• Norepinephrine (Levophed). Norepinephrine has become the go-to pressor for nearly all types of shock for several reasons. Unsurprisingly, it is also a fantastic push-dose pressor.⁴ It has more a₁ than b₁, so most of the blood pressure effect is from peripheral vasoconstriction. Although it has some b₁ to support patients with myocardial depression, it doesn’t tend to have as much arrhythmogenic effect as epinephrine, making it a great balanced pressor. Because norepinephrine has been widely adopted as the go-to pressor in the ED, infusion bags are generally readily available, and the enterprising emergency physician can draw a bolus dose directly from the bag (which will helpfully be labeled with the concentration). Dosing is similar to epinephrine, 10-20 micrograms every three to five minutes.

Although norepinephrine hasn’t historically had the same popularity as phenylephrine and epinephrine in the ED, I have found myself using it more often because of its balanced side-effect profile and easy availability.

• Vasopressin (“Vaso”). Vasopressin is a non-catecholamine vasopressor, acting primarily on the V₁ Because of its unique mechanism of action, it provides vasoconstriction but is generally less dependent on pH and may spare some of the pulmonary artery constriction seen with phenylephrine, a feature potentially desirable for patients with right heart decompensation or pulmonary hypertension. Use in the ED has mainly been described in case reports.⁵ Dosing is typically 0.4 to one unit once.

Perils and Pitfalls

Now that we have reviewed the common push-dose pressors and their dosing, what are the common perils and pitfalls? The most common, by far, is dosing. There have been a number of reports suggesting orders-of-magnitude errors; these tend to almost invariably result in overdoses.^1,6-8 Multiple sources will describe how to mix up push-dose pressors yourself.^9-11 For example, to make push-dose epinephrine from the code cart dose, you take the 1 mg in 10 mL syringe (1000 mcg in 10 mL = 100 mcg per mL), remove 1 mL (100 mcg) and then mix it into 9 mL of a saline flush, giving a final 10 mcg/mL concentration. However, that math is tricky even when you are relaxed, and mixing this under a high-stress, high-stakes scenario is a recipe for mistakes.¹² Instead, I suggest you work with the pharmacy to stock pre-made syringes and have them readily available.¹ These have the convenience of being compounded ahead of time and will have standardized concentrations.

Otherwise, the most common errors I have seen are trying to use a push-dose pressor when a continuous vasopressor is needed, and failing to diagnose or treat the underlying cause of the hypotension. If you intubate a profoundly hypotensive patient with propofol, no amount of push-dose pressor will be superior to resuscitating beforehand! Like peripheral administration of vasopressors, peripheral administration of push-dose pressors is safe; when administered into a large bore, well-functioning IV catheter, the risk of extravasation is minimal.^9,13,14