A large number of clinical trials have examined the use of ketamine in the perioperative period. Several systematic reviews and meta-analyses have assessed the benefits and risks of ketamine in surgical patients. Bell et al. concluded that perioperative ketamine reduced analgesic requirements or pain intensity, or both. The incidence of nausea and vomiting was reduced, and adverse events were mild or absent. Himmelseher et al. noted that intravenous subanesthetic ketamine in general anesthesia provided pain prevention after surgery. Jouguelet-Lacoste et al. determined that low-dose ketamine reduced opioid consumption by 40%. Pain scores were also reduced, and no major complications were noted. Laskowski et al. concluded that ketamine resulted in a reduction in opioid consumption across all studies, and lower pain score were reported in most investigations. No significant differences in adverse events were noted in most meta-analyses, with the exception of a lower risk of nausea and vomiting in patients randomized to receive ketamine (a higher risk of hallucinations was reported in one meta-analysis). A large number of different dosing strategies have been used for ketamine. However, the greatest efficacy appears to result when a bolus dose is given (0.5 mg/kg) before incision, followed by an intraoperative (0.25-0.5 mg/kg/hr) infusion, and a postoperative (0.06-0.12 mg/kg/hr) infusion continued for at least 24-48 hours