Sundberg A, Wattwil M
Acta Anaesthesiol Scand. 1987 Jan;31(1):81-6. doi: 10.1111/j.1399-6576.1987.tb02525.x.
Circulatory changes and the degree of sympathetic block were evaluated in 15 elderly patients with high thoracic epidural anaesthesia (T1-T5). Bupivacaine 5-6 ml 0.5% was injected via an epidural catheter at the T3-level. The quality of the sympathetic block was determined with the Valsalva manoeuvre. Induced hypercapnia was used to quantify the degree of sympathetic block. Following thoracic epidural anaesthesia (TEA), cardiac output, stroke volume and arterial blood pressure decreased. During hypercapnia, heart rate and arterial blood pressure increased both before and after established TEA. Thus the block of the sympathetic innervation to the heart with a high TEA using 0.5% bupivacaine was not sufficient to prevent mobilization of circulatory reserves during sympathetic stimulation. The most likely explanation is considered to be the lack of neural block of the efferent nerves leading to the adrenal medulla and the peripheral vascular bed.
对15例接受高位胸段硬膜外麻醉（T1-T5）的老年患者的循环变化和交感神经阻滞程度进行了评估。通过T3水平的硬膜外导管注入5-6毫升0.5%的布比卡因。通过瓦尔萨尔瓦动作确定交感神经阻滞的质量。采用诱导性高碳酸血症来量化交感神经阻滞的程度。胸段硬膜外麻醉（TEA）后，心输出量、每搏输出量和动脉血压下降。在高碳酸血症期间，无论是在确立TEA之前还是之后，心率和动脉血压均升高。因此，使用0.5%布比卡因进行高位胸段硬膜外麻醉时，对心脏的交感神经支配阻滞不足以防止交感神经刺激期间循环储备的调动。最可能的解释被认为是缺乏对通向肾上腺髓质和外周血管床的传出神经的神经阻滞。
