Algorithm Sensor Augmented Bolus Estimator for Semi-Closed Loop Infusion System

• US 20120259278A1
• Filed: 06/21/2012
• Published: 10/11/2012
• Est. Priority Date: 02/01/2005
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Hayes, Andrew C., Mastrototaro, John J., Moberg, Sheldon B., Mueller, John C. Jr., Clark, H. Bud, Tolle, Mike Charles Vallet, Williams, Gary L., Wu, Bihong, Steil, Garry M.
• Granted Patent: US 9,320,471 B2
• Time in Patent Office: Days
• US Class Current: 604/66
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61M 2005/14208 with a programmable infusion control system, characterised by the infusion program
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/35 Communication
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/201 Glucose concentration
• 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 40/63 for local operation
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

An infusion system is for infusing a fluid into the body of a patient. The infusion system includes at least one sensor for monitoring blood glucose concentration of the patient and an infusion device for delivering fluid to the patient. The sensor produces at least one sensor signal input. The infusion device uses the at least one sensor signal input and a derivative predicted algorithm to determine future blood glucose levels. The infusion device delivers fluid to the patient when future blood glucose levels are in a patient'"'"'s target range. The infusion device is capable of suspending and resuming fluid delivery based on future blood glucose levels and a patient'"'"'s low shutoff threshold. The infusion device suspends fluid delivery when future blood glucose levels falls below the low shutoff threshold. The infusion device resumes fluid delivery when a future blood glucose level is above the low shutoff threshold.

Claims

1-9. -9. (canceled)

10. An infusion system for infusing a fluid into the body of a patient, the system comprising:

a sensor system that includes a sensor for monitoring blood glucose concentration of a patient, and produces at least one sensor signal, which is representative of the blood glucose concentration of the patient, and wherein the at least one sensor signal is used to generate at least one sensor signal input;

a controller, wherein the controller uses the at least one sensor signal input to determine at least one sensor-derived blood glucose trend, and wherein the at least one sensor-derived blood glucose trend is used to determine blood glucose levels at a predetermined time in the future; and

a delivery system that infuses a fluid into the patient, wherein operation of the delivery system is affected by commands from the controller and the patient,

wherein the controller suspends fluid delivery if the at least one sensor-derived trend yields at least one blood glucose level reading that is below a predefined low shutoff threshold.

11. The system according to claim 10, wherein the controller resumes delivery of the fluid when the at least one sensor-derived trend yields at least one blood glucose level reading that is above the predefined low shutoff threshold.

12. The system according to claim 10, wherein the predefined low shutoff threshold is always above the infusion system'"'"'s lowest shutoff threshold.

13. The system according to claim 10, wherein the controller uses a derivative predicted algorithm to determine the at least one sensor-derived blood glucose trend.

14. The system according to claim 10, wherein the infused fluid is insulin.

15. The system according to claim 10, wherein the infusion system further includes an alarm to provide alerts to the patient.

16. The system according to claim 15, wherein the patient selects at least one alarm to activate, wherein the at least one alarm includes an audible alarm for providing audible alerts, a vibration alarm for providing tactile alert, and a visual alarm for providing visual alerts.

18. The system according to claim 13, wherein the derivative predicted algorithm calculates a first derivative of a sensor current sample from the at least one sensor signal input at time period n, and then calculates a first derivative of a sensor glucose value from the at least one sensor signal input using the first derivative of the sensor current sample to determine future blood glucose levels.

19. The system according to claim 13, wherein the controller recommends more fluid delivery based on a positive derivative from the derivative predicted algorithm, and the controller recommends less fluid delivery based on a negative derivative from the derivative predicted algorithm.

20. The system according to claim 10, wherein the controller commands the delivery system to deliver fluid to the patient when future blood glucose levels are in the patient'"'"'s predefined target range.

21. The system according to claim 18, wherein the derivative predicted algorithm utilizes at least one of current blood glucose concentration, meal carbohydrate content, sensor current sample at time period n, system calibration factor, and insulin-on-board at time period n.

22. The system according to claim 18, wherein the first derivative of the sensor current sample is calculated from a slope of the sensor current sample versus time using a Savitzky-Golay finite impulse response filter.

17. (canceled)