A rigorous programme of maintenance needs to be in place to ensure the pumps and other components are in perfect working order, and sufficient stocks of tubing, connectors and oxygenators are required An ECMO circuit can be primed with crystalloid fluids in advance of its use, as long as a strict aseptic technique is used This circuit can be kept in a safe area for several weeks The benefit of a primed circuit that is immediately available is obvious in case of sudden mechanical failure Failure is often not an option(back-up equipment must be available, as mechanical failure may happen even in perfectly maintained devices). Bespoke systems allow greater flexibility as only the broken component(usually the pump motor) needs replacing.