Effects of epidural anaesthesia on surgical stress-induced immunosuppression during upper abdominal surgery

BACKGROUND: Previously, we have demonstrated that surgical stress rapidlyinduced transient hyporesponsiveness of blood cells to endotoxinand that monocyte mCD14 and HLA-DR expression decreased soonafter the start of surgery under general anaesthesia. This studywas designed to investigate the effects of epidural anaesthesiaon surgical stress-induced immunosuppression in patients undergoingupper abdominal surgery. METHODS: After having obtained informed consent, patients were randomlyallocated to receive general anaesthesia (Group G) or generalanaesthesia with epidural anaesthesia (Group E). Perioperativechanges in neutrophil phagocytic activity, neutrophil respiratoryburst activity, monocyte mCD14 and HLA-DR expression, plasmaIL-10 concentration, and the LPS-induced TNF- production inwhole blood were measured. RESULTS: Surgical stress rapidly depressed neutrophil phagocytic activity,monocyte mCD14 and HLA-DR expression, and LPS-induced TNF- productionex vivo (P < 0.05 vs preoperation) in both Group G and GroupE. In contrast, the plasma IL-10 concentration increased significantly2 h after the start of surgery (P < 0.05) in both groups.There were no significant differences between the two groups.The neutrophil respiratory burst activity did not change duringthe operation in either group. CONCLUSION: This study showed that the innate immune system is suppressedfrom the early period of upper abdominal surgery. Subgroup analysissuggested that epidural anaesthesia to T4 dermatome as wellas general anaesthesia may not protect patients from this immunosuppression.These results in part explain the impairment of host-defensemechanisms seen in the perioperative period.