NZ740655A - Apparatus for infusing fluid - Google Patents

Abstract

A pump for pumping fluid includes a tube platen, a plunger configured for actuation toward and away from the tube platen when the tube platen is disposed opposite to the plunger, a bias member configured to urge the plunger toward the tube platen, an inlet valve upstream of the plunger configured for actuation between an occluding position and a non-occluding position, an outlet valve downstream of the plunger configured for actuation between an occluding position and a non-occluding position, an actuator mechanism configured to control the actuation of the plunger, the inlet valve and the outlet valve, a pressure sensor disposed adjacent to at least one of the inlet valve, the outlet valve, and the plunger, and a processor coupled to the pressure sensor to receive a pressure signal from the pressure sensor, wherein, the inlet valve, the outlet valve, and the plunger are configured to pump fluid in a plurality of cycles, each cycle having a trough pressure level and a peak pressure level, and the processor is configured to, using the pressure signal, determine a downstream occlusion exists when a difference between a first trough pressure level of a first cycle and a second trough pressure level of a second cycle is greater than a predetermined threshold, the first and second cycles are cycles of the plurality of cycles, and wherein the plunger is configured to engage and disengage from the actuator mechanism and the pressure sensor is configured to measure the peak pressure level after the plunger disengages from the actuator in each cycle. Such an arrangement permits a pump which provides efficient and accurate notice of downstream occlusion in order to promote patient safety.