System and method for providing closed loop infusion formulation delivery

• US 8,152,789 B2
• Filed: 05/20/2004
• Issued: 04/10/2012
• Est. Priority Date: 10/23/2001
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Starkweather, Timothy J., Lebel, Ronald J., Shah, Rajiv, Miller, Michael E.
• Primary Examiner(s): Mehta, Bhisma
• Assistant Examiner(s): Bosques, Edelmira
• Application Number:
  US10/850,637
• Publication Number:
  US 20040220517A1
• Time in Patent Office: 2,882 Days
• Field of Search: 604/93.01, 604/67, 604/66, 604/131, 604/113, 604/500, 604/503, 604/504, 600/476, 600/365, 600/347, 600/316, 600/300
• US Class Current: 604/504
• CPC Class Codes: A61M 2005/14208 with a programmable infusion control system, characterised by the infusion program
• CPC Class Codes: A61M 2230/201 Glucose concentration
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• 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 50/30 for calculating health indices; for individual health risk assessment

Abstract

A system and method for providing closed loop infusion formulation delivery which accurately calculates a delivery amount based on a sensed biological state by adjusting an algorithm'"'"'s programmable control parameters. The algorithm calculates a delivery amount having proportional, derivative, and basal rate components. The control parameters may be adjusted in real time to compensate for changes in a sensed biological state that may result from daily events. Safety limits on the delivery amount may be included in the algorithm. The algorithm may be executed by a computing element within a process controller for controlling closed loop infusion formulation delivery. The biological state is sensed by a sensing device which provides a signal to the controller. The controller calculates an infusion formulation delivery amount based on the signal and sends commands to an infusion formulation delivery device which delivers an amount of infusion formulation determined by the commands.

Claims

1. A method for delivering insulin formulation, the method comprising:

delivering an amount of insulin formulation in accordance with a predefined delivery profile having a plurality of components, including a basal component that comprises a predefined amount of insulin formulation that is delivered to maintain a target blood glucose level;

sampling a blood glucose level at predefined timed intervals;

comparing the sampled blood glucose level to a predefined blood glucose level threshold; and

disabling delivery of the basal component of the delivery profile, if the sampled blood glucose level is less than the predefined blood glucose level threshold.

2. The method recited in claim 1, further comprising:

determining if a predefined time interval has been exceeded since a previous bolus delivery; and

disabling the bolus delivery if the predefined time interval has not been exceeded.

3. The method of claim 1, wherein comparing the sampled blood glucose level to the predefined blood glucose level threshold is performed independent of values other than the sampled blood glucose level and the predefined blood glucose level threshold.

4. The method recited in claim 1, wherein the basal rate component comprises an amount of insulin to deliver when the blood glucose level is at a desired level, to maintain the blood glucose level at the desired level.

5. The method recited in claim 1, wherein the plurality of components further includes a difference component based on the difference between a desired blood glucose level and the sampled blood glucose level.

6. The method recited in claim 1, wherein the plurality of components further includes a derivative component based on the rate at which the blood glucose level is changing.

7. The method recited in claim 1, wherein the plurality of components further includes a derivative component based on the rate at which the blood glucose level is changing and also based on whether or not the blood glucose level is rising.

8. The method recited in claim 1, wherein delivering an insulin formulation comprises defining a delivery amount at a time (t) using the predefined delivery profile, including determining the plurality of components for the time (t) and adding the plurality of components determined for the time (t).

27. The method recited in claim 8, further comprising filtering out high frequency components of the sampled blood glucose level.

28. The method recited in claim 27, wherein filtering comprises filtering with a low pass filter.

9. A method for delivering an insulin formulation, the method comprising:

delivering an amount of insulin formulation in accordance with a predefined delivery profile having a plurality of components, including a basal component;

sampling a blood glucose level at predefined timed intervals;

comparing the sampled blood glucose level to a predefined blood glucose level threshold; and

disabling delivery of the basal component of the delivery profile, if the sampled blood glucose level crosses the predefined blood glucose level threshold.

10. The method recited in claim 9, wherein disabling delivery of the basal component of the delivery profile occurs if the sampled blood glucose level is less than the predefined blood glucose level threshold.

11. The method recited in claim 9, wherein the insulin formulation is delivered as a bolus.

12. The method recited in claim 11, further comprising:

determining if a predefined time interval has been exceeded since a previous bolus delivery; and

disabling the bolus delivery if the predefined time interval has not been exceeded.

13. The method recited in claim 11, further comprising:

determining a time window for disabling a calculation of a delivery rate of the insulin formulation;

sampling a current time;

determining if the current time is within the time window; and

disabling the calculation of the delivery rate of the insulin formulation if the current time is within the time window.

14. The method recited in claim 13, wherein determining a time window further comprises providing programmable start and stop times for the time window.

15. The method recited in claim 14, wherein the programmable start and stop times for the time window are determined from historical physiological data.

16. The method recited in claim 13, further comprising enabling the calculation of the delivery rate of the insulin formulation if the current time is not within the time window.

17. The method recited in claim 13, further comprising delivering a minimal insulin formulation if the current time is within the time window.

18. The method recited in claim 13, further comprising delivering no insulin formulation if the current time is within the time window.

19. The method recited in claim 9, further comprising delivering a bolus of insulin formulation if the sampled blood glucose level is greater than the predefined blood glucose level threshold.

20. The method recited in claim 9, further comprising:

calculating an amount by which the sampled blood glucose level exceeds the predefined blood glucose level threshold;

determining a rate at which the sampled blood glucose level is changing; and

delivering an amount of insulin formulation based on the amount which the sampled blood glucose level exceeds the predefined blood glucose level threshold and the rate at which the sampled blood glucose level is changing.

21. The method recited in claim 20, further comprising introducing an adjustment into the amount of insulin formulation delivered, wherein the adjustment is not related to the amount which the sampled blood glucose level exceeds the predefined blood glucose level threshold or the rate at which the sampled blood glucose level is changing.

22. The method recited in claim 21, wherein the adjustment is introduced via programmable control parameters.

23. The method recited in claim 20, wherein determining a rate at which the sampled blood glucose level is changing occurs at predetermined intervals.

24. The method recited in claim 23, wherein the predetermined intervals are programmable.

25. The method recited in claim 20, wherein delivering an an amount of insulin formulation comprises delivering a basal rate of insulin formulation.

26. The method recited in claim 20, further comprising calculating an amount by which the sampled blood glucose level is offset over time from the predefined blood glucose level threshold.

29. A system for delivering an insulin formulation comprising:

an infusion device for delivering an amount of insulin formulation in accordance with control commands based on a predefined delivery profile having a plurality of components, including a basal rate component;

a data acquisition unit for sampling a blood glucose level at predefined timed intervals;

a comparator for comparing the sampled blood glucose level acquired by the data acquisition unit to a predefined blood glucose level threshold; and

a controller configured to provide control commands to the infusion device including a command for disabling delivery of the basal component of the delivery profile, if the sampled blood glucose level crosses the predefined blood glucose level threshold.

30. The system of claim 29, wherein the controller is configured to disable insulin formulation delivery if the sampled blood glucose level is less than the predefined blood glucose level threshold.

31. The system of claim 29, wherein the controller is configured to cause the insulin formulation to be delivered as a bolus.

32. The system of claim 31, wherein the data acquisition unit is further configured to determine if a predefined time interval has been exceeded since a previous bolus delivery;

and

wherein the controller disables the bolus delivery if the predefined time interval has not been exceeded.

33. The system of claim 31, wherein the data acquisition unit is further configured to determine if the sampled blood glucose level is rising at a predefined rate;

and

wherein the controller disables the bolus delivery if the sampled blood glucose level is rising at a rate less than the predefined rate.

34. The system of claim 31, wherein the data acquisition unit is configured to sample a current time;

and

wherein the controller is configured to;

determine a time window for disabling a calculation of a delivery rate of the insulin formulation;

determine if the current time is within the time window; and

disable the calculation of the delivery rate of the insulin formulation if the current time is within the time window.

35. The system of claim 34, wherein the controller is configured to provide programmable start and stop times for the time window.

36. The system of claim 35, wherein the controller determines the programmable start and stop times for the time window from historical physiological data.

37. The system of claim 34, wherein the controller is configured to enable the calculation of the delivery rate of the insulin formulation if the current time is not within the time window.

38. The system of claim 34, wherein the controller is configured to cause delivery of a minimal insulin formulation if the current time is within the time window.

39. The system of claim 34, wherein the controller is configured to cause delivery of no insulin formulation if the current time is within the time window.

40. The system of claim 29, wherein the controller causes an insulin formulation to be delivered if the sampled blood glucose level is greater than the predefined blood glucose level threshold.

41. The system of claim 29, wherein the controller is further configured to:

calculate an amount by which the sampled blood glucose level exceeds the predefined blood glucose level threshold;

determine a rate at which the sampled blood glucose level is changing; and

deliver an amount insulin formulation based on the amount which the sampled blood glucose level exceeds the predefined blood glucose level threshold and the rate at which the sampled blood glucose level is changing.

42. The system of claim 41, wherein the controller is configured to cause an adjustment to be introduced into the amount of insulin formulation delivered not related to the amount which the sampled blood glucose level exceeds the predefined blood glucose level threshold or the rate at which the sampled blood glucose level is changing.

43. The system of claim 42, wherein the controller is configured with programmable control parameters for introduction of the adjustment.

44. The system of claim 41, wherein the controller is configured to determine at predetermined intervals the rate at which the sampled blood glucose level is changing.

45. The system of claim 44, wherein the predetermined intervals are programmable.

46. The system of claim 41, wherein the controller is configured to calculate an amount by which the sampled blood glucose level is offset over time from the predefined blood glucose level threshold.

47. The system of claim 29, further comprising a filter for filtering out high frequency components of the sampled blood glucose level.

48. The system of claim 47, wherein the filter is a low pass filter.