Ketamine does not reduce postoperative morphine consumption after tonsillectomy in children

Tonsillectomy is one of the most frequently performed operations in children and frequently associated with moderate-to-severe pain.

The aim of the present study was to assess the effect of a subhypnotic dose of ketamine on postoperative pain and morphine consumption after tonsillectomy in children.

This randomized double-blind study involved 84 children, 2 to 12-year-olds, undergoing elective outpatient tonsillectomy. Children were assigned to 2 groups. Group K received morphine and ketamine, 0.25 mg/kg, at induction and Group M received morphine. Modified Children's Hospital of Eastern Ontario (mCHEOP) scale was used to evaluate postoperative pain. Pain, morphine consumption, and unwanted side effects were recorded for a 24-hour period. One-way analysis of variance and chi2 tests were used for statistical analysis.

Pain scores and adverse events were similar between the 2 groups. Although morphine consumption was less in the ketamine group during the immediate postoperative period, total morphine consumption over the course of the study was not significantly different between the 2 groups. Fewer patients in the ketamine group required supplementary oral analgesia in the postoperative surgical unit.

The addition of ketamine 0.25 mg/kg at induction of anesthesia did not decrease postoperative morphine consumption in children undergoing tonsillectomy.