Effects of Intraoperative Administration of Dexmedetomidine on the Percentage of T-Lymphocyte Subsets and Natural Killer Cells in Patients with Colorectal Cancer

Study Objective: To observe the effect of dexmedetomidine (DEX) on T-lymphocyte subsets and natural killer (NK) cells in the peripheral blood of perioperative patients with colorectal cancer. Design: A random double-blind control clinical study. Setting: A university hospital. Patients: Forty patients with colorectal cancer, ASA I-П. Interventions: All patients were randomly divided into a DEX group (n = 20) and a control group (n = 20). Before induction of anesthesia, epidural catheters were placed in the L1-L2 or T12-L1 intervertebral spaces. The DEX group received 1 μg/kg of DEX (200 μg/50 ml) intravenously for 15 min prior to the surgery, which was then infused at a rate of 0.5 μg/kg/h until 30 min before the end of the surgery. The control group received an intravenous infusion of saline (50 ml) instead of DEX during the same periods as the DEX group. All patients received routine anesthesia and postoperative analgesia. Measurements: Blood samples from all patients were collected at the following time points: before anesthesia (T0), 24 h after surgery (T1), 48 h after surgery (T2) and 72 h after surgery (T3). Changes in T-lymphocyte subsets (CD3+, CD4+, CD8+, CD4+/CD8+) and NK cells were determined by flow cytometry. Main Results: Compared with the control group, the percentages of CD3+ and CD4+ cells and the CD4+/CD8+ ratio in the DEX group increased significantly from T1 to T3 (p < 0.05), while the percentage of CD8+ cells decreased significantly at T1 and T2 (p < 0.05). Meanwhile, the concentration of NK cells in the control group decreased significantly from T1 to T3 (p < 0.05), while it increased significantly in the DEX group from T1 to T3 (p < 0.05). Conclusions: Intraoperative use of DEX can reduce perioperative immunosuppression and favor the immune function of patients with colorectal cancer.