Methemoglobin levels during epidural anesthesia for renal transplantation--comparison of prilocaine with bupivacaine.

BACKGROUND AND OBJECTIVE One goal of anesthesia for renal transplantation is to avoid an excess load to be imposed on the newly functioning kidney, by using appropriate agents and dosages in the perioperative management. The purpose of this study was to investigate the effect of prilocaine on serum methemoglobin levels when used as the local anesthetic in epidural anesthesia for renal transplantation, and to compare its effects with that of bupivacaine, which is the standard local anesthetic used. METHODS 26 adult renal recipients were randomized into 2 equal groups according to the local anesthetic used for epidural anesthesia during the operation. Patients in group P (n = 13) were given prilocaine and those in group B (control, n = 13) received bupivacaine. The methemoglobin measurement intervals were at: baseline before administration of local anesthetic, and then at 2 hours, 5 hours, and 12 hours of local anesthetic administration. RESULTS Methemoglobin levels in the prilocaine group were above the normal range in all measurements other than baseline. In the bupivacaine group, methemoglobin levels increased only at 5 hours of local anesthetic administration. However, methemoglobin concentrations and hemoglobin levels were comparable between the two groups at all time intervals, and none of the patients demonstrated clinical symptoms. CONCLUSION The use of prilocaine in epidural anesthesia for renal transplantation surgery resulted in an increase in methemoglobin levels, which did not cause any clinical symptoms and was similar to those of bupivacaine at all time measurements.