9.2 Distributive Shock
Key Takeaways
- Distributive shock is low systemic vascular resistance: septic, anaphylactic, and neurogenic pictures, often warm early and cold late.
- Sepsis-3 is organ dysfunction from infection; cultures if they will not delay drugs, then antibiotics, an SSC 30 mL/kg crystalloid start (guideline, not BCEN law), and early norepinephrine.
- Anaphylaxis gets intramuscular epinephrine 0.3–0.5 mg of 1:1,000 in the anterolateral thigh—not a 1 mg intravenous arrest push—plus fluids and an early airway.
- Neurogenic shock is warm, dry, and bradycardic; use phenylephrine or norepinephrine and a higher MAP for cord perfusion (Chapter 11).
- Adrenal crisis is only a distributive look-alike—the 2026 outline removed standalone adrenal disorders. Start pressors on the ramp and fly to source control.
Distributive shock is a pipe problem: the tank and pump may be adequate, but the pipes are too open, so systemic vascular resistance (SVR) collapses. Domain 2.C.2.c of the August 2026 Board of Certification for Emergency Nursing (BCEN) Certified Flight Registered Nurse (CFRN) outline tests distributive shock as septic, anaphylactic, and neurogenic pictures. Early distributive shock is often warm shock—flushed, bounding pulses, wide pulse pressure. Late or mixed pictures turn cold. You cannot wait for a laboratory Sequential Organ Failure Assessment (SOFA) score at 3,000 feet. Give the first-line drug and pick a destination that can finish the job.
Septic shock: organ failure plus infection, not a number cult
Sepsis-3 conceptually, not a qSOFA statute
Sepsis-3 defines sepsis as life-threatening organ dysfunction caused by a dysregulated response to infection. The bedside quick SOFA (qSOFA) cluster—respiratory rate 22 or more, altered mentation, systolic blood pressure (SBP) 100 mm Hg or less—is a conceptual prompt, not a sensitive single screen and not a BCEN statute. Treat the infected, organ-failing, hypotensive patient in front of you.
If cultures will not delay the first dose, draw them. Then give antibiotics that match the likely source before the rotor drowns the conversation. Surviving Sepsis Campaign (SSC) guidance still uses 30 mL/kg of crystalloid as a starting point for sepsis-induced hypoperfusion. That is guideline teaching, not BCEN law, and not a reason to drown a failing right ventricle or a wet lung. Reassess after each bolus: mean arterial pressure (MAP), end-tidal carbon dioxide (ETCO2), lactate if you carry it, and the lungs. If still hypotensive after reasonable volume, start norepinephrine early. Destination is source control: an operating room, interventional radiology, or an intensive-care unit—not a clinic that can only hang another bag.
Anaphylaxis: intramuscular epinephrine first
Anaphylactic shock is immunoglobulin E (IgE) or non-IgE mast-cell release: urticaria, wheeze, stridor, cramping, and distributive collapse. The first drug is intramuscular (IM) epinephrine 0.3–0.5 mg of 1:1,000 (1 mg/mL) in the anterolateral thigh, repeatable every 5–15 minutes. That is not the 1 mg intravenous (IV) cardiac-arrest push, and it is not a diphenhydramine experiment. IV epinephrine for refractory anaphylaxis is a dilute infusion, not a crash-cart bolus while a pulse remains.
While the epinephrine works:
- Open the airway early if the voice changes, the tongue swells, or stridor starts. Angioedema can close on climb.
- Give large-volume crystalloid. The pipes are open and plasma is leaking.
- Add an H1 blocker, an H2 blocker, and a corticosteroid as adjuncts, not as the drug that raises pressure.
- Remove the stinger, stop the infusion, or wipe off the latex.
A second IM dose, an intubation, or an IV epinephrine infusion belongs in a monitored bed, not a helipad lobby.
Neurogenic shock and the adrenal look-alike
Warm, slow, and a higher MAP for the cord
Neurogenic shock is loss of sympathetic tone after a high spinal cord injury (SCI), usually cervical or high thoracic. The skin is warm and dry below the lesion; the heart is bradycardic; the blood pressure is low. That is not hypovolemic trauma until you prove bleeding. Do not skip a Focused Assessment with Sonography in Trauma (FAST) because the feet are warm.
Support MAP with phenylephrine or norepinephrine. Phenylephrine is a pure alpha agonist and can reflex-slow an already slow heart; many programs prefer norepinephrine because a little beta-1 support protects the rate. Either is acceptable if you watch the pulse. MAP goals are often higher than a routine 65 mm Hg when the issue is cord perfusion; many protocols still discuss values near 85 mm Hg. Chapter 11 owns the full SCI debate. Destination is a spine-capable trauma center.
Adrenal crisis is a look-alike, not a 2026 lecture
The 2026 CFRN outline removed adrenal disorders as a standalone medical topic. Do not build a full Addison lecture. Remember adrenal crisis only as a distributive look-alike: a steroid-dependent or Waterhouse-Friderichsen patient who is shocked, sometimes hypoglycemic, and unresponsive to usual pressors. Hydrocortisone after you have treated sepsis or hemorrhage is reasonable. It is not a reason to skip antibiotics or Chapter 8 volume.
| Picture | Skin / rate | First-line drug | Flight trap |
|---|---|---|---|
| Septic | Warm early, cold late; tachycardic | Antibiotics, SSC-style 30 mL/kg start, early norepinephrine | Waiting on SOFA; drowning lungs |
| Anaphylactic | Flush, urticaria, wheeze or stridor | IM epinephrine 0.3–0.5 mg of 1:1,000 in the thigh | IV 1 mg push; antihistamine-first |
| Neurogenic | Warm, dry, bradycardic | Phenylephrine or norepinephrine; higher MAP for SCI | Treating only as hypovolemia |
| Adrenal look-alike | Variable; may be refractory | Stress-dose steroid after usual resuscitation | Full Addison workup in the cabin |
Warm versus cold, and why pressors start on the ramp
Warm shock means low SVR: flushed skin, bounding pulses, a wide pulse pressure—early sepsis, anaphylaxis, and neurogenic shock. Cold shock means high SVR or a dying pump: mottled skin, delayed capillary refill, a narrow pulse pressure. Late sepsis and mixed pictures look cold. A septic patient who turns cold in your litter is not compensating—start the pressor and reassess.
Flight rules for distributive shock:
- Give the first-line drug on the ramp. IM epinephrine and norepinephrine do not require cruise altitude.
- Do not withhold a pressor to finish a textbook 30 mL/kg if the lungs are wet or the aircraft is lifting.
- Choose a source-control destination: operating room, interventional radiology, spine center, or intensive-care unit—not the closest clinic.
- Recheck the airway after every IM epinephrine dose and every cabin-altitude change.
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