Hemodynamic effects of epinephrine associated to an epidural clonidine-bupivacaïne mixture during combined lumbar epidural and general anesthesia.

Clonidine or epinephrine are frequently combined to epidural local anesthetics to strengthen sensory block and prolong analgesia. Both drugs impair the hemodynamic profile of central neural blockade but the effects of their combination on arterial pressure and heart rate are not known and were examined in this double-blind prospective randomised study. Forty four patients scheduled for lumbar disc surgery were allocated to two groups. Epidural anesthesia was obtained by administration of 150 micrograms clonidine in 15 ml bupivacaine 0.25% solution without (group C) or with (group C + E) 37.5 micrograms epinephrine. Systolic, mean, diastolic arterial pressure and heart rate were measured throughout the study. Combined epidural and general anesthesia induced a significant decrease in arterial pressure and heart rate in both groups. SAP and MAP decreased significantly less in the patients receiving epinephrine. Low dose epidural epinephrine decreases arterial pressure instability during combined epidural and general anesthesia.