A study on the effect of remimazolam on cellular immune function during the perioperative period in older adults who are having laparoscopic surgery for colorectal cancer.

OBJECTIVE: To investigate the effect of remimazolam on perioperative cellular immune function in elderly patients undergoing laparoscopic colorectal cancer surgery. METHODS: Sixty elderly patients were randomly assigned to receive either propofol (Group P, n=30) or remimazolam (Group R, n=30) for anesthesia induction and maintenance. Hemodynamic parameters, Bispectral Index (BIS), emergence time, vasopressor requirement, and adverse reactions were recorded. T lymphocyte subsets (CD3+, CD4+, CD8+) and NK cells were measured by flow cytometry at designated timepoints (T0: pre-induction; T3: 60 minutes after establishing pneumoperitoneum; T5: 5min post-extubation; T6: 24h postoperatively), and the CD4+/CD8+ ratio was calculated. RESULTS: Mean arterial pressure (MAP) at T5 was significantly higher in Group R compared to Group P (P<0.05). Group R had a significantly lower intraoperative vasopressor usage rate (P<0.05) but a longer emergence time (P<0.05). CD4+ cells and the CD4+/CD8+ ratio at T5 were significantly lower in Group R than in Group P (P<0.05). No significant differences were observed in other T-cell subsets, NK cells at other time points, intraoperative analgesic consumption, or the incidence of adverse reactions. CONCLUSION: No statistically significant difference was detected between remimazolam and propofol in the primary endpoint (NK cell percentage at 24 hours postoperatively); however, this superiority-designed study was not powered to demonstrate equivalence. Remimazolam reduced intraoperative vasopressor requirement but may prolong emergence time, with a temporary decrease in CD4+ cells and CD4+/CD8+ ratio at 5 minutes after extubation.