811: EVALUATION OF SUBDISSOCIATIVE-DOSE KETAMINE FOR PROCEDURAL SEDATION IN THE EMERGENCY DEPARTMENT

Abstract

Introduction: Recent literature has shown efficacy of sub-dissociative dose ketamine (< 0.5 mg/kg) for acute pain management while also minimizing its adverse event profile; however, the advantages and disadvantages of sub-dissociative dose ketamine for indications other than analgesia is unknown. This study evaluated the safety and efficacy of sub-dissociative dose ketamine (SDK, < 0.5 mg/kg) compared to dissociative dose ketamine (DK, ≥0.5 mg/kg) for procedural sedation and analgesia (PSA) in the emergency department (ED). Methods: This was a two-center, retrospective, case-matched cohort study of adult patients admitted to the ED between 2016-2021 who received intravenous push ketamine for PSA. Patients were stratified into two cohorts based on ketamine dose and case-matched 1:1 based on age, mean arterial pressure, and procedure type. The primary outcome was the comparative differences in adjunctive analgosedative requirements at 2 hours. Secondary outcomes included the change in numeric rating scale pain scores before versus after ketamine, PSA success rates, incidence of adverse events, and risk factor determination for PSA failure. Results: Sixty-two patients per group were case-matched and included. Demographics were similar between groups. Median ketamine PSA dose was lower in the SDK group (0.3 [IQR 0.27-0.3 mg/kg] vs 1.1 [IQR 0.98-1.5 mg/kg], p< 0.001). Greater reductions in pain scores were seen in the DK group (-3 [IQR -6 to 0] vs -5.5 [IQR -8 to -1], p=0.03), with similar median morphine milligram equivalent requirements (SDK, 0 [IQR 0-8 mg] vs DK, 0 [IQR 0-0 mg], p=0.17). However, patients receiving SDK required less median lorazepam milligram equivalents (0 [IQR 0-0 mg] vs 0 [IQR 0-0.5 mg], p< 0.001). PSA success rates were similar between groups, with decreased adverse events in the SDK group (28 [45.2%] vs 57 [91.9%], p< 0.001). Comorbidities of hypertension and diabetes, and procedures performed by the orthopedic surgery team were identified as independent risk factors for PSA failure. Conclusions: Sub-dissociative dose ketamine administration for PSA in the ED provided comparable procedural sedation and analgesia success at lower doses compared to dissociative dose ketamine along with a significant reduction in adverse events.