罗哌卡因胸段硬膜外阻滞对急性心肌缺血/再灌注损伤的保护作用

Myocardial protective effects of thoracic epidural anesthesia with ropivacaine during acute myocardial ischemia reperfusion

目的 探讨罗哌卡因胸段硬膜外阻滞对急性心肌缺血再灌注损伤的保护作用。方法健康杂种犬 18条 ,随机分为罗哌卡因组 (Ⅰ组 )、布比卡因组 (Ⅱa组 )和生理盐水组 (Ⅱb组 )。静脉全麻后控制呼吸 ,T6～ 7间隙穿刺置入硬膜外导管 ,按分组分别硬膜外注射 0 5 %罗哌卡因、0 5 %布比卡因或生理盐水 12ml。 15min后 ,阻断左冠状动脉 45min。分别在给药前和开放后 6h抽取右心房血。以Cardiac试剂条测定血浆心肌肌钙蛋白T(cTnT)浓度 ,并取左心室梗塞区心肌组织作透射电镜观察。结果 阻断前血浆cTnT浓度三组均 <0 0 5ng/L。开放 6h三组各有 4例升高、2例无变化 ,其中Ⅰ组 4例均 <0 1ng/L ,Ⅱa组 2例 <0 1ng/L、2例介于 0 1～ 3ng/L ,Ⅱb组 4例均介于 0 1～ 3ng/L。Ⅰ组与Ⅱb组比较有显著性差异 (P <0 0 5 )。开放后 6h的梗塞区心肌组织的电镜学观察结果显示 ,Ⅰ组心肌肌纤维排列完整、规律 ,线粒体未见异常 ;Ⅱa组肌纤维间隙增宽 ,核膜模糊 ,线粒体基本正常 ;Ⅱb组肌纤维排列极度紊乱 ,正常肌节结构消失 ,区域内出现大量空泡区。结论 0 5 %罗哌卡因胸段硬膜外阻滞对急性心肌缺血再灌注损伤有明显的保护作用 ,其效果优于相同浓度的布比卡因。

Objective To evaluate the myocardial protective effects of thoracic epidural anesthesia (TEA) with 0 5% ropivacaine during acute myocardial ischemia reperfusion Methods Eighteen healthy hybrid dogs were randomly divided into three groups: ropivacaine group (group Ⅰ), bupivacaine group (group Ⅱa) and normal saline group (group Ⅱb) Anesthesia was induced and maintained with intravenous anesthesia and ventilation was mechanically controlled Epidural catheter was placed at T 6 7 and 0 5% ropivacaine, 0 5% bupivacaine or normal saline 12ml was administered epidurally 15min after epidural administration of local anesthetics or normal saline, the anterior descending branch of left coronary artery was temporarilly occluded for 45min Blood samples were taken from right atrium and assayed for cardiac troponin T (cTnT) before epidural administration and 6h after reperfusion Myocardial tissues of left ventricular infarction area were examined by electron microscopy Results Plasma cTnT levels were comparable (P<0 05 ng/L) in the three groups before epidural administration but increased significantly in 4 dogs of each group 6 h after reperfusion The difference between group Ⅰand groupⅡb was significant (P<0 05) Electron microscope examination of the infarct myocardium showed that myocardial fibers were regularly arranged with normal mitochondria in group Ⅰ ;the intercellular spaces were enlarged with unclear nuclar membrane and near normal mitochondria in groupⅡa; the myocardial fibers were irregularly arranged with a number of vacuoles and no normal sarcomere structure was seen in the cytoplasm in group Ⅱb .Conclusions TEA with 0 5% ropivacaine can afford effective protection against acute myocardial ischemia reperfusion injury and the effect is better than TEA with bupivacaine at the same concentration