Calibration factor adjustments for infusion devices and related methods and systems
First Claim
1. A method of autonomously operating an infusion device operable to deliver fluid to a user based on measurements indicative of a physiological condition of the user provided by a sensing arrangement during a startup period upon initialization of an interstitial glucose sensing element of the sensing arrangement, the fluid influencing the physiological condition of the user, the method comprising:
- sampling, by a control module coupled to the interstitial glucose sensing element of the sensing arrangement, output signals provided by the interstitial glucose sensing element to obtain one or more uncalibrated measurements indicative of the physiological condition, wherein the output signals are influenced by the physiological condition;
obtaining, by the control module, one or more reference measurements of the physiological condition, each respective reference measurement of the one or more reference measurements corresponding to a respective uncalibrated measurement of the one or more uncalibrated measurements;
determining, by the control module, a raw calibration factor based on a relationship between the one or more uncalibrated measurements and the one or more reference measurements corresponding to the respective uncalibrated measurements of the one or more uncalibrated measurements; and
when the raw calibration factor is outside of a range of acceptable values during the startup period where the sensitivity of the interstitial glucose sensing element is unsettled and deviates from a likely long-term sensitivity;
dynamically determining, by the control module, an adjusted calibration factor based at least in part on an expected calibration factor as a function of an elapsed time since a time associated with the raw calibration factor and the raw calibration factor, wherein the adjusted calibration factor is dynamically adjusted from the raw calibration factor towards the expected calibration factor as the elapsed time increases by calculating the adjusted calibration factor using the equation CFADJ=CFR+t(p1CFR+p2), where CFR is the raw calibration factor, t is the elapsed time since the time associated with the raw calibration factor, and p1 and p2 are scalar values configured to linearly adjust the adjusted calibration factor towards the expected calibration factor;
multiplying an uncalibrated measurement value obtained by sampling an output signal provided by the interstitial glucose sensing element by the adjusted calibration factor to obtain a sensed measurement value indicative of the physiological condition of the user; and
autonomously operating the infusion device to deliver the fluid in accordance with a delivery command determined using the sensed measurement value.
1 Assignment
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Accused Products
Abstract
Infusion systems, infusion devices, and related operating methods are provided. An exemplary method of operating an infusion device capable of delivering fluid to a user involves obtaining one or more uncalibrated measurements indicative of the physiological condition, obtaining one or more reference measurements of the physiological condition, determining a raw calibration factor based on a relationship between the one or more uncalibrated measurements and the one or more reference measurements corresponding to the respective uncalibrated measurements of the one or more uncalibrated measurements, and determining an adjusted calibration factor based at least in part on an expected calibration factor and the raw calibration factor, wherein operation of the infusion device to deliver the fluid is influenced by the adjusted calibration factor.
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Citations
18 Claims
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1. A method of autonomously operating an infusion device operable to deliver fluid to a user based on measurements indicative of a physiological condition of the user provided by a sensing arrangement during a startup period upon initialization of an interstitial glucose sensing element of the sensing arrangement, the fluid influencing the physiological condition of the user, the method comprising:
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sampling, by a control module coupled to the interstitial glucose sensing element of the sensing arrangement, output signals provided by the interstitial glucose sensing element to obtain one or more uncalibrated measurements indicative of the physiological condition, wherein the output signals are influenced by the physiological condition; obtaining, by the control module, one or more reference measurements of the physiological condition, each respective reference measurement of the one or more reference measurements corresponding to a respective uncalibrated measurement of the one or more uncalibrated measurements; determining, by the control module, a raw calibration factor based on a relationship between the one or more uncalibrated measurements and the one or more reference measurements corresponding to the respective uncalibrated measurements of the one or more uncalibrated measurements; and when the raw calibration factor is outside of a range of acceptable values during the startup period where the sensitivity of the interstitial glucose sensing element is unsettled and deviates from a likely long-term sensitivity; dynamically determining, by the control module, an adjusted calibration factor based at least in part on an expected calibration factor as a function of an elapsed time since a time associated with the raw calibration factor and the raw calibration factor, wherein the adjusted calibration factor is dynamically adjusted from the raw calibration factor towards the expected calibration factor as the elapsed time increases by calculating the adjusted calibration factor using the equation CFADJ=CFR+t(p1CFR+p2), where CFR is the raw calibration factor, t is the elapsed time since the time associated with the raw calibration factor, and p1 and p2 are scalar values configured to linearly adjust the adjusted calibration factor towards the expected calibration factor; multiplying an uncalibrated measurement value obtained by sampling an output signal provided by the interstitial glucose sensing element by the adjusted calibration factor to obtain a sensed measurement value indicative of the physiological condition of the user; and autonomously operating the infusion device to deliver the fluid in accordance with a delivery command determined using the sensed measurement value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An infusion system for autonomously delivering fluid to a user based on measurements indicative of a physiological condition of the user during a startup period upon initialization of an interstitial glucose sensing element, the fluid influencing the physiological condition of the user, the infusion system comprising:
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a sensing arrangement including the interstitial glucose sensing element to provide output signals influenced by the physiological condition in a body of the user, the sensing arrangement determining uncalibrated measurements of the physiological condition based at least in part on the output signals; and an infusion device comprising; a motor operable to deliver the fluid to the body of the user; and a control system to determine a delivery command for operating the motor based at least in part on a sensed measurement value obtained by multiplying an uncalibrated measurement value obtained by sampling an output signal provided by the interstitial glucose sensing element by an adjusted calibration factor for converting the uncalibrated measurements when the calibration factor is outside of a range of acceptable values during a startup period associated with the sensing arrangement where the sensitivity of the interstitial glucose sensing element is unsettled and deviates from a likely long-term sensitivity, wherein; the calibration factor is dynamically adjusted based at least in part on an expected calibration factor as a function of a raw calibration factor and an elapsed time since a time associated with the raw calibration factor; the raw calibration factor is calculated based on one or more reference measurements for the physiological condition and one or more of the uncalibrated measurements; the adjusted calibration factor is dynamically adjusted from the raw calibration factor towards the expected calibration factor as the elapsed time increases by calculating the adjusted calibration factor using the equation CFADJ=CFR+t(p1CFR+p2), where CFR is the raw calibration factor, t is the elapsed time since the time associated with the raw calibration factor, and p1 and p2 are scalar values configured to linearly adjust the adjusted calibration factor towards the expected calibration factor; and each of the one or more of the uncalibrated measurements is paired with a respective reference measurement of the one or more reference measurements. - View Dependent Claims (13, 14, 15, 16)
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17. A device comprising:
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an interstitial glucose sensing element to provide one or more signals influenced by a physiological condition of a user; and a control module coupled to the interstitial glucose sensing element to; sample the one or more signals provided by the interstitial glucose sensing element to obtain one or more uncalibrated measurements indicative of the physiological condition based on the one or more signals; obtain one or more reference measurements of the physiological condition, each respective reference measurement of the one or more reference measurements corresponding to a respective uncalibrated measurement of the one or more uncalibrated measurements; determine a raw calibration factor based on a relationship between the one or more uncalibrated measurements and the one or more reference measurements corresponding to the respective uncalibrated measurements of the one or more uncalibrated measurements; and when the raw calibration factor is not within a range of acceptable values during a startup period where the sensitivity of the interstitial glucose sensing element is unsettled and deviates from a likely long-term sensitivity, dynamically determine an adjusted calibration factor based at least in part on an expected calibration factor as a function of the raw calibration factor and an elapsed time since a time associated with the raw calibration factor, wherein; the adjusted calibration factor is dynamically adjusted from the raw calibration factor towards the expected calibration factor as the elapsed time increases by calculating the adjusted calibration factor using the equation CFADJ=CFR+t(p1CFR+p2), where CFR is the raw calibration factor, t is the elapsed time since the time associated with the raw calibration factor, and p1 and p2 are scalar values configured to linearly adjust the adjusted calibration factor towards the expected calibration factor; and autonomous delivery of a fluid influencing the physiological condition is influenced by a sensed measurement value obtained by multiplying an uncalibrated measurement value obtained by sampling an output signal provided by the interstitial glucose sensing element by the adjusted calibration factor. - View Dependent Claims (18)
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Specification