The use of extracorporeal life support (ECLS) is considered in children who (1) have an acute life-threatening heart or lung disease, (2) are normal before the illness and are likely to be normal if they survive, and (3) have an 80% chance of death. Our use of a constrained vortex pump (CVP) offers a number of potential advantages compared to a roller pump. The circuit is designed to provide the capability of changing over to a new circuit while maintaining full support and is primed to match the biochemistry of the patient as closely as possible. Since May 1989 at the Royal Children's Hospital, Melbourne, Australia, we have provided ECLS to 30 neonates (20 of whom survived) and 22 children (eight of whom survived). ECLS is a useful technique for supporting patients who are unable to be adequately ventilated or oxygenated or who have an inadequate cardiac output.