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Administration of vasoactive medications in combination with volume resuscitation may be required to reverse systemic hypoperfusion from shock. These agents increase vasoconstriction and may support inotropy and chronotropy [65]. Although a wide variety of vasoactive agents are available in the hospital, the drugs carried by prehospital services are limited by local, regional, or statewide protocols or regulations. Historically, most services carried epinephrine and dopamine. Norepinephrine is increasingly used in place of dopamine, following randomized controlled trials demonstrating improved survival with norepinephrine over dopamine in cardiogenic and distributive shock [40, 66]. Vasopressin, a potent vasoconstrictor that is effective at low pH, is available in some systems. It may be beneficial in patients with shock refractory to norepinephrine [67]. Among patients with hemorrhagic shock, vasopressin decreases blood product requirements, but additional studies are necessary to demonstrate improved patient‐centered outcomes [68].

The choice of vasopressor depends on the suspected underlying pathological process and the patient’s response to therapy. Unfortunately, in the field, the etiology of the shock state is often unclear, and close monitoring of vital signs is difficult. The administration of vasoactive agents in the field has multiple challenges including the need to calculate weight‐based dosages, mix and dilute drugs, and administer precise volumes. EMS clinicians should use calculators or templates or seek direct medical oversight. When available, portable IV infusion pumps should be used to ensure accurate and precise medication administration.

An alternative to vasopressor infusions are boluses of vasopressors used to temporize patients in profound shock or peri‐arrest until the patient can be stabilized with volume or vasopressor infusions. Extrapolated from anesthesia practices to the emergency department, hypotension may be treated with boluses of phenylephrine or epinephrine [69]. Prehospital “push dose” vasopressors increase blood pressure but may increase mortality [70, 71]. Further research is necessary to identify the appropriate patient population, agent, and dose for prehospital push dose vasopressors.