Ketamine for Agitated Patients in the Emergency Department

Educational Objectives

The goal of this program is to improve use of ketamine for managing agitation in the emergency department. After hearing and assimilating this program, the clinician will be better able to:

1. Utilize ketamine when appropriate to manage patients with acute agitation.
2. Identify complications that are more likely to occur with ketamine than with other agents used for managing agitation.

Summary

Ketamine: agitation is not an indication for ketamine use, but it can be useful for certain patients under specific circumstances with proper monitoring; psychomotor agitation is an extreme form of arousal associated with increased verbal and motor activity; it accounts for 2.6% of emergency department (ED) visits; patients exhibiting agitation may need psychopharmacologic interventions; traditional agents used include antipsychotics, benzodiazepines, α-1 antagonists, α-2 agonists, anticholinergics, and antihistaminergic agents; there are limitations to using these; availability of intramuscular (IM) and intravenous (IV) formulations, ability to induce sedation, onset of action, and need for redosing should be considered; patients may have fragile vital signs that can be compromised by these medications; each class also has its own adverse effects; ketamine was derived from phencyclidine and has been used for anesthesia for >50 yr; it is a racemic mixture of equal parts of positive and negative enantiomers; it works as a noncompetitive inhibitor on N-methyl D-aspartate receptors, primarily in the prefrontal cortex and hippocampus; it also works on the acetylcholine, opioid, and dopamine neurotransmitter systems

Ketamine for agitation: in 2017, the American College of Emergency Physicians endorsed the use of ketamine for agitation; emergency physicians are familiar with it, and ketamine offers immediate control in acute agitation to ensure patient and staff safety; several formulations are available; bioavailability ranges from <20% for oral ketamine to 100% for IV and >90% for IM, which is the most important route; dosing can be subdissociative or dissociative; pain and depression require subdissociative dosing (0.5 mg/kg IV push) while agitation and anesthesia require higher doses; for anesthesia, a 70-kg patient requires 70 to 315 mg, but for agitation, the dose is 2 to 6 mg/kg; there is reservation about using >500 mg IM as a single dose; ketamine is consistently effective in producing sedation, with a response rate >95%; it is as effective or superior to other agents for inducing sedation; onset of action is faster than with other agents; in the first 15 to 20 min of administration, more patients respond to ketamine than to benzodiazepines or antipsychotics, but the gap closes nearer to 30 min; a study found that median time to achieve sedation was <6 min with 5 mg ketamine and 15 min with 5 mg haloperidol plus 5 mg midazolam; this is important when patients are agitated and aggressive toward staff

Other considerations: ketamine has a short half-life of 2 to 4 min; however, when used at 4 mg/kg, redosing is needed in ≈22% of cases vs≈20% with haloperidol plus lorazepam; ketamine can cause a transient increase in heart rate and blood pressure unlike other agents used to treat agitation which tend to cause bradycardia and hypotension; this is important when treating patients with fragile vital signs at baseline or who have been given medications that cause hypotension and bradycardia; other common side effects include vomiting, hypersalivation, and emergence reactions; compared with other agents, ketamine has a lower risk for respiratory depression but higher risk for intubation, lower risk for extrapyramidal side effects, no QTc prolongation concerns, no antimuscarinic side effects, and no additive actions when mixed with other agents; intubation rates range from <20% in the ED setting to >60% in the pre-ED setting; intubation is often done to protect the airways and is not based on objective signs; this may account for the increased rate in the pre-ED setting as the threshold for intubation is different in the ED; there is debate on whether the risk is dose-dependent; there is concern that ketamine use is increased with cocaine use; intubation typically lasts <24 hr; blood pressure, heart rate, oxygenation, and cardiac monitoring are needed; immediate access to intubation is also important

Readings

Barbic D, Andolfatto G, Grunau B, et al. Rapid agitation control with ketamine in the emergency department: A blinded, randomized controlled trial. Ann Emerg Med. 2021;78(6):788-795. doi:10.1016/j.annemergmed.2021.05.023; Lin J, Figuerado Y, Montgomery A, et al. Efficacy of ketamine for initial control of acute agitation in the emergency department: A randomized study. Am J Emerg Med. 2021;44:306-311. doi:10.1016/j.ajem.2020.04.013; Mo H, Campbell MJ, Fertel BS, et al. Ketamine safety and use in the emergency department for pain and agitation/delirium: A health system experience. West J Emerg Med. 2020;21(2):272-281. Published 2020 Jan 27. doi:10.5811/westjem.2019.10.43067; Olives TD, Nystrom PC, Cole JB, et al. Intubation of profoundly agitated patients treated with prehospital ketamine. Prehosp Disaster Med. 2016;31(6):593-602. doi:10.1017/S1049023X16000819.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose. Dr. Shobassy's lecture contains information related to the off-label or investigational use of a product, therapy, or device.

Acknowledgements

Dr. Shobassy was recorded at the 15th Annual National Update on Behavioral Emergencies, held in Phoenix, AZ, on December 9-11, 2024, and presented by the American Association of Emergency Psychiatry. For information about upcoming CME activities from this presenter, please visit https://www.emergencypsychiatry.org. Audio Digest thanks the speakers and presenters for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.50 CE contact hours.

Lecture ID:

PS540602

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.

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