Comparison of the ED(90) of Esketamine for Suppressing Laryngeal Mask Airway Insertion Responses During Propofol Induction with or without Intravenous Lidocaine Pretreatment: A Randomized Double-Blind Dose-Finding Trial.

内容摘要

Esketamine has been increasingly used as an adjunct to propofol induction because of its analgesic and sympathomimetic properties. However, the ED90 of esketamine for suppressing laryngeal mask airway (LMA) insertion responses under a fixed propofol background, with or without intravenous lidocaine pretreatment, remains unclear. This study aimed to determine and compare this ED90 in patients receiving intravenous lidocaine or normal saline. In this randomized, double-blind, dose-finding trial, adult patients undergoing elective arthroscopic shoulder surgery received intravenous lidocaine 1 mg·kg-1 (Group L) or an equal volume of normal saline (Group N) before anesthesia induction. Thirty seconds later, esketamine was administered according to a biased coin design, followed by propofol 2 mg·kg-1. LMA insertion responses were assessed using a predefined four-item behavioral scoring system, and successful suppression was defined as a total score of 4. Enrollment continued until at least 45 effective responses were obtained in each group. The primary outcome was the ED90 of esketamine, estimated by centered isotonic regression with bootstrap confidence intervals. Ninety-nine patients completed the study. The estimated ED90 of esketamine was 0.173 mg·kg-1 (95% CI, 0.138-0.209 mg·kg-1) in Group L and 0.229 mg·kg-1 (95% CI, 0.190-0.263 mg·kg-1) in Group N, with an absolute between-group difference of -0.056 mg·kg-1 (95% CI, -0.102 to -0.002 mg·kg-1). Compared with Group N, Group L also showed lower heart rate immediately before and 3 min after LMA insertion, as well as a lower incidence of tachycardia. Other peri-induction adverse events were similar between groups. Intravenous lidocaine pretreatment was associated with a lower ED90 of esketamine for suppressing LMA insertion responses during propofol induction, suggesting an esketamine-sparing effect within this specific induction framework.