@rishimd Phenylephrine is a selective alpha-1 receptor agonist used in various settings for its vasoconstrictive properties. Whether this is as a decongestant (constricting vessels in the nasal/sinus mucosa) or a mydriatic to perform a fundoscopic exam, this medication’s selectivity gives me an idea of the expected response as well as potential side effects. ☺️
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I most commonly use phenylephrine in the ICU and OR to treat acute hypotension caused by vasodilation from hypnotics, halogenated volatile anesthetics, or acute blood loss in tandem with ongoing resuscitation. I’m comfortable using a peripheral IV to bolus 40-120 mcg over a short period of time, but in the rare event of tissue infiltration, phenylephrine’s alpha agonist effects can be antagonized with medications like phentolamine administered subcutaneously. If the need for long term afterload enhancement arises, I almost always switch to a norepinephrine or vasopressin drip. 💊
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Acute increases in systemic vascular resistance (SVR) will activate baroreceptors (ie, the carotid sinuses) which, in turn, increase vagal tone to the heart. Since phenylephrine does not have any beta-agonist properties, the unopposed increase in vagal tone is the mechanism by which the patient’s heart rate decreases in response to an acutely elevated SVR. 💉👨🏽‍⚕️
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Tag a friend who uses phenylephrine, let me know if/when you’ve used it, and drop me a comment with questions! 👇
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About the Author
I am an experienced trauma nurse who has seen a lot of super tragic and gnarly things. On the flip side, I’ve have seen and done a lot of amazing things in my 20 years of nursing as well. I’ve saved lives for a living and I have had the privilege and the honor of holding patients hands as they take their last breath. I have seen SO many patients and their loved ones in their most fragile moments. I am proud of my profession, and for the fact that I have fought so valiantly to be here. Sometimes nurses get burnt out, but I have been blessed to be at the bedside all of my career. I have earned multiple degrees and certifications in nursing. I am the nurse you want at your bedside when you’re critically injured and dying. I put my blood, sweat and tears into being clinically astute & relevant. This blog is to help new nurses, nursing students, paramedics, experienced nurses, or whomever comes across my blogs path and think it is intriguing, educational or inspiring to them. In this career, we are all here to share and help one another grow. I believe in building others up, so they can reach the next level, whatever their goal may be. Carpe Diem & ENJOY!

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