Gulec S, Aydin Y, Uzuner K, Yelken B, Senturk Y
Osmangazi University Medical School, Department of Anaesthesiology, Eskisehir, Turkey.
Eur J Anaesthesiol. 2004 Mar;21(3):205-9. doi: 10.1017/s0265021504003072.
Clonidine has cardiac and systemic effects that can modify the potentially lethal cardiovascular effects of local anaesthetics. We evaluated the effects of clonidine pre-treatment on cardiotoxicity induced by an infusion of bupivacaine or ropivacaine and the success rate of resuscitation in anaesthetized rats.
Thirty-two Sprague-Dawley rats (250-300 g) were anaesthetized with thiopental and ketamine. Lung ventilation was maintained mechanically, and the electrocardiograph and invasive blood pressure were recorded continuously. Two separate groups of rats were treated with intravenous clonidine 5 microg kg(-1) (n = 16) or saline (n = 16) in a randomized fashion. Fifteen minutes later, each group was randomly subdivided into two equal groups and an infusion of bupivacaine or ropivacaine, 3 mg kg(-1) min(-1), was given until cardiac arrest (asystole) occurred. The times when the cardiotoxic events (25%, 50% and 75% reduction of arterial pressure and heart rate, first dysrhythmia and asystole, respectively), induced by the local anaesthetic, occurred and the resuscitation outcome scores were recorded.
Clonidine reduced heart rate and arterial pressure (P < 0.01). Clonidine did not alter cardiotoxicity or the success rate of resuscitation in bupivacaine-treated rats. In the ropivacaine group, clonidine increased the 25%, 50% and 75% reduction times of arterial pressure and the 50% and 75% reduction times of heart rate, times to first dysrhythmia and asystole (P < 0.05). Clonidine also increased the success rate of resuscitation in ropivacaine-treated rats (P < 0.05).
Although pre-treatment with clonidine protects the effects of ropivacaine cardiotoxicity and increases the success rate of resuscitation, it does not affect bupivacaine toxicity.
可乐定具有心脏和全身效应，可改变局部麻醉药潜在的致命性心血管效应。我们评估了可乐定预处理对布比卡因或罗哌卡因输注诱导的心脏毒性以及麻醉大鼠复苏成功率的影响。
32只体重250 - 300克的Sprague-Dawley大鼠用硫喷妥钠和氯胺酮麻醉。机械维持肺通气，并持续记录心电图和有创血压。将两组大鼠随机分别给予静脉注射5微克/千克可乐定（n = 16）或生理盐水（n = 16）。15分钟后，每组再随机分为两个相等的组，以3毫克/千克·分钟的速度输注布比卡因或罗哌卡因，直至发生心脏骤停（心搏停止）。记录局部麻醉药诱导的心脏毒性事件（动脉压和心率分别降低25%、50%和75%、首次出现心律失常和心搏停止）发生的时间以及复苏结果评分。
可乐定降低了心率和动脉压（P < 0.01）。可乐定未改变布比卡因处理大鼠的心脏毒性或复苏成功率。在罗哌卡因组中，可乐定增加了动脉压降低25%、50%和75%以及心率降低50%和75%的时间、首次出现心律失常和心搏停止的时间（P < 0.05）。可乐定还提高了罗哌卡因处理大鼠的复苏成功率（P < 0.05）。
虽然可乐定预处理可保护罗哌卡因的心脏毒性效应并提高复苏成功率，但它不影响布比卡因的毒性。
