DETECTING CONDITIONS ASSOCIATED WITH MEDICAL DEVICE OPERATIONS USING MATCHED FILTERS

• US 20150051573A1
• Filed: 08/13/2013
• Published: 02/19/2015
• Est. Priority Date: 08/13/2013
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Tieck, R. Marie, Alderete, Juan M. Jr., Haller, Matthew I.
• Granted Patent: US 9,402,949 B2
• Time in Patent Office: Days
• US Class Current: 604/500
• CPC Class Codes: A61M 2005/16863 Occlusion detection
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/332 Force measuring means
• CPC Class Codes: A61M 2205/3584 using modem, internet or bluetooth
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2230/201 Glucose concentration
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/14248 of the skin patch type
• 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

Abstract

Apparatus are provided for infusion devices and related operating methods. An exemplary device includes a sensing arrangement to provide an output indicative of a characteristic that is influenced by operation of the device, and a control module that is coupled to the sensing arrangement to apply a matched filter corresponding to a condition associated with the operation of the device to the output of the sensing arrangement and detect that condition based on the filtered output. In one example, the device includes a motor coupled to a plunger of a reservoir and operable to displace the plunger, wherein the characteristic is a force opposing displacement of the plunger and the control module detects an occlusion condition in a fluid path from the reservoir based on filtered force measurements.

Claims

1. A device comprising:

a sensing arrangement to provide an output indicative of a characteristic influenced by operation of the device; and

a control module coupled to the sensing arrangement to;

apply a matched filter to the output of the sensing arrangement, resulting in a filtered output, the matched filter corresponding to a condition associated with the operation of the device; and

detect the condition based on the filtered output.

2. The device of claim 1, further comprising a motor, wherein the characteristic is influenced by operation of the motor.

3. The device of claim 2, wherein:

the motor is coupled to a plunger of a reservoir;

the motor is operable to displace the plunger; and

the characteristic comprises a force opposing displacement of the plunger.

4. The device of claim 3, wherein the condition comprises an occlusion condition in a fluid path from the reservoir.

5. The device of claim 4, wherein an impulse response of the matched filter corresponds to an expected output from the sensing arrangement in response to the occlusion condition.

6. The device of claim 3, further comprising a gear assembly to couple a rotor of the motor to a shaft of the plunger, wherein the sensing arrangement is integrated with the gear assembly.

7. The device of claim 3, wherein the control module identifies a delivery configuration for the device and selects the matched filter associated with the delivery configuration.

8. The device of claim 7, wherein the delivery configuration comprises one or more of a type of infusion set coupled to the reservoir to provide a fluid path from the reservoir to a user, a length of tubing of an infusion set coupled to the reservoir to provide the fluid path from the reservoir to the user, a type of the reservoir, or a volume of the reservoir.

9. The device of claim 3, wherein the control module identifies a delivery mode for the device and selects the matched filter associated with the delivery mode.

10. The device of claim 9, wherein the delivery mode comprises a basal delivery mode or a bolus delivery mode.

11. The device of claim 9, wherein the delivery mode comprises a rate of delivery of fluid from the reservoir.

12. The device of claim 1, wherein the matched filter comprises a first set of values corresponding to an expected output from the sensing arrangement in response to the condition.

13. The device of claim 12, the expected output having a first slope, wherein the first set of values have a second slope substantially equal to a negative of the first slope.

14. The device of claim 12, wherein an integral of the matched filter is equal to zero.

15. The device of claim 12, wherein the matched filter further comprises a second set of values to cancel the first set of values such that an integral of the matched filter is equal to zero, the second set of values comprising integer values equal to a power of two.

16. A fluid infusion device comprising:

a motor operable to displace a plunger of a reservoir;

a sensing arrangement to provide an output indicative of a characteristic influenced by displacement of the plunger; and

a control module coupled to the sensing arrangement to;

apply a matched filter to the output of the sensing arrangement, resulting in a filtered output, the matched filter corresponding to a condition; and

detect the condition based on the filtered output.

17. The fluid infusion device of claim 16, the condition comprising an occlusion condition in a fluid path from the reservoir, wherein the sensing arrangement comprises a force sensing arrangement providing the output indicative of a force opposing the displacement of the plunger.

18. The fluid infusion device of claim 16, the condition comprising a leakage condition, wherein the sensing arrangement comprises a volume sensing arrangement providing the output indicative of a remaining volume of fluid in the reservoir.

19. A method of detecting a condition associated with operation of a device, the method comprising:

obtaining an output indicative of a characteristic influenced by the operation of the device from a sensing arrangement;

applying a matched filter corresponding to the condition to the output, resulting in a filtered output; and

detecting the condition based on the filtered output.

20. The method of claim 19, further comprising:

identifying a configuration of the device; and

selecting the matched filter associated with the configuration.

21. The method of claim 19, further comprising:

identifying an operating mode for the device; and

selecting the matched filter associated with the operating mode.

22. The method of claim 19, the device comprising a fluid infusion device including a motor operable to displace a plunger of a reservoir to deliver fluid to a user, wherein the output is influenced by displacement of the plunger.

23. The method of claim 22, wherein:

obtaining the output comprises obtaining a force measurement output indicative of a force opposing the displacement of the plunger from a force sensing arrangement;

applying the matched filter comprises applying the matched filter corresponding to an occlusion condition to the force measurement output, resulting in a filtered force measurement; and

detecting the condition comprises detecting the occlusion condition when a magnitude of the filtered force measurement is greater than an occlusion force threshold.

24. The method of claim 22, wherein:

obtaining the output comprises obtaining a volume measurement output indicative of a remaining volume of fluid in the reservoir from a volume sensing arrangement;

applying the matched filter comprises applying the matched filter corresponding to a leakage condition to the volume measurement output, resulting in a filtered volume measurement; and

detecting the condition comprises detecting the leakage condition based on the filtered volume measurement.