In vitro characterization and performance testing of the Ension pediatric cardiopulmonary assist system

In the last 40 years, mechanical circulatory support devices have become an effective option for the treatment of end-stage heart failure in adults. Few possibilities, however, are available for pediatric cardiopulmonary support. Ension Inc. (Pittsburgh, PA) is developing a pediatric cardiopulmonary assist system (pCAS) intended to address the limitations of existing devices used for this patient population. The pCAS device is an integrated unit containing an oxygenator and pump within a single casing, significantly reducing the size and blood-contacting surface area in comparison to current devices. Prototype pCAS devices produce appropriate flows and pressures while minimizing priming volume and preparation time. The pCAS was tested on a mock circulation designed to approximate the hemodynamic parameters of a small infant using a 10-Fr. extracorporeal membrane oxygenation inflow cannula and an 8-Fr. extracorporeal membrane oxygenation outflow cannula. Revision 4 of the device provided a flow rate of 0.42 L/min at 6,500 RPM. Revision 5, featuring improved impeller and diffuser designs, provided a flow rate of 0.57 L/min at 5,000 RPM. The performance tests indicate that for this cannulae combination, the pCAS pump is capable of delivering sufficient flows for patients <5 kg.