Extracorporeal membrane oxygenation as "bridge" to lung transplantation: what remains in order to make it standard of care?

Since its introduction into clinical practice, lung transplantation (LTx) is gradually becoming a worldwide standard treatment for patients with a broad spectrum of end-stage respiratory diseases (1–3). From 1995 to 2010, more than 30,000 LTx have been performed, and it is worth noting that in recent years the number of LTx has been progressively increasing to more than 3,000/year in 2010, with a post-transplant graft half-life that went from 4.7 in the 1990s to 5.9 in the new millennium (4). However, the crude mortality rate of patients awaiting LTx is higher than mortality for other solid organs. Mortality rate in 2009 for patients on the waiting list for LTx was about 14.1% in North America (www.srtr.org) and 14.7% in Italy (www.airt.it). What are the reasons for these unacceptable mortality rates? First, patients have to wait for the graft longer than patients waiting for other organs because of the small number of lungs suitable for transplantation (5). Second is the lack of supportive therapies that are able to replace respiratory function when the primary pulmonary diseases evolve from “respiratory insufficiency” to “respiratory failure,” characterized by refractory hypoxemia and hypercapnia.