Abstract

Twenty patients scheduled for elective urologic surgery received epidural anesthesia with 20 ml 0.5% bupivacaine. Ten patients received an epinephrine-free solution and ten patients received epinephrine 5 μg · ml⁻¹ added to the local anesthetic solution. The mean maximum level of sensory blockade was not different between the two groups (T7 and T8). After epidural administration of 20 ml of either solution, the mean arterial blood pressure decreased significantly from preblockade values. After administration of 0.5% bupivacaine with epinephrine, cardiac output, stroke volume and end diastolic volume increased significantly from pre-blockade control values. These changes occurred within two to four minutes after injection of the local anesthetic solution and are caused by the systemic effects of epinephrine. After 15 minutes, the ejection fraction in the plain bupivacaine group decreased significantly from pre-blockade control values and the bupivacaine with epinephrine group. The differences in hemodynamic effects of the two solutions can be explained by the vasoactive effects of epinephrine and the cardiodepressive effects of bupivacaine.