Intravenous and peritonsillar infiltration of ketamine for postoperative pain after adenotonsillectomy: a randomized placebo-controlled clinical trial.

OBJECTIVE To evaluate the efficacy of preoperative intravenous or peritonsillar infiltration of ketamine for postoperative pain control in children following adenotonsillectomy. PATIENTS AND METHODS 78 children between 5 and 18 years of age who were scheduled for elective adenotonsillectomy were randomly assigned to four groups: group 1 (n = 19) received intravenous ketamine (0.5 mg/kg), group 2 (n = 21) intravenous normal saline, group 3 (n = 19) ketamine (0.5 mg/kg) injected through the tonsillar capsule, and group 4 (n = 19) normal saline injected in the same location. The incidence of postoperative pain and vomiting as well as the severity of postoperative pain were compared between study groups during the 6-hour postoperative period using a visual analog scale (VAS) at rest, upon swallowing saliva, drinking liquids and eating ice cream. RESULTS There were no demographic differences between the four groups. The incidence of postoperative pain was significantly lower in groups 1 [7 (36.8%) vs. 10 (47.6%); p = 0.032] and 3 [5 (31.5%) vs. 12 (63.2%); p = 0.001] compared with their controls. The amount (in milligrams) of pethidine and metoclopramide used for pain and nausea control was significantly lower in groups 1 (12.5 ± 5.3 vs. 19.6 ± 9.6 mg, p = 0.038, and 2.9 ± 1.1 vs. 4.6 ± 2.6 mg, p = 0.042, respectively) and 3 (8.6 ± 3.1 vs. 21.6 ± 8.4 mg, p < 0.001, and 1.6 ± 0.9 vs. 5.3 ± 3.2 mg, p = 0.002, respectively) compared with their controls. These values were also higher in group 1 compared with group 3. The VAS scores on swallowing saliva (3.9 ± 2.7 vs. 2.7 ± 1.2; p = 0.018), on drinking liquids (3.7 ± 2.6 vs. 2.8 ± 1.6; p = 0.013) and on eating ice-cream (4.3 ± 2.4 vs. 2.8 ± 1.5; p = 0.001) were also significantly higher in group 1 compared with group 3. CONCLUSIONS Our results show that peritonsillar infiltration of ketamine was more effective in reducing the postoperative pain severity, need for analgesics and need for antiemetics. Thus, peritonsillar infiltration of ketamine is suggested for postoperative pain control in those undergoing adenotonsillectomy.