Method and/or system for multicompartment analyte monitoring

• US 9,907,491 B2
• Filed: 10/22/2012
• Issued: 03/06/2018
• Est. Priority Date: 10/25/2011
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Li, Xialong, Kannard, Brian T., Shah, Rajiv
• Primary Examiner(s): Cheng, Jacqueline
• Assistant Examiner(s): PREMRAJ, ANGELINE L
• Application Number:
  US13/657,642
• Publication Number:
  US 20130102866A1
• Time in Patent Office: 1,961 Days
• CPC Class Codes: A61B 5/1451 for interstitial fluid
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/6849 in combination with a needle set
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

Subject matter disclosed herein relates to monitoring and/or controlling levels of an analyte in bodily fluid. In particular, estimation of a concentration of the analyte in a first physiological compartment based upon observations of a concentration of the analyte in a second physiological compartment may account for a latency in transporting the analyte between the first and second physiological compartments.

Claims

1. A method of using an analyte monitoring system comprising:

modeling a latency in transportation of an analyte between first and second physiological compartments;

compensating for the latency in estimating a concentration of the analyte in the first physiological compartment based, at least in part, on one or more measurements of a concentration of the analyte in the second physiological compartment, wherein compensating for the latency is based at least in part on a first parameter comprising a ratio of a volume of a plasma or fluid in the second physiological compartment to a volume of a plasma or fluid in the first physiological compartment, and wherein the one or more measurements are obtained based, at least in part, on one or more values of a sensor signal;

compensating for an attenuation of the concentration of the analyte in the second physiological compartment in estimating the concentration of the analyte in the first physiological compartment, wherein compensating for the attenuation is based at least in part on the first parameter and a second parameter, wherein the second parameter comprises a ratio of a third parameter to a fourth parameter,

wherein the third parameter comprises a sum of a rate of cellular uptake of the analyte and a flux rate for analyte transportation from the second physiological compartment to the first physiological compartment, and

wherein the fourth parameter comprises a flux rate for analyte transportation from the first physiological compartment to the second physiological compartment, and

wherein the estimating of the concentration of the analyte in the first physiological compartment further comprises;

multiplying an estimated rate of change in the sensor signal by a first coefficient to provide a first product, wherein the first coefficient is based, at least in part, on the first parameter;

multiplying a first one of the one or more sensor signal values by a second coefficient to provide a second product, wherein the second coefficient is different than the first coefficient and is based, at least in part, on the first and second parameters; and

combining the first and second products with an attenuation offset to provide an estimate of the concentration of the analyte in the first physiological compartment,

wherein the attenuation offset is based, at least in part, on the rate of cellular uptake of the analyte; and

wherein the method further comprises generating a command to one or more infusion pumps for infusion of insulin, wherein the command is computed based, at least in part, on the estimated concentration of the analyte in the first physiological compartment.

2. The method of claim 1, wherein the analyte comprises glucose, the first physiological compartment comprises blood plasma, and the second physiological compartment comprises interstitial fluid.

3. The method of claim 1, wherein the one or more measurements are obtained based, at least in part, on one or more values of a sensor signal, and wherein modeling the latency further comprises modeling the latency based, at least in part, on an estimated rate of change in the sensor signal.

4. The method of claim 3, wherein the estimated rate of change comprises an estimated first derivative of the sensor signal.

5. The method of claim 3, wherein the one or more values of the sensor signal comprise a measured current responsive to the concentration of the analyte in the second physiological compartment.

6. The method of claim 1, wherein the latency is based, at least in part, on a latency of a presence of glucose in a patient'"'"'s interstitial fluid to be affected by a blood glucose concentration in the patient.

7. The method of claim 1, wherein the estimating of the concentration of the analyte in the first physiological compartment further comprises integrating an expression comprising at least in part a sensor signal value and a second offset different than the attenuation offset.

8. The method of claim 7, further comprising calculating the second offset based, at least in part, on correlated pairings of sample sensor signal values and blood glucose reference samples.

9. An apparatus for use with insulin, for use with one or more insulin infusion pumps, and for use with an analyte in a second physiological compartment, the apparatus comprising:

a sensor to generate a sensor signal responsive to a concentration of the analyte in the second physiological compartment; and

a processor configured to;

model a latency in transportation of the analyte between the second physiological compartment and a first physiological compartment; and

compensate for the latency in a concentration estimation of the analyte in the first physiological compartment to be based, at least in part, on one or more measurements of the concentration of the analyte in the second physiological compartment, wherein compensation for the latency is to be based at least in part on a first parameter to comprise a ratio of a volume of a plasma or fluid in the second physiological compartment to a volume of a plasma or fluid in the first physiological compartment, and wherein the one or more measurements are to be obtained based, at least in part, on one or more values of the sensor signal;

compensate for an attenuation of the concentration of the analyte in the second physiological compartment in the concentration estimation of the analyte in the first physiological compartment, wherein compensation for the attenuation is to be based at least in part on the first parameter and a second parameter, wherein the second parameter comprises a ratio of a third parameter to a fourth parameter,

wherein the third parameter comprises a sum of a rate of cellular uptake of the analyte and a flux rate for analyte transportation from the second physiological compartment to the first physiological compartment, and

wherein the fourth parameter comprises a flux rate for analyte transportation from the first physiological compartment to the second physiological compartment, and

wherein the processor is further configured to estimate the concentration of the analyte in the first physiological compartment by;

multiplying an estimated rate of change in the sensor signal by a first coefficient to provide a first product, wherein the first coefficient is based, at least in part, on the first parameter;

multiplying a first one of the one or more sensor signal values by a second coefficient to provide a second product, wherein the second coefficient is different than the first coefficient and is based, at least in part, on the first and second parameters; and

combining the first and second products with an attenuation offset to provide an estimate of the concentration of the analyte in the first physiological compartment,

wherein the attenuation offset is based, at least in part, on the rate of cellular uptake of the analyte; and

wherein the processor is further configured to generate a command to the one or more infusion pumps to infuse the insulin, wherein the command is computed based, at least in part, on the estimated concentration of the analyte in the first physiological compartment.

10. The apparatus of claim 9, wherein the signal generated responsive to the concentration of the analyte is to comprise a measured current responsive to the concentration of the analyte in the second physiological compartment.

11. The apparatus of claim 9, wherein the analyte is to comprise glucose, the first physiological compartment is to comprise blood plasma, and the second physiological compartment is to comprise interstitial fluid.

12. The apparatus of claim 9, wherein the latency is to be based, at least in part, on a latency of a presence of glucose in a patient'"'"'s interstitial fluid to be affected by a blood glucose concentration in the patient.

13. The apparatus of claim 9, wherein the processor is further configured to estimate the concentration of the analyte in the first physiological compartment based, at least in part, on an expression comprising at least in part a sensor signal value and a second offset different than the attenuation offset, the expression to be integrated to remove sensor signal noise.

14. An article for use with a sensor configured to provide a sensor signal, for use with insulin, for use with one or more infusion pumps, and for use with an analyte in a second physiological compartment, the article comprising:

a non-transitory computer-readable storage medium having machine-readable instructions stored thereon which are executable by a special purpose computing apparatus configured to;

model a latency in transportation of the analyte between the second physiological compartment and a first physiological compartment;

compensate for the latency in a concentration estimation of the analyte in the first physiological compartment to be based, at least in part, on one or more measurements of a concentration of the analyte in the second physiological compartment, wherein compensation for the latency is to be based at least in part on a first parameter to comprise a ratio of a volume of a plasma or fluid in the second physiological compartment to a volume of a plasma or fluid in the first physiological compartment, and wherein the one or more measurements are obtained based, at least in part, on one or more values of the sensor signal;

compensate for an attenuation of the concentration of the analyte in the second physiological compartment in the concentration estimation of the analyte in the first physiological compartment, wherein compensation for the attenuation is to be based at least in part on the first parameter and a second parameter, wherein the second parameter comprises a ratio of a third parameter to a fourth parameter,

wherein the third parameter comprises a sum of a rate of cellular uptake of the analyte and a flux rate for analyte transportation from the second physiological compartment to the first physiological compartment, and

wherein the fourth parameter comprises a flux rate for analyte transportation from the first physiological compartment to the second physiological compartment;

wherein the machine-readable instructions are further executable by the special purpose computing apparatus to estimate the concentration of the analyte in the first physiological compartment by;

multiplying an estimated rate of change in the sensor signal by a first coefficient to provide a first product, wherein the first coefficient is based, at least in part, on the first parameter;

multiplying a first one of the one or more sensor signal values by a second coefficient to provide a second product, wherein the second coefficient is different than the first coefficient and is based, at least in part, on the first and second parameters; and

combining the first and second products with an attenuation offset to provide an estimate of the concentration of the analyte in the first physiological compartment,

wherein the attenuation offset is based, at least in part, on the rate of cellular uptake of the analyte, and

wherein the machine-readable instructions are further executable by the special purpose computing apparatus to generate a command to the one or more infusion pumps to infuse the insulin, wherein the command is to be computed based, at least in part, on the estimated concentration of the analyte in the first physiological compartment.

15. The article of claim 14, wherein the machine-readable instructions are further executable by the special purpose computing apparatus to model the latency based, at least in part on an estimated rate of change in the sensor signal.

16. The article of claim 14, wherein the analyte is to comprise glucose, the first physiological compartment is to comprise blood plasma, and the second physiological compartment is to comprise interstitial fluid.

17. The article of claim 14, wherein the latency is to be based, at least in part, on a latency of a presence of glucose in a patient'"'"'s interstitial fluid to be affected by a blood glucose concentration in the patient.

18. The article of claim 14, wherein the machine-readable instructions are further executable by the special purpose computing apparatus to estimate the concentration of the analyte in the first physiological compartment based, at least in part, on an expression comprising at least in part a sensor signal value and a second offset different than the attenuation offset, the expression to be integrated to remove sensor signal noise.

19. An apparatus for use with a sensor configured to provide a sensor signal, for use with insulin, for use with one or more infusion pumps, and for use with an analyte in a second physiological compartment, the apparatus comprising:

means for modeling a latency in transportation of the analyte between the second physiological compartment and a first physiological compartment;

means for compensating for the latency in estimating a concentration of the analyte in the first physiological compartment based, at least in part, on one or more measurements of a concentration of the analyte in the second physiological compartment, wherein compensating for the latency is based at least in part on a first parameter comprising a ratio of a volume of a plasma or fluid in the second physiological compartment to a volume of a plasma or fluid in the first physiological compartment, and wherein the one or more measurements are obtained based, at least in part, on one or more values of the sensor signal;

means for compensating for an attenuation of the concentration of the analyte in the second physiological compartment in estimating the concentration of the analyte in the first physiological compartment, wherein compensating for the attenuation is based at least in part on the first parameter and a second parameter, wherein the second parameter comprises a ratio of a third parameter to a fourth parameter,

wherein the third parameter comprises a sum of a rate of cellular uptake of the analyte and a flux rate for analyte transportation from the second physiological compartment to the first physiological compartment, and

wherein the fourth parameter comprises a flux rate for analyte transportation from the first physiological compartment to the second physiological compartment;

wherein the estimating of the concentration of the analyte in the first physiological compartment further comprises;

means for multiplying an estimated rate of change in the sensor signal by a first coefficient to provide a first product, wherein the first coefficient is based, at least in part, on the first parameter;

means for multiplying a first one of the one or more sensor signal values by a second coefficient to provide a second product, wherein the second coefficient is different than the first coefficient and is based, at least in part, on the first and second parameters; and

means for combining the first and second products with an attenuation offset to provide an estimate of the concentration of the analyte in the first physiological compartment,

wherein the attenuation offset is based, at least in part, on the rate of cellular uptake of the analyte, and

wherein the apparatus further comprises means for generating a command to the one or more infusion pumps for infusing the insulin based, at least in part, on the estimated concentration of the analyte in the first physiological compartment.