0.5微克·千克-1·小时-1输注（第1组，n = 10）或4微克/千克，随后以1微克·千克-1·小时-1输注（第2组，n = 20）或8微克·千克-1·小时-1，随后以2微克·千克-1·小时-1输注（第3组，n = 20）。手术期间，对丙泊酚推注（0.5毫克/千克）无反应的动脉血压或心率升高，用静脉注射利多卡因推注（1毫克/千克）治疗。允许连续注射三次。当基线值未恢复时，添加阿片类药物，患者退出研究。术后，可乐定输注维持12小时。在此期间，每30分钟记录一次静息和咳嗽时的镇静评分及视觉模拟量表值。如果静息时主观评分高达5厘米或咳嗽时高达8厘米，患者可使用可提供硬膜外布比卡因的患者自控镇痛装置。一旦患者按下镇痛给药按钮，即达到研究终点。
手术期间，第1组60%的患者因麻醉不足退出研究方案，而第2组为33%，第3组仅为5%（P < 0.05）。术后，硬膜外可乐定在第1组提供了持续30±21分钟的完全镇痛，而第2组为251±237分钟，第3组为369±256分钟（第1组与第2组和第3组相比，第2组与第3组相比，P < 0.05）。
硬膜外可乐定用作单一镇痛剂可对与手术刺激相关的血流动力学变化提供剂量依赖性控制。它还产生剂量依赖性的术后镇痛且无主要副作用。
