Optimising Pain Management in Paediatric Tonsillectomy: Evaluation of Intravenous Lidocaine at a 50% Efficacy Dose for Postoperative Throat Pain Prevention

Background: Intravenous lidocaine is effective in preventing post-operative throat pain. However, concerns about lidocaine toxicity and limited administration methods persist. Consequently, the optimal 50% effective dose (ED 50 ) of lidocaine for preventing post-operative throat pain in children undergoing tonsillectomy remains unclear. Methods: We enrolled 27 children aged 3 to 15 years who underwent tonsillectomy. A predetermined continuous lidocaine infusion (1.5 mg/kg) was administered throughout the surgery. Throat pain was assessed at 1 h post-operation using the Children’s and Infants’ Postoperative Pain Scale (CHIPPS) and visual analogue scale (VAS) scores. The lidocaine administration rate for each subsequent child was determined based on the scores. The initial child received lidocaine at a rate of 0.5 mg/kg/h, and subsequent children received higher rates if the CHIPPS or VAS score was ≥ 4 at 1 h post-operation. Those with a CHIPPS or VAS score < 4 received the same or lower rates. All patients received the same induction protocol (sufentanil, propofol, and rocuronium), and anaesthesia was maintained using sevoflurane. The primary outcome was the CHIPPS or VAS score for throat pain at 1 h post-operation. The secondary outcomes were post-operative nausea, vomiting, and time to extubation. Intra-operative respiratory and cardiac events were monitored for safety. Results: The ED 50 of intravenous lidocaine for throat pain was determined to be 0.477 (0.378–0.617) mg/kg/h. The effective dose for preventing post-operative throat pain in 95% of patients administered lidocaine was 0.624 (0.545–2.458) mg/kg/h. Conclusions: Intravenous lidocaine (ED 50 ) effectively treats post-operative throat pain in children. TRIAL REGISTRATION : This study was approved by the Institutional Review Board of Yichang Central People’s Hospital (HEC-KYJJ-2020-038-04) on 16 Feburary 2023. The trial was registered on 21 Mach 2023(21/03/2023) at www.chictr.org.cn (ChiCTR2300069567).