The process of having your blood sucked out of your body and forced through a gas-enriched sponge is neither effortlessly self-sustaining nor consequence-free. One can predict that some sort of complications might arise, and some sort of monitoring and maintenance might be required.
Additionally, some other factors play a major role, even though they are not specific to the ECMO scene:
Many thanks to Veronique B.(you know who you are) for enhancing the quality of this article by identifying some errors in it, and bringing them to my attention.
www.elso.org is the home of the Extracorporeal Life Support Organisation, and they offer an international standard in the form of guidelines, a Specialist Training Manual, and the famous Red Book (which is actually bright red).
Allen, Steve, et al. "A review of the fundamental principles and evidence base in the use of extracorporeal membrane oxygenation (ECMO) in critically ill adult patients." Journal of intensive care medicine 26.1 (2011): 13-26.
The Royal Adelaide Hospital ICU ECMO Guidelines are an excellent resource
Wildschut, E. D., et al. "Determinants of drug absorption in different ECMO circuits." Intensive care medicine 36.12 (2010): 2109-2116.
Mulla, Hussain, et al. "Drug disposition during extracorporeal membrane oxygenation (ECMO)." Paediatric and Perinatal Drug Therapy 4.3 (2001): 109-120.
Shekar, Kiran, et al. "Sequestration of drugs in the circuit may lead to therapeutic failure during extracorporeal membrane oxygenation." Critical Care16.5 (2012): R194.