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

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

This protocol describes a feasibility trial that will evaluate the feasibility of conducting a full-scale phase 3 trial testing the hypothesis that a postoperative sustained, low-dose ketamine infusion can prevent postoperative depressive symptoms when administered to a targeted population of neurosurgical patients with a history of depression.

This protocol describes a feasibility trial that will evaluate the feasibility of conducting a full-scale phase 3 trial. Both the feasibility trial and the full-scale trial will follow a randomized, placebo-controlled, double-blinded, parallel design. The trial will follow a superiority design. This trial will take place at a single site (Washington University in St. Louis School of Medicine/Barnes-Jewish Hospital).

Following extubation, patients will be randomized to the intervention (ketamine group) or to control (control group). Patients in the ketamine group will receive a bolus of ketamine 0.5 mg/kg intravenously over 10 minutes, followed by an infusion at 0.3 mg/kg/h for an additional 2 hours 50 minutes. Patients in the control group will receive an equal volume of normal saline. Patients, research staff performing assessments, and research staff performing data analysis will be blinded to treatment allocation.

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