国产盐酸左旋布比卡因用于蛛网膜下腔阻滞的实验研究

目的观察不同浓度国产盐酸左旋布比卡因注入犬蛛网膜下腔后对脊髓、脊神经根及脑脊液(CFS)的影响。方法健康杂种犬18只,随机分为生理盐水2ml(A)组、0.5%左旋布比卡因2ml(B)组和0.75%左旋布比卡因2ml(C)组,每组各6只。动物基础麻醉后行L3-4间隙穿刺,见CSF后注入上述各组药物。分别于注药前和注药后1、2、3h测定CFS中氧分压(PO2)及乳酸(Lac)值。3h后处死动物取L1～L2段脊髓及神经根组织,用透射电镜观察脊髓及神经根组织超微结构的改变,检测脊髓组织中Ca2+、MDA含量和SOD活力的变化。结果注药前、后CFS中PO2及Lac值组间比较差异无显著性(P>0.05);脊髓组织中Ca2+、MDA含量及SOD活力组间比较差异无显著性(P>0.05);A组脊髓及神经根组织的早期超微结构基本正常,神经元胞质内线粒体和内质网结构完整清晰,有髓神经纤维的髓鞘完整;B、C组神经元胞质接近正常,多数线粒体、内质网结构完整,有髓神经纤维的板层结构基本正常。结论临床常用浓度和剂量的盐酸左旋布比卡因用于犬蛛网膜下腔阻滞对脊髓、神经根和脑脊液无明显影响。

The effects of intrathecal domestic levobupivacaine hydrochloride on spinal cord and nerve roots in dogs

Aim To investigate the effects of intrathecal domestic levobupivacaine hydrochloride on spinal cord,nerve roots and cerebrospinal fluid in dogs.Methods Eighteen mongrel dogs of either sex weighing about 12~15 kg were randomly divided into 3 groups of 6 animals each. Normal saline 2 ml,0.5% levobupivacaine 2 ml and 0.75% levobupivacaine 2 ml were intrathecally injected in group A,B and C respectively.Anesthesia was induced with intramuscular ketamine 20 mg·kg-1 and atropine 0.05 mg·kg-1,and maintained with continuous infusion fentanyl and vecuronium and intermittent inhaled isoflurane. Left internal jugular artery was cannulated for intra-arterial pressure and blood gas monitoring. An incision was made in the back at L_3-4 and lumbar puncture was confirmed by aspiration of cerebrospinal fluid(CSF).Normal saline or local anesthetics was then injected over 20 seconds.The blood gas and CSF lactic acid levels and hemodynamics were measured at before and 1 h,2 h and 3h after intrathecal administration. Three hours after intrathecal administration the animals were sacrificed and L_1-2 segment of spinal cord and nerve roots were immediately removed for Ca2+,MDA contents and SOD activity determination and electron microscopic examination. Results The levels of PO_2 and lactic acid in CSF among three groups were not significant different(P>0.05) at various measurement time.The Ca2+ and MDA contents and SOD activities of spinal cord were no significant differences in the three groups(P>0.05).Electron microscopic examination revealed that in group A,B and C neurolemma of the nerve roots and the mitochondria and endoplasmic reticulum of the neurons in the spinal cord were basically intact.No significant difference of histological findings was observed between group B and group C.Conclusion Intrathecal anesthesia with domestic levobupivacaine hydrochloride is safe and feasible.