Contributor: Aaron Lessen MD

Educational Pearls:

• Lorazepam (Ativan) is dosed at 0.1 mg/kg up to a maximum of 4 mg in status epilepticus

• • Some ED protocols only give 2 mg initially

• The maximum recommended dose of levetiracetam (Keppra) is 60 mg/kg or 4.5 g

• In one retrospective study, only 50% of patients received the correct dose of lorazepam

• • For levetiracetam, it was only 35% of patients

• Underdosing leads to complications

• • Higher rates of intubations

  • More likely to progress to refractory status epilepticus

References

1. Cetnarowski A, Cunningham B, Mullen C, Fowler M. Evaluation of intravenous lorazepam dosing strategies and the incidence of refractory status epilepticus. Epilepsy Res. 2023;190(November 2022):107067. doi:10.1016/j.eplepsyres.2022.107067

2. Sathe AG, Tillman H, Coles LD, et al. Underdosing of Benzodiazepines in Patients With Status Epilepticus Enrolled in Established Status Epilepticus Treatment Trial. Acad Emerg Med. 2019;26(8):940-943. doi:10.1111/acem.13811

Summarized by Jorge Chalit, OMSII | Edited by Meg Joyce & Jorge Chalit

Contributor: Travis Barlock MD

Educational Pearls:

Ketamine is an NMDA receptor antagonist with a wide variety of uses in the emergency department. To dose ketamine remember the numbers 0.3, 1, and 3.

Pain dose

• For acute pain relief administer 0.3 mg/kg of ketamine IV over 10-20 minutes (max of 30 mg).

• Note: There is evidence that a lower dose of 0.1-0.15 mg/kg can be just as effective.

Dissociative dose

• To use ketamine as an induction agent for intubation or for procedural sedation administer 1 mg/kg IV over 1-2 minutes.

IM for acute agitation

• If a patient is out of control and a danger to themselves or others, administer 3 mg/kg intramuscularly (max 500 mg).

• If you are giving IM ketamine it has to be in the concentrated 100 mg/ml vial.

Additional pearls

• Pushing ketamine too quickly can cause laryngospasm.

• Between .3 and 1 mg/kg is known as the recreational dose. You want to avoid this range because this is where ketamine starts to pick up its dissociative effects and can cause unpleasant and intense hallucinations. This is colloquially known as being in the “k-hole”.

References

1. Gao, M., Rejaei, D., & Liu, H. (2016). Ketamine use in current clinical practice. Acta pharmacologica Sinica, 37(7), 865–872. https://doi.org/10.1038/aps.2016.5

2. Lin, J., Figuerado, Y., Montgomery, A., Lee, J., Cannis, M., Norton, V. C., Calvo, R., & Sikand, H. (2021). Efficacy of ketamine for initial control of acute agitation in the emergency department: A randomized study. The American journal of emergency medicine, 44, 306–311. https://doi.org/10.1016/j.ajem.2020.04.013

3. Stirling, J., & McCoy, L. (2010). Quantifying the psychological effects of ketamine: from euphoria to the k-Hole. Substance use & misuse, 45(14), 2428–2443. https://doi.org/10.3109/10826081003793912

Summarized by Jeffrey Olson MS2 | Edited by Jorge Chalit, OMS II

Contributor: Travis Barlock MD

Educational Pearls:

• Thrombolytic therapy (tPA or TNK) is often used in the ED for strokes

• Use of anticoagulants with INR > 1.7 or PT >15

• • Warfarin will reliably increase the INR

• Current use of Direct thrombin inhibitor or Factor Xa inhibitor

• • aPTT/PT/INR are insufficient to assess the degree of anticoagulant effect of Factor Xa inhibitors like apixaban (Eliquis) and rivaroxaban (Xarelto)

• Intracranial or intraspinal surgery in the last 3 months

• • Intracranial neoplasms or arteriovenous malformations also increase the risk of bleeding

• Current intracranial or subarachnoid hemorrhage

• • History of intracranial hemorrhage from thrombolytic therapy also contraindicates tPA/TNK

• Recent (within 21 days) or active gastrointestinal bleed

• Hypertension

• • BP >185 systolic or >110 diastolic

  • Administer labetalol before thrombolytics to lower blood pressure

• Timing of symptoms

• • Onset > 4.5 hours contraindicates tPA

• Platelet count < 100,000

• BGL < 50

• • Potential alternative explanation for stroke-like symptoms obviating need for thrombolytics

References

1. Fugate JE, Rabinstein AA. Absolute and Relative Contraindications to IV rt-PA for Acute Ischemic Stroke. The Neurohospitalist. 2015;5(3):110-121. doi:10.1177/1941874415578532

2. Powers WJ, Rabinstein AA, Ackerson T, et al. Guidelines for the Early Management of Patients with Acute Ischemic Stroke: 2019 Update to the 2018 Guidelines for the Early Management of Acute Ischemic Stroke a Guideline for Healthcare Professionals from the American Heart Association/American Stroke Association. Vol 50.; 2019. doi:10.1161/STR.0000000000000211

Summarized by Jorge Chalit, OMSII | Edited by Jorge Chalit