Malfunction Detection With Derivative Calculation
First Claim
1. A method for detecting a malfunction in an infusion pump having a non-mechanically driven movable partition, comprising:
- (a) for each of a plurality of instances;
(i) activating the infusion pump for a first pre-determined amount of time to induce movement of the movable partition of the pump and to release a shot of fluid from the pump, (ii) de-activating the infusion pump for a second pre-determined amount of time, and (ii) determining a position of the movable partition using a sensor;
(b) calculating a derivative for each of the plurality of instances, the derivative being based on a change in position of the movable partition with respect to a change in the number of shots released;
(c) calculating a moving average using calculated derivative values corresponding to each of the plurality of instances; and
(d) comparing the calculated moving average with a predetermined threshold value, to determine whether the infusion pump is malfunctioning.
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Accused Products
Abstract
Systems and methods of detecting occlusions and fluid-loss conditions (e.g., disconnects and/or leakages) in an infusion pump are discussed. For example, electrokinetic infusion pumps may develop an occlusion in the fluid flow path, which can disrupt control of fluid dispersed from the pump. As well, an infusion set disconnect can also result in a fluid-loss that can be disruptive. Such disruptions can be troublesome to systems that control the infusion pump, such as closed loop controllers. Accordingly, systems and methods described herein can be used to detect such occlusions and fluid-loss conditions during infusion pump operation. For example, a position sensor can be used to monitor fluid flow from the infusion pump, with the measurement being compared with an expected value to detect an occlusion or fluid-loss condition. Other algorithms for utilizing the position sensor are also described.
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Citations
28 Claims
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1. A method for detecting a malfunction in an infusion pump having a non-mechanically driven movable partition, comprising:
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(a) for each of a plurality of instances;
(i) activating the infusion pump for a first pre-determined amount of time to induce movement of the movable partition of the pump and to release a shot of fluid from the pump, (ii) de-activating the infusion pump for a second pre-determined amount of time, and (ii) determining a position of the movable partition using a sensor;
(b) calculating a derivative for each of the plurality of instances, the derivative being based on a change in position of the movable partition with respect to a change in the number of shots released;
(c) calculating a moving average using calculated derivative values corresponding to each of the plurality of instances; and
(d) comparing the calculated moving average with a predetermined threshold value, to determine whether the infusion pump is malfunctioning. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A system for detecting a malfunction in an infusion pump, comprising:
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an infusion pump having a non-mechanically driven movable partition disposed therein;
a position sensor disposed on the pump;
a controller associated with the infusion pump and adapted to operate the infusion pump in an activate/de-activate cycle, the cycle comprising activating the pump for a first pre-determined amount of time to induce movement of the movable partition and release a shot of fluid, and de-activating the pump for a second pre-determined amount of time; and
a processor associated with the position sensor, the processor adapted to determine whether the infusion pump is malfunctioning at least by comparing a calculated moving average of a plurality of derivatives to a pre-determined threshold value, each derivative based on a change in position of the movable partition with respect to a change in the number of shots released by the pump. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification