Effect of tramadol on perioperative immune function in patients undergoing gastric cancer surgeries

BACKGROUND: A prospective randomized controlled trial was designed to observe the effect of tramadol on T-lymphocyte subsets, activated T cell and natural killer (NK) cells of patients undergoing gastric cancer surgeries. SUBJECTS AND METHODS: Thirty patients undergoing elective gastric cancer surgeries under general anesthesia were randomly divided into two groups. Before anesthesia induction, Group I did not receive any drugs and Group II received intramuscular tramadol 1 mg/kg. Peripheral venous blood samples were taken before anesthesia, 1 h after incision and postoperation. CD3(+), CD3(+) CD4(+), CD3(+) CD8(+), CD3(–)CD16(+) CD56(+) (NK) cells and CD3(+) human leukocyte antigen (HLA)-DR(+) (activated T cell) were measured by flow cytometer. RESULTS: One hour after incision, CD3(+), CD3(+) CD4+, CD3(+) CD4(+)/CD3(+) CD8(+), CD3(-)CD16(+) CD56(+), and CD3(+) HLA-DR(+) cells in the experimental and control group were significantly decreased compared with their baselines (P < 0.05), while the values of Group I were lower than those of Group II (P < 0.05). After surgery, the values of Group I were lower than their baselines (P < 0.05). But the values of Group II had no significant difference compared with their baselines. CONCLUSION: Tramadol can reduce the decrease of T-lymphocytes subsets and NK cells, thus improve the cellular immune function in the perioperation of gastric cancer.