INFUSION DEVICES AND RELATED PATIENT RATIO ADJUSTMENT METHODS

• US 20170049961A1
• Filed: 04/11/2016
• Published: 02/23/2017
• Est. Priority Date: 08/21/2015
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Roy, Anirban
• Granted Patent: US 10,293,108 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61M 2005/14208 with a programmable infusion control system, characterised by the infusion program
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/702 automatically during use
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/201 Glucose concentration
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

Infusion systems, infusion devices, and related operating methods are provided. An exemplary method of operating an infusion device to deliver a bolus amount of fluid influencing a physiological condition in a body of a user involves identifying, based on measurement values for the physiological condition, a residual value for the physiological condition resulting from the bolus amount of the fluid and determining an updated ratio for a subsequent bolus by adjusting an initial ratio influencing the bolus amount to compensate for the residual value. The updated ratio may be stored in a data storage element for use in determining a subsequent bolus amount in lieu of the initial ratio value.

Claims

1. A method of operating an infusion device to deliver fluid to a body of a user, the method comprising:

identifying, based on measurement values for a physiological condition in the body of the user, a residual value for the physiological condition resulting from a bolus amount of the fluid delivered by the infusion device, wherein the physiological condition is influenced by the fluid delivered by the infusion device and the bolus amount is influenced by an initial ratio associated with the user, the initial ratio being stored in a data storage element onboard the infusion device;

determining an updated ratio by adjusting the initial ratio to compensate for the residual value; and

storing the updated ratio in the data storage element, wherein a subsequent bolus amount is influenced by the updated ratio.

2. The method of claim 1, wherein determining the updated ratio comprises scaling the initial ratio by an adjustment factor influenced by the residual value.

3. The method of claim 2, further comprising converting the residual value to a residual amount of the fluid, wherein scaling the initial ratio comprises multiplying the initial ratio by a ratio of the bolus amount to a sum of the bolus amount and the residual amount.

4. The method of claim 2, further comprising converting the residual value to a residual amount of carbohydrates, the bolus amount being influenced by the initial ratio and an input amount of carbohydrates, wherein scaling the initial ratio comprises multiplying the initial ratio by a ratio of a difference between the input amount and the residual amount to the input amount.

5. The method of claim 1, wherein identifying the residual value comprises:

identifying an initial measurement value for the physiological condition corresponding to delivery of the bolus amount;

identifying a post-prandial settling value from among the measurement values following the delivery of the bolus amount; and

determining the residual value as a difference between the post-prandial settling value and the initial measurement value.

6. The method of claim 5, further comprising converting the residual value to a residual amount of the fluid, wherein determining the updated ratio comprises multiplying the initial ratio by a ratio of the bolus amount to a sum of the bolus amount and the residual amount.

7. The method of claim 6, wherein converting the residual value to the residual amount of the fluid comprises:

obtaining a fluid sensitivity factor associated with the user; and

dividing the residual value by the fluid sensitivity factor to obtain the residual amount of the fluid.

8. The method of claim 5, further comprising converting the residual value to a residual amount of carbohydrates, the bolus amount being influenced by the initial ratio and an input amount of carbohydrates, wherein determining the updated ratio comprises scaling the initial ratio by a ratio of a second difference between the input amount and the residual amount to the input amount.

9. The method of claim 1, the fluid comprising insulin, the physiological condition comprising a glucose level, and the initial ratio comprising an initial carbohydrate ratio, the method further comprising:

receiving, via a user interface, an input amount of carbohydrates; and

determining the bolus amount of insulin by dividing the input amount by the initial carbohydrate ratio, wherein;

identifying the residual value comprises identifying a residual glucose value; and

determining the updated ratio comprises determining an updated carbohydrate ratio by adjusting the initial carbohydrate ratio to compensate for the residual glucose value.

10. The method of claim 9, further comprising:

receiving, via the user interface, a subsequent input amount of carbohydrates; and

determining the subsequent bolus amount of insulin by dividing the subsequent input amount by the updated carbohydrate ratio.

11. The method of claim 9, further comprising converting the residual glucose value to a residual insulin amount, wherein determining the updated carbohydrate ratio comprises scaling the initial carbohydrate ratio based on a relationship between the residual insulin amount and the bolus amount of insulin.

12. The method of claim 9, further comprising converting the residual glucose value to a residual carbohydrate amount, wherein determining the updated carbohydrate ratio comprises scaling the initial carbohydrate ratio based on a relationship between the residual carbohydrate amount and the input amount of carbohydrates.

13. The method of claim 1, further comprising:

identifying a current delivery context; and

identifying the initial ratio associated with the current delivery context from among a plurality of different ratios associated with a plurality of different delivery contexts stored in the data storage element.

14. The method of claim 13, wherein identifying the current delivery context comprises identifying a current time corresponds to a time window associated with the initial ratio.

15. An infusion device comprising:

an actuation arrangement operable to deliver fluid to a body of a user;

a data storage element;

a communications interface to receive measurement values indicative of a physiological condition in the body of the user influenced by the fluid; and

a control module coupled to the actuation arrangement, the data storage element, and the communications interface to operate the actuation arrangement to deliver a bolus amount of the fluid influenced by an initial value for a ratio stored by the data storage element, identify a residual value for the physiological condition based at least in part on one or more of the measurement values after delivery of the bolus amount, determine an updated value for the ratio by adjusting the initial value to compensate for the residual value, and store the updated value for the ratio in the data storage element.

16. The infusion device of claim 15, further comprising a user interface to receive an input carbohydrate amount, wherein the control module determines the bolus amount based on the initial value and the input carbohydrate amount.

17. The infusion device of claim 16, wherein the control module determines a subsequent bolus amount based on the updated value and a second carbohydrate amount received via the user interface.

18. The infusion device of claim 15, wherein the control module determines an adjustment factor based on the residual value and determines the updated value by scaling the initial value by the adjustment factor.

19. The infusion device of claim 15, wherein the residual value comprises a difference between a first measurement value of the measurement values after a post-prandial peak value of the measurement values and a second measurement value associated with the delivery of the bolus amount.

20. A method of operating an infusion device to deliver insulin to a user, the method comprising:

determining, by a control module of the infusion device, a bolus amount of insulin based on an input carbohydrate amount and a value for a carbohydrate ratio stored onboard the infusion device;

identifying, by the control module, a residual glucose value based on glucose measurement values after delivery of the bolus amount of insulin;

determining, by the control module, an adjustment factor for the carbohydrate ratio based on the residual glucose value;

scaling, by the control module, the value by the adjustment factor, resulting in an updated value for the carbohydrate ratio;

storing, by the control module, the updated value for the carbohydrate ratio onboard the infusion device; and

thereafter determining, by the control module, a second bolus amount of insulin based on a second input carbohydrate amount and the updated value for the carbohydrate ratio stored onboard the infusion device.