Patent ID: 9636445
Date: 2017-05-02
CPC Classifications: A61M

Claim:
1. An ambulatory ultrafiltration device for connection to the vascular system of a subject, comprising: a blood filter having a blood side configured for fluid communication with the vascular system of the subject, an ultrafiltrate side configured for fluid communication with a receptacle for receiving ultrafiltrate, and a semipermeable membrane disposed between the blood side and the ultrafiltrate side; a blood pump including a membrane chamber which defines a blood side and a drive fluid side separated by a flexible membrane, the blood side of the membrane chamber connected in fluid communication with the blood side of the blood filter, the blood pump operable to alternate between a withdrawal phase and a return phase, wherein the withdrawal phase comprises blood being withdrawn along a blood path in fluid communication with the subject and the blood filter to the blood side of the membrane chamber, and the return phase comprises blood being returned from the blood side of the membrane chamber to the subject on said blood path; a drive fluid pump in fluid communication with the drive fluid side of the membrane chamber and the receptacle, the drive fluid pump operable to pump liquid from the receptacle out of and into the drive fluid side of the membrane chamber during the withdrawal and return phases; and a control unit programmed to cause the blood filter to perform ultrafiltration, such that the blood filter separates ultrafiltrate from plasma in the blood without changing a plasma concentration of small solutes in the blood, during at least one of the withdrawal and return phases.