Hongyi Xiao,1,2 Xiuxia Gu,1,2 Xinyuan Shi,2 Shiyu Yu,2 Ruoyi Ji,3 Fanceng Ji,1,2 Peihe Nie1,2 

1Department of Anesthesiology, Weifang People’s Hospital, Weifang, 261041, People’s Republic of China; 2School of Anaesthesiology, Shandong Second Medical University, Weifang, 261053, People’s Republic of China; 3School of Psychology and Cognitive Sciences, Peking University, Beijing, 100871, People’s Republic of China

Correspondence: Peihe Nie, Department of Anesthesiology, Weifang People’s Hospital, Weifang, 261041, People’s Republic of China, Email peihenie@126.com

Purpose: This study compared the effects of different body mass indexes (BMI) on the induction dose of remimazolam in patients undergoing gynaecological day surgery, aiming to explore the appropriate weight index of remimazolam for overweight or obese people.
Patients and Methods: This was a retrospective, observational study based on propensity score matching (PSM). The patients were divided into two groups according to normal BMI boundaries: group N (BMI< 24 kg/m²) and group F (BMI≥ 24 kg/m²). The primary observation of the study was the anesthetic induction dose per kg of remimazolam calculated on the basis of total body weight (TBW), ideal body weight (IBW), lean body weight (LBW) and corrected body weight (CBW).
Results: A total of 250 patients were included in the analysis. After PSM, 94 patients were finally included in each group. The primary observation: there was a significant difference between the two groups in the induction dose per kg of TBW and IBW (P=0.001), but not in the induction dose per kg of LBW and CBW (P> 0.05). The Secondary observation:the time to loss of consciousness was shorter in group F than in group N (P=0.030), but there was no significant difference in recovery time (P=0.868). There were also no significant differences between the two groups in perioperative adverse effects and changes in circulating blood pressure before and after induction (P> 0.05). In addition, the induction dose of remimazolam per kg calculated based on TBW exhibits a negative correlation with BMI (r=− 0.362, P=0.001).
Conclusion: When calculated based on TBW, the induction dose of remimazolam per kilogram (mg/kg) was lower in overweight or obese patients compared to normal-weight patients. For these patients, we recommend using CBW for dose calculation when applying the 0.2– 0.4 mg/kg dosing regimen.

Keywords: remimazolam, body mass index, induction dose, anesthesia, general