Category: Critical Care
Keywords: Critical Care, Hypotension, Shock, Vasopressors (PubMed Search)
With a shortage of push dose epi, this may be an opportune time to review alternative options (see also Ashley's email on the subject).
The dose of vasopressor required to reverse hypotension has been most studied in pregnant women undergoing c-section who get epidurals and experience spinal-induced vasoplegia and hypotension (not necessarily our patient population, but we can extrapolate...)
Phenylephrine was found to reverse hypotension 95% of the time at a dose of 159 micrograms (a neo stick has 100 ug/mL, so around 1-2 mL out of the stick)
Norepinephrine reversed hypotension in 95% of patients at a dose of 5.8 ug. The starting dose for our norepi order in Epic is 0.01 ug/kg/min, so if you have a levophed drip hanging and have an acutely hypotensive patient, you may want to briefly infuse at a higher rate such as 0.1 ug/kg/min (for a typical weight patient), or bolus approximately 3-7 ug for a typical patient. Of course the degree of hypotension, particular characteristics of your patient and clinical context should be taken into consideration. When your a lucky enough to have this resource, always consult your pharmacist.
Bottom Line: To reverse acute transient hypotension you may consider:
-A bolus of phenylephrine 50-200 ug (0.5-2 mL from neo-stick)
-A bolus of norepinephrine 3-7 ug
-Briefly increasing your norepinephrine drip (if you have one) to something around 0.1 ug/kg/min in a typical weight patient
-Always search for other causes of hypotension and consider clinical context.
Onwochei DN, Ngan kee WD, Fung L, Downey K, Ye XY, Carvalho JCA. Norepinephrine Intermittent Intravenous Boluses to Prevent Hypotension During Spinal Anesthesia for Cesarean Delivery: A Sequential Allocation Dose-Finding Study. Anesth Analg. 2017;125(1):212-218. (https://www.ncbi.nlm.nih.gov/pubmed/28248702)
Tanaka M, Balki M, Parkes RK, Carvalho JC. ED95 of phenylephrine to prevent spinal-induced hypotension and/or nausea at elective cesarean delivery. Int J Obstet Anesth. 2009;18(2):125-30. (https://www.ncbi.nlm.nih.gov/pubmed/19162468)
Weingart S. Push-dose pressors for immediate blood pressure control. Clin Exp Emerg Med. 2015;2(2):131–132. Published 2015 Jun 30. doi:10.15441/ceem.15.010 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5052865/)