A. McGeorge

Extracorporeal Membrane Oxygenation for Treating Severe Cardiac and Respiratory Failure in Adults: Part 2: Technical Considerations

i a N THIS SECOND OF 2 articles on the use of extracorporeal membrane oxygenation (ECMO) for treating severe cardiac nd respiratory failure in adults, the physiology, technical coniderations, and complications of this technique are reviewed. lthough ECMO remains a technically and logistically deanding undertaking, recent advances in the design of circuit omponents, particularly the oxygenator, have improved the ase of use and durability of the technique, such that extracororeal support can be maintained relatively safely for several eeks.

Venovenous Extracorporeal Membrane Oxygenation in Adults: Practical Aspects of Circuits, Cannulae, and Procedures

NTEREST IN extracorporeal membrane oxygenation (ECMO) for treating severe respiratory failure in adults has increased substantially in the last 5 years. There are several reasons for this increase. The first reason is the publication of the CESAR study in 2009, which showed improved survival in adults with severe acute respiratory distress syndrome (ARDS) randomized to consideration of ECMO compared with patients treated conventionally.1 Second is the H1N1 influenza pandemic of 2009 and 2010, which resulted in a substantial increase in the use of ECMO for treating severe respiratory failure. 2 The outcome from ECMO in this group of patients was excellent, with reported survival rates of 68% to 77%. 3-5 The third factor has been improvements in the equipment used for ECMO; in particular, the introduction of polymethylpentene (PMP) oxygenators, second-generation centrifugal pumps, and cannulae specifically designed for ECMO. Finally, ECMO increasingly is being used for patients undergoing surgical correction of critical airway obstruction (eg, tracheal papilloma).6,7 There are 2 basic forms of ECMO: venoarterial (VA) and venovenous (VV). VA ECMO supports the lungs and the heart (left and right ventricles), whereas VV supports the lungs only. In adults, VA ECMO is used for treating acute cardiac and cardiorespiratory failure. For acute cardiac failure, ECMO may be used instead of a ventricular assist device (VAD), as a bridging technique either to recovery or to a long-term VAD. Historically, VA ECMO also was used for treating respiratory failure in adults 8 and is still used commonly for treating neonatal respiratory failure. 2 However, VV ECMO is now the preferred mode of extracorporeal support for adults with ARDS because it avoids 2 important disadvantages associated with VA ECMO: the need for arterial cannulation and upper-body hypoxemia. Upper-body hypoxemia occurs in patients with respiratory failure but good cardiac function who are supported with peripheral VA ECMO in which the arterial cannula is placed in the femoral artery. Oxygenated blood from the ECMO circuit perfuses the lower body, but deoxygenated blood, passing through the nonfunctioning lungs and ejected from the left ventricle, perfuses the upper body (coronary arteries and cerebral circulation).

Use of Extracorporeal Membrane Oxygenation during Resection of Tracheal Papillomatosis

WE present two cases of the use of veno-venous extracorporeal membrane oxygenation (VV-ECMO) during resection of obstructing tracheal papillomata. Conventional anesthesia techniques may be unsafe with near obstructing papillomatous disease of the trachea. The advantage of ECMO in this circumstance is that gas exchange can be totally supported for the duration of the procedure while at the same time providing an apneic unobstructed surgical field. There are reports of the use of ECMO during surgery for tracheal obstruction and resection in neonates and children, but to our knowledge this is the first account of its use in adults.

Extracorporeal membrane oxygenation for cardiorespiratory failure in four patients with pandemic H1N1 2009 influenza virus and secondary bacterial infection

We report four patients with pandemic H1N1 2009 influenza virus and secondary bacterial infection who were treated with extracorporeal membrane oxygenation (ECMO) for cardiorespiratory failure. Three of the four patients had profound shock, necessitating support with venoarterial ECMO. Two patients died during ECMO support. The two survivors had prolonged hospital stays, which were complicated by renal failure and limb ischaemia.

Cardiac Transplantation and Aortic Coarctation Repair in Severe Heart Failure

A 37-year-old man presented with severe dilated cardiomyopathy secondary to occult aortic coarctation. He was successfully managed with combined orthotopic heart transplantation and aortic coarctation repair.