CALCULATING INSULIN ON BOARD FOR EXTENDED BOLUS BEING DELIVERED BY AN INSULIN DELIVERY DEVICE

• US 20100017141A1
• Filed: 07/18/2008
• Published: 01/21/2010
• Est. Priority Date: 07/18/2008
• Status: Active Grant

• Current Assignee: Insulet Corporation
• Original Assignee: Insulet Corporation
• Inventors: Campbell, Robert, Abramovich, Amanda
• Granted Patent: US 8,140,275 B2
• Time in Patent Office: Days
• US Class Current: 702/19
• 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 5/14244 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

Abstract

A system and method may be used to calculate insulin on board (IOB) for an extended bolus being delivered by an insulin infusion pump. In general, the system and method calculates an extended bolus IOB value for the extended bolus, which takes into account the insulin currently on board from the extended bolus and the insulin scheduled to be delivered by the extended bolus over a subsequent time period equivalent to a duration of insulin action. The extended bolus IOB value may be used to calculate a suggested bolus.

Claims

1. A method of calculating insulin on board (IOB) for an extended bolus being delivered by an insulin infusion device, the method comprising:

determining a completed IOB value representing an amount of insulin on board from a completed portion of the extended bolus that has been completed within a previous time period substantially equal to a duration of insulin action;

determining a scheduled IOB value representing an amount of insulin scheduled to be delivered during a scheduled portion of the extended bolus within a subsequent time period substantially equal to the duration of insulin action; and

adding the completed IOB value to the scheduled IOB value to produce an extended bolus IOB value.

2. The method of claim 1 wherein the completed portion of the extended bolus is represented by a series of immediate bolus portions delivered at different times during the previous time period, and wherein determining the completed IOB value includes calculating IOB values for each of the series of immediate bolus portions at the respective times and adding the calculated IOB values for the series of immediate bolus portions.

3. The method of claim 2 wherein the calculated IOB values for each of the immediate bolus portions is calculated according to the equation V×

(1−

T_e/DIA), wherein V is the volume of the immediate bolus portion, DIA is the duration of insulin action, and T_e is the elapsed time since the immediate bolus portion was delivered.

4. The method of claim 1 wherein the extended bolus is a meal bolus.

5. A method of calculating insulin on board (IOB) for a user of an insulin infusion device, the method comprising:

determining if the insulin infusion device is currently delivering an extended bolus;

if the insulin infusion device is currently delivering at least one extended bolus, calculating at least one extended bolus insulin on board (IOB) value that takes into account an amount of insulin currently on board up to that point in time from the extended bolus and an amount of insulin scheduled to be delivered from the extended bolus within a subsequent time period substantially equal to a duration of insulin action;

determining if the insulin infusion device has delivered any previous bolus within a previous time period substantially equal to the duration of insulin action;

if the insulin infusion device has delivered at least one previous bolus within the previous time period, calculating at least one previous insulin on board (IOB) value for the at least one previous bolus; and

adding the at least one extended bolus IOB value and the at least one previous IOB value to produce a total IOB value.

6. The method of claim 5 wherein calculating the at least one previous IOB value includes calculating a meal IOB value representing insulin currently on board from a previous meal bolus given within the previous time period and a correction IOB value representing insulin currently on board from a previous correction bolus given within the previous time period.

7. The method of claim 5 wherein calculating the extended bolus IOB value comprises:

determining a completed IOB value representing an amount of insulin on board from a completed portion of the extended bolus that has been completed within a previous time period substantially equal to a duration of insulin action;

determining a scheduled IOB value representing an amount of insulin scheduled to be delivered during a scheduled portion of the extended bolus within a subsequent time period substantially equal to the duration of insulin action; and

adding the completed IOB value to the scheduled IOB value to produce the extended bolus IOB value.

8. A method of determining a suggested bolus of insulin to be delivered by an insulin infusion device, the method comprising:

determining if the insulin infusion device is currently delivering an extended bolus;

if the insulin infusion device is currently delivering at least one extended bolus, calculating at least one extended bolus insulin on board (IOB) value that takes into account an amount of insulin currently on board up to that point in time from the extended bolus and an amount of insulin scheduled to be delivered from the extended bolus within a subsequent time period substantially equal to a duration of insulin action;

determining if the insulin infusion device has delivered any previous bolus within a previous time period substantially equal to the duration of insulin action;

if the insulin infusion device has delivered at least one previous bolus within the previous time period, calculating at least one previous insulin on board (IOB) value for the at least one previous bolus; and

calculating a suggested bolus using at least one calculated IOB value selected from the group consisting of the at least one extended bolus IOB value and the at least one previous IOB value.

9. The method of claim 8 wherein calculating the extended bolus IOB value comprises:

determining a completed IOB value representing an amount of insulin on board from a completed portion of the extended bolus that has been completed within a previous time period substantially equal to a duration of insulin action;

determining a scheduled IOB value representing an amount of insulin scheduled to be delivered during a scheduled portion of the extended bolus within a subsequent time period substantially equal to the duration of insulin action; and

adding the completed IOB value to the scheduled IOB value to produce the extended bolus IOB value.

10. The method of claim 8 wherein calculating a suggested bolus dose includes:

calculating a meal bolus portion representing an amount of insulin to cover a carbohydrate intake;

calculating a correction bolus portion representing an amount of insulin to correct blood glucose to within a target blood glucose range; and

adding the carbohydrate bolus and the correction bolus and subtracting the at least one calculated IOB value.

11. The method of claim 8 wherein calculating the at least one previous IOB value includes calculating a meal IOB value representing insulin currently on board from a previous meal bolus given within the previous time period and a correction IOB value representing insulin currently on board from a previous correction bolus given within the previous time period.

12. The method of claim 11 wherein calculating a suggested bolus dose includes calculating a meal bolus representing an amount of insulin to cover a carbohydrate intake and subtracting the correction IOB value.

13. The method of claim 11 wherein calculating a suggested bolus dose includes calculating a correction bolus representing an amount of insulin to correct blood glucose to within a target blood glucose range and subtracting the at least one extended bolus IOB value, the meal IOB value, and the correction IOB value.

14. The method of claim 10 wherein the suggested bolus is an extended bolus.

15. A machine-readable medium whose contents cause a processor to perform a method of calculating insulin on board (IOB) for an extended bolus delivered by an insulin infusion device, the method comprising:

determining a completed IOB value representing an amount of insulin on board from a completed portion of the extended bolus that has been completed within a previous time period substantially equal to a duration of insulin action;

determining a scheduled IOB value representing an amount of insulin scheduled to be delivered during a scheduled portion of the extended bolus within a subsequent time period substantially equal to the duration of insulin action; and

adding the completed IOB value to the scheduled IOB value to produce an extended bolus IOB value.

16. The machine-readable medium of claim 15 wherein the completed portion of the extended bolus is represented by a plurality of bolus portions delivered at different times during the previous time period, and wherein determining the completed IOB value includes calculating IOB values for each of the plurality of bolus portions at the respective times and adding the calculated IOB values for the plurality of bolus portions.

17. The machine-readable medium of claim 15 wherein each of the calculated IOB values is calculated according to the equation V×

(1−

T_e/DIA), wherein V is the volume of the bolus portion, DIA is the duration of insulin action, and T_e is the elapsed time since the bolus portion was delivered.

18. A method of calculating bolus on board (BOB) for an extended bolus being delivered by a drug delivery device, the method comprising:

determining a completed BOB value representing an amount of the drug on board from a completed portion of the extended bolus that has been completed within a previous time period substantially equal to a duration of action of the drug;

determining a scheduled BOB value representing an amount of the drug scheduled to be delivered during a scheduled portion of the extended bolus within a subsequent time period substantially equal to the duration of action; and

adding the completed BOB value to the scheduled BOB value to produce an extended bolus BOB value.