Kopacz D J, Emanuelsson B M, Thompson G E, Carpenter R L, Stephenson C A
Department of Anesthesiology, Virginia Mason Medical Center, Seattle, Washington.
Anesthesiology. 1994 Nov;81(5):1139-48. doi: 10.1097/00000542-199411000-00007.
Intercostal blockade produces the highest serum local anesthetic concentrations of all regional anesthetic techniques. The purpose of this study was to determine the pharmacokinetic properties of ropivacaine and bupivacaine after bilateral intercostal blockade.
The pharmacokinetics of ropivacaine (n = 7) and bupivacaine (n = 7) were determined in adult human volunteers from venous samples drawn over 24 h after bilateral intercostal blockade of T5-T11 with 140 mg of either drug (0.25% plain solutions, 56 ml). Sensory (pinprick, temperature, and touch) and motor blockade (RAM-test and integrated electromyography) were assessed every 2 h.
There was no significant difference between the maximum plasma concentrations (Cmax) obtained for either drug (ropivacaine 1.1 +/- 0.4 microgram/ml, bupivacaine 0.9 +/- 0.2 microgram/ml, P = 0.39), and there were no toxic signs observed in the obtained plasma concentration ranges. Plasma concentrations tended to peak (tmax) earlier with ropivacaine (21 +/- 9 versus 30 +/- 8 min, P = 0.09). The terminal half-life (t1/2 beta) of ropivacaine (2.3 +/- 0.8 h) was significantly less than that for bupivacaine (4.6 +/- 2.6 h, P = 0.04). Sensory blockade measured by pinprick was of shorter duration with ropivacaine (6.0 +/- 2.5 h versus bupivacaine 10.0 +/- 3.0 h; P < 0.001). Likewise, motor blockade was less intense and of shorter duration for ropivacaine by RAM-test (P = 0.02).
The results of this pharmacokinetic study indicate that 0.25% ropivacaine and 0.25% bupivacaine (56 ml, 140 mg) produce peak plasma levels less than those considered toxic when used in bilateral intercostal blockade. Studies of ropivacaine for intercostal blockade in surgical patients are necessary before the optimum concentration for efficacy and anesthetic/analgesic duration is identified.
在所有区域麻醉技术中，肋间神经阻滞产生的血清局部麻醉药浓度最高。本研究的目的是确定双侧肋间神经阻滞后罗哌卡因和布比卡因的药代动力学特性。
在成年志愿者中，于用140mg罗哌卡因或布比卡因（0.25%原液，56ml）对T5 - T11进行双侧肋间神经阻滞后24小时内，通过采集静脉血样来测定罗哌卡因（n = 7）和布比卡因（n = 7）的药代动力学。每2小时评估感觉（针刺、温度和触觉）和运动阻滞（RAM试验和肌电图积分）。
两种药物的最大血浆浓度（Cmax）之间无显著差异（罗哌卡因1.1±0.4μg/ml，布比卡因0.9±0.2μg/ml，P = 0.39），在所测得的血浆浓度范围内未观察到毒性体征。罗哌卡因的血浆浓度达到峰值（tmax）的时间更早（21±9分钟对30±8分钟，P = 0.09）。罗哌卡因的终末半衰期（t1/2β）（2.3±0.8小时）显著短于布比卡因（4.6±2.6小时，P = 0.04）。通过针刺测量的感觉阻滞持续时间，罗哌卡因较短（6.0±2.5小时对布比卡因10.0±3.0小时；P < 0.001）。同样，通过RAM试验，罗哌卡因的运动阻滞强度较小且持续时间较短（P = 0.02）。
本药代动力学研究结果表明，0.25%罗哌卡因和0.25%布比卡因（56ml，140mg）在双侧肋间神经阻滞中产生的血浆峰值水平低于被认为有毒的水平。在确定手术患者肋间神经阻滞的最佳疗效浓度和麻醉/镇痛持续时间之前，有必要对罗哌卡因进行进一步研究。
