Randomization and concealment of allocation will be pharmacy-controlled using a computer-based random number generator. The treating physician, research assistant, and participant will be blinded to the intervention. Eligible participants will be randomized in a 1:1 allocation ratio with a stratified block design of six to either (1) IN ketamine (each single dose, 8 mg/kg prepared in 0.9% NS in 3 mL syringe and atomizer, to a maximum of 1.5 mL) PLUS IV 0.9% NS 0.02 mL/kg or (2) IV ketamine (single dose, 1 mg/kg, to a maximum 100 mg) PLUS intranasal 0.9% NS 0.08 mL/kg divided to both nares. Due to the perceptible differences in interventional routes, each participant will receive both IV and IN interventions using this double-dummy approach. For IN dose volumes less than or equal to 0.5 mL, the entire dose will be delivered into 1 nostril and for doses greater than 0.5 mL, the dose will be divided equally between both nares. Adjuctive sedation will be given as needed in the form of IV ketamine, 1 mg/kg every 10 minutes for participants who do not achieve adequate sedation at 20 minutes (UMSS score of 4). A figure of the atomizer device used to deliver the IN agent has been uploaded. Eligible participants (defined in section 2.5 above) will be identified by the treating physician after viewing the radiographs and performing a clinical assessment. The physician will then inform a research assistant (RA) that the participant is eligible. The RA will then seek informed consent and explain the protocol to the family. Baseline demographic information will be obtained. Informed consent for PCS and a pre-anesthetic assessment will be performed by the treating physician in accordance with the usual standard of care. UMSS scores will be obtained by a trained RA at 5 minutes pre-intervention, intervention (0 minutes) and every 5 minutes thereafter for 60 minutes post-intervention or until the participant is ambulatory and drinking well, whichever is longer. Participants will receive standard monitoring of oxygen saturation, blood pressure, respiratory rate, apnea, heart rate, and rash by the attending nurse and physician every 5 minutes as per the usual standard of care. The usual standard of care also includes monitoring post-anesthetic for the presence of known idiosyncratic effects of ketamine that include vomiting, seizure, headache, emergence reaction, and hypersensitivity. The RA will obtain this information from the nursing record at discharge. Immediately prior to discharge, the RA will also record the duration of stay in the ED and parental satisfaction with PCS. 1. Chiaretti et al. 2011. Intranasal lidocaine and midazolam for procedural sedation in children. Arch Dis Child. 96;160-163