Method for storing a series of measurements

• US 9,014,986 B2
• Filed: 04/15/2010
• Issued: 04/21/2015
• Est. Priority Date: 10/16/2007
• Status: Active Grant

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics International AG (Roche Holding AG)
• Inventors: Krieftewirth, Michael
• Primary Examiner(s): Lin, Jerry
• Application Number:
  US12/760,808
• Publication Number:
  US 20110106453A1
• Time in Patent Office: 1,832 Days
• Field of Search: 702/19
• US Class Current: 702/19
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: G01D 9/005 Solid-state data loggers

Abstract

A method reducing storage volume of a series of measured time-dependent parameters measured in or on the human body such as glucose values from a continuous glucose monitor while permitting retrospective reconstruction of measured data with sufficient accuracy. The series comprises a first number of measured values, and a second number of values that are stored. In this case, the second number is smaller than the first number. A first storage mode is provided, in which an interval of time between successive stored values is variable and which is adjusted on the basis of a time-based variability of the measured values. A second storage mode may also be provided, in which the interval, of time between successive stored values is constant. Embodiments of the invention include a measuring apparatus and a computer program.

Claims

1. A method for improving storage of an apparatus that stores a series of measured values which represent a time-dependent parameter measured in or on the human body by a sensor, comprising:

providing an apparatus for storing the series of measured values, the apparatus comprising a system controller having a memory and a first storage mode in which an interval of time between each successively stored measured value is variable based on automatic selection of the time interval by the system controller using a storage criterion determined from information on at least one event which influenced the time-dependent parameter;

measuring by the sensor a first number of measured values in a series; and

storing in the memory by the system controller a second number of measured values in the series of measured values as measured data using the first storage mode, wherein the second number is smaller than the first number which reduces a stored volume of the measured data in the memory of the apparatus needed to reproduce a profile based on the time-dependent parameter from the measured data.

2. The method according to claim 1, wherein the first storage mode the interval of time is adjusted on the basis of a time-based variability of the measured values.

3. The method according to claim 2, wherein a measure of error in an interpolation between a last stored value and a most recently measured value is formed for a relevant range of the series of measured values, wherein a value from the relevant range of the series is stored if the measure of error exceeds a certain maximum value.

4. The method according to claim 3, wherein linear interpolation is performed between the last stored value and the most recently measured value.

5. The method according to claim 1, further comprising a second storage mode in which the interval of time between each successively stored value is constant, wherein particularly the first storage mode is used if a variability of the measured values is below a prescribed value, and the second storage mode is used if the variability exceeds the prescribed value.

6. The method according to claim 1, wherein trend values are ascertained from the series of measured values.

7. The method according to claim 6, wherein a Kalman filter is used to ascertain the trend values.

8. The method according to claim 1, wherein a current measured value is stored if a trend value change associated with the currently measured value exceeds a prescribed minimum value.

9. The method according to claim 6, wherein a current measured value is stored if a trend value change associated with the currently measured value exceeds a prescribed minimum value.

10. The method according to claim 6, wherein trend values are also stored besides the stored values.

11. The method according to claim 10, wherein trend change values corresponding to a second derivative of the measured values are ascertained from the series of measured values.

12. The method according to claim 10, wherein time-based interpolation points are provided, at which the relevant trend value and/or trend change value, but not the measured value itself, is stored.

13. The method according to claim 1, wherein the time-dependent parameter measured in or on the human body is a physiological glucose concentration.

14. The method according to claim 1, wherein the at least one event which influenced the time-dependent parameter is selected from an analyses of the measured values or values derived therefrom, a discrepancy or error value in the measured values from a prediction or extrapolation, fluctuations based on time scale, noise, or appliance-related short-term measurement inaccuracies, time of day, carbohydrate content of meals taken, administered insulin boluses, nature and duration of an undertaken activity, fasting state, and sleeping state.

15. A method for improving storage of an apparatus that stores a series of measured time-dependent glucose values from a continuous glucose monitor while permitting retrospective reconstruction of measured data with sufficient accuracy, comprising:

providing an apparatus for storing the series of measured values, the apparatus comprising a system controller having a memory and a first storage mode in which an interval of time between each successively stored measured value is variable based on automatic selection of the time interval by the system controller using a storage criterion determined from information on at least one event which influenced the time-dependent parameter, and the apparatus comprising a second storage mode;

measuring a first number of glucose values in a series by a continuous glucose monitor;

analyzing by the system controller whether the first number of glucose values is below or above a prescribed value;

using by the system controller the first storage mode that is adaptive if the first number of glucose values is below the prescribed threshold to store in the memory of the apparatus a second number of glucose values with the interval of time between each successively stored value being variable and the second number of glucose values being smaller than the first number which reduces a stored volume of measured data in the memory of the apparatus;

using by the system controller the second storage mode that is constant if the first number of glucose values is above the prescribed threshold to store in the memory of the apparatus the second number of glucose values with the interval of time between each successively stored value being constant and the second number of glucose values being smaller than the first number which further reduces the stored volume of the measured data in the memory of the apparatus; and

,

storing in the memory of the apparatus by the system controller trend values with the second number of glucose values to improve reconstruction of the first number of glucose values from the stored volume of the measured data for a measurement curve.

16. An apparatus for storing a series of measured values which represent a time-dependent parameter measured in or on the human body, comprising:

a measuring apparatus which continuously measures and feeds in a series of measured values for a parameter measured on, or in a human body, wherein the parameter is a glucose concentration;

a system controller having a memory unit for storing the measured values,

wherein the system controller is programmed such that, for a first number of the values covered by the series, a second number of values are stored in memory by the system controller as measured data using a first storage mode of the apparatus in which an interval of time between each successively stored measured value is variable based on automatic selection of the time interval by the apparatus using a storage criterion determined from information on at least one event which influenced the time-dependent parameter, and

wherein the second number is smaller than the first number which reduces a stored volume of the measured data in the memory of the apparatus needed to reproduce a profile based on the time-dependent parameter from the measured data.

17. The apparatus according to claim 16, wherein a buffer store is provided which can be used to buffer-store continuously measured values, and also an evaluation apparatus for analyzing a variability of the measured values is present.

18. The apparatus according to claim 16, wherein the system controller calculates at least one of trend values using an expected future profile of the measured parameter, a derivative of the measured values with respect to time, and a derivative of the trend values with respect to time.

19. The apparatus according to claim 16, wherein the apparatus is a portable apparatus.

20. A computer program product embodied on a tangible computer readable medium comprising instructions that when executed on an apparatus having a system controller and memory cause the apparatus to:

a) receive by the system controller a first number of the values covered by a series of measured values which represent a time-dependent parameter measured in or on a human body by a measuring apparatus in communication with the apparatus, and

b) store in memory by the system controller a second number of values covered by the series as measured data using a first storage mode of the apparatus in which an interval of time between each successively stored measured value is variable based on automatic selection of the time interval by the system controller using a storage criterion determined from information on at least one event which influenced the time-dependent parameter, wherein the second number is smaller than the first number which reduces a stored volume of the measured data in the memory of the apparatus needed to reproduce a profile based on the time-dependent parameter from the measured data.

21. The computer program product according to claim 20, further comprising instructions that when executed on the apparatus having the system controller and memory cause the apparatus to:

c) store in a buffer continuously measured values received by the system controller, and analyze the measured values by the system controller for variability.

22. The computer program product according to claim 20, further comprising instructions that when executed on the apparatus having the system controller and memory cause the apparatus to:

d) calculate trend values using an expected future profile of the measured parameter.

23. The computer program product according to claim 20, wherein the instructions cause the apparatus to calculate the trend values using the expected future profile of the measured parameter by causing the system controller to calculate a derivative of the measured values with respect to time and to determine a derivative of the trend values with respect to time.