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CEN — Emergency Nursing
CEN Shock & Sepsis Recognition Review
Shock and sepsis are where the emergency department's recognition speed translates directly into survival. The CEN tests the four shock categories with their field-recognizable profiles, early sepsis identification and bundle execution, lactate and fluid logic, and the distributive-shock pitfalls (neurogenic, anaphylactic, septic) that trip up pattern-matching.
This guide reviews shock classification and emergency sepsis care with CEN-style questions and rationales. Educational review only — bundle timing, fluid volumes, and vasopressor choices follow current guidelines and your department's protocols; verify before applying.
The four shock categories
Hypovolemic: volume loss (hemorrhage, burns, dehydration) → low preload, compensatory high SVR (cool, clamped skin), narrow pulse pressure; fix the tank (volume/blood). Cardiogenic: pump failure → low output, high SVR, congestion (crackles, JVD); support the pump and avoid fluid-flooding a failing heart. Distributive: vasodilation — septic (infection source, warm early), anaphylactic (exposure + hives + airway/circulation involvement → epinephrine first), neurogenic (spinal injury: hypotension with bradycardia and warm dry skin — the sympathetic outflow is interrupted) → restore tone with volume and vasopressors. Obstructive: mechanical blockage — tension pneumothorax (decompress), cardiac tamponade (pericardiocentesis), massive PE (thrombolysis/embolectomy) — no infusion fixes the mechanical problem.
The CEN's favorite discriminators: neurogenic shock's missing tachycardia and warm dry skin (versus hypovolemia's cold clamminess), recognizing the obstructive causes as 'shock with breath-sound or heart-sound findings' needing a mechanical fix, and catching compensated shock — tachycardia, narrowed pulse pressure, anxiety, cool skin — before hypotension, which is a late, ominous sign especially in young patients. Classifying the shock correctly is what makes the treatment correct.
Sepsis recognition and the bundle
Early recognition is the survival lever: sepsis is organ dysfunction from a dysregulated response to infection, and the early physiology (fever or hypothermia, tachycardia, tachypnea, leukocyte changes, subtle altered mentation, hypotension trending down, rising lactate) precedes overt collapse. The ED job is to identify the at-risk patient — infection plus signs of hypoperfusion/organ dysfunction — and start the clock. Septic shock is sepsis with vasopressor-requiring hypotension and elevated lactate despite fluids.
The bundle: obtain cultures before antibiotics when feasible, give broad-spectrum antibiotics urgently (every hour of delay in septic shock costs survival), measure and trend lactate, resuscitate with crystalloid (a commonly cited starting target around 30 mL/kg, individualized by reassessment), and start vasopressors (norepinephrine first-line) for fluid-refractory hypotension to maintain MAP ≥65. Source control — drain the abscess, remove the infected line — is definitive and frequently the missing step in scenarios. The CEN throughline: recognize sepsis early, execute the time-critical bundle, and don't flood a fluid-unresponsive vasoplegic patient when the unaddressed problem is vascular tone.
Practice questions with answers & rationales
Q1. A trauma patient is hypotensive with a heart rate of 58 and warm, dry skin below the level of injury. What shock is this and why the unusual vitals?
Answer: Neurogenic shock from a high spinal-cord injury — the injury interrupts sympathetic outflow, so the vasculature can't constrict (hypotension, warm dry skin) and the heart can't mount a compensatory tachycardia (normal or slow rate). That's why it looks different from hemorrhagic shock's cold, clammy, tachycardic picture. Management involves volume and often vasopressor/chronotropic support per protocol — and recognizing 'hypotension without tachycardia after trauma' as neurogenic is the tested discrimination.
Q2. A patient with pneumonia is febrile, tachycardic, tachypneic, and confused with a lactate of 4.0 and MAP 60. What's your priority set?
Answer: Treat as sepsis/septic shock: cultures (and source identification) without delaying care, urgent broad-spectrum antibiotics, crystalloid resuscitation for the hypotension and elevated lactate, and reassessment; if MAP stays below 65 after adequate fluids, start norepinephrine. Trend the lactate as a resuscitation compass and pursue source control. Antibiotic timing and the fluid-then-pressor sequence are the most-tested elements — delay is the planted error.
Q3. Why won't a fluid bolus fix a hypotensive cardiogenic-shock patient?
Answer: Cardiogenic shock is pump failure with already-high filling pressures and pulmonary congestion; adding preload pushes the failing ventricle further up (and over) the Frank-Starling curve, worsening pulmonary edema and oxygenation without improving output. Management targets the pump (inotropic support), cautious preload/afterload management, and the cause. Crackles plus hypotension should stop the reflexive fluid bolus — distinguishing cardiogenic from hypovolemic shock is the key safety point.
Q4. A septic patient remains hypotensive after adequate fluid resuscitation. What's the next step and why not more fluid?
Answer: Start a vasopressor (norepinephrine) to maintain MAP ≥65 — persistent hypotension after adequate fluids defines the need for pressors, because the unaddressed problem in distributive shock is low vascular tone, not volume. Continuing to flood a fluid-unresponsive, vasoplegic patient risks pulmonary and tissue edema without fixing tone. Assess fluid responsiveness before more boluses, and pursue source control. Knowing when to transition from fluids to pressors is the tested judgment.
Q5. Why is hypotension considered a late, ominous sign in shock — especially in young patients?
Answer: Compensation maintains blood pressure through tachycardia and vasoconstriction until a large fraction of volume/perfusion is lost — so by the time the pressure falls, the patient is decompensating with little reserve. Young, healthy patients (and children) compensate especially well, masking serious shock behind a 'normal' pressure. The early signs — tachycardia, narrowing pulse pressure, anxiety, cool skin — are what you act on; waiting for hypotension is the trap the exam repeatedly sets.
Q6. Which shock states are mechanical problems that drugs and fluids won't fix?
Answer: Obstructive shock: tension pneumothorax (needs decompression), cardiac tamponade (needs pericardiocentesis/drainage), and massive pulmonary embolism (may need thrombolysis/embolectomy). In each, flow is mechanically blocked, so vasopressors and fluids only buy minutes — the definitive treatment relieves the obstruction. Recognizing the obstructive pattern (e.g., Beck's triad for tamponade; absent breath sounds with JVD and hypotension for tension pneumothorax) and escalating for the mechanical fix is the tested competency.
Q7. A patient stung by a bee has hives, lip swelling, wheezing, and a falling blood pressure. What's the diagnosis and the first action?
Answer: Anaphylaxis (a distributive shock) — airway/breathing involvement and hypotension after an exposure. The first action is epinephrine intramuscularly, immediately — it's the only first-line treatment, addressing the vasodilation, bronchoconstriction, and mediator release at once; antihistamines and steroids are adjuncts that never precede or replace it. Then oxygen, positioning, fluids for hypotension, and monitoring for biphasic recurrence. Delaying epinephrine for other medications is the documented fatal error the exam tests.
Common mistakes to avoid
- Waiting for hypotension to recognize shock — compensated shock (tachycardia, narrow pulse pressure, cool skin) comes first.
- Missing neurogenic shock because the heart rate isn't fast, or septic shock because the skin is warm early.
- Delaying antibiotics in septic shock, or flooding a fluid-unresponsive vasoplegic patient instead of starting a vasopressor.
- Bolusing fluids into cardiogenic shock with congestion.
- Treating obstructive shock (tamponade, tension pneumothorax, massive PE) with drugs instead of the mechanical fix.
- Sequencing antihistamines or 'monitoring' ahead of immediate epinephrine in anaphylaxis.