Use of intramuscular ketamine by paramedics in the management of severely agitated patients.

Objective: Administration of a sedative agent is required for safe transport of prehospital patients with severe agitation to EDs. Ambulance services in Australasia use ketamine, droperidol or midazolam as first line agent but the optimal agent is uncertain. In Victoria, intramuscular (IM) ketamine is used. The present study aimed to examine the prehospital characteristics and ED outcomes of patients with severe agitation after IM ketamine administration.

Methods: A retrospective review was conducted for patients who received IM ketamine for severe agitation over a 2-year period. Data were sourced from Ambulance Victoria and linked to hospital data. The primary outcome was time to sedation. Data collected included baseline characteristics, adverse events and ED outcomes.

Results: Three hundred and fifty-eight prehospital cases transported to 32 hospitals were included. Outcome data were available for 305 patients (21 hospitals). Median age was 31 years (IQR 23-40). 71.2% were male. Adequate sedation was achieved in 96.9% of cases in a median time of 5.0 min (IQR 3.0-7.0; range 1-31 min). Adverse events were transient hypoxia (5.0%), hyper-salivation (4.2%) and emergence reactions (0.8%). A total of 45 (14.8%) patients were intubated; two prehospital.

Conclusion: Intramuscular ketamine is effective with a low rate of prehospital complications in severely agitated patients in the prehospital setting. Given the variation in ambulance practice in Australasia, prospective, randomised trials in the prehospital setting comparing ketamine to other sedating agents such as droperidol in patients with severe agitation are required.