The extracorporeal life support (ECLS) allows a maximum of a few weeks of cardio-respiratory assistance. Using standard ECLS, the circuit must be replaced after a few days or sometimes more frequently, in case of dysfunction. Classically, the replacement needs the interruption of the support inducing a temporarily hemodynamic instability. We report a simple technique, allowing this replacement without interruption of the assistance, based on the implantation of a new circuit in parallel. We describe the original modification, the complete procedure and our results. This method has been used in 34 ECLS replacements in 14 patients without any incident or thrombo-embolic events. This simple technique is safe, reliable, and avoids the hemodynamic instability induced by classical replacements.