#### Summary points Extracorporeal life support (ECLS) is a variation of cardiopulmonary bypass. Whereas cardiopulmonary bypass facilitates open heart surgery for a number of hours, extracorporeal life support maintains tissue oxygenation for days to weeks in patients with life threatening respiratory or cardiac failure (or both). As technology advances, indications increase, and the numbers of specialist centres rise, more doctors are likely to find themselves assessing patients for early referral, discussing this support option with relatives, directly or indirectly managing patients on extracorporeal life support, and providing follow-up outpatient and community based care. During the recent H1N1 influenza A pandemic, one third of patients admitted to the intensive care unit with severe respiratory failure required extracorporeal life support.1 Evidence from case series, cohort studies, registry database analyses, and randomised controlled trials form the basis of this overview. #### Sources and selection criteria We searched PubMed, Embase, and the Cochrane Library for systematic reviews, randomised trials, large population based studies, case controlled studies, case series, scientific and clinical reviews, evidence based guidelines, and published consensus statements between 1996 and 2010. We used the search terms “extracorporeal membrane oxygenation”, “extracorporeal circulation”, and “extracorporeal life support”. We also consulted the registry database of the Extracorporeal Life Support Organization, personal databases, reference collections, and contemporary …