[Effective dose and adverse reactions analysis of Remimazolam for sedation in elderly patients undergoing...

Objective: To explore the 50% effective dose (ED50) and 95% effective dose (ED95) of Remimazolam during gastroscopic sedation in elderly patients, and to observe the adverse reactions during anesthesia. Methods: From July to November 2020, 39 elderly patients, of which there were 18 males and 21 females, aged from 65 to 82 (72±5) years, were examined by gastroscopy in the Second Affiliated Hospital of Hainan Medical University, who American Society of Anesthesiologists (ASA) was grade Ⅰ or Ⅱ. Sufentanil 0.1 μg/kg and test dose Remimazolam were injected intravenously, and the initial dose of Remimazolam was 0.17 mg/kg. The dose of the next patient was determined according to the modified Dixon sequential method. If the former patient had a positive reaction during gastroscopy, such as cough, nausea, vomiting and/or body movement reaction occurred when the gastroscope was placed into the pharynx or in the 2 min, the next patient would increase the dose, otherwise, the dose would be reduced. The dose increase and decrease gradient of Remimazolam was 0.01 mg/kg, and the test was stopped after 12 times of return. At the same time, the occurrence of adverse reactions during anesthesia was observed. Results: A total of 39 elderly patients completed the trial, of which 21 were effective and 18 were ineffective. When the elderly patients were sedated by gastroscopy, the ED50 of single intravenous injection of Remimazolam was 0.153 mg/kg (95%CI:0.151-0.154 mg/kg) and the ED95 was 0.164 mg/kg (95%CI:0.160-0.166 mg/kg). The total dose of Remimazolam was (10.6±2.8) mg, the recovery time was (10.0±3.4) min, and the stay time in resuscitation room was (8.2±2.6) min. During anesthesia, nausea and vomiting occurred in 1 case, transient hypotension in 4 cases, and no other adverse reactions were found. Conclusion: The ED50 of Remimazolam during gastroscopic sedation in elderly patients is 0.153 mg/kg, ED95 is 0.162 mg/kg, and the incidence of adverse reactions is low.