Taniguchi M, Kasaba T, Takasaki M
Department of Anesthesiology, Miyazaki Medical College, Japan.
Anesth Analg. 1997 Feb;84(2):391-7. doi: 10.1097/00000539-199702000-00029.
To evaluate compensatory sympathetic excitation during epidural anesthesia, we measured cardiac and renal sympathetic nerve activity during thoracic or lumbar epidural anesthesia in cats. Thirteen cats were divided into three groups: five cats received thoracic epidural anesthesia, five received lumbar epidural anesthesia, and three received lumbar epidural anesthesia after the carotid sinus and vagoaortic nerves were severed (denervated lumbar group). Heart rate (HR), mean arterial pressure (MAP), and cardiac and renal sympathetic nerve activity were measured repeatedly after administration of a single dose of 0.1 mL/kg of 1% lidocaine via the epidural catheter. Epidural solution spread from a median of C-8 to T-6 in the thoracic epidural group, T-8 to L-3 in the lumbar epidural group, and T-7 to L-3 in the denervated lumbar group. During thoracic epidural anesthesia, HR, MAP, and cardiac sympathetic nerve activity decreased, while renal nerve activity increased. Similarly, HR, MAP, and renal sympathetic nerve activity decreased during lumbar epidural anesthesia, and cardiac activity increased. In the denervated lumbar group, HR, MAP, and renal sympathetic nerve activity decreased but cardiac activity remained unchanged. Sympathetic nerve activity in corresponding unanesthetized segments increased during thoracic or lumbar epidural anesthesia in association with significant decreases in MAP and HR. After severance of the carotid sinus and vagoaortic nerves, the absence of sympathetic excitation in the unanesthetized segments during lumbar epidural anesthesia suggests that the compensatory response is produced by the baroreceptor reflex response to anesthesia-induced hypotension.
为评估硬膜外麻醉期间的代偿性交感神经兴奋，我们在猫的胸段或腰段硬膜外麻醉期间测量了心脏和肾交感神经活动。13只猫被分为三组：5只接受胸段硬膜外麻醉，5只接受腰段硬膜外麻醉，3只在切断颈动脉窦和迷走主动脉神经后接受腰段硬膜外麻醉（去神经腰段组）。通过硬膜外导管单次给予0.1 mL/kg的1%利多卡因后，反复测量心率（HR）、平均动脉压（MAP）以及心脏和肾交感神经活动。硬膜外溶液在胸段硬膜外组从C-8中位数扩散至T-6，在腰段硬膜外组从T-8扩散至L-3，在去神经腰段组从T-7扩散至L-3。在胸段硬膜外麻醉期间，HR、MAP和心脏交感神经活动降低，而肾神经活动增加。同样，在腰段硬膜外麻醉期间，HR、MAP和肾交感神经活动降低，而心脏活动增加。在去神经腰段组，HR、MAP和肾交感神经活动降低，但心脏活动保持不变。在胸段或腰段硬膜外麻醉期间，相应未麻醉节段的交感神经活动增加，同时MAP和HR显著降低。在切断颈动脉窦和迷走主动脉神经后，腰段硬膜外麻醉期间未麻醉节段缺乏交感神经兴奋，这表明代偿反应是由压力感受器反射对麻醉诱导的低血压的反应产生的。
