Objective:To evaluate the efficacy of esketamine combined with different doses of remimazolam for induction of general anesthesia in pediatric patients.Methods:One hundred and sixty pediatric patients of either sex, aged 3-6 yr, of American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ, with body mass index of 13-20 kg/m 2, undergoing elective general anesthesia under a laryngeal mask, were divided into 4 groups ( n=40 each) by the random number table method: esketamine combined with propofol group (KP group) and esketamine combined with different doses of remimazolam group (0.2, 0.3, 0.4 mg/kg) groups (KR1 group, KR2 group, KR3 group). Esketamine 0.8 mg/kg was intravenously injected in the preanesthesia room. After entering the operating room, propofol 2.5 mg/kg was intravenously injected in KP group, and remimazolam 0.2, 0.3 and 0.4 mg/kg were intravenously injected in KR1, KR2 and KR3 groups, respectively. When the child lost consciousness and the Modified Observer′s Assessment of Alertness/Sedation Scale score<1, sufentanil and mevacurium were intravenously injected. When the Modified Observer′s Assessment of Alertness/Sedation Scale score≥1, rescue sedation was performed, and 3 min later the laryngeal mask airway was inserted. The onset time of sedation, response to laryngeal mask airway placement, rescue sedation, hypotension, tachycardia, bradycardia, bucking, hiccup, injection pain and apnea were recorded, and the increase rate of perfusion index (PI) was calculated. Results:No response to laryngeal mask implantation occurred in the four groups. Compared with KP group, the onset time of sedation was significantly prolonged, the incidence of hypotension, bradycardia, injection pain and apnea was decreased, the incidence of tachycardia was increased, and the increase rate of PI was decreased in KR1, KR2 and KR3 groups, and the rate of rescue sedation and incidence of bucking were increased in KR1 and KR2 groups ( P<0.05). Compared with KR1 group, the onset time of sedation was significantly shortened in KR2 group and KR3 group, and the rate of rescue sedation and incidence of bucking were decreased in KR3 group ( P<0.05). Compared with KR2 group, the onset time of sedation was significantly shortened, and the rate of rescue sedation was decreased in KR3 group ( P<0.05). There was no significant difference in the increase rate of PI, hypotension, bradycardia, tachycardia, injection pain and apnea among KR1, KR2 and KR3 groups ( P>0.05). There was no significant difference in the incidence of hiccup among the four groups ( P>0.05). Conclusions:Esketamine 0.8 mg/kg combined with remimazolam 0.4 mg/kg can be safely and effectively used for anesthesia induction and has milder inhibition of respiration and circulation as compared with esketamine combined with propofol in pediatric patients.

Objective:To evaluate the interaction between remimazolam and propofol for sedation during hysteroscopy.Methods:American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ patients, aged 20-45 yr, with body mass index of 18-28 kg/m 2, scheduled for elective hysteroscopy, were included. The test was conducted in two steps. Up-and-down sequential allocation was used to determine the median effective dose (ED 50) of remimazolam (group A) and propofol (group B). The ED 50 obtained in A and B groups were then used as the standard to determine the combination regimen in group C (0.25×ED 50 of remimazolam+ 0.75×ED 50 of propofol as the initial dose), in group D (0.5×ED 50 of remimazolam+ 0.5×ED 50 of propofol as the initial dose), and in group E (0.75×ED 50 of remimazolam+ 0.25×ED 50 of propofol as the initial dose). Up-and-down sequential allocation was used to determine the ED 50 of propofol when propofol and remimazolam were combined in C, D and E groups. The interaction between the sedative effects of two drugs was analyzed using the isobolographic analysis method, and the interaction coefficient and synergistic dose ratio of two drugs were calculated. Results:The ED 50 of remimazolam was 0.180 mg/kg in group A, and the ED 50 of propofol was 1.167 mg/kg in group B. The results of isobolographic analysis showed that remimazolam and propofol had a synergistic effect. When remimazolam 0.045, 0.090 and 0.135 mg/kg were combined with propofol 0.546, 0.288 and 0.160 mg/kg, the interaction coefficients were 1.393, 1.339 and 1.127 respectively. The synergistic dosage ratio of remimazolam and propofol was 1.0∶(3.2 to 12.0). Conclusions:Remimazolam and propofol have a synergistic effect on sedation when used for hysteroscopy, and the dose ratio is 1.0∶(3.2-12.0).