The first 500: initial experience with widespread use of low-dose ketamine for acute pain management in the ED.

Objectives: The objective of this study is to describe the clinical use and safety profile of low-dose ketamine (LDK) (0.1-0.3 mg/kg) for pain management in the emergency department (ED).

Methods: This was a retrospective case series of consecutive patients given LDK for pain at a single urban ED between 2012 and 2013. Using a standardized data abstraction form, 2 physicians reviewed patient records to determine demographics, indication, dose, route, disposition, and occurrence of adverse events. Adverse events were categorized as minor (emesis, psychomimetic or dysphoric reaction, and transient hypoxia) and serious (apnea, laryngospasm, hypertensive emergency, and cardiac arrest). Additional parameters measured were heart rate and systolic blood pressure.

Results: Five hundred thirty patients received LDK in the ED over a 2-year period. Indications for LDK were diverse. Median patient age was 41 years, 55% were women, and 63% were discharged. Route of administration was intravenous in 93% and intramuscular in 7%. Most patients (92%) received a dose of 10 to 15 mg. Comorbid diseases included hypertension (26%), psychiatric disorder (12%), obstructive airway disease (11%), and coronary artery disease (4%). There was no significant change in heart rate or systolic blood pressure. Thirty patients (6%) met our criteria for adverse events. Eighteen patients (3.5%) experienced psychomimetic or dysphoric reactions. Seven patients (1.5%) developed transient hypoxia. Five patients (1%) had emesis. There were no cases of serious adverse events. Agreement between abstractors was almost perfect.

Conclusion: Use of LDK as an analgesic in a diverse ED patient population appears to be safe and feasible for the treatment of many types of pain.