Evaluation of the Use of Ketamine for Acute Pain in the Emergency Department at a Tertiary Academic Medical Center

Introduction: At subdissociative doses of 0.1 - 0.5 mg/kg, ketamine provides effective analgesia when used alone or as an adjunct to opioid analgesics without causing cardiovascular or respiratory compromise. Ketamine is a beneficial analgesic agent in the emergency department (ED), particularly in patients with opioid-resistant pain or polytrauma patients who are hemodynamically unstable. Purpose: The purpose of this study was to evaluate current practice and describe clinical outcomes associated with the use of low-dose ketamine for acute pain in the ED. Methods: Adult patients receiving ketamine were retrospectively evaluated between March 1, 2012 and March 31, 2013. Patients were included if they were ordered for ketamine in the ED to treat acute pain. Outcomes included dose administered, cumulative doses, concurrent opioid administration, and any efficacy or adverse events documented after the administration of ketamine. Continuous variables are reported as mean (standard deviation [SD]) or median (interquartile range [IQR]). Results: A total of 46 patients were evaluated for inclusion. Of the 25 patients included, 38 doses of ketamine were documented. The mean age was 41 years old with 64% of the patients being female. The average initial ketamine dose was 0.12 ± 0.06 mg/kg and 8 (32%) patients received multiple doses of ketamine (1.5 ± 0.8 doses per patient). Ketamine was added to opioid therapy in 23 (92%) patients. Pain scores decreased post administration of ketamine from 10 (9 - 10) to 5 (4 - 7). Adequate pain relief was documented in 11 (44%) patients (felt comfortable going home); partial pain relief was noted in 5 (20%) patients; 3 (12%) patients reported no pain relief; 3 (12%) patients were able to have a procedure done, and efficacy was not documented in 3 (12%) patients. Anxiety and agitation were documented in 2 (8%) patients. No adverse outcomes were documented in 84% of patients. Conclusion: Administration of low-dose ketamine for acute pain in the ED demonstrated improvement in patients’ pain scores with minimal documented adverse outcomes.