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Extracorporeal membrane oxygenation (ECMO) is a form of modified cardiopulmonary bypass that has evolved since the beginnings of bypass in the 1950s.1 It can be used for days to weeks to support patients with severe cardiac or respiratory failure. Since the first successful use of ECMO in the 1970s, several developments have been made related to cannulation strategies and machinery. However, several topics related to ECMO remain controversial and ill defined, including patient selection (“ECMO candidacy”), timing of ECMO initiation, and proper anticoagulation.2


Although the Extracorporeal Life Support Organization (ELSO) and several other groups have attempted to standardize guidelines for patient selection, no set of inclusive guidelines exists. General guidelines for patient selection can be found on the ELSO website or within the text published by the organization.3

Despite the lack of inclusive guidelines, patients who are admitted to the pediatric intensive care unit or cardiac intensive care unit with respiratory failure, cardiac failure, or high likelihood of sudden cardiac death should be assessed for ECMO candidacy early in their hospital course. This status may change as patient disease status and chance of survival changes. Patient selection and timing of initiation of ECMO will generally depend on the expertise and experience of individual centers.2


  • Acute, reversible disease

  • Respiratory and/or cardiac failure

  • Postoperative cardiac surgery patient with inability to separate from mechanical circulatory support/cardiac bypass

  • Weight >2.0 kg

  • Gestational age >35 weeks


  • Intraventricular hemorrhage > grade II in neonates or intracranial hemorrhage in older children

  • Irreversible disease state

    • Defining irreversible conditions may be difficult

  • Fatal congenital diseases


In general, two basic modes of ECMO exist, and they are defined by their site of cannula placement: venoarterial (VA) or venovenous (VV). Although a few physiologic differences exist between the two modes, the basic principles and circuit design are similar.2 Sites of cannulation, advantages, and disadvantages can be seen in Table 25-1.

TABLE 25-1

Modes of ECMO: Venoarterial versus Venovenous

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