Study to Find the Dose of Rapidly Administered Ketamine for Brief Painful Procedures in Children

The purpose of the study is to find the dose of rapidly administered ketamine in 3 different pediatric age groups (2-5, 6-11 and 12-17) for abscess drainage and fracture reduction. Ketamine is the most common drug administered to children to facilitate painful procedures in the emergency setting because it achieves potent sedation, pain relief and amnesia with minimal adverse cardiopulmonary effects.(1-5) However, the 1-2 hour recovery period (1,6) associated with standard ketamine administration guidelines(7) strains work flow because it requires bedside one-on-one nurse monitoring in a treatment room, tying up these limited and valuable resources. Consequently, a combination of two other drugs, propofol + fentanyl (P/F), with recovery of 20-30 minutes, is rapidly gaining popularity for procedural sedation despite more frequent respiratory depression, apnea and hypotension caused by this technique.(2,4,8,9) The investigators believe recovery associated with our novel method for administering ketamine is significantly shorter than with the standard larger dose more slowly administered ketamine technique(7). Through the investigators clinical experience, the investigators have found rapid infusion of smaller than standard doses of ketamine safely achieves the drug's sedative effect, with the benefit of more rapid recovery due to the use of a smaller dose. However, this novel technique challenges published beliefs that time of recovery from ketamine sedation does not differ significantly with the dose administered, within the usual dose ranges, and that rapid infusion may cause respiratory depression, similar to that seen with other classes of sedative-analgesic drugs.(7,10) the investigators believe the slow infusion recommended by standard guidelines(7) requires a larger ketamine dose necessary to achieve effective sedation, and, consequently, prolongs recovery. It is the prolonged recovery that has prompted increased use of other less safe but briefer sedatives, such as propofol/fentanyl. By demonstrating patients recover rapidly with new ketamine technique, without increased adverse cardiopulmonary effects, the investigators will provide clinicians with an important new method for ketamine procedural sedation. The investigators believe clinicians will prefer more rapid recovery ketamine technique because it is safer and reduces pain and distress better than the propofol/fentanyl combination for sedation. The investigators complete proposal requires two steps. In Step One, this proposal, the investigators will determine the minimum effective dose of rapidly infused ketamine that achieves deep sedation for at least 5 minutes in 95% of children (ED95). Two groups of patients will be studied: one group is patients undergoing abscess incision and drainage and the other group is patients undergoing fracture reduction in our Emergency Department. The investigators believe that the ED95 is different for both the groups as the severity of pain is different. The investigators will compare the safety and recovery times to published standard ketamine techniques. In the following study, Step Two, the investigators will compare this novel technique, in a blinded randomized trial using the ED95 ketamine dose determined in Step One to the standard ketamine technique to determine if the novel technique results in significantly shorter recovery without an increase in the frequency of adverse effects. The study the investigators are proposing in this submission is Step One only.