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KEY POINTS

KEY POINTS

  1. Extracorporeal membrane oxygenation (ECMO) can provide cardiac/cardiopulmonary support via venoarterial (VA) ECMO or pulmonary support via venovenous (VV) ECMO.

  2. The indications typically being bridge to recovery, bridge to transplant, or bridge to decision.

  3. Early use of ECMO showed poor response leading to a loss of interest in ECMO as a potential therapeutic modality, reappraisal of early results suggests patient selection, and technological limitations precluded successful results.

  4. The results of the CESAR trial and H1N1 experience along with technological improvements and a general improvement in the care of critically ill patients have led to renewed interest in the use of ECMO.

  5. Modification of cannulation options either at central or at peripheral locations can affect unloading of the heart as well as impacting the ability to oxygenate the cardiac and cerebral circulations.

  6. Improvement in skill of critical care ultrasonography by intensivists has allowed cannulation to move from the operating room and catheterization laboratory to the bedside for VV ECMO and peripherally cannulated VA ECMO.

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is a form of partial heart–lung bypass for patients with severe but potentially reversible respiratory and/or cardiac disease who have failed conventional therapies. There are 2 basic types of ECMO: venovenous (VV), which provides the support for the lung only, and venoarterial (VA), which provides support for both heart and lung. In both modalities, blood drained from the venous system is oxygenated outside the body. VA ECMO is similar to standard cardiopulmonary bypass in that both lungs and heart are bypassed. The purpose of ECMO is to allow time for intrinsic recovery of the lungs and/or the heart, also known as salvage therapy. It can also be used as a bridge to destination therapy such as patients waiting for heart/lung transplant or in certain instances as bridge to decision. During VV ECMO, gas exchange can be supported even in the absence of any pulmonary function but no direct cardiac support is provided. However, the cardiac functions often improve owing to increased oxygen delivery to the heart and concurrently reduced mechanical ventilation. In VA ECMO,

HISTORY OF ECMO

ECMO utilization in adults with respiratory failure dates back to 1970s. A multicenter trial evaluating prolonged venoarterial (VA) ECMO for patients with severe acute respiratory failure failed to show reduction in mortality (> 90% mortality in both groups).1 The study was later criticized for several reasons such as premature closure, lack of established ECMO experience in some centers, exclusive use of VA ECMO, extensive blood loss during the procedure, and lack of “lung rest” ventilator settings among ECMO patients.2 ECMO regained cautious attention in the 1990s after several trials showed successful application in neonates and children.3,4,5 In an uncontrolled study by Gattinoni and colleagues, venovenous (VV) ECMO improved survival in patients with acute respiratory failure while keeping lungs “at rest” (actual mortality 51.2% vs expected ...

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