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