The effects of pre-emptive epidural sufentanil on human immune function

Background: Surgical stress and general anaesthesia suppress immune functions, including natural killer cell (NK) activity. This suppression could be attributed, at least in part, to the effect of opiates. Methods: Twenty patients undergoing abdominal hysterectomy received epidural sufentanil (50 mug) either before (pre-emptive) or at the end (control group) of surgery. Post-operative pain relief was provided using sufentanil from a patient-controlled epidural analgesia (PCEA) system. Systemic immunity was assessed by determining leucocyte counts, NK cell counts and activity, lymphocyte response to mitogen stimulation, and secretion of pro-inflammatory cytokines. Results: In the pre-emptive group there was a significant decrease in NK activity on the first and third post-operative day (P < 0.05) compared with baseline values and on the third postoperative day (P < 0.05) compared with the control group. The number of total leucocytes and neutrophiles increased in both groups post-operatively, but no differences were found in the levels of mononuclear lymphocyte populations or in their mitogen responses. Interleukin-6 (IL-6) concentration increased in both groups after the operation. In addition, at the end of the surgery the IL-6 level was greater in the control group than in the pre-emptive group. Interleukin-1 (IL-1) levels had decreased significantly at the end of surgery and 4 h later compared with baseline levels in the pre-emptive, but not in the control group. Conclusions: Pre-emptive epidural sufentanil during combined propofol and isoflurane anaesthesia had minor effects on the immune response after hysterectomy. The lower production of pro-inflammatory cytokines (IL-1, IL-6) in the pre-emptive group compared with the control group is beneficial, but its clinical importance remains to be determined.