Objective: To describe intravenous ketamine dosing regimens for children requiring brief procedural sedation.
Methods: Time-concentration and sedation profiles were simulated in children (2, 6, and 12 years old) using published pediatric pharmacokinetic and pharmacodynamic parameter estimates. Single-dose, repeat-dosing, and infusion regimens to achieve sedation level of less than 2 (arouses slowly to consciousness, with sustained painful stimulus) for 15 minutes were investigated.
Results: A single bolus dose of 1.5 and 1.75, 2, and 2.125 mg/kg (for adult and 12-, 6-, and 2-year-olds, respectively) was required to achieve the desired sedation. Anticipated recovery would be slow, and a sedation level of 4 (drowsy, eyes open or closed but easily arouses to consciousness with verbal stimulus) was reached only after 70 minutes. The use of a smaller initial bolus with a subsequent half-dose "top-up" at 8 minutes achieves the same sedation level but with earlier recovery. A smaller initial dose of 0.25 and 0.275, 0.3, and 0.35 mg/kg followed by an infusion 2.5 and 2.75, 3, and 3.5 mg/kg per hour (for adult and 12-, 6-, and 2-year-olds, respectively) for 15 minutes gives a more even sedation level and rapid recovery (20 minutes to sedation level 4).
Conclusions: Dosing increases with decreasing age. A large single dose is associated with deep sedation, possible adverse effects, and delayed recovery. Between-subjects variability is large, and dose should be tailored to clinical monitoring and requirement. Intermittent pain insult is better suited to a top-up technique, whereas continuous pain is better suited to an infusion technique.