Bupivacaine cardiotoxicity and subendocardial microcirculation

心室颤动和心肌收缩力下降是布比卡因引起心脏毒性的两个重要因素。观察利多卡因对布比卡因诱发的心室颤动的治疗效果及布比卡因的血管收缩作用。在第一组实验中，将0.25%布比卡因、1%利多卡因和0.25%布比卡因加利多卡因溶液按0、1、2、4、8、16 mL/hr的递增顺序注入左冠状动脉前降支，持续15 min，共3组8头猪。用声速测量法评价局部心肌功能。虽然Lid组没有VF，但布比卡因组在输注速度为4 mL/hr和8 mL/hr时出现1例VF，布比卡因加利多卡因组在输注速度为8 mL/hr和16 mL/hr时出现1例和7例VF。虽然三组局部心肌功能均呈剂量相关性下降，但布比卡因的心肌抑制作用明显大于利多卡因，且与布比卡因加利多卡因的心肌抑制作用无差异。在第二组实验中，将6份含布比卡因的自体血液（0、0.25、1.25、2.5、5、10马克/毫升）通过放置在第一对角支的导管注射到5只猪的冠状动脉中，同时用针状视频显微镜观察左心室间隔区心内膜下微血管（直径50-100mum）。直径

Ventricular fibrillation (VF) and depression of myocardial contractility are two important factors for bupivacaine-induced cardiotoxicity. The efficacy of lidocaine for bupivacaine-induced VF and the vasoconstricting effects of bupivacaine were examined in the beating hearts in vivo. In the first set of the experiment, 0.25% bupivacaine, 1% lidocaine and 0.25% bupivacaine plus lidocaine solutions were infused into the left anterior descending coronary artery (LAD) in an increasing sequence of 0,1,2,4,8 and 16 mL/hr for 15 min into the LAD in three groups consisting of eight pigs. Regional myocardial function was evaluated by the sonomicrometry technique. While there were no VF in the Lid group, VF occurred in one at 4 mL/hr and seven at 8 mL/hr infusion rates in the bupivacaine group, and in one at 8 mL/hr and seven at 16 mL/hr infusion rates in the bupivacaine plus lidocaine group. Although regional myocardial function decreased in a dose-related manner in the three groups, the myocardial depressant effects of bupivacaine were significantly greater than that of lidocaine, and did not differ with that of bupivacaine plus lidocaine. In the second set of the experiment, six samples of bupivacaine-containing autologous blood (0,0.25,1.25,2.5,5,10mug/mL) were injected into the coronary artery via a catheter placed in the first diagonal branch in the five pigs, while left ventricular subendocardial microvessels (50-100mum in diameter) in the septal region were visualized by a needle type video microscope. Diameter of the