Abstract: Objective To analyze the effect of different doses of remimazolam tosilate on hemodynamic parameters and immune function in elderly patients after laparoscopic surgery. 
Methods Ninety elderly patients admitted to our hospital for laparoscopic surgery were selected. All patients received endotracheal intubation combined with inhalation anesthesia. According to different doses of remimazolam tosilate, they were divided into low-dose group (n=30, 0.1 mg/kg), medium-dose group (n=30, 0.15 mg/kg) and high-dose group (n=30, 0.2 mg/kg). The mean arterial pressure (MAP) and heart rate before induction of anesthesia (T0), at the time of section (T1), at 30 min after operation (T2) and at the end of operation (T3) were compared among the three groups. The levels of mini-mental state examination (MMSE) scale score, malondialdehyde (MDA), superoxide dismutase (SOD), CD4+ and CD8+ before and at 24 h after operation were compared among the three groups, and the anaesthesia-related adverse reactions were compared among the three groups. 
Results The heart rate and MAP of the three groups were increased with the prolongation of time, and there were significant differences in interactions between groups, time points and time points between groups (P＜0.05). At 24 h after operation, the MMSE score of the three groups was decreased (P＜0.05), the MMSE score of the high-dose group was higher than that of the low-dose and medium-dose groups (P＜0.05), and the MMSE score of the medium-dose group was higher than that of the low-dose group (P＜0.05). At 24 h after operation, MDA in all three groups was increased (P＜0.05), while SOD in all three groups was decreased (P＜0.05). MDA was the lowest in the high-dose group, followed by medium-dose group and low-dose group (P＜0.05), and SOD was the highest in the high-dose group, followed by medium-dose group and low-dose group (P＜0.05). At 24 h after operation, CD4+ was increased in all three groups (P＜0.05), while CD8+ was decreased in all three groups (P＜0.05). CD4+ was the highest in the high-dose group, followed by medium-dose group and low-dose group (P＜0.05), while CD8+ was the lowest in the high-dose group, followed by medium-dose group and low-dose group (P＜0.05). There were no difference in the total incidence of anaesthesia-related adverse reactions among the three groups (P＞0.05). 
Conclusion 0.2 mg/kg remimazolam tosilate is more effective in maintaining hemodynamics, improving immune function and cognitive function, and reducing oxidative stress in elderly patients after laparoscopic surgery, which is safe and reliable.

Key words: laparoscopy, remimazolam tosilate, hemodynamics