Micro-Dose Pressors

Microdose vasopressors are a bridge for peri-intubation or shock-related hypotension when a vasopressor infusion is not ready yet. In emergency airway management and crashing patients, safer terminology, standardized concentrations, and team preparation matter as much as the drug choice.

Microdose Pressors in the ED

• Bridge before infusion: Microdose epinephrine or phenylephrine buys time when hypotension cannot wait for a vasopressor drip, especially around intubation or after adequate fluid resuscitation in a patient with a high shock index.
• Safer bedside terminology: Calling these medications microdose pressors instead of push-dose pressors reduces ambiguity, because code epinephrine is also technically a push dose and that wording has contributed to dangerous dosing errors.
• Standard epinephrine language: Referring to epinephrine in mcg rather than mg cuts conversion mistakes at the bedside; a common microdose syringe is labeled 100 mcg in 10 mL, and we get into the practical wording in the episode.
• Headline dosing ranges: Typical adult dosing uses epinephrine 10 to 50 mcg or phenylephrine 40 to 200 mcg every 2 to 5 minutes as needed, with the setup nuances for real resuscitations covered in the chapter.
• Preparation and team safety: Pharmacist involvement lowers cognitive load for the team leader and helps prevent medication delays and compounding errors during critical events, especially when local prep methods and stock differ.
• Simulation for competence: Microdose pressors are high-risk and low-frequency, making simulation the right tool for initial training, syringe preparation practice, and debriefing near misses. We walk through a workable training model in the podcast.

References:

• https://criticalcarenow.com/pearls-and-pitfalls-with-push-dose-pressors/
• http://www.emdocs.net/push-dose-vasopressors-an-update-for-2019/
• Mohta M, et al. Effect of different phenylephrine bolus doses for treatment of hypotension during spinal anaesthesia in patients undergoing elective caesarean section. Anaesth Intensive Care. 2015;43(1):74-80. PMID: 25579292
• Panchal AR, Satyanarayan A, Bahadir JD, Hays D, Mosier J. Efficacy of Bolus-dose Phenylephrine for Peri-intubation Hypotension. J Emerg Med. 2015;49(4):488-494. PMID: 26104846
• Gottlieb M. Bolus dose of epinephrine for refractory post-arrest hypotension. CJEM. 2018;20(S2):S9-S13. PMID: 28069098
• Rotando A, Picard L, Delibert S, Chase K, Jones CMC, Acquisto NM. Push dose pressors: Experience in critically ill patients outside of the operating room. Am J Emerg Med. 2019;37(3):494-498.  PMID: 30553634
• Swenson K, Rankin S, Daconti L, Villarreal T, Langsjoen J, Braude D. Safety of bolus-dose phenylephrine for hypotensive emergency department patients. Am J Emerg Med. 2018;36(10):1802-1806. PMID: 29472039
• Schwartz MB, Ferreira JA, Aaronson PM. The impact of push-dose phenylephrine use on subsequent preload expansion in the ED setting. Am J Emerg Med. 2016;34(12):2419-2422. PMID: 27720568
• Bakhsh A, Alotaibi L. Push-Dose Pressors During Peri-intubation Hypotension in the Emergency Department: A Case Series. Clin Pract Cases Emerg Med. 2021 Nov;5(4):390-393. PMID: 34813426.
• Cole JB, Knack SK, Karl ER, Horton GB, Satpathy R, Driver BE. Human Errors and Adverse Hemodynamic Events Related to "Push Dose Pressors. Epub 2019 Jul 3. PMID: 31270748.