Pressors in Hypovolemia Double Mortality

BLUF*: Hypotensive trauma patients need the cause of their hypotension fixed: whether that is aggressive hemorrhage control, administration of blood products, or needle decompression for tension pneumothorax. IVF is a very temporary fix; blood products would be better. Push dose vasopressors make the numbers on the monitor look more comfortable while at least doubling the casualty’s mortality.

🕖 Reading Time, 3 minutes Recently, while conducting scenario training with rookie paramedics in my fire department, two gave push dose vasopressor medications to a simulated trauma patient who remained hypotensive despite IV fluid.

Hypotensive trauma patients need blood and potentially an operation to fix their problems and injuries. We use IV fluid prehospital solely because we don’t have blood products. Soon, there may be freeze-dried plasma available for prehospital use in the US, as it is in many other countries. Although IV fluid has never been shown to improve survival in hypotensive trauma patients, there is literature showing prehospital hypotension correlates with increased injury severity and worse outcome.¹

Even with hypotensive resuscitation paradigms, we intervene to try and raise blood pressure at low enough blood pressures. TCCC and TECC guidelines use the marker of an absent radial pulse or altered mental status as an indicator the casualty needs blood/fluid. With the addition of push dose pressors to many prehospital protocols, I suspect some think this technique applies to all hypotensive patients. It doesn’t. Push dose vasopressor medications can raise patients’ blood pressure, but clear literature on their use improving survival is lacking.² In patients whose hypotension is a byproduct of vasodilation (sepsis) or cardiogenic shock, their use makes empiric sense, as those patients can benefit from increased peripheral vasoconstriction, inotropy, and preload/afterload changes. Hypovolemia is not a reason to use push dose pressors.

Using pressors in hypovolemic shock is very controversial, and many think it is harmful. Vasoactive medications increase cardiac workload, afterload, oxygen consumption, and possibly decrease tissue perfusion.³ Additionally, animal literature with pigs shows that at a systolic blood pressure of 94 mmHg, previously bleeding blood vessels that have “clotted” themselves off will rebleed secondary to the increased blood pressure.⁴

In another study, the US military looked at 124 casualties who received vasopressor medications while hypotensive. Their odds of survival were markedly decreased, even controlling for the level of hypotension.  Many other studies have shown similar effects, generally doubling mortality if the trauma patient received prehospital pressors. Essentially, there is no real data showing a benefit to pressors in hypotensive trauma patients and a lot of literature showing definite harm to giving them.⁵

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*For those unfamiliar with this term, BLUF is “Bottom Line Up Front,” Notes: ¹ Damme CD, Luo J, Buesing KL. Isolated prehospital hypotension correlates with injury severity and outcomes in patients with trauma. Trauma Surg Acute Care Open. 2016 Aug 12;1(1):e000013. ² Guyette FX, Martin-Gill C, Galli G, McQuaid N, Elmer J. Bolus Dose Epinephrine Improves Blood Pressure but is Associated with Increased Mortality in Critical Care Transport. Prehosp Emerg Care. 2019 Nov-Dec;23(6):764-771. ³ Richards JE, Harris T, Dünser MW, Bouzat P, Gauss T. Vasopressors in Trauma: A Never Event? Anesth Analg. 2021 Jul 1;133(1):68-79. ⁴ Sondeen JL, Coppes VG, Holcomb JB. Blood pressure at which rebleeding occurs after resuscitation in swine with aortic injury. J Trauma. 2003 May;54(5 Suppl):S110-7. ⁵ Fisher AD, April MD, Cunningham C, Schauer SG. Prehospital Vasopressor Use Is Associated with Worse Mortality in Combat Wounded. Prehosp Emerg Care. 2021 Mar-Apr;25(2):268-273.