Infusion devices and related methods and systems for preemptive alerting

• US 10,307,535 B2
• Filed: 12/19/2014
• Issued: 06/04/2019
• Est. Priority Date: 12/19/2014
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Palerm, Cesar C., Myers, Jeffrey C.
• Primary Examiner(s): Gray, Phillip A
• Application Number:
  US14/578,174
• Publication Number:
  US 20160175520A1
• Time in Patent Office: 1,628 Days
• Field of Search: 604504
• 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: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• 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

Infusion systems, infusion devices, and related operating methods are provided. An exemplary method of alerting a user associated with an infusion device delivering fluid to the body of the user involves obtaining a measurement value for a physiological condition being influenced by the fluid, obtaining a current amount of active fluid in the body of the user, determining a homeostasis metric based at least in part on the current amount of active fluid and the measurement value for the physiological condition, and generating an alert based at least in part on the homeostasis metric.

Claims

1. A method of alerting a user, the method comprising:

periodically obtaining interstitial fluid measurement values for a physiological condition in a body of the user from a sensing arrangement including one or more interstitial sensing elements, the physiological condition being influenced by a fluid delivered by an infusion device; and

in response to each new interstitial fluid measurement value of the interstitial fluid measurement values;

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

determining an estimated correction bolus amount of the fluid based at least in part on the current amount of active fluid, a target value for the physiological condition, and a current interstitial fluid measurement value for the physiological condition;

determining a trend adjustment factor based on a difference between the current interstitial fluid measurement value and a preceding interstitial fluid measurement value;

adjusting the estimated correction bolus amount by multiplying the estimated correction bolus amount by the trend adjustment factor; and

generating an alert when the estimated correction bolus amount is greater than an alert threshold value.

2. The method of claim 1, wherein:

periodically obtaining the interstitial fluid measurement values comprises periodically obtaining a current measurement value of an interstitial fluid glucose level of the user.

3. The method of claim 2, further comprising:

obtaining a current insulin sensitivity factor for the user, wherein determining the estimated correction bolus amount comprises determining the estimated correction bolus amount based at least in part on the current amount of active fluid, an amount of fluid pending delivery, the current insulin sensitivity factor, and the current measurement value.

4. The method of claim 3, further comprising determining the alert threshold value based at least in part on the current insulin sensitivity factor for the user.

5. The method of claim 1, further comprising:

obtaining a reference measurement value of a glucose level of the user at a time of a bolus;

determining an expected glucose measurement value at a subsequent time based at least in part on the current amount of active fluid and the reference measurement value; and

generating a notification based on a relationship between the expected glucose measurement value and a current measurement value of the glucose level of the user at the subsequent time.

6. The method of claim 5, further comprising:

obtaining an amount of fluid pending delivery at the subsequent time; and

obtaining a current insulin sensitivity factor for the user, wherein determining the expected glucose measurement value comprises;

determining an expected drop in the glucose level at the subsequent time based on the current insulin sensitivity factor and a difference between an amount of the bolus and a sum of the current amount of active fluid and the amount of fluid pending delivery; and

determining the expected glucose measurement value based on the expected drop and the reference measurement value.

7. The method of claim 1, further comprising:

obtaining a current measurement value of a glucose level of the user;

determining an excess insulin amount based at least in part on the current amount of active fluid and the current measurement value; and

generating a notification when the excess insulin amount is greater than a second threshold value.

8. 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.

9. The method of claim 1, wherein:

periodically obtaining the interstitial fluid measurement values comprises a control system of the infusion device obtaining the interstitial fluid measurement values from the sensing arrangement configured to obtain the interstitial fluid measurement values for the physiological condition from the body of the user; and

generating the alert comprises the control system generating the alert via a user interface.

10. The method of claim 9, wherein:

the fluid comprises insulin influencing a glucose level in the body of the user;

the infusion device comprises a motor operable to deliver the insulin to the body of the user;

the current interstitial fluid measurement value comprises a current interstitial fluid measurement value of the glucose level in the body of the user; and

the alert comprises a graphical notification of the estimated correction bolus amount.

11. The method of claim 1, wherein the estimated correction bolus amount is indicative of whether the future physiological condition of the user will likely be at an acceptable level or within an acceptable range of values without any affirmative action by the user.

12. The method of claim 1, wherein the estimated correction bolus amount is indicative of whether the physiological condition of the user will settle or achieve homeostasis at an acceptable level in the future.

13. The method of claim 1, wherein the alert comprises a notification recommending a correction bolus having a dosage equal to the estimated correction bolus amount.

14. The method of claim 1, further comprising suppressing any alerts that would be generated based on a predicted glucose level for the user using the estimated correction bolus amount.

15. The method of claim 1, wherein the interstitial fluid measurement values comprise interstitial fluid glucose measurement values.

16. The method of claim 1, wherein determining the estimated correction bolus amount of the fluid is governed by the equation

17. The method of claim 16, further comprising calculating the alert threshold value based at least in part on the sensitivity factor.

18. The method of claim 17, wherein calculating the alert threshold value is governed by the equation

19. The method of claim 16, further comprising:

obtaining pending delivery information pertaining to one or more pending delivery commands that have been generated or scheduled for implementation in the future; and

determining the amount of the fluid pending delivery based on the pending delivery information.

20. The method of claim 1, further comprising suppressing or disabling an alert when a predicted glucose level for the user exceeds an upper glucose threshold value and the estimated correction bolus is less than the alert threshold value.