METHOD AND APPARATUS FOR DETECTION AND MANAGEMENT OF AIR-IN-LINE
First Claim
1. A method of detecting an air-in-line condition with respect to flow of liquid through tubing connected to an infusion pump, the method comprising:
- providing an air-in-line sensor at a sensing location along the tubing, the air-in-line sensor generating a signal indicating whether a volume of fluid observed by the sensor at a given time is air or liquid;
operating the pump to deliver fluid at a therapy flow rate;
sampling the sensor signal as fluid flows past the sensor;
calculating a total volume of air observed by the sensor since the sensor last observed liquid;
operating the pump to deliver a bolus volume of fluid at a bolus flow rate greater than the therapy flow rate when the total volume of air exceeds a first threshold; and
detecting the air-in-line condition when the total volume of air exceeds a second threshold greater than the first threshold.
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Accused Products
Abstract
In an infusion pump operable to deliver fluid to a patient at a programmed therapy flow rate, air-in-line sensing is improved by commanding the pumping mechanism to deliver a bolus volume of fluid at a flow rate higher than the therapy flow rate when an uninterrupted volume of air is detected that exceeds a first threshold. In many cases, the bolus will be effective to clear microbubbles from an observation zone of the air-in-line sensor to avoid an air-in-line alarm condition. If the uninterrupted volume of air continues to grow beyond a second threshold in spite of the bolus, then an alarm may be triggered. The invention reduces false alarms.
48 Citations
18 Claims
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1. A method of detecting an air-in-line condition with respect to flow of liquid through tubing connected to an infusion pump, the method comprising:
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providing an air-in-line sensor at a sensing location along the tubing, the air-in-line sensor generating a signal indicating whether a volume of fluid observed by the sensor at a given time is air or liquid; operating the pump to deliver fluid at a therapy flow rate; sampling the sensor signal as fluid flows past the sensor; calculating a total volume of air observed by the sensor since the sensor last observed liquid; operating the pump to deliver a bolus volume of fluid at a bolus flow rate greater than the therapy flow rate when the total volume of air exceeds a first threshold; and detecting the air-in-line condition when the total volume of air exceeds a second threshold greater than the first threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of clearing air microbubbles from an observation zone of an air-in-line sensor arranged to observe fluid flowing through tubing connected to an infusion pump, wherein the pump is programmed to deliver fluid at a therapy flow rate, the method comprising:
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calculating a total volume of air observed by the sensor since the sensor last observed liquid; and operating the pump to deliver a bolus volume of fluid at a bolus flow rate greater than the therapy flow rate when the total volume of air exceeds a predetermined threshold. - View Dependent Claims (11)
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12. An infusion pump comprising:
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a pumping mechanism operable to cause fluid flow through tubing connected to the pumping mechanism, the pumping mechanism including a motor and a motor controller for energizing the motor; an air-in-line sensor arranged at a sensing location along the tubing to observe fluid flowing through the tubing, the air-in-line sensor generating a signal indicating whether a volume of fluid observed by the sensor at a given time is air or liquid; a memory module; and a microprocessor connected to the memory module, the pumping mechanism and the air-in-line sensor, wherein the microprocessor is programmable to command the pumping mechanism deliver fluid at a therapy flow rate; wherein the memory module stores programming instructions causing the microprocessor to command the pumping mechanism to deliver a bolus volume of fluid at a bolus flow rate greater than the therapy flow rate in response to signals from the air-in-line sensor indicating an uninterrupted volume of air flowing through the tubing is greater than a predetermined first volume threshold. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification