Effect of anaesthesia on the cytokine responses to abdominal surgery

Plasma concentrations of interleukins, particularly IL-6, increase after trauma and surgery. We have undertaken this study to see if the choice of anaesthetic directly or indirectly influences cytokine release. Twenty women (ASA I-II, aged 26-60 yr) undergoing elective hysterectomy for non-malignant disease were allocated randomly to receive either inhalation anaesthesia with isoflurane and nitrous oxide (group 1), or total i.v. anaesthesia with alfentanil and propofol (group 2). Blood samples for measurement of interleukins IL-1 beta and IL-6, and cortisol and prolactin concentrations were obtained at intervals from before induction to 6 h after surgery. IL-1 beta concentrations did not change during the study. IL-6 increased significantly in both groups (P < 0.05). The IL-6 increase in group 1 began earlier than in group 2. Median IL-6 concentrations were greater in group 1 (median 62 (range 0-214) pg ml-1 vs 46 (0-220) pg ml-1) (P < 0.01). Cortisol concentrations increased more rapidly and reached greater maximum concentrations in group 1. Prolactin concentrations increased immediately and to the same degree after induction in both groups, but were greater in group 2 after operation. We conclude that anaesthesia with alfentanil and propofol diminished release of IL-6 in response to abdominal surgery compared with isoflurane and that this reduction was an effect of alfentanil.