What is the optimal dose of intramuscular ketamine for pediatric sedation?

Objective: The optimal dose of IM ketamine for ED procedural sedation in children is not known. The authors wished to quantify the dose-response of ketamine with respect to sedation adequacy, time to discharge, and adverse effects in order to identify an optimal dose. Methods: The study was a consecutive case series of 1,022 children less than or equal to 15 years of age given IM ketamine in the EDs of a university medical center and an affiliated county hospital over a nine-year period. Adequacy of sedation, time to discharge, and adverse effects were compared with dose administered. Results: Doses in the sample averaged 3.96 +/- 0.69 mg/kg, with a range of 0.48 to 9.09 mg/kg. Children judged to be adequately sedated received higher doses compared with those inadequately sedated (3.94 +/- 0.44 mg/kg vs 3.77 +/- 0.49 mg/kg, p = 0.041), and a nonsignificant trend was noted toward uniformly adequate sedation with increasing dose (less than or equal to 91% at <4.00 mg/kg, 93% at 4.00-4.49 mg/kg, and 100% at greater than or equal to 4.50 mg/kg). No significant difference or trend in time to discharge or adverse effects was noted between the children receiving <4.00 mg/kg and those receiving greater than or equal to 4.00 mg/kg of ketamine, and the study had power (alpha = 0.05, beta = 0.20) to detect a B-minute difference in times to discharge, a 3.3% difference in rates of airway complications, a 5.6% difference in rates of emesis, and a 12.3% difference in rates of recovery agitation. Conclusion: Ketamine doses of 4 to 5 mg/kg IM produced adequate sedation in 93%-100% of children, suggesting that this dosing range may be optimal for ED procedural sedation. No difference in time to discharge or adverse effects was observed for lower or higher doses.