Dexmedetomidine, which will be used in this study, is a highly selective α2-adrenoceptor agonist that has been demonstrated to result in a sedated sleep similar to natural sleep without causing respiratory depression. Though there have been some reports of transient bradycardia and blood pressure changes in response to dexmedetomidine infusion (usually transient hypotension of 10% with slow infusion) these cardiovascular effects are mitigated by co-administration of a bolus of ketamine. These patients would already have been using dexmedetomidine or a different anesthesia for their tonsil surgery. The dexmedetomidine is not an intervention or part of this study.