(930) Ketamine Infusion (at Sub-Anesthetic Doses) for Analgesia in Adults

Introduction: An enterprise-wide hospital guideline for the use of ketamine at sub-anesthetic doses in analgesia was established in March 2019. Since its implementation, guideline compliance and ketamine’s effectiveness and tolerability have not been comprehensively assessed. This study aimed to evaluate the appropriateness, tolerability, and effectiveness of ketamine utilization for analgesia according to the hospital guideline.

Methods: This retrospective chart review includes adult inpatients who received ketamine infusion for analgesia between June 2021 and June 2023 at an academic medical center. Patients who were mechanically ventilated, received ketamine infusion for less than 24 hours, administered ketamine orally or via IV push, or initiated on ketamine in the operating room, post-anesthesia care unit, or emergency department were excluded. The primary outcome was adherence to the hospital ketamine guideline. Secondary outcomes included efficacy and tolerability of ketamine. Efficacy was assessed by change in opioid consumption and pain scores; descriptive statistics were utilized to characterize the data.

Results: Out of 325 patients reviewed, 100 met the inclusion criteria. The median patient age was 46 years, with 53% admitted to the intensive care unit and a median ketamine duration of 94 hours. Overall compliance with vital signs documentation according to the guideline was approximately 10%. Documentation rates were particularly lower with ketamine initiation and dose changes. Most patients received appropriate dosing per guideline (99%) and were placed on telemetry in the first 24 hours (81.6%). Only 19% of non-ICU patients had Modified-Patient Opioid and Sedation Scale documented daily. Additionally, while vital sign abnormalities were frequently observed (98%), oversedation and psychomimetic effects were rare (14.7% and 7%, respectively). Ketamine administration correlated with a notable decrease in median opioid consumption (-126 MME) and pain scores (-1).

Conclusions: Adherence to vital signs documentation was poor, warranting re-education and clarification of the guideline. Nevertheless, the reduction in opioid consumption and pain scores underscore the potential benefits of a standardized ketamine protocol for analgesia to optimize efficacy and minimize toxicity.