What's Your Diagnosis? Ketamine Therapy in the ED

Welcome to this month’s What’s Your Diagnosis Challenge!

But before we begin, check to see if you got the previous case on Managing Emergency Department Patients With Otalgia correct.

Case Presentation: Current Concepts in Ketamine Therapy in the Emergency Department

A 43-year-old man presents to the ED after a trip and fall onto his outstretched hand…

The patient’s examination is notable for a dinner-fork deformity, and wrist radiograph shows a distal radius fracture with dorsal angulation.
In order to reduce the fracture, procedural sedation with ketamine is performed. Though the usual dissociative dose of ketamine is ≥1 mg/kg IV, because you anticipated the procedure to be very brief, you chose a smaller dose of 40 mg.
Shortly after administration, the patient begins screaming in terror and is obviously anguished by hallucinations and feelings of unreality. The clinical team is very concerned and looks to you for next steps…

Case Conclusion

You administered an additional 40 mg IV ketamine, the patient became dissociated and calm, and the procedure was carried out uneventfully. It is commonly believed that since a dissociative dose causes complete dissociation, for less painful or briefer procedures, a subdissociative dose may be beneficial. However, ketamine is not titratable in this way, and this strategy may result in partial dissociation, where the patient experiences distressing perceptual disturbance that can cause severe agitation. In this case, because this occurred before the procedure began (ie, on induction), the correct treatment was to push the patient to full dissociation with more ketamine.