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 microg) 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.