Patent ID: 9101712
Filing Date: 2015-08-11
Classification: A61M,G16H

Abstract:
1. A method of detecting an occlusion in tubing connected to an infusion pump by a cassette removably received by the infusion pump, the infusion pump having a pumping mechanism operable to cause fluid flow through the tubing in an intended flow direction, a cassette access sensor providing a signal indicative of whether there is access to the cassette to allow removal of the cassette and installation of a new cassette, an upstream sensor at a location along the tubing upstream from the pumping mechanism in the flow direction, and a downstream sensor at a location along the tubing downstream from the pumping mechanism in the flow direction, wherein the upstream sensor and downstream sensor each provide a respective sensor signal indicative of a respective local fluid pressure in the tubing, the method comprising the steps of: establishing an upstream sensor signal baseline corresponding to fluid pressure equilibrium at the upstream sensor location and a downstream sensor signal baseline corresponding to fluid pressure equilibrium at the downstream sensor location; making an antiratchet decision in response to a signal from the cassette access sensor, the antiratchet decision determining whether or not occluded tubing was replaced; keeping the established upstream sensor signal baseline and the downstream sensor signal baseline when the antiratchet decision determines that occluded tubing was not replaced; establishing a new upstream sensor signal baseline and a new downstream sensor signal baseline when the antiratchet decision determines that occluded tubing was replaced; monitoring a difference between the upstream sensor signal and the upstream sensor baseline signal to detect an occlusion in the tubing upstream from the pumping mechanism; and monitoring a difference between the downstream sensor signal and the downstream sensor baseline signal to detect an occlusion in the tubing downstream from the pumping mechanism.