When does someone need a pressor?
When the SBP is <30 from baseline or the MAP <60 with evidence of end-organ damage. However, MAP guidelines vary by indication and institution.
What kind of pressor should be given?
The specific agent will depend on etiology, e.g., dobutamine for cardiogenic shock. Try to give the max dose of the first agent before moving to the second. Pressors should be given through a central catheter, although a peripheral is okay if you don’t have a central in.
What are side effects to watch out for?
Tachyphylaxis is a phenomenon by which efficacy can decrease over time, so it requires intense monitoring. Side effects include: hypoperfusion (dusky toes), dysrhythmias (sinus tach and afib are most common), MI.
A list of the most commonly used pressors:
- Levophed (norepinephrine)—A1, B1 effects. #1 for septic shock and undifferentiated shock–this should be a first go-to, supported by the literature
- Vasopressin—ADH analogue. Second line for refractory shock, a good “add-on” pressor
- Neo (phenylephrine)—A1. A weak A1 agonist, so would be considered to have weaker effects than levophed. However, it may be better in situations where levophed is causing tachyarrythymias. May decrease stroke volume and increase afterload, so not as favorable for cardiogenic shock.
- Epi (epinephrine)—A1, B1, B2. Can cause splanchnic vasoconstriction. Most useful for anaphylactic shock. This medication WILL cause lactate to rise, so don’t fret if you see a mild bump.
- Dopamine—1-2 mcg/kg=selective vasodilation (D1). 5-10 mcg/kg=inc MAP and CO, B1. >10=A1, dysrhythmias. ***associated with higher mortality risk so this medication is falling out of favor
- Dobutamine=B1, B2, used more as an inotrope as opposed to pressor effects. Dobutamine may cause peripheral vasodilation, so not uncommon for pts to have a second pressor added on for support
- Milrinone—PDE inhibitor. Inotrope but also vasodilatory, and usually seen in the setting of severe chronic heart failure.