Objective To investigate the effectiveness and optimal dose of remimazolam combined with fentanyl in painless gastroscopy.

Methods  A total of 200 patients who planned to undergo painless gastroscopy were selected as study objects. They were randomly divided into R1 group (0.05 mg fentanyl combined with remimazolam 0.20 mg/kg group), R2 group (0.05 mg fentanyl combined with remimazolam 0.30 mg/kg group), R3 group (0.05 mg fentanyl combined with remimazolam 0.40 mg/kg group) and C group (0.05 mg fentanyl combined with propofol 2.00 mg/kg, control group), with 50 cases in each group. General data of the four groups were compared; heart rate (HR), mean arterial pressure (MAP), success rate of sedation, time to gastroscopy, time to recovery, time to leave hospital and incidence of adverse reactions were compared before examination (T₀), at admission (T₁), 2 min after admission (T₂) and 4 min after admission (T₃).

Results  There was no statistical significance in the general data of the four groups (P > 0.05). Compared with the group C, the success rate of sedation in the R1 group was significantly decreased, the time of examination was significantly prolonged, the time of recovery was significantly shortened, and the incidence of body movement and cough was significantly increased (P < 0.05); the incidence rates of hypotension, hypoxemia and injection pain in the R1, R2 and R3 groups were significantly decreased, while the incidence of hiccup in the R3 group was significantly increased (P < 0.05). Compared with the R1 group, the success rates of sedation in the R2 and R3 groups were significantly increased, and the incidence of body movement and cough was significantly decreased (P < 0.05). Compared with the R3 group, the time to wake up and time to leave hospital in the R2 group were significantly shortened (P < 0.05). Compared with group C, HR and MAP in R1, R2 and R3 groups were significantly increased at T₁ (P < 0.05); compared with the R1 group, HR and MAP in the R2 and R3 groups at T₁ were significantly decreased (P < 0.05); the MAP and HR at T₁ in the R1 group were significantly higher than those at other time points; the MAP of the C group at T₁ was significantly lower than that at other time points (P < 0.05). Conclusion 0.30 mg/kg remazolam combined with 0.05 mg fentanyl has high success rate of sedation, little influence on circulation and respiratory system, low incidence of intraoperative adverse reactions, and the best effect.