8.3 Vasopressors and Circulatory Support Drugs

Vasopressors are not a fluid. Domain 2.C.1 of the August 2026 Board of Certification for Emergency Nursing (BCEN) Certified Flight Registered Nurse (CFRN) outline tests vasopressors because starting norepinephrine into an empty bleeder, or mixing 1:1,000 epinephrine as if it were 1:10,000, will not get a second look from the cabin. Use these drugs to support tone or inotropy after you have a working tank—or as a brief bridge while blood is handed up. Chapter 9 covers shock phenotypes; this section is the drug box and the pump.

First-line choices and the usual add-ons

Norepinephrine, epinephrine, and the add-on drugs

Norepinephrine is first-line for septic shock and other distributive states once you have given reasonable volume. It is a strong alpha agonist with useful beta-1 activity, so it raises mean arterial pressure (MAP) without the pure-alpha reflex bradycardia of phenylephrine. Start it peripherally for a short, watched interval if a central line is not yet in, then move it centrally when you can.

Epinephrine is the drug for anaphylaxis (intramuscular first) and for peri-arrest hypotension. It is also a reasonable infusion when you need both vasoconstriction and inotropy. It will raise lactate and heart rate; that is expected pharmacology, not automatic worsening sepsis.

Vasopressin is an add-on, not a solo first-line drip for most flight patients. A fixed low-dose infusion (commonly about 0.03–0.04 units/minute in adult septic-shock teaching) spares catecholamines. It is not titrated like norepinephrine and is not first-line in a dry trauma patient.

Phenylephrine is pure alpha-1. It raises afterload, can trigger reflex bradycardia, and provides no inotropy. That profile can fit anesthesia-related vasodilation in a patient with a full tank. It is a poor choice for cardiogenic shock, bradycardia, or an empty bleeder.

Dopamine is rarely preferred. Current adult septic-shock teaching moved away from it because of arrhythmias. Do not pick it as the modern first-line agent unless it is the only pump drug in the aircraft. Dobutamine and milrinone are inodilators for cardiogenic shock (Chapter 9). They can drop blood pressure.

A working adult MAP goal in distributive shock is about 65 mm Hg (Surviving Sepsis–style teaching, not a BCEN-owned number). A neurologically injured patient may need a higher MAP to protect cerebral perfusion pressure (CPP). Aortic injury and uncontrolled hemorrhage change the target downward or toward permissive goals from section 8.1. Titrate to the organ you are protecting.

Push-dose epinephrine, concentrations, and the line

The vial in your hand

Push-dose epinephrine is a dilute intravenous bridge for peri-intubation or peri-arrest hypotension while an infusion is mixing. A common preparation takes 1:10,000 cardiac epinephrine (0.1 mg/mL) and dilutes it further to about 10 micrograms/mL, then gives 10–20 micrograms at a time. Those micrograms are clinical teaching. The exam-critical safety point is the vial.

• 1:10,000 = 0.1 mg/mL = the cardiac prefilled syringe (typically 1 mg in 10 mL).
• 1:1,000 = 1 mg/mL = the intramuscular anaphylaxis vial (typically 1 mg in 1 mL).
• Pushing 1 mg of 1:1,000 intravenously as if it were a dilute push-dose is a medication error.
• Intramuscular 1:1,000 remains correct for anaphylaxis. Do not convert that vial into an unlabeled intravenous push.

A well-watched, large proximal peripheral line can run a dilute catecholamine for a short flight. A hand vein or a leaking intraosseous (IO) line is the wrong plan. Extravasation causes tissue ischemia. Stop the infusion, leave the catheter in at first so you can aspirate and give the program antidote (phentolamine is the classic teaching agent), then restart in a confirmed proximal line.

Flight pump problems

Syringe pumps are the flight standard. Confirm battery state before lift. A dead pump is a homemade gravity drip in turbulence. Use a dedicated channel. Never piggyback a vasopressor blindly into blood, a warmer line, or a sedative. When the other bag empties or is clamped, the patient gets a bolus of pressor or none.

Dead-space in long extension tubing delays every rate change. A 1 mL/hour infusion in a 4 mL extension has not reached the patient when you think it has. Prime the line with the drug, keep tubing short, and recheck MAP after loading, climb, and every tubing change. Vibration can loosen a syringe flange; tape it and watch the milliliters remaining, not only the screen.

A pressor is a temporizing tool in hemorrhage, never a substitute for blood (section 8.4). In sepsis it is support after volume. In anaphylaxis it is the actual treatment.

CFRN practice bankPractice questions with detailed explanations