Ketamine hydrochloride is a phencyclidine derivative that causes dissociation between the cortical and limbic systems preventing the higher centers from perceiving visual, auditory, or painful stimuli. It possesses a rapid onset and short duration of action and produces profound sedation and analgesia. Ketamine is also a non-competitive NMDA antagonist, which complements NO. However, laryngeal reflexes are maintained and respiratory depression is rare. These properties have made ketamine a very popular agent for procedural sedation and analgesia in pediatric emergency department patients . Unfortunately, when given to adult patients, it frequently causes emergence anxiety, nightmares, hallucinations, and delirium. These emergence reactions have limited the use of ketamine in adults. The incidence of these reactions is about 7-10% in children. Emergence reactions may be a product of the state in which the patient becomes disassociated . Therefore, if the patient is more relaxed prior to ketamine administration through the adjunct use of NO, adverse emergence reactions may be reduced.