Occlusion detection for a fluid infusion device

• US 9,033,951 B2
• Filed: 01/30/2013
• Issued: 05/19/2015
• Est. Priority Date: 12/22/2010
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Kow, Hsiao-Yu S., Bazargan, Afshin, Hanson, Ian B., Vazquez, Pablo, Alderete, Juan M. Jr., Monirabbasi, Salman
• Primary Examiner(s): BERDICHEVSKY, AARTI
• Application Number:
  US13/754,829
• Publication Number:
  US 20130133438A1
• Time in Patent Office: 839 Days
• Field of Search: 604/503, 604/504, 604/505
• US Class Current: 604/503
• CPC Class Codes: A61M 2005/16863 Occlusion detection
• CPC Class Codes: A61M 2205/332 Force measuring means
• CPC Class Codes: A61M 5/14 Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• 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 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: A61M 5/5086 for indicating if defective, used, tampered with or unsterile
• CPC Class Codes: G01F 13/00 Apparatus for measuring by volume and delivering fluids or fluent solid materials, not provided for in the preceding groups
• CPC Class Codes: G01L 1/26 Auxiliary measures taken, or devices used, in connection with the measurement of force, e.g. for preventing influence of transverse components of force, for preventing overload

Abstract

A device for delivering fluid to a user includes a housing, a drive motor assembly in the housing, a force sensor, and an electronics module. The drive motor assembly regulates delivery of fluid by actuating a piston of a fluid reservoir, and the force sensor generates output levels in response to force imparted thereto during, for example, fluid delivery operations. The electronics module processes the output levels of the force sensor to assess the operating health of the force sensor, to check for occlusions in the fluid delivery path, and to monitor the seating status of the fluid reservoir.

Claims

1. In a fluid infusion device comprising a drive motor assembly and a force sensor associated with the drive motor assembly, a method of detecting occlusions in a fluid path of the fluid infusion device, the method comprising:

determining a plurality of force measurements for a fluid delivery action of the drive motor assembly, the plurality of force measurements indicating measures of actuation force imparted to the force sensor for the fluid delivery action;

determining a plurality of quantity measurements for the fluid delivery action, each of the plurality of quantity measurements being determined relative to a reference quantity measurement, and each of the plurality of quantity measurements indicates a quantity of fluid dispensed by the fluid infusion device;

indicating an occlusion in the fluid path based on a first slope of force-versus-quantity for a large sample of the plurality of quantity measurements, the first slope of force versus-quantity greater than or equal to a first threshold slope value; and

indicating the occlusion in the fluid path based on both;

(a) a second slope of force-versus-quantity for a small sample of the plurality of quantity measurements, the second slope of force-versus-quantity greater than or equal to a second threshold slope value; and

(b) a current one of the plurality of force measurements, the current one of the plurality of force measurements greater than or equal to a threshold force value.

2. The method of claim 1, wherein each of the plurality of quantity measurements corresponds to a respective one of the plurality of force measurements.

3. The method of claim 1, wherein the first threshold slope is greater than the second threshold slope.

4. The method of claim 1, further comprising initiating corrective action for the fluid infusion device when the occlusion is indicated.

5. The method of claim 4, wherein initiating corrective action comprises generating a user alert at the fluid infusion device.

6. The method of claim 1, further comprising:

initiating the fluid delivery action;

determining an initial force measurement that indicates an initial measure of actuation force imparted to the force sensor; and

indicating the occlusion when the initial force measurement is greater than an initial force limit, wherein the initial force limit is greater than the threshold force value.

7. The method of claim 1, wherein each of the plurality of force measurements is determined by averaging a number of actuation force measures sampled while the drive motor assembly is stationary.

8. The method of claim 1, wherein size of the large sample of the plurality of quantity measurements varies as a function of the current one of the plurality of force measurements.

9. The method of claim 1, wherein size of the small sample of the plurality of quantity measurements varies as a function of the current one of the plurality of force measurements.

10. The method of claim 1, wherein the first threshold slope value varies as a function of the current one of the plurality of force measurements.

11. The method of claim 1, wherein the second threshold slope value varies as a function of the current one of the plurality of force measurements.

12. In a fluid infusion device comprising a drive motor assembly and a force sensor associated with the drive motor assembly, a method of detecting occlusions in a fluid path of the fluid infusion device, the method comprising:

determining a plurality of force measurements for a fluid delivery action of the drive motor assembly, the plurality of force measurements indicating measures of actuation force imparted to the force sensor for the fluid delivery action;

determining a plurality of quantity measurements for the fluid delivery action, each of the plurality of quantity measurements being determined relative to a reference quantity measurement and each of the plurality of quantity measurements indicates a quantity of fluid dispensed by the fluid infusion device; and

indicating an occlusion in the fluid path based on a first slope of force-versus-quantity for a large sample of the plurality of quantity measurements, the first slope of force versus-quantity greater than or equal to a first threshold slope value; and

indicating the occlusion in the fluid path based on (a) a second slope of force-versus-quantity for a small sample of the plurality of quantity measurements, the second slope of force-versus-quantity greater than or equal to a second threshold slope value; and

(b) a current one of the plurality of force measurements, the current one of the plurality of force measurements greater than or equal to a threshold force value,

wherein indicating the occlusion in the fluid path based on the second slope of force-versus-quantity and the current one of the plurality of force measurements occurs based on a comparison of the first slope of force-versus quantity to the first threshold slope value.

13. The method of claim 12, wherein if the first slope is less than the first threshold slope value, the method indicates the occlusion in the fluid path based on the second slope of force-versus-quantity and the current one of the plurality of force measurements.

14. The method of claim 12, wherein the first threshold slope is greater than the second threshold slope.

15. The method of claim 12, further comprising initiating corrective action for the fluid infusion device when the occlusion is indicated.

16. The method of claim 12, further comprising:

initiating the fluid delivery action;

determining an initial force measurement that indicates an initial measure of actuation force imparted to the force sensor; and

indicating the occlusion when the initial force measurement is greater than an initial force limit, wherein the initial force limit is greater than the threshold force value.

17. The method of claim 12, wherein each of the plurality of force measurements is determined by averaging a number of actuation force measures sampled while the drive motor assembly is stationary.

18. The method of claim 12, wherein the first threshold slope value varies as a function of the current one of the plurality of force measurements.

19. The method of claim 12, wherein the second threshold slope value varies as a function of the current one of the plurality of force measurements.