Ketamine for the Agitated/Violent Patient

By Alex Koyfman MD, expert input by Reuben Strayer MD

Edited by Stephen Alerhand MD

Your next 3 patients…

#1: 20yo M brought in by 6 police officers for aggressive behavior

#2: 36yo F BIBEMS for magical thinking

#3: 43yo M with excited delirium

Ketamine abuse

– Dissociative anesthetic (appear awake but unaware of all sensory input); effects similar to PCP but shorter duration (most recover within 1 hour)

– Common recreational intake: 100-200 mg

– Common presentation: tachycardia, palpitations, chest pain, anxiety

– Rare presentations: significant agitation, altered mental status, rhabdomyolysis

– Most patients discharged after several hours of ED observation

– Management: supportive care; benzodiazepines PRN

Ketamine’s potential

– NMDA antagonist

– Anesthesia without CV/respiratory depression unless given at very high doses

– Widely used for procedural sedation/RSI/DSI

– Many advocate for its use as an analgesic => http://www.emdocs.net/ketamine-analgesia-ed/

– Evolving evidence for use in the agitated/violent patient (focus of this write-up)

– Refuted side effects: clinically significant increases in ICP and IOP; true contraindication in psychotic patients

Agitated and Violent Patient

– 1-2 mg/kg IV/IO; 4-5 mg/kg IM;

– Unpredictable effects at sub-dissociative doses, not appropriate for agitated patients

Advantages:

– Rapid sedation (< 5mins)

– Short duration

– Predictable dose-response relationship

– Can be given IM => bodes well for pre-hospital and early ED use

– Solid fit for tranquilization of uncontrollably violent patient

Potential side effects:

– Hypersalivation (apply suction)

– Hypoxia (administer O2)

– Laryngospasm (jaw thrust, O2, BMV, intubation)

– Emergence reaction (BZD)

– HTN/tachycardia

– Main concern would be covering up a major diagnosis 2/2 unreliable exam i.e. infection, seizure, ICH, SI

– Treat as if using procedural sedation – resuscitative monitoring, complete airway set-up, clinician at bedside

Bottom-line: Ketamine has strong support for procedural sedation and intubation purposes. While promising for the management of the agitated and violent patient, more data is needed before it supplants the regular use of benzodiazepines and butyrophenones. Of note: while sedating a patient, it is crucial to concurrently look for other underlying causes of this presentation.