Objective  To explore the feasibility of using remimazolam alone in painless gastroscopy.

Methods  A total of 350 patients undergoing painless gastroscopy were selected as study objects, and they were Ⅰ to Ⅱ grade of American Society of Anesthesiologists (ASA) classification. They were randomly divided into seven groups, with 50 patients per group. Group R1, group R2, group R3, group R4, group R5, and group R6 were respectively injected 0.30, 0.35, 0.40, 0.45, 0.50 and 0.55 mg/kg of remimazolam, while control group injected 2 mg/kg of propofol intravenously. The dosage of 30 to 50 mg of propofol was added if the patient had obvious cough or body movement reaction during the operation. The success rates of sedation of different groups were recorded, and the mean arterial pressure (MAP) and heart rate (HR) were observed before drug administration and 1 min after drug administration. The occurrence of adverse reactions such as cough, body movement, hiccup, hypoxemia, injection pain, gastroscopy time, awakening time and discharge time were observed in each group.

Results  The success rates of sedation in the R1, R2, R3, R4 and R5 groups were 16.0%, 34.0%, 38.0%, 48.0% and 58.0%, respectively, which were lower than 82.0% in the control group, and the differences were statistically significant (P < 0.05). There was no significant difference in sedation success rate between R6 group (72.0%) and control group (P>0.05). Compared with the control group, the incidence rates of cough, body movement and hiccup in the R1, R2, R3, R4, R5 and R6 groups were increased, the incidence rates of hypoxemia and injection pain were decreased, and the time of leaving hospital was prolonged, and the differences were statistically significant (P < 0.05). The awakening time of the R2 group, R3 group, R4 group, R5 group and R6 group were (13.0±3.9) min, (14.6±5.0) min, (16.2±6.5) min, (17.5±5.4) min and (20.2±7.2) min, respectively, which were all longer than (10.0±3.3) min in the control group, and the differences were statistically significant (P < 0.05). The HR changes in the R1, R2, R3, R4, R5 and R6 groups were higher than those in the control group, and the differences were statistically significant (P < 0.05).

Conclusion  In painless gastroscopy, the sedation success rate of rematazolam alone is positively correlated with dosage, and the sedation success rate of rematazolam alone at a dosage of 0.55 mg/kg is comparable to that of propofol at a dose of 2 mg/kg. However, rematazolam can increase the incidence rates of cough, body movement and hiccup, and prolong the awakening time and discharge time.