Method and apparatus for detecting occlusions in an ambulatory infusion pump

Patent metadata

Field	Value
Publication number	US-9364608-B2
Application number	US-201414169563-A
Country	US
Kind code	B2
Filing date	Jan 31, 2014
Priority date	Oct 29, 1998
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

An improved pump, reservoir and reservoir piston are provided for controlled delivery of fluids. A motor is operably coupled to a drive member, such as a drive screw, which is adapted to advance a plunger slide in response to operation of the motor. The plunger slide is removably coupled to the piston. A method, system, and an article of manufacture for automatically detecting an occlusion in a medication infusion pump is provided. The electrical current to an infusion pump is measured. Based on a series of measurements of one or more variables, the infusion pump detects whether there is an occlusion in the system.

First claim

What is claimed is:

1. A method of detecting an occlusion in an infusion pump having a drive mechanism that includes a motor and one or more drive train components coupled to a reservoir for delivering fluid from the reservoir through a fluid path into a body of a user, the method comprising:
taking a series of measurements of a parameter associated with the motor or one of the drive train components;
after each measurement in the series of measurements is taken, performing a comparison between the measurement taken and a calculated threshold value before taking the next measurement in the series of measurements; and
if the comparison indicates that the measurement taken is less than the calculated threshold value, determining that there is no occlusion, and delivering said fluid to the user's body; and
wherein, if the comparison indicates that the measurement taken is greater than the calculated threshold value, then an additional measurement of said parameter is taken, up to a predetermined total number of measurements, and wherein, if the additional measurement is greater than the calculated threshold value and the predetermined total number of measurements has been reached, the method further includes: (a) calculating a weighted average of the total number of measurements, (b) comparing the weighted average to a comparison value, and (c) determining whether an occlusion has occurred in the fluid path of the infusion pump by determining whether the weighted average is greater than the comparison value.

2. The method of claim 1 , wherein the calculated threshold value is equal to N multiplied by a calculated conversion value, wherein N is less than 1.0.

3. The method of claim 1 , further including activating an alarm if a determination is made that the weighted average is greater than the comparison value.

4. The method of claim 1 , wherein said weighted average is calculated by applying a weighting factor to each measurement in the total number of measurements to determine a weighted value corresponding to each said measurement and calculating the average of the weighted values.

5. The method of claim 4 , further including removing the highest weighted value and the lowest weighted value prior to calculating the average of the weighted values.

6. The method of claim 4 , wherein the total number of measurements includes at least three measurements, and wherein the total number of measurements is filtered to remove at least two measurements before calculating the weighted values.

7. The method of claim 6 , wherein the total number of measurements includes at least five measurements, and further including removing the highest weighted value and the lowest weighted value prior to calculating the average of the weighted values.

8. The method of claim 4 , wherein each measurement after the first measurement in the total number of measurements is taken a predetermined time after the previous measurement.

9. The method of claim 4 , wherein a different weighting factor is applied to each measurement in the total number of measurements to determine the weighted value corresponding to each said measurement.

10. The method of claim 1 , further including determining a drive count value based on the motor drive count and calculating the comparison value based on the drive count value.

11. The method of claim 10 , wherein the comparison value is calculated by multiplying the drive count value by a calculated conversion value.

12. The method of claim 11 , wherein the calculated conversion value is calculated from a formula including at least one factor selected from the group consisting of current, time of powering the motor, drive count, coast count, and standard deviation of force readings.

13. The method of claim 1 , wherein the infusion pump includes a sensor to measure force.

14. The method of claim 1 , wherein said parameter is motor drive count, and the infusion pump includes an encoder to measure the motor drive count.

Assignees

• Medtronic Minimed Inc

Inventors

• Moberg Sheldon B
• Hanson Ian B
• Talbot Cary D

Classifications

• A61M2005/14208

  with a programmable infusion control system, characterised by the infusion program · CPC title

• A61M5/16854

  by monitoring line pressure · CPC title

• A61M2205/70

  with testing or calibration facilities · CPC title

• A61M5/16831 Primary

  Monitoring, detecting, signalling or eliminating infusion flow anomalies (low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066) · CPC title

• A61M5/14244

  adapted to be carried by the patient, e.g. portable on the body · CPC title