Does the anesthetic technique influence the epinephrine and norepinephrine concentration during pelvic surgery?

Abstract

Background: Epinephrine and norepinephrine concentrations increase by up to ten-fold immediately after surgical injury depending on the severity of the injury. However, the plasma levels of epinephrine and norepinephrine do not necessarily increase concurrently. The plasma epinephrine levels increase for about 48 h, while the norepinephrine levels remain elevated for about 8-10 days after injury. The choice of anesthesia has been shown to influence the secretion of epinephrine and norepinephrine. Materials and Methods: We compared the effects of balanced combined spinal-epidural anesthesia (CSEA, n = 20) and general anesthesia relaxant (GAR, n = 20) on epinephrine and norepinephrine concentrations during major pelvic surgery in patients with uterine mass > 20 weeks gestation. Blood samples for epinephrine and norepinephrine were analyzed at preinduction and 1, 3, and 4 h after surgical incision using enzyme-linked immunosorbent assay technique. Results: The mean norepinephrine concentration differs significantly after incision; at 1 h, CSEA 230.11 ± 42.85 versus GAR 51.25 ± 29.15 pg/ml, P = 0.015; and at 3 h, CSEA 116.22 ± 39.91 versus GAR 27.00 ± 19.89 pg/ml, P = 0.045. The norepinephrine concentrations increased from preinduction values after incision; at 1 h, increased in CSEA by +168% but increased in GAR by +31.7%; at 3 h, increased in CSEA by +35.64% but decreased in GAR by -22.85%; while at 4 h, decreased in CSEA by −3.37% but increased in GAR by +38.94% , P = 0.04 [Figure 2]. The mean epinephrine was comparable during the study, P > 0.05, while the mean heart rate, mean arterial blood pressure, and estimated blood loss were significantly lower with CSEA. Conclusion: We have demonstrated that in patients with uterine mass >20 weeks gestation, CSEA when compared to general anesthesia resulted in an initial increase in mean norepinephrine concentration 1 h after surgical incision followed by gradual decrease toward preinduction values.