METHOD AND SYSTEM FOR CLOSED-LOOP CONTROL OF AN ARTIFICIAL PANCREAS

• US 20140276554A1
• Filed: 03/15/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: JDRF International
• Original Assignee: Animas Corporation (Johnson & Johnson)
• Inventors: McCann, Thomas, Finan, Daniel
• Granted Patent: US 9,795,737 B2
• Time in Patent Office: Days
• US Class Current: 604/504
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61M 2005/14296 Pharmacokinetic models
• CPC Class Codes: A61M 2205/3553 remote, e.g. between patient's home and doctor's office
• CPC Class Codes: A61M 2205/3561 local, e.g. within room or hospital
• CPC Class Codes: A61M 2205/3584 using modem, internet or bluetooth
• CPC Class Codes: A61M 2205/3592 using telemetric means, e.g. radio or optical transmission
• 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 2209/01 Remote controllers for specific apparatus
• CPC Class Codes: A61M 2230/201 Glucose concentration
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: G16H 20/17 delivered via infusion or injection
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders

Abstract

Methods and systems for controlling an insulin pump in response to glucose measurements are responsive to a base insulin delivery profile and a temporary insulin delivery profile. These can be used, e.g., to control blood glucose level of a subject using a continuous glucose monitor and an insulin infusion pump. During a selected time range, an insulin amount for the pump to supply is determined using the temporary insulin delivery profile. Outside that time range, the insulin amount is determined using the base insulin delivery profile. The temporary insulin delivery profile can specify an exact amount to be supplied (a “hard” profile), a nominal amount to be supplied if doing so does not drive glucose out of a desired zone (“soft”), or a soft profile with a minimum amount of insulin to be delivered (“semi-soft”).

Claims

1. A method to control an infusion pump responsive to a controller that receives data from a glucose sensor, the method comprising:

measuring a glucose level of a physiological fluid from a user with the glucose sensor; and

automatically performing the following steps using the controller;

receiving from the glucose sensor respective glucose level measurements for each time interval of a series of discrete time intervals;

receiving a temporary insulin delivery profile extending over a selected time range of the time intervals;

calculating a candidate insulin delivery amount for a selected one of the time intervals based on a model predictive controller that;

predicts an excursion of the glucose level from a selected target glucose range using at least some of the glucose measurements;

computes an estimated insulin delivery amount; and

adjusts the estimated insulin delivery amount to provide the candidate insulin delivery amount, the adjustment performed in accordance with the predicted excursion, a base insulin delivery profile, or, if the selected time interval is in the selected range, the temporary insulin delivery profile;

determining an approved insulin delivery amount from the candidate insulin delivery amount; and

commanding the infusion pump to deliver the approved insulin delivery amount.

2. The method according to claim 1, wherein the step of receiving a temporary insulin delivery profile includes receiving a profile modifier and applying the profile modifier to the base insulin delivery profile to produce the temporary insulin delivery profile.

3. The method according to claim 1, wherein the adjustment includes:

if the selected time interval is in the selected range, adjusting the estimated delivery amount in accordance with the predicted excursion and the temporary insulin delivery profile; and

if the selected time interval is not in the selected range, adjusting the estimated delivery amount in accordance with the predicted excursion and the base insulin delivery profile.

4. The method according to claim 1, wherein the adjustment includes:

if the selected time interval is in the selected range, adjusting the estimated delivery amount in accordance with the predicted excursion and the temporary insulin delivery profile and constraining the calculated insulin delivery amount to be at least a difference between the temporary insulin delivery profile and the base insulin delivery profile in the selected time interval; and

if the selected time interval is not in the selected range, adjusting the estimated delivery amount in accordance with the predicted excursion and the base insulin delivery profile.

5. The method according to claim 1, wherein the determining-approved-amount step includes providing the candidate insulin delivery amount as the approved insulin delivery amount.

6. The method according to claim 1, wherein the determining-approved-amount step includes reducing the candidate delivery amount to provide the approved insulin delivery amount according to a safety model.

7. The method according to claim 1, wherein the temporary insulin delivery profile includes former and latter subranges of the selected time range and specifies higher amounts or rates of insulin delivery in the former subrange than in the latter subrange.

8. A method to control an infusion pump responsive to a controller that receives data from a glucose sensor, the method comprising:

measuring a glucose level of a physiological fluid from a user with the glucose sensor; and

automatically performing the following steps using the controller;

receiving from the glucose sensor respective glucose level measurements for each time interval of a series of discrete time intervals;

receiving a temporary insulin delivery profile extending over a selected time range of the time intervals;

calculating a candidate insulin delivery amount for a selected one of the time intervals based on a model predictive controller that;

if the selected time interval is outside the selected range,

predicts an excursion of the glucose level from a selected target glucose range using at least some of the glucose measurements;

computes an estimated insulin delivery amount; and

adjusts the estimated insulin delivery amount to provide the candidate insulin delivery amount, the adjustment performed in accordance with the predicted excursion and a base insulin delivery profile; and

if the selected time interval is in the selected range, retrieves the candidate insulin delivery amount for the selected time interval from the temporary insulin delivery profile;

determining an approved insulin delivery amount from the candidate insulin delivery amount; and

commanding the infusion pump to deliver the approved insulin delivery amount.

9. The method according to claim 8, wherein the determining-approved-amount step includes using a safety model to determine whether a hypoglycemic excursion is predicted and, if so, reducing the candidate delivery amount to provide the approved insulin delivery amount.

10. Apparatus for the delivery of insulin, the apparatus comprising:

a) a glucose monitor adapted to measure respective glucose levels of a subject at discrete time intervals and provide respective glucose measurement data indicating each measured glucose level;

b) an insulin infusion pump configured to deliver insulin in response to a delivery control signal;

c) a memory configured to store a base insulin delivery profile;

d) an interface adapted to selectively receive a temporary insulin delivery profile extending over a selected time range of the time intervals and to provide a first signal indicating whether the temporary insulin delivery profile was received; and

e) a controller adapted to, for each of a plurality of the discrete time intervals;

i) receive the glucose measurement data for that time interval from the glucose monitor;

ii) determine an insulin delivery amount for that time interval using model predictive control based on a selected target glucose concentration range, the received glucose measurement data, the stored base insulin delivery profile, or, in response to the first signal and if that time interval is in the selected time range, the received temporary insulin delivery profile; and

iii) provide to the insulin infusion pump a delivery control signal corresponding to the determined insulin delivery amount, whereby a corresponding amount of insulin is delivered.

11. The apparatus according to claim 10, wherein the interface is adapted to receive the temporary insulin delivery profile by receiving change information and modifying the stored base insulin delivery profile in the selected time range according to the change information to provide the temporary insulin delivery profile.

12. The apparatus according to claim 10, wherein the controller is adapted to determine the insulin delivery amount for a selected time interval using:

a) if the temporary insulin delivery profile was not received or the selected time interval is outside the selected time range, the selected target glucose concentration range, the received glucose measurement data, the stored base insulin delivery profile;

b) otherwise, the selected target glucose concentration range, the received glucose measurement data, and the received temporary insulin delivery profile.

13. The apparatus according to claim 10, wherein the controller is further adapted to, in response to the first signal and if a selected time interval is in the selected time range, constrain the determined insulin delivery amount for the selected time interval to be at least a difference between respective values of the temporary insulin delivery profile and the stored base insulin delivery profile for the selected time interval.

14. The apparatus according to claim 10, wherein the controller is further adapted to:

a) predict an excursion of a glucose level of the subject from the selected target glucose range using a safety model and at least some of the glucose measurement data for a plurality of the time intervals; and

b) reduce the determined insulin delivery amount according to the predicted excursion.

15. The apparatus according to claim 10, wherein the temporary insulin delivery profile includes former and latter subranges of the selected time range and specifies higher amounts or rates of insulin delivery in the former subrange than in the latter subrange.

16. The apparatus according to claim 10, wherein the glucose monitor includes a plurality of glucose sensors.

17. The apparatus according to claim 10, wherein the interface is further adapted to provide an activation signal and the controller, in response to the activation signal, retrieves the stored base insulin delivery profile and retrieves or determines the insulin delivery amount.

18. Apparatus for the delivery of insulin, the apparatus comprising:

a) a glucose monitor adapted to measure respective glucose levels of a subject at discrete time intervals and provide respective glucose measurement data indicating each measured glucose level;

b) an insulin infusion pump configured to deliver insulin in response to a delivery control signal;

c) a memory configured to store a base insulin delivery profile;

d) an interface adapted to receive a temporary insulin delivery profile extending over a selected time range of the time intervals; and

a controller adapted to, for each of a plurality of the discrete time intervals;

i) receive the glucose measurement data for that time interval from the glucose monitor;

ii) if that time interval is in the selected time range, retrieve a corresponding insulin delivery amount from the temporary insulin delivery profile, or else determine an insulin delivery amount for that time interval using model predictive control based on a selected target glucose concentration range, the received glucose measurement data, and the base insulin delivery profile; and

iii) provide to the insulin infusion pump a delivery control signal corresponding to the insulin delivery amount, whereby a corresponding amount of insulin is delivered.

19. The apparatus according to claim 18, wherein the controller is further adapted to:

a) predict an excursion of a glucose level of the subject from the selected target glucose range using a safety model and at least some of the glucose measurement data for a plurality of the time intervals; and

b) reduce the determined insulin delivery amount according to the predicted excursion.

20. The apparatus according to claim 18, wherein the glucose monitor includes a plurality of glucose sensors.

21. The apparatus according to claim 18, wherein the interface is further adapted to provide an activation signal and the controller, in response to the received activation signal, retrieves the stored base insulin delivery profile and retrieves or determines the insulin delivery amount.