Reference — Critical Care
ECMO Reference
Quick-access ECMO reference for bedside nurses — VV vs VA configuration comparison, anticoagulation targets, complications, and nursing monitoring priorities.
Educational use only. ECMO management is directed by specialized teams under strict institutional protocols; this overview supports concept review only. 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.
VV vs VA ECMO Comparison
| Feature | VV ECMO | VA ECMO |
|---|---|---|
| Support Type | Respiratory only | Cardiac + Respiratory |
| Drainage Site | Femoral vein or right IJ | Femoral vein (peripheral) or right atrium (central) |
| Return Site | Right atrium / femoral vein (venous) | Femoral artery (peripheral) or aorta (central) |
| Heart Still Works? | Yes — heart must pump normally | Partially or not — circuit replaces cardiac output |
| Primary Indication | Severe ARDS / refractory respiratory failure | Cardiogenic shock, cardiac arrest (eCPR), post-cardiotomy failure |
| Typical ECMO Flow | 3–5 L/min | 4–6 L/min |
| Recirculation Risk | Yes — oxygenated blood may re-enter drainage cannula | No (different vascular compartments) |
| Harlequin Syndrome Risk | No | Yes — upper body may receive hypoxic blood from native cardiac output |
| Limb Ischemia Risk | Low | High (femoral artery return cannula); requires distal perfusion catheter |
| LV Distension Risk | No | Yes — retrograde flow increases LV afterload; may need LV venting |
| Anticoagulation | Heparin; ACT 180–220 sec (varies by protocol) | Heparin; ACT 180–220 sec (varies by protocol) |
ECMO Indications
VV ECMO
- ›Severe ARDS (P/F ratio <80 on optimal vent settings)
- ›Refractory hypoxemia despite lung-protective ventilation
- ›CO₂ retention / respiratory acidosis unresponsive to vent
- ›Bridge to lung transplantation
VA ECMO
- ›Cardiogenic shock refractory to medical therapy
- ›Refractory cardiac arrest (eCPR) with reversible cause
- ›Massive PE with hemodynamic collapse
- ›Post-cardiotomy failure (unable to wean from bypass)
- ›Fulminant myocarditis
- ›Bridge to heart transplantation or LVAD
Anticoagulation Monitoring
| Test | Typical Target | Frequency | Notes |
|---|---|---|---|
| Activated Clotting Time (ACT) | 180–220 seconds (varies) | Every 1–2 hours | Point-of-care test; bedside availability critical for rapid titration |
| aPTT | 60–80 seconds (varies) | Every 4–6 hours | Lab-based; used alongside or instead of ACT depending on protocol |
| Anti-Xa | 0.3–0.5 units/mL | Per protocol (often q6–12h) | More specific for heparin effect; used at some institutions |
| Platelet Count | >80,000/µL (varies) | Daily | Low platelets increase bleeding risk; watch for HIT (drop >50% from baseline) |
| Fibrinogen | >150–200 mg/dL | Daily or per protocol | Low fibrinogen = consumptive coagulopathy; may need cryoprecipitate |
Complications Quick Reference
| Complication | Type | Clinical Signs | Nursing Response |
|---|---|---|---|
| Bleeding | Both | Cannula site oozing, hemodynamic instability, falling Hgb | Pressure at sites; adjust anticoagulation per order; transfuse per protocol; notify provider |
| Limb Ischemia | VA (peripheral) | Cool, pale, pulseless distal extremity; poor Doppler signal | Notify provider STAT; check distal perfusion catheter; emergent vascular surgery consult |
| Harlequin Syndrome | VA (peripheral) | Right radial SpO₂ < left pedal SpO₂; upper body cyanosis | Compare bilateral oximetry; notify provider; optimize lung recruitment; ECMO flow adjustment |
| Circuit Thrombosis | Both | Dark clot visible in circuit; high circuit pressures | Notify provider and perfusionist; prepare for emergent circuit change; do not return blood if clot large |
| Air Embolism | Both | Visible air in circuit; sudden hemodynamic collapse | Immediately clamp circuit; Trendelenburg; notify provider STAT; do not return blood |
| Stroke | Both (higher VA) | New focal neuro deficit, unequal pupils, decreased LOC | Neuro assessment; notify provider; emergent imaging |
Related Resources
Standards & sources
Fact-checked Jun 20, 2026This page is written to align with Society of Critical Care Medicine (SCCM) · Surviving Sepsis Campaign · American Association of Critical-Care Nurses (AACN). 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 →