Ketamine for Postoperative Avoidance of Depressive Symptoms: The K-PASS Feasibility Trial

Inclusion Criteria: 1. Able to provide written, informed consent 2. Aged 18 or older 3. Scheduled for non-ambulatory surgery scheduled to last at least 2 hours at Barnes-Jewish Hospital 4. Past medical history of depression, defined as one or more of the following criteria 1. Previous diagnosis by a psychiatrist or primary care physician in an outpatient or inpatient setting, by patient report or chart documentation 2. Prescription of an oral antidepressant by a psychiatrist or primary care physician for a mood disorder Exclusion Criteria: 1. Bipolar depression 2. Concurrent use of a medication contraindicated with ketamine 3. Emergent surgery 4. Known or suspected elevation in intracranial pressure 5. Current subarachnoid hemorrhage 6. Carotid endarterectomy or arteriovenous malformation repair 7. Allergy to ketamine 8. Any condition in which a significant elevation of blood pressure would constitute a serious hazard (e.g., aortic dissection, pheochromocytoma) 9. Known history of dementia 10. Pregnancy or lactation 11. Inability to converse in English 12. Concurrent enrollment in another interventional trial