INTRATHECAL SUFENTANIL FOR LABOR ANALGESIA DOES NOT CAUSE A SYMPATHECTOMY

Background Intrathecal sufentanil (ITS) is frequently used to provide analgesia during labor. Decreases in blood pressure and sensory change s in this circumstance suggest that ITS may have a local anesthetic ef fect and thus cause a sympathectomy. To determine whether FTS given to laboring women causes a sympathectomy, the authors evaluated central and lower extremity temperature changes after ITS administration. Thes e findings were compared with those in a control group of women having spinal anesthesia with bupivacaine for elective cesarean section in w hom an extensive sympathectomy was expected. Methods: Twenty parturien ts classified as American Society of Anesthesiologists' physical statu s 1 or 2 had temperatures measured centrally, at the calf, and at the great toe at frequent intervals after receiving 10 mu g ITS for labor analgesia (sufentanil group, n = 10), or hyperbaric bupivacaine 12 mg in their spinal anesthetic for cesarean section (bupivacaine group, n = 10). Calf-to-toe temperature indices (C-T) were calculated by subtra cting toe temperature from calf temperature. A decrease in this index means that the toe had warmed compared with the calf and is an indicat ion of vasodilation and a sympathectomy. Results: There was no signifi cant change in the C-T indices or central temperature in the sufentani l group, but the C-T indices and central temperature decreased signifi cantly in the bupivacaine group. Conclusions The decreases in the C-T index and central temperature in the bupivacaine group indicate the pr esence of a sympathectomy. The lack of change in the C-T indices and c entral temperature in the sufentanil group indicates that no significa nt vasodilation occurred. Therefore, the decrease in blood pressure se en after ITS administration for labor analgesia is unlikely to be the result of a sympathectomy.