Implementation and Preliminary Evaluation of an Intravenous Ketamine Protocol for Psychiatric Conditions in Medical and Surgical Units: A One-Year Pilot Study.

Abstract

Ketamine is an emerging therapy in psychiatry, but its implementation in the general hospital setting remains limited due to monitoring requirements, personnel allocation, and safety concerns in medically complex patients. Consultation-liaison (C-L) psychiatry services are well-positioned to deliver such interventions, yet practical models for doing so are lacking. To describe the implementation and feasibility of an intravenous ketamine protocol for depression and other psychiatric indications on general medical and surgical units at a quaternary academic medical center. A psychiatry-specific IV ketamine protocol was developed and approved through institutional pharmacy and nursing committees. The infusion rate was capped at 5 mcg/kg/min, with doses ranging from 0.5 to 1.0 mg/kg. Patients were maintained at routine floor-level care with continuous pulse oximetry during infusion. Feasibility was assessed through operational integration into existing hospital workflows, including the need for additional staffing, aborted procedures, care escalations, and the sustained use of the protocol. Tolerability outcomes included side effects, PRN medication use, and infusion rate adjustments or discontinuations. When applicable, depression and anxiety were assessed using the Montgomery-Åsberg Depression Rating Scale, Patient Health Questionnaire-9, and Generalized Anxiety Disorder-7 at baseline and after each infusion. The protocol was implemented hospital-wide beginning February 2025, with data collection concluding February 2026. Sixteen patients received a total of 51 infusions across medical and surgical units. Primary indications included major depressive episodes, bipolar depression, catatonia, and anxiety. The protocol was sustained over a one-year observation period without additional staffing, modifications to existing unit workflows, or aborted procedures. No infusions required rate adjustment or discontinuation, and no patients required escalation to higher-acuity monitoring or transfer to the ICU or PACU. Eight patients reported transient side effects; no serious adverse events occurred, and one instance of a PRN medication (ondansetron) was administered across all infusions. Among 14 patients treated for depression, 12 showed improvement from baseline to last recorded score, while five met thresholds for response and three for remission. The protocol remains in active use. A capped-rate IV ketamine protocol tailored for psychiatry was feasibly delivered on general medical and surgical floors. The protocol integrated into existing C-L workflows and may serve as a scalable model for expanding access to rapid-acting psychiatric intervention in medically ill populations.