Shock Nursing Guide 2026
⚕️ Medical Disclaimer: This content is for educational purposes only and is intended for licensed healthcare professionals. It does not constitute medical advice and should not replace clinical judgment, facility protocols, or physician orders. Always verify medications, doses, and procedures with your institution's guidelines.
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All four shock types, hemodynamic profiles, vasopressor selection, fluid resuscitation targets, and clinical recognition — from bedside assessment to ICU management.
1. What Is Shock?
Shock = life-threatening circulatory failure resulting in inadequate oxygen delivery to meet metabolic demand. The result is cellular hypoxia, anaerobic metabolism, lactic acidosis, and eventually multi-organ failure if not reversed.
Key formula: DO2 (oxygen delivery) = CO × CaO2. Shock occurs when DO2 falls below critical threshold or VO2 (consumption) increases beyond delivery capacity.
2. Four Types of Shock
| Shock Type | Mechanism | CO | SVR | PCWP | Classic Example |
|---|
| Hypovolemic | Decreased preload from volume loss | Low | High (compensatory) | Low | Hemorrhage, severe dehydration, burns, DKA |
| Cardiogenic | Heart pump failure → decreased CO | Low | High (compensatory) | High (backed up) | STEMI, decompensated HF, massive PE (also obstructive), cardiac tamponade |
| Distributive | Massive vasodilation → low SVR despite normal/high CO | High (initially) | Low | Low/normal | Septic shock, anaphylactic shock, neurogenic shock |
| Obstructive | Physical obstruction to blood flow | Low | High | Variable | Massive PE, cardiac tamponade, tension pneumothorax |
Hemodynamic memory trick:
Hypovolemic: Low everything (CO, PCWP) + high SVR (body squeezing to compensate)
Cardiogenic: Low CO + high PCWP (fluid backs up) + high SVR (compensatory)
Distributive/Septic: High CO + low SVR (vasodilated) = warm, flushed skin early
Obstructive: Low CO + variable filling pressures depending on type
3. Hemodynamic Parameters (Swan-Ganz / PA Catheter)
| Parameter | Normal Range | Clinical Use |
|---|
| CO (Cardiac Output) | 4–8 L/min | Direct measure of pump function |
| CI (Cardiac Index = CO/BSA) | 2.4–4.0 L/min/m² | CO indexed to body size; <2.2 = cardiogenic shock |
| SVR (Systemic Vascular Resistance) | 800–1,200 dynes/sec/cm-5 | Afterload; low = distributive; high = hypovolemic/cardiogenic |
| PCWP (Pulmonary Capillary Wedge Pressure) | 8–12 mmHg | Estimates LV preload/filling; >18 = volume overload/LV failure |
| CVP (Central Venous Pressure) | 2–8 mmHg | RV preload estimate; less accurate than PCWP for LV status |
| MAP (Mean Arterial Pressure) | 70–100 mmHg | Goal ≥65 in shock; ≥70–80 in septic with prior hypertension |
| ScvO2 (Central venous O2 sat) | ≥70% | <70% = tissues extracting more O2 than normal = inadequate delivery |
| Lactate | <2 mmol/L | Marker of anaerobic metabolism; >4 = severe shock; serial trending guides resuscitation |
4. Universal Shock Recognition
Classic shock signs (mnemonic: "5 Ps of Shock"):
- Pressure: Hypotension (SBP <90 or MAP <65 mmHg)
- Pulse: Tachycardia (>100 bpm; may be bradycardic in neurogenic shock)
- Perfusion: Cool/clammy skin (in hypovolemic/cardiogenic); warm/flushed early in septic
- Pallor: Pallor, mottling, cyanosis of extremities
- Pee: Oliguria (UO <0.5 mL/kg/hr) — one of earliest reliable signs
- Plus: Altered mental status (agitation early, confusion, stupor later); lactate rise
5. Hypovolemic Shock
Hemorrhagic Shock (ATLS Classification)
| Class | Blood Loss | HR | BP | UO (mL/hr) | Mental Status |
|---|
| I | <750 mL (<15%) | Normal | Normal | ≥30 | Normal/slightly anxious |
| II | 750–1,500 mL (15–30%) | 100–120 | Normal/orthostatic | 20–30 | Mildly anxious |
| III | 1,500–2,000 mL (30–40%) | 120–140 | Decreased | 5–15 | Confused |
| IV | >2,000 mL (>40%) | >140 or bradycardia | Very low | Negligible | Lethargic/coma |
Hypovolemic Shock Treatment
- Stop the source of bleeding (tourniquet, pressure, surgical control)
- IV access: 2 large-bore (16g+) IVs; IO if no IV access
- Crystalloid resuscitation: LR preferred over NS (hyperchloremic acidosis with large NS volumes); 1–2 L rapid infusion
- Blood products: PRBCs, FFP, platelets in 1:1:1 ratio for massive transfusion (trauma)
- Permissive hypotension in penetrating trauma (before surgical control): target SBP 80–90 to reduce coagulopathy; do NOT in TBI or blunt trauma with concern for brain injury
- Vasopressors: generally avoid until volume-resuscitated; if needed as bridge → norepinephrine
6. Cardiogenic Shock
Heart cannot pump adequate CO despite adequate preload. Mortality ~30–50% even with early PCI.
Presentation
- SBP <90 mmHg or MAP <60, despite adequate filling
- Signs of poor perfusion: cool extremities, oliguria, AMS
- Signs of congestion: crackles, JVD, S3 gallop
- Low CI (<2.2 L/min/m²) + high PCWP (>15) on PA catheter
Treatment
- Treat underlying cause: primary PCI for STEMI-related cardiogenic shock (emergent revascularization is primary treatment)
- Inotropes: dobutamine (first-line for inotropy without BP support needed) or milrinone; both increase contractility and reduce afterload
- Vasopressors: norepinephrine if also hypotensive (dopamine associated with worse outcomes vs NE)
- Mechanical circulatory support: IABP (intra-aortic balloon pump), Impella, ECMO for refractory cardiogenic shock
- Avoid: aggressive fluid boluses (worsens congestion), high-dose vasopressors without inotropes
7. Distributive Shock
Septic Shock
Most common distributive shock. Vasodilation from inflammatory mediators → low SVR → hypoperfusion despite high CO. See Sepsis Nursing Guide for full management.
- MAP goal ≥65 mmHg (higher in patients with chronic hypertension or TBI)
- Fluid resuscitation: 30 mL/kg IV crystalloid within 3 hr
- Vasopressor if MAP <65 after adequate fluids: norepinephrine is first-line
- Vasopressin 0.03 units/min added second (saves catecholamine dose)
- Antibiotics within 1 hour
Anaphylactic Shock
Anaphylaxis treatment: Epinephrine FIRST — every time, no exceptions
- Epinephrine 0.3–0.5 mg IM (1:1,000) into lateral thigh — give immediately, repeat q5–15 min PRN
- Call for help; position: supine + legs elevated (if no respiratory distress)
- IV access and normal saline bolus 1–2 L
- Supplemental O2; prepare for intubation (airway edema)
- Diphenhydramine (Benadryl) 25–50 mg IV/IM — antihistamine (H1 blocker); helps symptoms but does NOT replace epinephrine
- Ranitidine or famotidine — H2 blocker
- Methylprednisolone 125 mg IV — helps prevent biphasic reaction (occurs 1–72 hr later)
- Glucagon 1–5 mg IV for patients on beta-blockers (refractory anaphylaxis — bypasses beta-blockade)
- Remove trigger (stop offending medication, remove stinger)
- Observe × 4–8 hr minimum; 24 hr if severe (biphasic reaction risk)
Neurogenic Shock
Spinal cord injury above T6 → loss of sympathetic tone → vasodilation + bradycardia (classic: hypotension + bradycardia without tachycardia — distinguishes from hypovolemic shock). Warm, dry extremities (loss of vasoconstriction). Treatment: IV fluids + vasopressors (norepinephrine or phenylephrine); atropine for symptomatic bradycardia.
8. Obstructive Shock
Tension Pneumothorax
Tension pneumothorax = clinical diagnosis — treat before CXR
Signs: hypotension + tachycardia + absent breath sounds (affected side) + tracheal deviation AWAY from affected side + JVD. Treatment: immediate needle decompression — 14–16g needle, 2nd intercostal space, midclavicular line → then chest tube.
Cardiac Tamponade
Beck's Triad: Hypotension + JVD (elevated CVP) + muffled heart sounds. Pulsus paradoxus: SBP drops >10 mmHg with inspiration (pathological sign of tamponade). Echocardiography: pericardial effusion + RV collapse. Treatment: emergency pericardiocentesis or surgical drainage (pericardial window). Bridge: IV fluids to maintain preload (RV is preload-dependent).
9. Vasopressor Reference
| Vasopressor | Receptors | Effect | First-Line For |
|---|
| Norepinephrine (Levophed) | Alpha-1 + Beta-1 | Vasoconstriction + mild inotropy; increases SVR and MAP | Septic shock (first-line); distributive shock of any cause |
| Vasopressin (Pitressin) | V1 receptor | Vasoconstriction (non-catecholamine); fixed dose 0.03–0.04 units/min | Add-on second vasopressor to spare catecholamine doses in septic shock |
| Phenylephrine (Neo-Synephrine) | Pure alpha-1 | Pure vasoconstriction; no inotropy; may cause reflex bradycardia | Vasodilatory shock without tachycardia; neurogenic shock; anesthesia-induced hypotension |
| Epinephrine | Alpha-1 + Beta-1 + Beta-2 | Inotropy + vasoconstriction + bronchodilation; raises HR and contractility significantly | Anaphylaxis (first-line IM); cardiac arrest (ACLS); refractory septic or cardiogenic shock |
| Dopamine | Dose-dependent | Renal at low doses (unproven benefit); beta-1 at medium; alpha-1 at high | Generally avoided; historically used for septic/cardiogenic shock |
NCLEX High-Yield Shock Points
- Four types: Hypovolemic / Cardiogenic / Distributive / Obstructive
- Distributive/septic: warm flushed skin early (vasodilated); high CO, low SVR
- Cardiogenic: cool clammy skin; low CO, high SVR, high PCWP
- Universal shock goal: MAP ≥65 mmHg; UO ≥0.5 mL/kg/hr
- Anaphylaxis first drug: epinephrine 0.3 mg IM (lateral thigh) — not diphenhydramine first
- Neurogenic shock: hypotension + bradycardia (NOT tachycardia) + warm extremities
- Beck's triad (tamponade): hypotension + JVD + muffled heart sounds
- Tension pneumothorax: tracheal deviation AWAY from affected side; treat with needle decompression
- First-line vasopressor for septic shock: norepinephrine
- Hemorrhagic shock Class III: blood loss 30–40% → hypotension + tachycardia + confusion
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