Adaptive control of peristaltic pumps during continuous venovenous hemofiltration

Continuous venovenous hemofiltration (CVVH) is a lifesaving renal replacement therapy used in clinical intensive care settings. Patients undergoing a life threatening illness often develop renal failure, and CVVH performs the blood filtering process while the kidneys recover. The open-loop fluid flow induced by the peristaltic pumps utilized in CVVH cannot provide the fluid balance accuracy necessary to treat neonates. The paper presents a hierarchical control architecture for CVVH. The control methodology uses a direct adaptive control scheme for the peristaltic pumps and a supervisory control algorithm for high-level decisions on the safe operation of the system. Adaptive control of the pumps results in improved accuracy of fluid flow, while the supervisory controller provides greater autonomy and reduces the burden on clinical personnel. The performance of the proposed hierarchical controller is illustrated by experiments on a hemofiltration machine using a simulated patient.