THE EFFECTS OF EPIDURAL-ANESTHESIA ON THE NEUROENDOCRINE RESPONSE TO MAJOR SURGICAL STRESS - A RANDOMIZED PROSPECTIVE TRIAL

It has long been held that the acute-phase and neuroendocrine response to stress requires afferent neural input for its propagation. To furt her clarify the role of afferent neural impulses in this process and t o determine the ability of epidural anesthesia to attenuate the normal perioperative stress response, 39 patients undergoing uncomplicated a bdominal aortic replacement were randomized to receive either general anesthesia with postoperative patient-controlled intravenous morphine (n = 19) or combined regional/general anesthesia with intraoperative e pidural catheter anesthesia using Bupivacaine to the T4 dermatome leve l followed by postoperative epidural morphine (n = 20). The stress res ponse was quantitated by blinded measurement of baseline and postopera tive (0, 12, 24, 48, and 72 hours) serum cortisol, epinephrine norepin ephrine, total catecholamines, interleukin (IL)-1 beta, IL-6, tumor ne crosis factor (TNF)-alpha, and C-reactive protein (CRP). Total operati ve time (4.2 +/- 0.3 vs 4.3 +/- 0.4 hours), 72-hour fluid requirement (7.0 +/- 0.6 vs 6.8 +/- 0.71 mL), and length of hospitalization (7.8 /- 1.4 vs 8.1 +/- 1.2 days) were not different between groups. All pat ients showed a significant increase in cortisol, epinephrine, norepine phrine, total catecholamines, CRP, and IL-6 in the postoperative perio d (P < 0.05). IL-1 beta and TNF-alpha were less predictable and undete ctable in most patients. There was no difference in any of the stress response indices between those patients receiving patient-controlled o r epidural catheter anesthesia. In fact, the only parameter that was p redictive of increased activation of the stress response was the lengt h of operation, irrespective of anesthetic method. Those patients with operative times greater than 5 hours (n = 10) developed significantly higher CRP, IL-1 beta, IL-6, and TNF-alpha levels (P < 0.05) at 12 an d 24 hours postoperatively than those with total operative times less than 4 hours (n = 16). The neuroendocrine response to major surgical s tress is propagated normally despite epidural blockade and is intensif ied with prolonged operative times. The inflammatory cytokines appear to play a major role in this process.