Patent ID: 7452190
Filing Date: 2008-11-18
Classification: A61M

Abstract:
1. A method for determining operating conditions in a medical pump having a cassette with a pumping chamber, comprising: monitoring the pump cycle with a position sensor; starting a testing timer for a pre-determined test time at a specified portion of the pump cycle; closing the pumping chamber to flow during at least a portion of the specified portion of the pump cycle; acquiring a plurality of pressure reference values during a first portion of test time from a single pressure sensor; calculating and storing a pressure anchor value by averaging the reference values; setting a first prior integration term of zero; acquiring a pressure data value from the pressure sensor; calculating and storing a new integration term by subtracting the anchor value from the data value to obtain a resultant, multiplying the resultant by a weighting value to obtain a product, and adding the product to the prior integration term; repeating the steps of acquiring the pressure data value and calculating and storing the new integration term until the pre-determined test time has expired; and comparing the new integration term with a pre-determined threshold value to determine the operating condition of the pump.