System and Method for Preventing Hypoglycaemia in a Human Type 1 Diabetic Patient During Physical Activity

• US 20080214905A1
• Filed: 07/28/2006
• Published: 09/04/2008
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: Universita' Degli Studi Di Trieste (Repubblica Italiana), Universita' Degli Studi Di Udine (Repubblica Italiana)
• Original Assignee: Universita' Degli Studi Di Udine (Repubblica Italiana)
• Inventors: Accardo, Agostino, Francescato, Maria P., Carrato, Sergio, Geat, Mario, Silli, Elena, Blokar, Marco
• Granted Patent: US 9,204,826 B2
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: G16H 20/17 delivered via infusion or injection
• CPC Class Codes: G16H 20/30 relating to physical therapies or activities, e.g. physiotherapy, acupressure or exercising

Abstract

A method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity, comprises the following steps: defining of working constants and standard parameters; introducing of patient and therapy specific parameters, calculating of patient specific reference curves for a percentage carbohydrates consumption (% CHO); scheduling a training session; estimating the amount of carbohydrates (CHO) to be eaten before said physical activity; updating in real time the residual carbohydrates still available during said physical activity; and estimating the amount of carbohydrates to be restored after said physical activity.

Claims

1. A method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity, comprising the following steps:

defining of working constants and standard parameters;

introducing of patient and therapy specific parameters;

calculating of patient specific reference curves for a percentage carbohydrates consumption (% CHO);

scheduling a training session;

estimating the amount of carbohydrates (CHO) to be eaten before said physical activity;

updating in real time the residual carbohydrates still available during said physical activity; and

estimating the amount of carbohydrates to be restored after said physical activity wherein;

said step of introducing of patient and therapy specific parameters comprises the value of glucose oxidation rate approximated with a linear relationship characterized by a slope (BGm) and intercept (BGq), as a carbohydrates consumption (grams/minutes) in function of the heart rate (beats/minutes) and

said step of updating in real time the residual carbohydrates still available during said physical activity comprises the calculation performed continuously of the current glucose oxidation rate calculated as the current heart rate using a linear relation.

2. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 1, wherein said step of defining the working constants and standard parameters comprises the steps of:

defining the number of hours of contribution of dinner insulin;

defining the relationship between effective insulinemy and percentage carbohydrates

defining the standard sensibility;

defining a reference glycemic curve;

defining the type-specific insulin curves; and

defining a type-specific standard insulin dose.

3. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 2, wherein the number of hours to be defined in said step of defining the number of hours of contribution of dinner insulin is 7 hours.

4. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 2, wherein said relationship between effective insulinemy and percentage carbohydrates is a linear relationship having a slope mpg=4.398 and intercept qpg=10.76.

5. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 2, wherein said standard sensibility is set as 4.836.

6. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 2, wherein said reference glycemic curve represents the standard value of glycaemia as a function of the time elapsed from the last meal.

7. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 2, wherein said type-specific insulin curves are curves representing the specific behaviour of each kind of insulin, presented as insulin blood concentration in function of time.

8. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 2, wherein said type-specific standard insulin dose is the standard amount of insulin yielding said type-specific insulin curves.

9. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 1, wherein said step of introducing of patient and therapy specific parameters further comprises the following values:

age;

weight;

sex;

extra cellular fluid (ECF).

10. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 9, wherein said value for the (ECF) when not available it can be approximated to (in Litres) 27% of the weight for men, and 22.5% of the weight for women.

11. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 1, wherein for each insulin assumption of the patient the following information must be specified:

kind of insulin;

dose in units;

time of the injection.

12. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 1, wherein said step of determining the personal glucose oxidation rate relationship of a patient can be obtained by performing measures during controlled physical activity of said patient and then performing a linear regression on the obtained set of values.

13. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 1, wherein said step of calculating patient specific reference curves for a percentage carbohydrates consumption (% CHO) further comprises the following steps:

calculate a dose ratio for each assumed insulin, said dose ratio being obtained dividing the assumed units of insulin by the weight of the subject, and then dividing the result by the standard dose for the specific kind of insulin;

calculate for each insulin the specific curve thereof by multiplying the corresponding standard curve by the dose ratio calculated on the abovementioned step;

cumulate each insulin curve to obtain the overall insulinemia of the patient expressed as concentration of micro units of insulin in the blood;

calculate a value of “

insulin for the period”

as the ratio between the cumulated insulin of a predetermined period and the overall insulin of the day, and multiplied by the units of insulin actually assumed;

calculate the ratio between the eaten carbohydrates and the sum of all the “

insulin for the period”

obtained at the previous step for each of the predetermined periods of the day, the obtained value being subsequently divided for the standard sensibility as obtained in the preceding steps to obtain the “

sensibility for the period”

(in grams of carbohydrates per units of insulin), which indicates the ability of insulin to oxidize the carbohydrates;

summing the curves of all the insulin assumptions to obtain a curve representing the blood concentration, and obtaining the curve of the total insulinemia for the whole day, said curve of the total insulinemia being further multiplied by said sensibility to obtain the effective insulinemia; and

normalising the obtained result into % CHO curves by a linear function having as slope (mpg) and as intercept (qpg).

14. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 1, wherein said step of scheduling the training session comprises the following data:

intensity of the activity, expressed as heart beats per minute (bpm);

starting time;

duration;

glycaemia half an hour before the starting time.

15. The method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 1, wherein said step of estimating of required carbohydrates to be eaten comprises the following steps:

calculate the grams of carbohydrates oxidized per minute, using a linear function of the bpm of the activity, having as slope (BGm) and as intercept (BGq);

multiplying the obtained value times the presumed session duration, the total value of oxidized carbohydrates is then calculated;

calculate the effective amount of carbohydrates to be assumed before the end of exercise by multiplying the estimated carbohydrates oxidation of the previous step by the mean of % CHO consumption within the time range that goes from the beginning of the session to its end;

calculate the actual carbohydrates surplus as the carbohydrates already available in the patient body before the activity, by multiplying the ECF by the difference between the glycaemia half an hour before said activity and the standard reference glycaemia for that time (defined by the reference glycemic curve); and

obtaining the estimated amount of carbohydrates to be assumed as the difference of the effective amount of carbohydrates to be consumed and the carbohydrates surplus of the previous steps.

16. The method for estimating the amount of carbohydrates needed by a DIP-1 during a specific session of physical activity according to claim 1, wherein said step of updating in real time the residual carbohydrates still available during said physical activity further comprises the following calculations performed continuously:

the value of the corresponding required carbohydrates calculated by multiplying the current glucose oxidation rate by the % CHO at the current time; and

the amount of overall required carbohydrates being updated cumulating the value of carbohydrates calculated in the previous step.

17. Apparatus for carrying out the method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 1, comprising the following items:

a chest strap for detecting a heart rate of a patient;

a control and input panel for inputting the data about the characteristics of the patient and the therapy thereof;

a processing unit for coordinating the peripherals of the overall system and run the software that allows interaction of the device with the user, and then calculating the desired values;

a solid memory (data memory) to store the characteristics of the patient and possibly the history of the various sessions;

a power supply which can be remote or via a rechargeable unit;

output peripherals such as a display for displaying the value of parameters, current status and show alarms in case of critical conditions;

interface ports such a PC connection;

external memory interfaces in order to exchange data, mainly the characteristics of the patient, but also session history;

further output peripherals such as LEDs and a beeper.

18. Apparatus for carrying out the method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 17, wherein the apparatus overall sizes are chosen among the following group:

an integration in gym or electro-medical devices fixed apparatus;

a wrist watch-like apparatus/device;

belt supported apparatus;

necklace supported apparatus;

arm-wearable supported;

simple pocket apparatus.

19. A computer program for carrying out the method for estimating the amount of carbohydrates needed by a DP-1 during a specific session of physical activity according to claim 1.