Emergency Medical Services
Background: Emergency clinicians often treat excited delirium (ExD) due to differing etiologies such as acute medical conditions, psychiatric illness and intoxicants. At electronic dance music festivals (EDMF), recreational drug use is rampant and attendees frequently become agitated posing a danger to themselves and public safety personnel. Although benzodiazepines and antipsychotics traditionally have been commonly used agents to treat ExD, these medications have limitations such as variable onset of action, efficacy and safety concerns. Ketamine has not previously been investigated to treat ExD in an exclusive cohort of patients diagnosed with psychostimulant drug-induced toxicity (PDIT). A recent systematic review found an overall intubation rate of 30.5% in undifferentiated ExD post ketamine administration. The rate of intubation was 40.4% when ketamine was administered prehospitally versus 1.8% when patients received ketamine in the ED. Objective:
Methods: This is a retrospective, observational study enrolling consecutive patients who presented for medical attention at a large outdoor EDMF on two consecutive extended weekends in 2017. The summertime EDMF had an estimated attendance of 40,000 per weekend. EMS providers obtained vital signs and EM physicians performed history and physical exams. The need for repeat dosing and the incidence of serious adverse events defined as copious hypersalivation, apnea, endotracheal intubation and transport to hospital were also assessed.
Results: Over the course of the EDMF, 1186 patients were enrolled. Of these, 303 had undifferentiated altered mental status. Of the patients presenting with AMS, 68 patients were chemically sedated with ketamine (22.4%) with an initial mean dose of 308 mg (SD 134) administered intramuscularly. There were four serious adverse outcomes (5.9%): Two patients had copious hypersalivation (2.9%) treated with atropine, one patient had transient apnea requiring assisted ventilation (1.5%), and one patient was intubated (1.5%). 18 patients required re-dosing of ketamine (26.5%) with a mean dose of 158 mg (SD 117). Of the patients given ketamine, one was transported to the hospital (1.5%).
Conclusions: Using ketamine to treat ExD in patients with PDIT is safe with few serious adverse events and a low intubation rate.