Ketamine reduces swallowing-evoked pain after paediatric tonsillectomy

Background: Ketamine efficacy as an analgesic adjuvant has been studied in several clinical settings with conflicting results. The aim of this study was to investigate the effect of ketamine on spontaneous and swallowing-evoked pain after tonsillectomy. Methods: Fifty children were randomized to receive premedication with either ketamine 0.1 mg kg−1 i.m. or placebo given 20 min before induction of a standard general anaesthesia. All children received rectal diclofenac 2 mg kg−1 and fentanyl 1 µg kg−1 i.v. before surgery. Results: The ketamine group showed significantly lower pain scores both at rest and on swallowing, with less total paracetamol consumption (P < 0.05) during the 24 h after surgery. Significantly more patients required postoperative morphine titration in the control group (P < 0.05). The time to the first oral intake, and duration of i.v. hydration, were significantly shorter and the quality of oral intake was significantly better in the ketamine group (P < 0.05). There were no differences in the incidence of vomiting or dreaming between the groups. Conclusion: Premedication with a small dose of ketamine reduces swallowing-evoked pain after tonsillectomy in children who received an analgesic regimen combining an opioid and a NSAID.