METHODS AND APPARATUSES FOR DETECTING OCCLUSIONS IN AN AMBULATORY INFUSION PUMP

• US 20100037680A1
• Filed: 10/22/2009
• Published: 02/18/2010
• Est. Priority Date: 10/27/2000
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Talbot, Cary D., Hanson, Ian B., MOBERG, SHELDON B.
• Granted Patent: US 8,182,447 B2
• Time in Patent Office: Days
• US Class Current: 73/37
• CPC Class Codes: A61M 2005/14264 with means for compensating influence from the environment
• CPC Class Codes: A61M 2005/16863 Occlusion detection
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/332 Force measuring means
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/70 with testing or calibration facilities
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/16831 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 Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

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. Methods, systems, and articles of manufacture for automatically detecting an occlusion in a medication infusion pump are provided. The electrical current to an infusion pump may be measured. Based on measurements of one or more variables, and/or multiple measurements of a single variable, such as force, the infusion pump detects whether there is an occlusion in the system. The methods of detecting occlusions may be dynamic.

Claims

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 for infusing fluid into a body of a user, the method comprising:

during delivery of a current pulse of infusion fluid, periodically measuring the amount of force that is applied to a drive train component to obtain a series of measurements;

determining a peak value of the series of measurements;

selecting a second value within the series of measurements later than the peak value;

calculating a difference between the peak value and the second value; and

declaring an occlusion has occurred if the difference exceeds a threshold value.

2. The method of claim 1, wherein the measuring the amount of applied force is continuous during the delivery of the pulse of infusion fluid.

3. 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 for infusing fluid into a body of a user, the method comprising:

during delivery of a current pulse of infusion fluid, periodically measuring the amount of force that is applied to a drive train component to obtain a series of measurements;

determining a peak value of the series of measurements;

selecting a second value within the series of measurements later than the peak value;

calculating a difference between the peak value and the second value;

incrementing a counter when the difference exceeds a threshold value;

restarting the counter when the difference is below the threshold value; and

declaring an occlusion has occurred when the counter exceeds an occlusion-detection count.

4. 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 for infusing fluid into a body of a user, the method comprising:

during delivery of a current pulse of infusion fluid, periodically measuring the amount of force that is applied to a drive train component to obtain a series of measurements;

determining a peak value of the series of measurements;

selecting a second value within the series of measurements later than the peak value;

calculating a current difference between the peak value and the second value;

retrieving a previous difference between a previous peak value and a previous second value later than the previous peak value calculated based on measurements of applied force during delivery of a previous pulse of infusion fluid;

calculating an average difference using the previous difference and the current difference; and

declaring an occlusion has occurred if the average difference exceeds a threshold value.

5. The method of claim 4, wherein the calculating an average difference further includes using a second previous difference calculated based on measurements of applied force during delivery of a second previous pulse of infusion fluid.

6. The method of claim 5, wherein the average difference is calculated based on measurements of applied force during delivery of three consecutive pulses of infusion fluid.

7. 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 for infusing fluid into a body of a user, the method comprising:

during delivery of a current pulse of infusion fluid, periodically measuring the amount of force that is applied to a drive train component to obtain a series of measurements;

determining a peak value of the series of measurements;

selecting a second value within the series of measurements later than the peak value;

measuring the amount of applied force before the delivery of the current pulse of infusion fluid to obtain a third value;

calculating a first difference between the peak value and the second value;

calculating a second difference between the third value and the peak value; and

determining whether an occlusion has occurred by comparing the second difference between the third value and the peak value to the first difference between the peak value and the second value.

8. The method of claim 7, wherein the comparing the second difference between the third value and the peak value to the first difference between the peak value and the second value includes calculating the first difference between the peak value and the second value as a percentage of the second difference between the third value and the peak value, and wherein the method further comprises declaring an occlusion has occurred if the percentage is below a threshold value.

9. 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 for infusing fluid into a body of a user, the method comprising:

during delivery of a current pulse of infusion fluid, periodically measuring the amount of force that is applied to a drive train component to obtain a series of measurements;

determining a peak value of the series of measurements;

selecting a second value within the series of measurements later than the peak value;

selecting a third value within the series of measurements later than the peak value;

calculating a slope of a line using the second and third values; and

determining whether an occlusion has occurred by comparing the slope to a threshold value.

10. The method of claim 9, further including declaring an occlusion has occurred if the slope exceeds the threshold value.

11. The method of claim 9, wherein the determining whether an occlusion has occurred is based upon a comparison of the slope to a predetermined percentage of the threshold value.

12. The method of claim 9, wherein the threshold value is predetermined for the infusion pump.

13. 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 for infusing fluid into a body of a user, the method comprising:

during delivery of a current pulse of infusion fluid, periodically measuring the amount of force that is applied to a drive train component to obtain a series of measurements;

determining a peak value of the series of measurements;

selecting a second value within the series of measurements later than the peak value;

calculating a current difference between the peak value and the second value; and

declaring an occlusion has occurred if the current difference exceeds a threshold value,

wherein the threshold value is dynamically updated based on measurements of applied force during delivery of at least one previous pulse of infusion fluid before the delivery of the current pulse of infusion fluid.

14. The method of claim 13, further comprising:

retrieving a first previous difference between a first previous peak value and a first previous second value later than the first previous peak value calculated based on measurements of applied force during delivery of a first previous pulse of infusion fluid;

retrieving a second previous difference between a second previous peak value and a second previous second value later than the second previous peak value calculated based on measurements of applied force during delivery of a second previous pulse of infusion fluid; and

calculating an average difference using the first previous difference and the second previous difference,

wherein the threshold value is the average difference.

15. The method of claim 14, wherein the calculating an average difference further includes using a third previous difference calculated based on measurements of applied force during delivery of a third previous pulse of infusion fluid.

16. The method of claim 15, wherein the average difference is calculated based on measurements of applied force during delivery of three consecutive pulses of infusion fluid.

17. The method of claim 16, wherein the average difference is calculated based on measurements of applied force during delivery of three consecutive pulses of infusion fluid that are at least three pulses prior to the delivery of the current pulse of infusion fluid.