Patent ID: 7632411

Claim:
A method for detecting filter clogging comprising: flowing blood through a hollow-fiber membrane from a blood inflow portion to a blood outflow portion, a waste liquid from the blood passing through the hollow filter membrane into a filtrate region; flowing a filtrate into the filtrate region through a filtrate inflow portion and out of a filtrate outflow portion; measuring pressure over time in at least two of the blood inflow portion, the blood outflow portion, the filtrate inflow portion, and the filtrate outflow portion and generating measured pressure signals indicative thereof; analyzing the measured pressure signals including determining a transform of the measured pressure signals and a difference of a phase in the transformed measured pressure signals indicative of measured pressure in at least two of the blood inflow portion, the blood outflow portion, the filtrate inflow portion, and the filtrate outflow portion; in response to determining a difference in the phase that is indicative of clogging of the hollow-fiber membrane, at least one of display filter clogging status and adjusting an amount of anti-coagulant in the blood entering the blood inflow portion.