Patent ID: 7815809
Filing Date: 2010-10-19
Classification: A61M,B01D,Y10T

Abstract:
1. A method for determining a conductivity of a treatment fluid downstream from a filtration unit in a blood processing machine, said unit comprising a first compartment for the circulation of blood and a second compartment for the circulation of the treatment fluid, said second compartment being separated from the first compartment by interposing at least a semi-permeable membrane; said method comprising the steps of: creating a flow of blood through the first compartment of the filtration unit; creating a flow of treatment fluid through the second compartment of the filtration unit; imposing, for a predetermined time interval, a change in the conductivity of the treatment fluid at an inlet of the filtration unit to cause an induced conductivity change in the fluid at an outlet of said filtration unit; measuring a predetermined number of conductivity values Cdo downstream from the filtration unit, said conductivity values Cdo defining a downstream conductivity curve; defining at least one interpolating mathematical function for estimating a pattern of said downstream conductivity curve in an interval of time after causing the induced conductivity change; wherein the mathematical function has the form: determining a characteristic measuring time tCalc calculating by means of a control unit a value of the interpolating mathematical function at said characteristic measuring time tCalc