颈神经丛阻滞麻醉致颈动脉窦和迷走神经阻滞的实验研究

Experimental study on carotid sinus and vagus during cervical plexus block

目的研究颈丛神经阻滞麻醉对颈动脉窦和迷走神经的影响，探讨颈丛神经阻滞麻醉引起心血管副反应的原因。方法杂种犬20只，通过对犬实施一点法颈深丛神经阻滞麻醉，解剖颈内动脉起始部和颈部迷走神经，观察该麻醉下颈动脉窦和颈部迷走神经被麻醉药物浸润情况；观察麻醉前后颈动脉窦按摩，及麻醉后刺激颈部迷走神经对犬血压及心率的影响。结果颈内动脉起始部距离第4颈椎（C4）横突1.0-1.4cm，而一点法颈深丛阻滞麻醉后距离C4横突约4．0cm范围内组织均明显被麻醉药物浸润。显微镜下观察：颈内动脉起始部血管壁和迷走神经均明显被麻醉药物浸润。颈丛神经阻滞麻醉前按摩颈动脉窦可引起明显的减压反射，而阻滞后按摩颈动脉窦或刺激迷走神经均未引起明显的血压及心率变化。结论颈丛神经阻滞麻醉致颈动脉窦和迷走神经阻滞是引起心血管副反应的主要原因。

[Objective] To study the effect on carotid sinus and vagus for the cause of hemodynamie response during cervical plexus block. [Methods] One-needle＇s cervical plexus block were performed in 20 dogs. The initiation part of internal carotid artery and vagus were anatomized to find the depth of anesthetic infiltration in them. The cardiovascular effects of the dogs were observed during the carotid sinus chirapsia or stimulating vagus before and after cervical plexus block. [Results] It was about 1.4 cm that the distance between the initiation part of .internal carotid artery and C4 transverse process in all the dogs. The range of anesthetic infrltration was about 4.0 cm. Observing with microscope, we found that the initiation part of internal carotid artery and vagus were infiltrated with anesthetic. The reflection of decompression was observed during the carotid sinus chirapsia before cervical plexus block, while not during the carotid sinus chirapsia or stimulating vagus after cervical plexus block. [Conclusion] The main factor of cardiovascular effects during cervical plexus block was that the carotid sinus and vagus were blocked.