Extracorporeal membrane oxygenation

Overview

Veno-arterial (VA) ECMO for cardiac or respiratory failure.
Veno-venous (VV) ECMO for respiratory failure.
  • Abbreviation: ECMO
    • Extracorporeal life support (ECLS) becoming a more common term
  • Extracorporeal circuit that oxygenates blood and removes carbon dioxide (functions as an out-of-body lung)
    • Can be high flow or low flow
  • Similar (but not identical) to cardiopulmonary bypass machine
    • Requires lower levels of anticoagulation and allows longer duration of treatment (time on pump)
  • Emerging therapy in Emergency Medicine (eCPR) but not yet well studied in this context

Types

  • Veno-venous (VV)
    • Most common
    • Blood drained from central vein → oxygenator → vein near RA
    • Supports severe respiratory failure without cardiac dysfunction
  • Veno-arterial (VA): can be peripheral or central
    • Blood drained from central vein → oxygenator → aorta
    • Supports cardiac failure with or without respiratory failure
  • Veno-pulmonary artery
    • Blood drained from central vein → oxygenator → pulmonary artery
    • Short term right ventricular/respiratory support after LVAD placement
  • Hybrid (VVA or VAV)

Indications

  • Acute, severe respiratory or cardiac failure + REVERSIBLE cause + refractory to usual treatment + high risk of death
    • Poor gas exchange
    • Compliance < 0.5ml/cmH20/kg
    • P:F Ratio <100
    • Shunt fraction >30%
  • Veno-venous (VV)
  • Veno-arterial (VA)
    • Massive PE, nonischemic cardiogenic shock, failure of transplanted heart or heart-lung, cardiac or great vessel trauma, massive pulmonary hemorrhage/trauma, sepsis, anaphylaxis, drug overdose, bridge to LVAD

Contraindications

  • Absolute
    • unwitnessed cardiac arrest
    • non-reversible, progressive cardiac disease in a patient who is not a transplant candidate
    • non-reversible, progressive respiratory disease
    • severe, chronic pulmonary hypertension
    • advanced cancer
  • Relative
    • older than 75 years
    • multisystem trauma
    • CNS injury
    • multiple organ failure
  • VV
    • unsupported cardiac failure, cardiac arrest, severe pulmonary hypertension, significant immunosupression
  • VA
    • Aortic dissection or severe aortic regurgitation

Equipment Needed

Procedure

Complications

  • Clot formation
  • Bleeding
  • Suck down and kicking (vessel collapse around access cannula)
  • Circut rupture, deccannulation, oxygenator failure, pump failure
  • VA can → left ventricle overdistension → cardiac damage, pulmonary bleed or infarction, aortic thrombosis, cardiac or cerebral hypoxia
  • North-South syndrome (cephalad hypoxia/cyanosis) may occur in patients with femoral-femoral cannulation for VA support

See Also

External Links

References