摘要
目的通过胸段硬膜外阻滞(TEA)交感神经,探讨TEA对迷走神经传出放电频率的影响。方法健康日本大耳白兔28只,随机均分为假手术(Sham)组、TEA组、硝普钠(SNP)组、胸段硬膜外麻醉+麻黄碱(TEA+EPH)组。在记录MAP、迷走传出端基础电位后,TEA组硬膜外腔给予0.5%布比卡因0.4ml/kg;Sham组在同样时点硬膜外腔注射等容量生理盐水;SNP组记录基础电位后静脉注射硝普钠盐溶液控制性降压,模拟TEA的降压过程,硬膜外腔隙注射等量生理盐水;TEA+EPH组通过硬膜外导管给予0.5%布比卡因0.4ml/kg后肌注麻黄碱维持血压在正常范围。应用BL-420S电生理系统记录并分析硬膜外腔注射前、注射后1、2、3h迷走神经传出放电变化。结果四组家兔注射前基础放电频率差异无统计学意义。TEA组、TEA+EPH组在注射后1、2、3h放电频率明显高于SNP组和Sham组(P<0.05)。TEA组、SNP组的MAP在注射后1、2、3h明显低于TEA+EPH组和Sham组(P<0.05)。TEA组和TEA和EPH组HR在注射后1、2、3h时明显慢于Sham组(P<0.05);SNP和TEA+EPH组在注射后1、2、3h时HR均明显快于TEA组(P<0.05)。结论 TEA可能通过阻滞交感神经,使迷走神经传出产生绝对兴奋,这种兴奋并不是因为TEA所致的血管扩张而引起的血压降低所致。
Objective To investigate the changes of cervical vagal efferent discharge after thoracic epidural anesthesia in rabbits.Methods After the placement of epidural catheter,twenty-eight rabbits were randomly divided into four groups with 7each.After the base frequency of cervical vagal efferent discharge and MAP were recorded,group Sham and group SNP（Sodium Nitroprusside）received normal saline（0.4ml/kg）through epidural catheter;group SNP were received Sodium Nitroprusside Solution to simulate the process of decreasing MAP of group TEA.group TEA（Thoracic epidural anesthesia）and group TEA＋EPH（ephedrine）were received 0.5%（0.4ml/kg）bupivacaine through the epidural catheter and then the latter group received ephedrine to maintain normal blood pressure.The BL-420 Selectrophysiological system was used to analyze the changes of vagal efferent discharge.Results The base frequency of cervical vagal efferent discharge of all groups had no significantly differences.MAP in groups TEA and SNP decreased significantly 1,2,3hafter injection compared with groups Sham and TEA＋EPH（P〈0.05）.The frequency of cervical vagal efferent discharge was significantly increased in groups TEA and TEA＋EPH 1,2,3hafter the injection of bupivacaine,while no significant changes in groups Sham and SNP after the injection of normal saline（P〈0.05）.In groups TEA and TEA＋EPH,HR decreased more significantly by at 1,2,3hthan in group Sham（P〈0.05）.In groups SNP and TEA＋EPH,HR were faster than in group TEA at 1,2,3h（P〈0.05）.Conclusion The current study showed that,first,the enhancement of cervical vagal efferent discharge might be due to the block of sympathetic nerve by thoracic epidural anesthesia;Second,the impact of decreased blood pressure on vagal efferent discharge can be excluded as cervical vagal efferent discharge enhanced in group TEA＋EPH and not enhanced in group SNP.
出处
《临床麻醉学杂志》
CAS
CSCD
北大核心
2014年第9期897-900,共4页
Journal of Clinical Anesthesiology
基金
国家自然科学基金(81141105)
湖北省自然科学基金(2011CDB189)
三峡大学硕士学位论文培优基金(2013py055)
关键词
胸段硬膜外麻醉
迷走神经
传出放电
交感神经阻滞
Thoracic epidural anesthesia
Vagal nerve
Efferent discharge
Sympathetic block
