Reference — Emergency Nursing
Shock Types Reference
Quick reference for the four major shock classifications — hypovolemic, cardiogenic, distributive, and obstructive — with mechanisms, common causes, clinical findings, and initial nursing priorities.
Educational use only. This content is intended for nursing students and exam preparation. Clinical decisions require licensed professional judgment and institutional protocols. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Mechanism: Inadequate circulating blood volume → reduced preload → reduced cardiac output → cellular hypoperfusion
Common Causes
- ✦Hemorrhagic: trauma, GI bleed, ruptured aortic aneurysm, ruptured ectopic pregnancy
- ✦Non-hemorrhagic: severe dehydration, burns (large surface area), severe diarrhea/vomiting, diuretic overuse, third-spacing (pancreatitis, bowel obstruction)
Hemodynamic Pattern
Clinical Findings
- ✦Tachycardia (earliest sign)
- ✦Hypotension (late sign — indicates 30–40% blood volume loss)
- ✦Decreased urine output (<0.5 mL/kg/hr)
- ✦Cool, pale, clammy skin
- ✦Increased capillary refill time (>2 sec)
- ✦Flat neck veins
- ✦Altered mental status (late)
Initial Priorities
- ✦Control hemorrhage source (tourniquet, pressure, pelvic binder)
- ✦Two large-bore peripheral IVs (16G or larger)
- ✦IV fluid resuscitation: NS or LR (crystalloid)
- ✦Blood transfusion for hemorrhagic shock — pRBCs, activate MTP if massive hemorrhage
- ✦Vasopressors only as bridge, not substitute for volume resuscitation
- ✦Treat underlying cause — surgery for internal hemorrhage
Mechanism: Pump failure → reduced cardiac output → increased preload and afterload → pulmonary edema + end-organ hypoperfusion
Common Causes
- ✦Acute MI (especially anterior STEMI with large left ventricle territory loss)
- ✦Acute decompensated heart failure
- ✦Severe cardiomyopathy (dilated, stress/Takotsubo, viral myocarditis)
- ✦Severe valvular dysfunction (aortic stenosis, acute mitral regurgitation)
- ✦Cardiac tamponade (pericardial effusion compressing ventricles)
- ✦Massive pulmonary embolism (right heart failure)
Hemodynamic Pattern
Clinical Findings
- ✦Hypotension (SBP <90 mmHg)
- ✦Tachycardia
- ✦Pulmonary edema: crackles, dyspnea, pink frothy sputum, orthopnea
- ✦JVD (jugular venous distension)
- ✦Cool, clammy, pale skin
- ✦Oliguria (renal hypoperfusion)
- ✦S3 gallop on auscultation
Initial Priorities
- ✦Cautious fluid administration — do NOT aggressively volume resuscitate (worsens pulmonary edema)
- ✦Vasopressors: norepinephrine first-line for BP support
- ✦Inotropes: dobutamine for cardiac output support
- ✦Treat underlying cause: emergent PCI for STEMI, pericardiocentesis for tamponade
- ✦Mechanical circulatory support: IABP, Impella for refractory cardiogenic shock
- ✦Continuous hemodynamic monitoring (arterial line, PA catheter in severe cases)
Mechanism: Widespread vasodilation → maldistribution of blood flow → relative hypovolemia → cellular hypoperfusion despite normal or high cardiac output
Common Causes
- ✦Septic shock (most common) — infection → inflammatory cascade → vasodilation + capillary leak
- ✦Anaphylactic shock — IgE-mediated release of histamine and mediators → massive vasodilation + bronchospasm
- ✦Neurogenic shock — spinal cord injury above T6 → loss of sympathetic tone → vasodilation and bradycardia
- ✦SIRS from non-infectious causes (pancreatitis, burns, major surgery, trauma)
Hemodynamic Pattern
Clinical Findings
- ✦Early septic: warm, flushed skin (vasodilated), fever, bounding pulse
- ✦Late septic: cool, mottled skin (vasoconstriction failure), hypotension
- ✦Anaphylaxis: urticaria, angioedema, bronchospasm, hypotension
- ✦Neurogenic: bradycardia (not tachycardia), hypotension, warm dry skin below injury level
- ✦Altered mental status, oliguria, elevated lactate (>2 mmol/L)
Initial Priorities
- ✦Septic: blood cultures before antibiotics → broad-spectrum IV antibiotics within 1 hour → 30 mL/kg crystalloid bolus → vasopressors (norepinephrine) if refractory → lactate monitoring
- ✦Anaphylaxis: IM epinephrine (0.3 mg 1:1000) thigh → remove trigger → IV diphenhydramine, methylprednisolone → airway management if stridor
- ✦Neurogenic: IV fluids for relative hypovolemia → vasopressors (norepinephrine or phenylephrine) → atropine for symptomatic bradycardia → spinal immobilization
Mechanism: Mechanical obstruction to blood flow (in or out of heart/great vessels) → reduced cardiac output → hypoperfusion despite normal volume and pump function
Common Causes
- ✦Tension pneumothorax — trapped air collapses lung + shifts mediastinum → kinks vena cava → obstructs venous return
- ✦Cardiac tamponade — fluid in pericardial sac compresses heart → can't fill → no output
- ✦Massive pulmonary embolism — clot obstructs main pulmonary artery → right heart failure → decreased left heart output
- ✦Aortic dissection — dissection flap occludes coronary or branch vessel ostia
Hemodynamic Pattern
Clinical Findings
- ✦Tension PTX: absent breath sounds one side + tracheal deviation AWAY from affected side + JVD + hypotension
- ✦Tamponade (Beck's triad): JVD + hypotension + muffled heart sounds. Pulsus paradoxus (BP drops >10 mmHg with inspiration).
- ✦Massive PE: severe dyspnea, pleuritic chest pain, hemoptysis, right heart strain on ECG (S1Q3T3 pattern), hypoxia
- ✦All types: tachycardia, hypotension, elevated CVP, oliguria
Initial Priorities
- ✦Tension PTX: immediate needle decompression (2nd ICS, MCL) → chest tube. Do NOT wait for chest X-ray if clinically evident.
- ✦Tamponade: emergent pericardiocentesis (needle aspiration of pericardial fluid). Avoid aggressive fluid loading — worsens compression.
- ✦Massive PE: systemic anticoagulation (unfractionated heparin) → thrombolytics (alteplase) for hemodynamic compromise → catheter-directed therapy or surgical embolectomy
- ✦All: treat the obstruction — volume and vasopressors are temporizing only
Related Resources
Standards & sources
Fact-checked Jun 20, 2026This page is written to align with Emergency Nurses Association (ENA) · AHA ACLS / PALS Guidelines · Advanced Trauma Life Support (ATLS). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →