Extracorporeal membrane oxygenation in adults.

SUMMARY This paper is the summation of five years' work studying clinical and economic outcomes comparing the use of extracorporeal membrane oxygenation (ECMO) and conventional medical care to treat severe respiratory failure. Extracorporeal membrane oxygenation is an intervention, which, like cardiac bypass, can support a failing myocardium when used in a veno-arterial mode. This trial, Conventional ventilation or ECMO for Severe Adult Respiratory failure (CESAR), studied pulmonary support alone, using ECMO in the veno-venous mode. Peek and colleagues screened 766 patients with respiratory failure between July 2001 and August 2006. A significant number were excluded, the most significant factors being ECMO bed availability, an inappropriate lung injury score (LIS) or difficult ventilation for greater than seven days. A total of 180 subjects were enrolled; 90 were randomised to the treatment limb and 90 to the conventional medical care limb. The primary outcomes studied were death or significant disability at six months post-randomisation. A holistic range of secondary outcome measures were also studied. In an intention-to-treat analysis the primary outcome of death or severe disability (37% vs 53%) did reach statistical significance, despite some missing data relating to disability status in the conventional treatment limb. On further analysis mortality outcomes alone, without inclusion of disability scoring, at six months in the treatment vs conventional limbs (37% vs 45%, p=0.07), did not reach statistical significance. Better outcomes were demonstrated in the treatment group despite only 76% of those randomised and transferred to a specialist centre actually receiving ECMO. The other 24%, if they had not died prior to arrival at the treatment centre, received only conservative management strategies that would be available in most intensive care units. The study group therefore recommend the transfer of adult patients with acute severe respiratory failure to a centre with the ability to initiate an ECMO-based management protocol. OPINION Extracorporeal membrane oxygenation is not a new technique. Indeed, it has become accepted in neonatal medical practice as a standard of care. In the UK, an ECMO service is provided by six centres registered with the Extracorporeal Life Support Organisation (ELSO). Only one, Glenfield Hospital in Leicester, currently provides a service for adult patients. As such, the CESAR study was in essence a single-centre trial, despite individual control patients receiving care in their referring intensive care unit (ICU). Blinding was impossible as all ECMO-randomised patients were transferred to a single site. An inherent degree of bias cannot …