Patent ID: 6638477
Filing Date: 2003-10-28
Classification: A61M

Abstract:
A fluid replacement system, comprising:a hemofilter that removes waste fluid from blood; a chamber including an interior wall dividing the chamber into a first compartment to retain a volume of waste fluid and a second compartment to retain a volume of replacement fluid, the interior wall responding to differential fluid pressure to displace waste fluid from the first compartment as replacement fluid is conveyed into the second compartment and vice versa, a waste line to conduct waste fluid from the hemofilter, a first pump assembly communicating with the waste line and the first compartment, a second pump assembly communicating with a source of replacement fluid and the second compartment, a third pump assembly communicating with the waste line and the first compartment in at a location upstream of the first pump assembly, and a controller coupled to the first, second, and third pump assemblies, being operable in a first cycle, during which the first and second pump assemblies are operated to convey a volume of waste fluid into the first compartment to displace a volume of replacement fluid from the second compartment, the controller also being operable in a second cycle, during which the first and second pump assemblies are operated to convey a volume of replacement fluid into the second compartment to displace a volume of waste fluid from the first compartment, the controller being selectively operable during the first and second cycles to operate the third pump assembly in a bolus mode, during which a volume of waste fluid is recirculated from the first compartment into the waste line to displace replacement fluid from the second compartment while limiting removal of additional waste fluid by the hemofilter.