Comparison of the Effects of Oral vs. Peritonsillar Infiltration of Ketamine in Pain Reduction after Tonsillectomy: a Randomized Clinical Trial.

BACKGROUND Although oral ketamine has been used in some cases to reduce pain in children, the use of this drug to reduce pain after tonsillectomy has not been studied yet. METHODS This double-blind clinical trial was conducted in 2009 in 92 children who were aged three to nine years old, met ASA I or II criteria, and were candidate for tonsillectomy. Patients were divided randomly into two groups. Half an hour before general anesthesia, 5 mg/kg ketamine mixed in 2 cc/kg apple juice was given to the children in oral ketamine group and 2 cc/kg of apple juice alone was given to the children in the peritonsillar group. After general anesthesia and three minutes before surgery 1 cc of 0.9% normal saline in the oral group and 1cc of ketamine (0.5 mg/kg) in the peritonsillar group was injected to the tonsil bed of patients. RESULTS There was no difference between the two groups in terms of sex, age, and weight. Duration of surgery was significantly shorter in the peritonsillar group (P < 0.001) and the severity of postoperative bleeding was significantly higher in peritonsillar group (P = 0.022). However, postoperative bleeding recurred in 25 patients (27%) and there was no statistically significant difference between the two groups. The level of pain in children six hours after surgery according to CHEOPS criteria was significantly lower in the peritonsillar group (0.9 ± 0.8) than in the oral group (2.6 ± 1) (P < 0.001). CONCLUSIONS The finding of this study showed that, compared with the peritonsillar infiltration of ketamine, the use of oral ketamine before general anesthesia was less effective in reducing postoperative pain of tonsillectomy in children.