Effects of induction of general and regional anesthesia for cesarean section on maternal plasma beta-endorphin levels

Abstract

Plasma beta-endorphin was measured in 40 healthy pregnant women undergoing cesarean section. Group 1 patients (N = 14) received general anesthesia by rapid-sequence induction and endotracheal intubation with curare, thiopental, and succinylcholine. Anesthesia was maintained with nitrous oxide, oxygen, and muscle relaxant until delivery. Group 2 patients (N = 26) received regional anesthesia (spinal, 14, and epidural, 12). Maternal blood samples were drawn from indwelling venous catheters prior to and after induction of either general or regional anesthesia. Plasma beta-endorphin was determined by radioimmunoassay following silicic acid extraction and gel chromatography. In the 14 patients who underwent general anesthesia, the mean (+/- SEM) plasma beta-endorphin increased significantly (p less than 0.025) from 46 +/- 7.4 to 111.6 +/- 8.9 fmol/ml. There was no significant change in plasma beta-endorphin level of the 26 patients who underwent regional anesthesia; beta-endorphin levels averaged 44.5 +/- 5.1 and 47.6 +/- 4.8 fmol/ml prior to and after induction of anesthesia, respectively. These data demonstrate that plasma beta-endorphin concentrations are elevated following induction of general anesthesia but not with induction of regional anesthesia, which suggests that less stress is associated with regional than with general anesthesia induction in patients undergoing cesarean section.