Effects of Lidocaine on Post-Tonsillectomy Pain in Children: A Triple-Blind Clinical Trial

Tonsillectomy is one of the most common surgical operations in children. It has complications such as pain, hemorrhage, laryngospasm, postoperative nausea, and vomiting. Post- tonsillectomy pain management is vital in reducing the suffering and restlessness of children. Several methods have been suggested to preventing and treat post-tonsillectomy pain. The aim of this study was to compare the effects of preoperative peritonsillar injection of lidocaine and placebo on postoperative pain relief. This randomized, triple-blind clinical trial was conducted on sixty 3-12-year-old children who were candidate for tonsillectomy in Imam Khomeini Hospital (Ardabil, Iran). Children were randomly assigned to the lidocaine or placebo group. Anesthesia was induced similarly for all patients. Peritonsillar injections of 1 mg/kg lidocaine (per 2 ml volume) and 2 ml normal saline were performed for the lidocaine and placebo groups, respectively. Patients’ vital signs were recorded in before the induction of anesthesia, during the operation, and in the recovery room. Pain was assessed by using the self-report Oucher Scale and the Children's Hospital of Eastern Ontario Pain Scale. Sedation state was also assessed through the Wilson Sedation Scale. Side effects such as nausea and vomiting, rebleeding after surgery, dyspnea, apnea, and laryngospasm were studied and recorded in the recovery room and 24 hours after the surgery. Data was analyzed with chi-square test, Student’s t-test, and repeated measures analysis of variance. Based on the Oucher Scale, the mean pain score in the lidocaine group was lower than the placebo group at the 5th, 15th, 30th, 60th, 120th and 240th minutes after the surgery. However, the difference was only statistically significant at the 240th postoperative minute (P = 0.03). The average sedation score in the placebo group was higher than the lidocaine group at the 15th and 30th minutes after the surgery (P > 0.05). There was no significant difference between the two groups in terms of rebleeding, need for oxygen, dyspnea, apnea, period of recovery room stay, and the need for painkillers in morning after the surgery. Preoperative peritonsillar injection of lidocaine was effective in reducing postoperative pain in children. Moreover, it did not result in any critical side effects during recovery and the first 24 hours after surgery. Thus, we certainly can use lidocaine for reducing postoperative pain in children.