INFUSION DEVICES AND RELATED METHODS AND SYSTEMS FOR REGULATING INSULIN ON BOARD

• US 20150306312A1
• Filed: 04/24/2014
• Published: 10/29/2015
• Est. Priority Date: 04/24/2014
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Palerm, Cesar C.
• Granted Patent: US 10,232,113 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 2005/1726 the body parameters being measured at, or proximate to, the infusion site
• 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 5/1684 by detecting the amount of infusate remaining, e.g. signalling end of infusion
• 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 capable of delivering fluid to a user involves determining a current amount of active fluid in the body of the user, determining a threshold amount of active fluid in the body of the user, and automatically altering operation of the infusion device to modify delivery of the fluid to the user based on a relationship between the current amount and the threshold amount.

Claims

1. A method of operating an infusion device operable to deliver fluid to a body of a user, the fluid influencing a physiological condition in the body, the method comprising:

determining a current amount of active fluid in the body of the user;

determining a threshold amount of active fluid in the body of the user; and

automatically altering operation of the infusion device to modify delivery of the fluid to the user based on a relationship between the current amount and the threshold amount.

2. The method of claim 1, wherein automatically altering operation of the infusion device comprises automatically operating the infusion device to regulate the current amount of active fluid to the threshold amount when the current amount is less than the threshold amount.

3. The method of claim 2, wherein determining the threshold amount comprises:

determining a reduced delivery rate based on a nominal delivery rate for the fluid; and

determining the threshold amount as a steady state result of the reduced delivery rate.

4. The method of claim 3, further comprising:

generating a delivery command configured to regulate the current amount of active fluid to the threshold amount;

generating a closed-loop delivery command based on a difference between a current measurement value for the physiological condition of the user and a target value for the physiological condition of the user, the closed-loop delivery command being configured to regulate the physiological condition of the user to the target value; and

operating the infusion device in accordance with the closed-loop delivery command when the closed-loop delivery command is greater than zero, wherein automatically altering operation of the infusion device comprises;

operating the infusion device in accordance with the delivery command when the closed-loop delivery command is less than or equal to zero.

5. The method of claim 1, wherein automatically altering operation of the infusion device comprises automatically transitioning the infusion device from a suspend delivery mode to an alternative delivery mode configured to regulate the current amount of active fluid to the threshold amount when the current amount is less than the threshold amount.

6. The method of claim 1, wherein automatically operating the infusion device to regulate the current amount of active fluid to the threshold amount comprises operating the infusion device to deliver the fluid based on a difference between the current amount of active fluid and the threshold amount of active fluid when a current measurement value for the physiological condition of the user is less than a target value for the physiological condition of the user.

7. The method of claim 1, further comprising:

determining a current value for the physiological condition of the user is less than a suspend enable threshold value;

determining a predicted value for the physiological condition of the user is less than a predictive suspend threshold value; and

prior to automatically altering operation of the infusion device, automatically disabling operation of the infusion device to deliver the fluid to the user when the current value is less than the suspend enable threshold value and the predicted value is less than the predictive suspend threshold value, wherein automatically altering operation of the infusion device comprises automatically enabling operation of the infusion device to deliver the fluid to the user in accordance with a delivery command configured to regulate the current amount to the threshold amount in response to determining the current amount of active fluid of the user is less than the threshold amount.

8. The method of claim 1, wherein automatically altering operation of the infusion device comprises automatically suspending the delivery of the fluid when the current amount is greater than the threshold amount.

9. The method of claim 8, further comprising operating the infusion device in a closed-loop mode to regulate the physiological condition of the user to a target value, wherein automatically altering operation of the infusion device comprises automatically suspending the delivery of the fluid upon transitioning from the closed-loop mode to an open-loop mode when the current amount is greater than the threshold amount.

10. The method of claim 9, further comprising, after automatically suspending the delivery, automatically enabling operation of the infusion device in accordance with the open-loop mode to deliver the fluid to the user when the current amount is less than the threshold amount.

11. The method of claim 8, wherein:

determining the threshold amount comprises determining a steady state threshold value for the fluid that is active in the body of the user based on a basal infusion rate; and

automatically suspending the delivery comprises automatically suspending the delivery of the fluid when the current amount is greater than the steady state threshold value.

12. A computer-readable medium having computer-executable instructions stored thereon that, when executed by a processing system associated with the infusion device, cause the processing system to perform the method of claim 1.

13. An infusion device comprising:

a motor operable to deliver fluid to a body of a user, delivery resulting in active fluid influencing a physiological condition in the body of the user; and

a control module coupled to the motor to operate the motor to deliver the fluid based on a difference between a current measurement value for the physiological condition and a target value for the physiological condition when the current measurement value is greater than the target value, and when the current measurement value is less than or equal to the target value;

operate the motor to deliver the fluid to regulate a current amount of the active fluid in the body of the user to a lower threshold amount for the active fluid in the body of the user when the current amount is less than the lower threshold amount; and

suspend operation of the motor when the current amount is greater than an upper threshold amount.

14. The infusion device of claim 13, the fluid comprising insulin, wherein:

the current measurement value comprises a current glucose measurement value for the user;

the lower threshold amount comprises a minimum insulin on board; and

the upper threshold amount comprises a steady-state insulin on board resulting from a basal infusion rate.

15. The infusion device of claim 13, the control module suspending operation of the motor based on the current measurement value, wherein the control module automatically enables operation of the motor when the current amount of the active fluid in the body of the user is less than the lower threshold amount.

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

identifying a minimum insulin on board for the user;

identifying a current insulin on board for the user;

generating a delivery command configured to regulate the current insulin on board to the minimum insulin on board; and

operating the infusion device in accordance with the delivery command.

17. The method of claim 16, further comprising:

generating a closed-loop delivery command based on a difference between a current glucose measurement value for the user and a target glucose value for the user, the closed-loop delivery command being configured to regulate the current glucose measurement value to the target glucose value; and

operating the infusion device in accordance with the closed-loop delivery command when the closed-loop delivery command is greater than zero, wherein operating the infusion device in accordance with the delivery command comprises operating the infusion device in accordance with the delivery command when the closed-loop delivery command is less than zero.

18. The method of claim 16, further comprising:

automatically suspending operation of a motor of the infusion device based at least in part on a current glucose measurement value for the user; and

prior to operating the infusion device in accordance with the delivery command, automatically enabling operation of the motor in response to determining the current insulin on board is less than the minimum insulin on board, wherein operating the infusion device comprises operating the motor in accordance with the delivery command.

19. The method of claim 18, further comprising determining the current glucose measurement value for the user is greater than a resume enable threshold value prior to automatically enabling operation of the motor.

20. The method of claim 16, further comprising identifying a nominal basal rate of delivery of the insulin, wherein identifying the minimum insulin on board comprises:

determining a reduced delivery rate based on the nominal basal rate; and

identifying the minimum insulin on board as a steady state insulin on board resulting from the reduced delivery rate.