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Despite the advances in lung-protective strategies and cardiac assist devices, severe pulmonary and cardiac failure continue to be associated with high mortality. Acute respiratory distress syndrome (ARDS) still maintains a mortality rate as high as 30–40%, 50% for patients with cardiogenic shock.1 Patients with failing conventional or advanced methods of therapy or patients who are worsening clinically have few rescue therapy options. Early referral to an extracorporeal membrane oxygenation (ECMO) center might be the only option. This chapter will review the clinical indications, contraindications, types of ECMO, and the complications of ECMO use.
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ECMO is a term used to describe a form of partial cardiopulmonary bypass used for temporary, albeit prolonged, support of respiratory and/or cardiac function. Cardiopulmonary bypass was initially developed for use in the operating room to provide short-term cardiopulmonary support (CPS) during cardiac surgery procedures. Extracorporeal membrane oxygenation is more commonly known as and referred to by the acronym ECMO. Other names synonymous with ECMO include extracorporeal lung assist (ECLA), extracorporeal CO2 removal (ECCOR), CPS, and extracorporeal cardiopulmonary resuscitation (ECPR).
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Currently ECMO is utilized in the critical care setting for patients with acute, severe, potentially lethal but reversible respiratory or cardiac failure unresponsive to conventional medical management. It is occasionally used in patients with irreversible cardiac or respiratory disease under the circumstances that the patient is a candidate for a heart or lung transplant. In these cases, ECMO may be used as a “bridge” before or after transplantation. ECMO is reserved for patients with potentially reversible disease who are unlikely to survive with conventional medical management. It is important to remember that the primary medical indication for ECMO therapy must be a potentially reversible condition, with possibility for other treatments such as revascularization or transplant.
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ECMO was developed in the 1970s from a modification of cardiopulmonary bypass. It uses a modified heart–lung bypass machine to provide gas exchange, and systemic perfusion if necessary, which can provide pulmonary and cardiac support. Unlike standard cardiopulmonary bypass, which is used for short-term support measured in hours, ECMO can provide longer support ranging from days to weeks in the intensive care unit (ICU). Additionally, the purpose of ECMO is to compensate for further harm or allow for intrinsic recovery of the heart and lungs, unlike standard cardiopulmonary bypass, which provides support during various cardiac surgical procedures.
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ECMO functions by providing membrane oxygenation to temporarily take over the role of the lung or the heart. It provides for gas exchange while mechanical ventilation settings are adjusted to prevent a high-pressure environment. This minimizes ventilator-induced lung injury (VILI) and maximizes lung recruitment of the functional residual capacity. By providing support without reliance on mechanical ventilation for gas exchange, the native lung has time to heal and potentially recover. Additionally, some believe that the injured lung activates the release of inflammatory mediators, which may precipitate renal failure, liver failure, cardiac failure, and other systemic consequences. Release of ...