Jingwen Zhang,1,2 Jiaxing Li,3,4 Juan Ni1,2 

1Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, People’s Republic of China; 2Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, People’s Republic of China; 3West China School of Public Health, Sichuan University, Chengdu, People’s Republic of China; 4West China Fourth University Hospital, Sichuan University, Chengdu, People’s Republic of China

Correspondence: Juan Ni, Department of Anesthesiology, West China Second University Hospital, Sichuan University, No. 20, Section 3, South of Renmin Road, Chengdu, Sichuan, 610041, People’s Republic of China, Tel +86 18180609890, Fax +86 2885503752, Email nijuankiki@163.com

Purpose: It has been demonstrated that administration of intravenous lidocaine promotes laryngeal mask airway (LMA) placement. This research aimed to evaluate the effect of intravenous lidocaine at a dosage of 1.0 mg/kg on the 50% and 95% effective doses (ED50 and ED95) of propofol required for the successful placement of a double-lumen LMA during propofol-fentanyl-based anesthesia in patients undergoing hysteroscopy.
Patients and Methods: Eighty patients who underwent hysteroscopy were screened and randomly enrolled in either lidocaine group (group L, n=40) or the saline group (group S, n=40). The propofol induction dose per patient was established via an up-and-down sequential method. Under the guidance of bispectral index (BIS) value monitoring, the propofol doses required for the successful placement of a double-lumen LMA in 50% and 95% of the patients in the two groups (ED50 and ED95) were compared. The total propofol induction dose, awakening duration, and adverse outcomes were documented and analyzed.
Results: The propofol’s ED50 was notably lower in the L group than in the S group (1.15± 0.27 mg/kg versus 1.83± 0.26 mg/kg; p< 0.05, Cohen’s d=2.56). The ED95 (95% confidence interval) of propofol was 2.04 (1.23– 2.85) mg/kg in the L group and 2.64 (1.95– 3.33) mg/kg in the S group, with a small effect size for the difference (Cohen’s d=0.25). The total propofol induction dose in the L group was lower than that in the S group (p< 0.05). There existed no variations in terms of awakening duration or incidence of adverse events.
Conclusion: In patients who underwent hysteroscopy, post-propofol intravenous lidocaine at 1.0 mg/kg markedly reduced the propofol’s ED50 in propofol-fentanyl-based anesthesia for successful placement of a double-lumen LMA without significant adverse reactions.

Keywords: lidocaine, propofol, laryngeal mask airway, median effective dose