Huayuan Gao,1,* Junmei Wu,1,* Youwen Chen MD,1,* Chengyu Wang,2 Minmin Yao,2 Yan Yang,2 Changhong Miao,2,* Chao Liang2,* 

1Department of Anesthesiology, Zhongshan Hospital (Xiamen), Fudan University, Xiamen, Fujian, People’s Republic of China; 2Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Chao Liang, Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China, Email superwm226@126.com Changhong Miao, Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China, Email Miaochangh@hotmail.com

Background: This study aimed to determine the 95% effective concentration (EC95) of propofol via target-controlled infusion (TCI) for endotracheal intubation at three different doses of dexmedetomidine.
Methods: One hundred and eighty patients aged 18– 60 and classified as American Society of Anesthesiologists (ASA) class I–II were enrolled to undergo general anesthesia. Patients were randomly assigned to one of the three groups (A, B, or C), receiving three different doses of dexmedetomidine (0.6, 0.8, or 1 μg/kg) infused over 10 min. Anesthesia was then induced with propofol TCI, followed by rocuronium. The biased coin design method was used to calculate the EC95 of propofol for successful intubation. The primary outcome endpoint was the EC95 of propofol for successful endotracheal intubation at each dexmedetomidine dose.
Results: Sixty patients in each group completed the trial. The time from propofol administration to intubation in group C (132.5 ± 10.7 s) was significantly shorter compared to group A (140.2 ± 14.4 s, P< 0.0001) and group B (142.6 ± 13.2 s, P=0.0037). Both the EC95 and the average total dose of propofol in group B [14.6 (10.8, 14.8) μg/mL and 3.6 ± 1.1 mg/kg] and C [12.7 (11.5, 12.8) μg/mL and 2.8 ± 1.0 mg/kg] were lower than those in group A [14.9 (4.5, 15.0) μg/mL and 3.8 ± 0.9 mg/kg] (P< 0.001). The incidence of hypotension and bradycardia during induction was low in each group.
Conclusion: The EC95 of propofol for endotracheal intubation across three different background doses of dexmedetomidine was determined. We suggest administering 1.0 μg/kg dexmedetomidine and then the EC95 of propofol for successful endotracheal intubation was 12.7 μg/mL.
Registration: Chinese Clinical Trial Registry; Registration number: ChiCTR2400089952, URL:http://www.chictr.org.cn/showproj.html?proj=221236.

Keywords: effective concentration, propofol, dexmedetomidine, opioid-free anesthesia, endotracheal intubation