Patent ID: 7402154
Filing Date: 2008-07-22
Classification: A61M,G05D

Abstract:
1. A method for determining a difference in a calibration between an inlet pressure sensor and an outlet pressure sensor in an infusion pump for infusing a fluid into a patient, comprising the steps of: (a) providing a cassette having a housing that defines a fluid path between an inlet port adapted to couple in fluid communication with the source and an outlet port adapted to couple in fluid communication with an infusion site on the patient, said cassette including an inlet pressure sensor that produces a signal indicative of a pressure proximate the inlet port, and an outlet pressure sensor that produces a signal indicative of a pressure proximate the outlet port, said fluid path including: (b) opening the inlet valve while the outlet valve is closed, thus filling the chamber with fluid, and closing the inlet valve when the chamber is filled with a desired volume of fluid; (c) determining a pressure proximate the inlet port and a pressure proximate the outlet port using the inlet and outlet pressure sensors; (d) adjusting a position of the elastomeric membrane such that a pressure of the fluid within the chamber is equivalent to the pressure proximate the outlet port; and (e) opening the outlet valve, and using the outlet pressure sensor, determining if a pressure spike accompanies the opening of the outlet valve, said pressure spike being indicative of a calibration difference between the inlet pressure sensor and the outlet pressure sensor.