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What are push dose pressors, and how do they work?

When we have a patient who is hypotensive, either in the peri-intubation period or post-cardiac arrest, one of the primary things we need to manage is blood pressure. When a patient is hypotensive (SBP <90 mmHg) in either of these settings, their mortality rate is almost 50%. If we can regulate their blood pressure, that rate drops to 20%[1]. These numbers support the need to regulate blood pressures. The question becomes “how do we do that safely and effectively?”

In 2008, Scott Weingart posted a protocol on his website Emcrit.org suggesting that we mix either phenylephrine or epinephrine and administer these drugs, at a diluter concentration, in order to achieve this goal[2]. He coined the term “push dose pressors” which is a preferable term to the technically correct “IV bolus pressers.” For EMS, epinephrine is probably the drug of choice. Epinephrine does have some draw backs, specifically that it can increase the heart rate, and thus increase myocardial oxygen demand. However, if the goal is to increase survival, then epinephrine might be one of the best drugs we have in our arsenal. Almost 50% of patients who experience a ROSC post-cardiac arrest will be hypotensive[3], and fluid resuscitation for these patients can take time. This is not to mention increasing the risk of pulmonary edema from fluid overload. Epinephrine also has the advantage of being safe in the presence of extravasation, so if you start a line in a chaotic arrest, and the line infiltrates, there will be little negative effect to the patient.

To mix this drug, you will take a vial or bristojet of you cardiac epinephrine (1:10,000) and draw 1mL out of the vial. This will then be mixed with 9mL of normal saline, preferably in a flush or syringe. The concentration of epinephrine you now have will be 1:100,000, with 10 mcg/ml. Give 1 mL every 1-3 minutes until you achieve a systolic blood pressure above 90mmHg. [4]

[1] Merlin, Mark EMS Week Presentation Newark Beth Isreal Medical Center 24 May 2017

[2] https://emcrit.org/wp-content/uploads/push-dose-pressors.pdf

[3] https://www.ncbi.nlm.nih.gov/pubmed/19866506

[4] http://ceemjournal.org/journal/view.php?number=45