Design of a novel fluid management device for use in a pediatric ECMO-CVVH setup
Problem definition:
Failure of the cardiac or respiratory system is a common problem in the pediatric and neonatal intensive care unit. When conventional management fails to improve the child’s condition, extracorporeal life support such as extracorporeal membrane oxygenation (ECMO) can serve to provide life-saving temporary heart and lung support. Studies have suggested that the addition of a renal replacement therapy such as continuous venovenous hemofiltration (CVVH) on ECMO can significantly improve fluid balance but use of this approach is hampered by potentially inaccurate fluid delivery/drainage by current intravenous fluid pumps, creating potential for excessive fluid removal and undesired degrees of dehydration.
Fig. 1: Schematic of a typical ECMO-CVVH loop
Objective:
In an effort to promote aggressive fluid management and improve outcomes in critically ill children on ECMO by the use of CVVH, this project aims at developing a novel automated and accurate fluid management system. The new device employs a conservation of volume approach to limit the inaccuracies observed in typical IV pumps.
Approach:
The novel fluid management system is based on a conservation of volume approach, is compact and easy to use. The achievement of a perfect fluid balance between the ultrafiltrate removal and the replacement fluid delivery is achieved via a double-syringe pump system driven by a unique linear positioner. The achievement of a negative fluid balance necessary to treat patients with fluid overload is realized via a second syringe pump that decreases the fluid replacement delivery flowrate with respect to that of the ultrafiltrate removal.
Fig. 2: Principles of the novel fluid management system: a) step 1: ultrafiltrate drainage and fluid replacement delivery; and b) step 2: replacement fluid chamber refill and ultrafiltrate chamber drainage into storage bag.
Fig. 3: CAD rendering of the new accurate CVVH system: a) front panel; and b) rear panel.
