Patent ID: 8491516

Claim:
A method of performing a blood treatment, comprising: withdrawing blood from a live patient and flowing withdrawn blood into a stack of rectangular microfluidic channels each sized and shaped, and at a flow rate, to produce a shear rate such that cellular components of the blood migrate to the center of each microfluidic channel and leave a sheath as cell-free, essentially pure plasma; each microfluidic channel having an aspect ratio perpendicular to the flow direction of at least 10, the minimum dimension being a depth and the maximum dimension being a width; withdrawing the essentially pure plasma from each microfluidic channel through two outlets positioned across the depth; simultaneously withdrawing plasma-depleted blood from each microfluidic channel from the middle of each microfluidic channel between the two outlets; combining withdrawn pure plasma flow from the stack of microfluidic channels and pumping the withdrawn pure plasma at a positive pressure through a membrane filter to ultrafilter water and uremic toxins therefrom to produce dehydrated plasma at an outlet of the filter; returning the dehydrated plasma and the plasma-depleted blood to the patient; performing the above operations continuously over a treatment period of time encompassing a majority of a day, the stack being a component of a wearable system, wherein the rate of water removal over the treatment period of time is sufficient to regulate the water burden of a patient with renal failure.