Intraoperative Low-dose Ketamine Infusion for Patients With Obstructive Sleep Apnea

Inclusion Criteria: * aged 19-100 * scheduled to undergo general ENT or Orthopedic Surgery * diagnosis of obstructive sleep apnea as confirmed by sleep study or deemed high risked for obstructive sleep apnea by clinical predictors (greater than 4 clinical predictors of obstructive sleep apnea as described by STOP BANG ). Exclusion Criteria: * positive pregnancy test * ASA \> III * history of alcohol or narcotic abuse in last 90 days * significant cardiovascular or respiratory disease (baseline oxygen saturation below 92%) * significant psychiatric or neurologic disease * history of significant hepatic or renal disease (baseline creatinine\>1.5) * history of allergy or contraindication to anesthetic agents or ketamine including patients with increased ICP * increased IOP * severe arrhythmias * history of delirium * history of hallucinations * history of psychosis * history of uncontrolled seizures * potential risk for malignant hyperthermia (family history) * history of difficult intubation that would preclude standard induction of anesthesia * prisoners * persons who are mentally impaired * non-English speakers