Intuitive user interface features and related functionality for a therapy delivery system

Disclosed is a method of controlling operation of a medical device that regulates delivery of a fluid medication to a user. The method receives meter-generated values that are indicative of a physiological characteristic of the user, and are produced in response to operation of an analyte meter device. The method obtains sensor-generated values that are indicative of the physiological characteristic of the user, and are produced in response to operation of a continuous analyte sensor device, different than the analyte meter device. The medical device is operated in different modes when: a valid meter-generated value is available; a valid meter-generated value is unavailable and a current sensor-generated value satisfies first quality criteria; or a valid meter-generated value is unavailable and the current sensor-generated value satisfies second quality criteria but does not satisfy the first quality criteria.

TECHNICAL FIELD

Embodiments of the subject matter described herein relate generally to a system that delivers therapy (e.g., medicine) to a user. More specifically, the subject matter described herein relates to user interface and quality checking features of an insulin infusion system that obtains glucose readings from a continuous glucose sensor.

BACKGROUND

Medical therapy delivery systems, such as fluid infusion pump devices, are relatively well known in the medical arts, for use in delivering or dispensing an agent, such as insulin or another prescribed medication, to a patient. A typical infusion pump includes a pump drive system that usually includes a small motor and drive train components that convert rotational motor motion to a translational displacement of a plunger (or stopper) in a fluid reservoir, which delivers medication from the reservoir to the body of a patient via a fluid path created between the reservoir and the body of a patient. Use of infusion pump therapy has been increasing, especially for delivering insulin for diabetics.

Control schemes have been developed to allow insulin infusion pumps to monitor and regulate a patient's blood glucose level in a substantially continuous and autonomous manner. Managing a diabetic's blood glucose level is complicated by variations in a patient's daily activities (e.g., exercise, carbohydrate consumption, and the like) in addition to variations in the patient's individual insulin response and potentially other factors. Some control schemes may attempt to proactively account for daily activities to minimize glucose excursions. At the same time, patients may manually initiate delivery of insulin prior to or contemporaneously with consuming a meal (e.g., a meal bolus or correction bolus) to prevent spikes or swings in the patient's blood glucose level that could otherwise result from the impending consumption of carbohydrates and the response time of the control scheme.

BRIEF SUMMARY

Disclosed herein is a method of controlling operation of a medical device that regulates delivery of a fluid medication to a user. An embodiment of the method involves: receiving meter-generated values that are indicative of a physiological characteristic of the user, the meter-generated values produced in response to operation of an analyte meter device; and obtaining sensor-generated values that are indicative of the physiological characteristic of the user, the sensor-generated values produced in response to operation of a continuous analyte sensor device, different than the analyte meter device. When a valid meter-generated value is available, the medical device is operated in a first mode to display the valid meter-generated value on a user monitoring screen of the medical device and on a therapy delivery control screen of the medical device, and operating the medical device in the first mode to calculate therapy dosage for delivery based on the valid meter-generated value. When a valid meter-generated value is unavailable and a current sensor-generated value of the sensor-generated values satisfies first quality criteria, the medical device is operated in a second mode to display the current sensor-generated value on the user monitoring screen and on the therapy delivery control screen, and to calculate therapy dosage for delivery based on the current sensor-generated value. When a valid meter-generated value is unavailable and the current sensor-generated value satisfies second quality criteria but does not satisfy the first quality criteria, the medical device is operated in a third mode to display the current sensor-generated value on the user monitoring screen, to inhibit display of the current sensor-generated value on the therapy delivery control screen, and to inhibit use of the current sensor-generated value for purposes of calculating therapy dosage for delivery.

Also disclosed herein is a medical device that regulates delivery of medication to a user. An embodiment of the medical device includes: a drive system; at least one processor device that regulates operation of the drive system to deliver a fluid medication from the medical device; a display device; and at least one memory element associated with the at least one processor device, the at least one memory element storing processor-executable instructions configurable to be executed by the at least one processor device to perform a method of controlling operation of the medical device. An embodiment of the method involves: receiving meter-generated values that are indicative of a physiological characteristic of the user, the meter-generated values produced in response to operation of an analyte meter device; and obtaining sensor-generated values that are indicative of the physiological characteristic of the user, the sensor-generated values produced in response to operation of a continuous analyte sensor device, different than the analyte meter device. When a meter-generated value is available, the medical device is operated in a first mode to display, on the display device, the valid meter-generated value on a user monitoring screen and on a therapy delivery control screen, and to calculate therapy dosage for delivery based on the valid meter-generated value. When a meter-generated value is unavailable and a current sensor-generated value of the sensor-generated values satisfies first quality criteria, the medical device is operated in a second mode to display, on the display device, the current sensor-generated value on the user monitoring screen and on the therapy delivery control screen, and to calculate therapy dosage for delivery based on the current sensor-generated value. When a valid meter-generated value is unavailable and the current sensor-generated value satisfies second quality criteria but does not satisfy the first quality criteria, the medical device is operated in a third mode to display, on the display device, the current sensor-generated value on the user monitoring screen, to inhibit display of the current sensor-generated value on the therapy delivery control screen, and to inhibit use of the current sensor-generated value for purposes of calculating therapy dosage for delivery.

Also disclosed herein is a non-transitory computer-readable storage medium comprising program instructions stored thereon, wherein the program instructions are configurable to cause at least one processor device to perform a method that involves: receiving meter-generated values that are indicative of a physiological characteristic of the user, the meter-generated values produced in response to operation of an analyte meter device; and obtaining sensor-generated values that are indicative of the physiological characteristic of the user, the sensor-generated values produced in response to operation of a continuous analyte sensor device, different than the analyte meter device. When a valid meter-generated value is available, the method operates the medical device in a first mode to display the valid meter-generated value on a user monitoring screen of the medical device and on a therapy delivery control screen of the medical device, and operates the medical device in the first mode to calculate therapy dosage for delivery based on the valid meter-generated value. When a valid meter-generated value is unavailable and a current sensor-generated value satisfies first quality criteria, the method operates the medical device in a second mode to display the current sensor-generated value on the user monitoring screen and on the therapy delivery control screen, and operates the medical device in the second mode to calculate therapy dosage for delivery based on the current sensor-generated value and not a meter-generated value. When a valid meter-generated value is unavailable and the current sensor-generated value satisfies second quality criteria but does not satisfy the first quality criteria, the method operates the medical device in a third mode to display the current sensor-generated value on the user monitoring screen, operates the medical device in the third mode to inhibit display of the current sensor-generated value on the therapy delivery control screen, and operates the medical device to inhibit use of the current sensor-generated value for purposes of calculating therapy dosage for delivery.

Also disclosed herein is a method of controlling operation of a medical device that regulates delivery of a fluid medication to a user, the method involving: obtaining a current sensor-generated value that is indicative of a physiological characteristic of the user, the current sensor-generated value produced in response to operation of a continuous analyte sensor device; calculating a sensor quality metric that indicates reliability and trustworthiness of the current sensor-generated value; adjusting, in response to the calculated sensor quality metric, therapy actions of the medical device to configure a quality-specific operating mode of the medical device; managing generation of user alerts at the medical device in response to the calculated sensor quality metric; and regulating delivery of the fluid medication from the medical device, in accordance with the current sensor-generated value and the quality-specific operating mode of the medical device.

Also disclosed herein is a medical device that regulates delivery of medication to a user. The medical device includes: a drive system; at least one processor device that regulates operation of the drive system to deliver a fluid medication from the medical device; a user interface; and at least one memory element associated with the at least one processor device, the at least one memory element storing processor-executable instructions configurable to be executed by the at least one processor device to perform a method of controlling operation of the medical device. An embodiment of the method involves: obtaining a current sensor-generated value that is indicative of a physiological characteristic of the user, the current sensor-generated value produced in response to operation of a continuous analyte sensor device; receiving or calculating a sensor quality metric that indicates reliability and trustworthiness of the current sensor-generated value; adjusting therapy actions of the medical device in response to the calculated sensor quality metric, to configure a quality-specific operating mode of the medical device; managing generation of user alerts at the user interface in response to the calculated sensor quality metric; and regulating delivery of the fluid medication from the medical device, in accordance with the current sensor-generated value and the quality-specific operating mode of the medical device.

Also disclosed herein is a method of assessing operational quality of a continuous analyte sensor device. An embodiment of the method involves: obtaining a current sensor-generated value that is indicative of a physiological characteristic of the user, the current sensor-generated value produced in response to operation of the continuous analyte sensor device; calculating a sensor quality metric that indicates reliability and trustworthiness of the current sensor-generated value, wherein the calculating is based on information generated by or derived from the continuous analyte sensor device; and formatting the sensor quality metric for compatibility with a fluid medication delivery device, such that therapy actions of the fluid medication delivery device are adjusted in response to the calculated sensor quality metric, and such that aggressiveness of fluid medication therapy provided by the fluid medication delivery device is proportional to quality of the current sensor-generated value as indicated by the calculated sensor quality metric.

DETAILED DESCRIPTION

Exemplary embodiments of the subject matter described herein are implemented in conjunction with medical devices, such as portable electronic medical devices. Although many different applications are possible, the following description focuses on embodiments that incorporate an insulin infusion device (or insulin pump) as part of an infusion system deployment. For the sake of brevity, conventional techniques related to infusion system operation, insulin pump and/or infusion set operation, and other functional aspects of the systems (and the individual operating components of the systems) may not be described in detail here. Examples of infusion pumps may be of the type described in, but not limited to, U.S. Pat. Nos. 4,562,751; 4,685,903; 5,080,653; 5,505,709; 5,097,122; 6,485,465; 6,554,798; 6,558,320; 6,558,351; 6,641,533; 6,659,980; 6,752,787; 6,817,990; 6,932,584; and 7,621,893; each of which are herein incorporated by reference.

Generally, a fluid infusion device includes a motor or other actuation arrangement that is operable to linearly displace a plunger (or stopper) of a fluid reservoir provided within the fluid infusion device to deliver a dosage of fluid medication, such as insulin, to the body of a user. Dosage commands that govern operation of the motor may be generated in an automated manner in accordance with the delivery control scheme associated with a particular operating mode, and the dosage commands may be generated in a manner that is influenced by a current (or most recent) measurement of a physiological condition in the body of the user. For example, in a closed-loop or automatic operating mode, dosage commands may be generated based on a difference between a current (or most recent) measurement of the interstitial fluid glucose level in the body of the user and a target (or reference) glucose setpoint value. In this regard, the rate of infusion may vary as the difference between a current measurement value and the target measurement value fluctuates. For purposes of explanation, the subject matter is described herein in the context of the infused fluid being insulin for regulating a glucose level of a user (or patient); however, it should be appreciated that many other fluids may be administered through infusion, and the subject matter described herein is not necessarily limited to use with insulin.

An insulin infusion pump can be operated in an automatic mode wherein basal insulin is delivered at a rate that is automatically adjusted for the user. While controlling the delivery of basal insulin in this manner, the pump can also control the delivery of correction boluses to account for rising glucose trends due to meals, stress, hormonal fluctuations, etc. Ideally, the amount of a correction bolus should be accurately calculated and administered to maintain the user's blood glucose within the desired range. In particular, an automatically generated and delivered correction bolus should safely manage the user's blood glucose level and keep it above a defined hypoglycemic threshold level.

Turning now toFIG.1, one exemplary embodiment of an infusion system100includes, without limitation, a fluid infusion device (or infusion pump)102, a sensing arrangement104, a command control device (CCD)106, and a computer108. The components of an infusion system100may be realized using different platforms, designs, and configurations, and the embodiment shown inFIG.1is not exhaustive or limiting. In some embodiments, the infusion device102and the sensing arrangement104are secured at desired locations on the body of a user (or patient), as illustrated inFIG.1. In this regard, the locations at which the infusion device102and the sensing arrangement104are secured to the body of the user inFIG.1are provided only as a representative, non-limiting, example. The elements of the infusion system100may be similar to those described in U.S. Pat. No. 8,674,288, the subject matter of which is hereby incorporated by reference in its entirety.

In the illustrated embodiment ofFIG.1, the infusion device102is designed as a portable medical device suitable for infusing a fluid, a liquid, a gel, or other medicament into the body of a user. In exemplary embodiments, the infused fluid is insulin, although many other fluids may be administered through infusion such as, but not limited to, HIV drugs, drugs to treat pulmonary hypertension, iron chelation drugs, pain medications, anti-cancer treatments, medications, vitamins, hormones, or the like. In some embodiments, the fluid may include a nutritional supplement, a dye, a tracing medium, a saline medium, a hydration medium, or the like.

The sensing arrangement104generally represents the components of the infusion system100configured to sense, detect, measure or otherwise quantify a condition of the user, and may include a sensor, a monitor, or the like, for providing data indicative of the condition that is sensed, detected, measured or otherwise monitored by the sensing arrangement. In this regard, the sensing arrangement104may include electronics and enzymes reactive to a biological condition, such as a blood glucose level, or the like, of the user, and provide data indicative of the blood glucose level to the infusion device102, the CCD106and/or the computer108. For example, the infusion device102, the CCD106and/or the computer108may include a display for presenting information or data to the user based on the sensor data received from the sensing arrangement104, such as, for example, a current glucose level of the user, a graph or chart of the user's glucose level versus time, device status indicators, alert messages, or the like. In other embodiments, the infusion device102, the CCD106and/or the computer108may include electronics and software that are configured to analyze sensor data and operate the infusion device102to deliver fluid to the body of the user based on the sensor data and/or preprogrammed delivery routines. Thus, in exemplary embodiments, one or more of the infusion device102, the sensing arrangement104, the CCD106, and/or the computer108includes a transmitter, a receiver, and/or other transceiver electronics that allow for communication with other components of the infusion system100, so that the sensing arrangement104may transmit sensor data or monitor data to one or more of the infusion device102, the CCD106and/or the computer108.

Still referring toFIG.1, in various embodiments, the sensing arrangement104may be secured to the body of the user or embedded in the body of the user at a location that is remote from the location at which the infusion device102is secured to the body of the user. In various other embodiments, the sensing arrangement104may be incorporated within the infusion device102. In other embodiments, the sensing arrangement104may be separate and apart from the infusion device102, and may be, for example, part of the CCD106. In such embodiments, the sensing arrangement104may be configured to receive a biological sample, analyte, or the like, to measure a condition of the user.

In some embodiments, the CCD106and/or the computer108may include electronics and other components configured to perform processing, delivery routine storage, and to control the infusion device102in a manner that is influenced by sensor data measured by and/or received from the sensing arrangement104. By including control functions in the CCD106and/or the computer108, the infusion device102may be made with more simplified electronics. However, in other embodiments, the infusion device102may include all control functions, and may operate without the CCD106and/or the computer108. In various embodiments, the CCD106may be a portable electronic device. In addition, in various embodiments, the infusion device102and/or the sensing arrangement104may be configured to transmit data to the CCD106and/or the computer108for display or processing of the data by the CCD106and/or the computer108.

In some embodiments, the CCD106and/or the computer108may provide information to the user that facilitates the user's subsequent use of the infusion device102. For example, the CCD106may provide information to the user to allow the user to determine the rate or dose of medication to be administered into the user's body. In other embodiments, the CCD106may provide information to the infusion device102to autonomously control the rate or dose of medication administered into the body of the user. In some embodiments, the sensing arrangement104may be integrated into the CCD106. Such embodiments may allow the user to monitor a condition by providing, for example, a sample of his or her blood to the sensing arrangement104to assess his or her condition. In some embodiments, the sensing arrangement104and the CCD106may be used for determining glucose levels in the blood and/or body fluids of the user without the use of, or necessity of, a wire or cable connection between the infusion device102and the sensing arrangement104and/or the CCD106.

In some embodiments, the sensing arrangement104and/or the infusion device102are cooperatively configured to utilize a closed-loop system for delivering fluid to the user. Examples of sensing devices and/or infusion pumps utilizing closed-loop systems may be found at, but are not limited to, the following U.S. Pat. Nos. 6,088,608, 6,119,028, 6,589,229, 6,740,072, 6,827,702, 7,323,142, and 7,402,153 or United States Patent Application Publication No. 2014/0066889, all of which are incorporated herein by reference in their entirety. In such embodiments, the sensing arrangement104is configured to sense or measure a condition of the user, such as, blood glucose level or the like. The infusion device102is configured to deliver fluid in response to the condition sensed by the sensing arrangement104. In turn, the sensing arrangement104continues to sense or otherwise quantify a current condition of the user, thereby allowing the infusion device102to deliver fluid continuously in response to the condition currently (or most recently) sensed by the sensing arrangement104indefinitely. In some embodiments, the sensing arrangement104and/or the infusion device102may be configured to utilize the closed-loop system only for a portion of the day, for example only when the user is asleep or awake.

FIGS.2-4depict one exemplary embodiment of a fluid infusion device200(or alternatively, infusion pump) suitable for use in an infusion system, such as, for example, as infusion device102in the infusion system100ofFIG.1. The fluid infusion device200is a portable medical device designed to be carried or worn by a patient (or user), and the fluid infusion device200may leverage any number of conventional features, components, elements, and characteristics of existing fluid infusion devices, such as, for example, some of the features, components, elements, and/or characteristics described in U.S. Pat. Nos. 6,485,465 and 7,621,893. It should be appreciated thatFIGS.2-4depict some aspects of the infusion device200in a simplified manner; in some embodiments, the infusion device200could include additional elements, features, or components that are not shown or described in detail herein.

As best illustrated inFIGS.2-3, the illustrated embodiment of the fluid infusion device200includes a housing202adapted to receive a fluid-containing reservoir205. An opening220in the housing202accommodates a fitting223(or cap) for the reservoir205, with the fitting223being configured to mate or otherwise interface with tubing221of an infusion set225that provides a fluid path to/from the body of the user. In this manner, fluid communication from the interior of the reservoir205to the user is established via the tubing221. The illustrated fluid infusion device200includes a human-machine interface (HMI)230(or user interface) that includes elements232,234that can be manipulated by the user to administer a bolus of fluid (e.g., insulin), to change therapy settings, to change user preferences, to select display features, and the like. The infusion device also includes a display device226, such as a liquid crystal display (LCD) or another suitable display device, that can be used to present various types of information or data to the user, such as, without limitation: the current glucose level of the patient; the time; a graph or chart of the patient's glucose level versus time; device status indicators; etc.

The housing202is formed from a substantially rigid material having a hollow interior214adapted to allow an electronics assembly204, a sliding member (or slide)206, a drive system208, a sensor assembly210, and a drive system capping member212to be disposed therein in addition to the reservoir205, with the contents of the housing202being enclosed by a housing capping member216. The opening220, the slide206, and the drive system208are coaxially aligned in an axial direction (indicated by arrow218), whereby the drive system208facilitates linear displacement of the slide206in the axial direction218to dispense fluid from the reservoir205(after the reservoir205has been inserted into opening220), with the sensor assembly210being configured to measure axial forces (e.g., forces aligned with the axial direction218) exerted on the sensor assembly210responsive to operating the drive system208to displace the slide206. In various embodiments, the sensor assembly210may be utilized to detect one or more of the following: an occlusion in a fluid path that slows, prevents, or otherwise degrades fluid delivery from the reservoir205to a user's body; when the reservoir205is empty; when the slide206is properly seated with the reservoir205; when a fluid dose has been delivered; when the infusion device200is subjected to shock or vibration; when the infusion device200requires maintenance.

Depending on the embodiment, the fluid-containing reservoir205may be realized as a syringe, a vial, a cartridge, a bag, or the like. In certain embodiments, the infused fluid is insulin, although many other fluids may be administered through infusion such as, but not limited to, HIV drugs, drugs to treat pulmonary hypertension, iron chelation drugs, pain medications, anti-cancer treatments, medications, vitamins, hormones, or the like. As best illustrated inFIGS.3-4, the reservoir205typically includes a reservoir barrel219that contains the fluid and is concentrically and/or coaxially aligned with the slide206(e.g., in the axial direction218) when the reservoir205is inserted into the infusion device200. The end of the reservoir205proximate the opening220may include or otherwise mate with the fitting223, which secures the reservoir205in the housing202and prevents displacement of the reservoir205in the axial direction218with respect to the housing202after the reservoir205is inserted into the housing202. As described above, the fitting223extends from (or through) the opening220of the housing202and mates with tubing221to establish fluid communication from the interior of the reservoir205(e.g., reservoir barrel219) to the user via the tubing221and infusion set225. The opposing end of the reservoir205proximate the slide206includes a plunger217(or stopper) positioned to push fluid from inside the barrel219of the reservoir205along a fluid path through tubing221to a user. The slide206is configured to mechanically couple or otherwise engage with the plunger217, thereby becoming seated with the plunger217and/or reservoir205. Fluid is forced from the reservoir205via tubing221as the drive system208is operated to displace the slide206in the axial direction218toward the opening220in the housing202.

In the illustrated embodiment ofFIGS.3-4, the drive system208includes a motor assembly207and a drive screw209. The motor assembly207includes a motor that is coupled to drive train components of the drive system208that are configured to convert rotational motor motion to a translational displacement of the slide206in the axial direction218, and thereby engaging and displacing the plunger217of the reservoir205in the axial direction218. In some embodiments, the motor assembly207may also be powered to translate the slide206in the opposing direction (e.g., the direction opposite direction218) to retract and/or detach from the reservoir205to allow the reservoir205to be replaced. In exemplary embodiments, the motor assembly207includes a brushless DC (BLDC) motor having one or more permanent magnets mounted, affixed, or otherwise disposed on its rotor. However, the subject matter described herein is not necessarily limited to use with BLDC motors, and in alternative embodiments, the motor may be realized as a solenoid motor, an AC motor, a stepper motor, a piezoelectric caterpillar drive, a shape memory actuator drive, an electrochemical gas cell, a thermally driven gas cell, a bimetallic actuator, or the like. The drive train components may comprise one or more lead screws, cams, ratchets, jacks, pulleys, pawls, clamps, gears, nuts, slides, bearings, levers, beams, stoppers, plungers, sliders, brackets, guides, bearings, supports, bellows, caps, diaphragms, bags, heaters, or the like. In this regard, although the illustrated embodiment of the infusion pump utilizes a coaxially aligned drive train, the motor could be arranged in an offset or otherwise non-coaxial manner, relative to the longitudinal axis of the reservoir205.

As best shown inFIG.4, the drive screw209mates with threads402internal to the slide206. When the motor assembly207is powered and operated, the drive screw209rotates, and the slide206is forced to translate in the axial direction218. In an exemplary embodiment, the infusion device200includes a sleeve211to prevent the slide206from rotating when the drive screw209of the drive system208rotates. Thus, rotation of the drive screw209causes the slide206to extend or retract relative to the drive motor assembly207. When the fluid infusion device is assembled and operational, the slide206contacts the plunger217to engage the reservoir205and control delivery of fluid from the infusion device200. In an exemplary embodiment, the shoulder portion215of the slide206contacts or otherwise engages the plunger217to displace the plunger217in the axial direction218. In alternative embodiments, the slide206may include a threaded tip213capable of being detachably engaged with internal threads404on the plunger217of the reservoir205, as described in detail in U.S. Pat. Nos. 6,248,093 and 6,485,465, which are incorporated by reference herein.

As illustrated inFIG.3, the electronics assembly204includes control electronics224coupled to the display device226, with the housing202including a transparent window portion228that is aligned with the display device226to allow the display device226to be viewed by the user when the electronics assembly204is disposed within the interior214of the housing202. The control electronics224generally represent the hardware, firmware, processing logic and/or software (or combinations thereof) configured to control operation of the motor assembly207and/or drive system208, as described in greater detail below in the context ofFIG.5. The control electronics224is also suitably configured and designed to support various user interface, input/output, and display features of the fluid infusion device200. Whether such functionality is implemented as hardware, firmware, a state machine, or software depends upon the particular application and design constraints imposed on the embodiment. Those familiar with the concepts described here may implement such functionality in a suitable manner for each particular application, but such implementation decisions should not be interpreted as being restrictive or limiting. In an exemplary embodiment, the control electronics224includes one or more programmable controllers that may be programmed to control operation of the infusion device200.

The motor assembly207includes one or more electrical leads236adapted to be electrically coupled to the electronics assembly204to establish communication between the control electronics224and the motor assembly207. In response to command signals from the control electronics224that operate a motor driver (e.g., a power converter) to regulate the amount of power supplied to the motor from a power supply, the motor actuates the drive train components of the drive system208to displace the slide206in the axial direction218to force fluid from the reservoir205along a fluid path (including tubing221and an infusion set), thereby administering doses of the fluid contained in the reservoir205into the user's body. Preferably, the power supply is realized one or more batteries contained within the housing202. Alternatively, the power supply may be a solar panel, capacitor, AC or DC power supplied through a power cord, or the like. In some embodiments, the control electronics224may operate the motor of the motor assembly207and/or drive system208in a stepwise manner, typically on an intermittent basis; to administer discrete precise doses of the fluid to the user according to programmed delivery profiles.

Referring toFIGS.2-4, as described above, the user interface230includes HMI elements, such as buttons232and a directional pad234, that are formed on a graphic keypad overlay231that overlies a keypad assembly233, which includes features corresponding to the buttons232, directional pad234or other user interface items indicated by the graphic keypad overlay231. When assembled, the keypad assembly233is coupled to the control electronics224, thereby allowing the HMI elements232,234to be manipulated by the user to interact with the control electronics224and control operation of the infusion device200, for example, to administer a bolus of insulin, to change therapy settings, to change user preferences, to select display features, to set or disable alarms and reminders, and the like. In this regard, the control electronics224maintains and/or provides information to the display device226regarding program parameters, delivery profiles, pump operation, alarms, warnings, statuses, or the like, which may be adjusted using the HMI elements232,234. In various embodiments, the HMI elements232,234may be realized as physical objects (e.g., buttons, knobs, joysticks, and the like) or virtual objects (e.g., graphical user interface elements that use touch-sensing and/or proximity-sensing technologies). For example, in some embodiments, the display device226may be realized as a touch screen or touch-sensitive display, and in such embodiments, the features and/or functionality of the HMI elements232,234may be integrated into the display device226and the HMI230may not be present. In some embodiments, the electronics assembly204may also include alert generating elements coupled to the control electronics224and suitably configured to generate one or more types of feedback, such as, without limitation: audible feedback; visual feedback; haptic (physical) feedback; or the like.

Referring toFIGS.3-4, in accordance with one or more embodiments, the sensor assembly210includes a back plate structure250and a loading element260. The loading element260is disposed between the capping member212and a beam structure270that includes one or more beams having sensing elements disposed thereon that are influenced by compressive force applied to the sensor assembly210that deflects the one or more beams, as described in greater detail in U.S. Pat. No. 8,474,332, which is incorporated by reference herein. In exemplary embodiments, the back plate structure250is affixed, adhered, mounted, or otherwise mechanically coupled to the bottom surface238of the drive system208such that the back plate structure250resides between the bottom surface238of the drive system208and the housing capping member216. The drive system capping member212is contoured to accommodate and conform to the bottom of the sensor assembly210and the drive system208. The drive system capping member212may be affixed to the interior of the housing202to prevent displacement of the sensor assembly210in the direction opposite the direction of force provided by the drive system208(e.g., the direction opposite direction218). Thus, the sensor assembly210is positioned between the motor assembly207and secured by the capping member212, which prevents displacement of the sensor assembly210in a downward direction opposite the direction of the arrow that represents the axial direction218, such that the sensor assembly210is subjected to a reactionary compressive force when the drive system208and/or motor assembly207is operated to displace the slide206in the axial direction218in opposition to the fluid pressure in the reservoir205. Under normal operating conditions, the compressive force applied to the sensor assembly210is correlated with the fluid pressure in the reservoir205. As shown, electrical leads240are adapted to electrically couple the sensing elements of the sensor assembly210to the electronics assembly204to establish communication to the control electronics224, wherein the control electronics224are configured to measure, receive, or otherwise obtain electrical signals from the sensing elements of the sensor assembly210that are indicative of the force applied by the drive system208in the axial direction218.

FIG.5depicts an exemplary embodiment of an infusion system500suitable for use with an infusion device502, such as any one of the infusion devices102,200described above. The infusion system500is capable of controlling or otherwise regulating a physiological condition in the body501of a patient to a desired (or target) value or otherwise maintain the condition within a range of acceptable values in an automated or autonomous manner. In one or more exemplary embodiments, the condition being regulated is sensed, detected, measured or otherwise quantified by a sensing arrangement504(e.g., a blood glucose sensing arrangement504) communicatively coupled to the infusion device502. However, it should be noted that in alternative embodiments, the condition being regulated by the infusion system500may be correlative to the measured values obtained by the sensing arrangement504. That said, for clarity and purposes of explanation, the subject matter may be described herein in the context of the sensing arrangement504being realized as a glucose sensing arrangement that senses, detects, measures or otherwise quantifies the patient's glucose level, which is being regulated in the body501of the patient by the infusion system500.

In exemplary embodiments, the sensing arrangement504includes one or more interstitial glucose sensing elements that generate or otherwise output electrical signals (alternatively referred to herein as measurement signals) having a signal characteristic that is correlative to, influenced by, or otherwise indicative of the relative interstitial fluid glucose level in the body501of the patient. The output electrical signals are filtered or otherwise processed to obtain a measurement value indicative of the patient's interstitial fluid glucose level. In exemplary embodiments, a blood glucose meter530, such as a finger stick device, is utilized to directly sense, detect, measure or otherwise quantify the blood glucose in the body501of the patient. In this regard, the blood glucose meter530outputs or otherwise provides a measured blood glucose value that may be utilized as a reference measurement for calibrating the sensing arrangement504and converting a measurement value indicative of the patient's interstitial fluid glucose level into a corresponding calibrated blood glucose value. For purposes of explanation, the calibrated blood glucose value calculated based on the electrical signals output by the sensing element(s) of the sensing arrangement504may alternatively be referred to herein as the sensor glucose value, the sensed glucose value, or variants thereof.

In exemplary embodiments, the infusion system500also includes one or more additional sensing arrangements506,508configured to sense, detect, measure or otherwise quantify a characteristic of the body501of the patient that is indicative of a condition in the body501of the patient. In this regard, in addition to the glucose sensing arrangement504, one or more auxiliary sensing arrangements506may be worn, carried, or otherwise associated with the body501of the patient to measure characteristics or conditions of the patient (or the patient's activity) that may influence the patient's glucose levels or insulin sensitivity. For example, a heart rate sensing arrangement506could be worn on or otherwise associated with the patient's body501to sense, detect, measure or otherwise quantify the patient's heart rate, which, in turn, may be indicative of exercise (and the intensity thereof) that is likely to influence the patient's glucose levels or insulin response in the body501. In yet another embodiment, another invasive, interstitial, or subcutaneous sensing arrangement506may be inserted into the body501of the patient to obtain measurements of another physiological condition that may be indicative of exercise (and the intensity thereof), such as, for example, a lactate sensor, a ketone sensor, or the like. Depending on the embodiment, the auxiliary sensing arrangement(s)506could be realized as a standalone component worn by the patient, or alternatively, the auxiliary sensing arrangement(s)506may be integrated with the infusion device502or the glucose sensing arrangement504.

The illustrated infusion system500also includes an acceleration sensing arrangement508(or accelerometer) that may be worn on or otherwise associated with the patient's body501to sense, detect, measure or otherwise quantify an acceleration of the patient's body501, which, in turn, may be indicative of exercise or some other condition in the body501that is likely to influence the patient's insulin response. While the acceleration sensing arrangement508is depicted as being integrated into the infusion device502inFIG.5, in alternative embodiments, the acceleration sensing arrangement508may be integrated with another sensing arrangement504,506on the body501of the patient, or the acceleration sensing arrangement508may be realized as a separate standalone component that is worn by the patient.

In the illustrated embodiment, the pump control system520generally represents the electronics and other components of the infusion device502that control operation of the fluid infusion device502according to a desired infusion delivery program in a manner that is influenced by the sensed glucose value indicating the current glucose level in the body501of the patient. For example, to support a closed-loop operating mode, the pump control system520maintains, receives, or otherwise obtains a target or commanded glucose value, and automatically generates or otherwise determines dosage commands for operating an actuation arrangement, such as a motor532, to displace the plunger517and deliver insulin to the body501of the patient based on the difference between the sensed glucose value and the target glucose value. In other operating modes, the pump control system520may generate or otherwise determine dosage commands configured to maintain the sensed glucose value below an upper glucose limit, above a lower glucose limit, or otherwise within a desired range of glucose values. In some embodiments, the infusion device502may store or otherwise maintain the target value, upper and/or lower glucose limit(s), insulin delivery limit(s), and/or other glucose threshold value(s) in a data storage element accessible to the pump control system520. As described in greater detail, in one or more exemplary embodiments, the pump control system520automatically adjusts or adapts one or more parameters or other control information used to generate commands for operating the motor532in a manner that accounts for a likely change in the patient's glucose level or insulin response resulting from a meal, exercise, or other activity.

Still referring toFIG.5, the target glucose value and other threshold glucose values utilized by the pump control system520may be received from an external component (e.g., CCD106and/or computing device108) or be input by a patient via a user interface element540associated with the infusion device502. In some embodiments, the one or more user interface element(s)540associated with the infusion device502typically include at least one input user interface element, such as, for example, a button, a keypad, a keyboard, a knob, a joystick, a mouse, a touch panel, a touchscreen, a microphone or another audio input device, and/or the like. Additionally, the one or more user interface element(s)540include at least one output user interface element, such as, for example, a display device (e.g., a light-emitting diode or the like), a display device (e.g., a liquid crystal display or the like), a speaker or another audio output device, a haptic feedback device, or the like, for providing notifications or other information to the patient. It should be noted that althoughFIG.5depicts the user interface element(s)540as being separate from the infusion device502, in some embodiments, one or more of the user interface element(s)540may be integrated with the infusion device502. Furthermore, in some embodiments, one or more user interface element(s)540are integrated with the sensing arrangement504in addition to and/or in alternative to the user interface element(s)540integrated with the infusion device502. The user interface element(s)540may be manipulated by the patient to operate the infusion device502to deliver correction boluses, adjust target and/or threshold values, modify the delivery control scheme or operating mode, and the like, as desired.

Still referring toFIG.5, in the illustrated embodiment, the infusion device502includes a motor control module512coupled to a motor532(e.g., motor assembly207) that is operable to displace a plunger517(e.g., plunger217) in a reservoir (e.g., reservoir205) and provide a desired amount of fluid to the body501of a patient. In this regard, displacement of the plunger517results in the delivery of a fluid, such as insulin, that is capable of influencing the patient's physiological condition to the body501of the patient via a fluid delivery path (e.g., via tubing221of an infusion set225). A motor driver module514is coupled between an energy source518and the motor532. The motor control module512is coupled to the motor driver module514, and the motor control module512generates or otherwise provides command signals that operate the motor driver module514to provide current (or power) from the energy source518to the motor532to displace the plunger517in response to receiving, from a pump control system520, a dosage command indicative of the desired amount of fluid to be delivered.

In exemplary embodiments, the energy source518is realized as a battery housed within the infusion device502(e.g., within housing202) that provides direct current (DC) power. In this regard, the motor driver module514generally represents the combination of circuitry, hardware and/or other electrical components configured to convert or otherwise transfer DC power provided by the energy source518into alternating electrical signals applied to respective phases of the stator windings of the motor532that result in current flowing through the stator windings that generates a stator magnetic field and causes the rotor of the motor532to rotate. The motor control module512is configured to receive or otherwise obtain a commanded dosage from the pump control system520, convert the commanded dosage to a commanded translational displacement of the plunger517, and command, signal, or otherwise operate the motor driver module514to cause the rotor of the motor532to rotate by an amount that produces the commanded translational displacement of the plunger517. For example, the motor control module512may determine an amount of rotation of the rotor required to produce translational displacement of the plunger517that achieves the commanded dosage received from the pump control system520. Based on the current rotational position (or orientation) of the rotor with respect to the stator that is indicated by the output of the rotor sensing arrangement516, the motor control module512determines the appropriate sequence of alternating electrical signals to be applied to the respective phases of the stator windings that should rotate the rotor by the determined amount of rotation from its current position (or orientation). In embodiments where the motor532is realized as a BLDC motor, the alternating electrical signals commutate the respective phases of the stator windings at the appropriate orientation of the rotor magnetic poles with respect to the stator and in the appropriate order to provide a rotating stator magnetic field that rotates the rotor in the desired direction. Thereafter, the motor control module512operates the motor driver module514to apply the determined alternating electrical signals (e.g., the command signals) to the stator windings of the motor532to achieve the desired delivery of fluid to the patient.

When the motor control module512is operating the motor driver module514, current flows from the energy source518through the stator windings of the motor532to produce a stator magnetic field that interacts with the rotor magnetic field. In some embodiments, after the motor control module512operates the motor driver module514and/or motor532to achieve the commanded dosage, the motor control module512ceases operating the motor driver module514and/or motor532until a subsequent dosage command is received. In this regard, the motor driver module514and the motor532enter an idle state during which the motor driver module514effectively disconnects or isolates the stator windings of the motor532from the energy source518. In other words, current does not flow from the energy source518through the stator windings of the motor532when the motor532is idle, and thus, the motor532does not consume power from the energy source518in the idle state, thereby improving efficiency.

Depending on the embodiment, the motor control module512may be implemented or realized with a general purpose processor, a microprocessor, a controller, a microcontroller, a state machine, a content addressable memory, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In exemplary embodiments, the motor control module512includes or otherwise accesses a data storage element or memory, including any sort of random access memory (RAM), read only memory (ROM), flash memory, registers, hard disks, removable disks, magnetic or optical mass storage, or any other short or long term storage media or other non-transitory computer-readable medium, which is capable of storing programming instructions for execution by the motor control module512. The computer-executable programming instructions, when read and executed by the motor control module512, cause the motor control module512to perform or otherwise support the tasks, operations, functions, and processes described herein.

It should be appreciated thatFIG.5is a simplified representation of the infusion device502for purposes of explanation and is not intended to limit the subject matter described herein in any way. In this regard, depending on the embodiment, some features and/or functionality of the sensing arrangement504may implemented by or otherwise integrated into the pump control system520, or vice versa. Similarly, in some embodiments, the features and/or functionality of the motor control module512may implemented by or otherwise integrated into the pump control system520, or vice versa. Furthermore, the features and/or functionality of the pump control system520may be implemented by control electronics224located in the fluid infusion device502, while in alternative embodiments, the pump control system520may be implemented by a remote computing device that is physically distinct and/or separate from the infusion device502, such as, for example, the CCD106or the computing device108.

FIG.6depicts an exemplary embodiment of a pump control system600suitable for use as the pump control system520inFIG.5in accordance with one or more embodiments. The illustrated pump control system600includes, without limitation, a pump control module602, a communications interface604, and a data storage element (or memory)606. The pump control module602is coupled to the communications interface604and the memory606, and the pump control module602is suitably configured to support the operations, tasks, and/or processes described herein. In various embodiments, the pump control module602is also coupled to one or more user interface elements (e.g., user interface230,540) for receiving user inputs (e.g., target glucose values or other glucose thresholds) and providing notifications, alerts, or other therapy information to the patient.

The communications interface604generally represents the hardware, circuitry, logic, firmware and/or other components of the pump control system600that are coupled to the pump control module602and configured to support communications between the pump control system600and the various sensing arrangements504,506,508. In this regard, the communications interface604may include or otherwise be coupled to one or more transceiver modules capable of supporting wireless communications between the pump control system520,600and the sensing arrangement504,506,508. For example, the communications interface604may be utilized to receive sensor measurement values or other measurement data from each sensing arrangement504,506,508in an infusion system500. In other embodiments, the communications interface604may be configured to support wired communications to/from the sensing arrangement(s)504,506,508. In various embodiments, the communications interface604may also support communications with another electronic device (e.g., CCD106and/or computer108) in an infusion system (e.g., to upload sensor measurement values to a server or other computing device, receive control information from a server or other computing device, and the like).

The pump control module602generally represents the hardware, circuitry, logic, firmware and/or other component of the pump control system600that is coupled to the communications interface604and configured to determine dosage commands for operating the motor532to deliver fluid to the body501based on measurement data received from the sensing arrangements504,506,508and perform various additional tasks, operations, functions and/or operations described herein. For example, in exemplary embodiments, pump control module602implements or otherwise executes a command generation application610that supports one or more autonomous operating modes and calculates or otherwise determines dosage commands for operating the motor532of the infusion device502in an autonomous operating mode based at least in part on a current measurement value for a condition in the body501of the patient. For example, in a closed-loop operating mode, the command generation application610may determine a dosage command for operating the motor532to deliver insulin to the body501of the patient based at least in part on the current glucose measurement value most recently received from the sensing arrangement504to regulate the patient's blood glucose level to a target reference glucose value. Additionally, the command generation application610may generate dosage commands for boluses that are manually-initiated or otherwise instructed by a patient via a user interface element.

In exemplary embodiments, the pump control module602also implements or otherwise executes a personalization application608that is cooperatively configured to interact with the command generation application610to support adjusting dosage commands or control information dictating the manner in which dosage commands are generated in a personalized, patient-specific manner. In this regard, in some embodiments, based on correlations between current or recent measurement data and the current operational context relative to historical data associated with the patient, the personalization application608may adjust or otherwise modify values for one or more parameters utilized by the command generation application610when determining dosage commands, for example, by modifying a parameter value at a register or location in memory606referenced by the command generation application610. In yet other embodiments, the personalization application608may predict meals or other events or activities that are likely to be engaged in by the patient and output or otherwise provide an indication of the predicted patient behavior for confirmation or modification by the patient, which, in turn, may then be utilized to adjust the manner in which dosage commands are generated to regulate glucose in a manner that accounts for the patient's behavior in a personalized manner.

Still referring toFIG.6, depending on the embodiment, the pump control module602may be implemented or realized with at least one general purpose processor device, a microprocessor, a controller, a microcontroller, a state machine, a content addressable memory, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In this regard, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in firmware, in a software module executed by the pump control module602, or in any practical combination thereof. In exemplary embodiments, the pump control module602includes or otherwise accesses the data storage element or memory606, which may be realized using any sort of non-transitory computer-readable medium capable of storing programming instructions for execution by the pump control module602. The computer-executable programming instructions, when read and executed by the pump control module602, cause the pump control module602to implement or otherwise generate the applications608,610and perform tasks, operations, functions, and processes described herein.

It should be understood thatFIG.6is a simplified representation of a pump control system600for purposes of explanation and is not intended to limit the subject matter described herein in any way. For example, in some embodiments, the features and/or functionality of the motor control module512may be implemented by or otherwise integrated into the pump control system600and/or the pump control module602, for example, by the command generation application610converting the dosage command into a corresponding motor command, in which case, the separate motor control module512may be absent from an embodiment of the infusion device502.

FIG.7depicts an exemplary closed-loop control system700that may be implemented by a pump control system520,600to provide a closed-loop operating mode that autonomously regulates a condition in the body of a patient to a reference (or target) value. In this regard, the control system700can be utilized to regulate the delivery of insulin to the patient during an automatic basal insulin delivery operation. It should be appreciated thatFIG.7is a simplified representation of the control system700for purposes of explanation and is not intended to limit the subject matter described herein in any way.

In exemplary embodiments, the control system700receives or otherwise obtains a target glucose value at input702. In some embodiments, the target glucose value may be stored or otherwise maintained by the infusion device502(e.g., in memory606), however, in some alternative embodiments, the target value may be received from an external component (e.g., CCD106and/or computer108). In one or more embodiments, the target glucose value may be calculated or otherwise determined prior to entering the closed-loop operating mode based on one or more patient-specific control parameters. For example, the target blood glucose value may be calculated based at least in part on a patient-specific reference basal rate and a patient-specific daily insulin requirement, which are determined based on historical delivery information over a preceding interval of time (e.g., the amount of insulin delivered over the preceding 24 hours). The control system700also receives or otherwise obtains a current glucose measurement value (e.g., the most recently obtained sensor glucose value) from the sensing arrangement504at input704. The illustrated control system700implements or otherwise provides proportional-integral-derivative (PID) control to determine or otherwise generate delivery commands for operating the motor532based at least in part on the difference between the target glucose value and the current glucose measurement value. In this regard, the PID control attempts to minimize the difference between the measured value and the target value, and thereby regulates the measured value to the desired value. PID control parameters are applied to the difference between the target glucose level at input702and the measured glucose level at input704to generate or otherwise determine a dosage (or delivery) command provided at output730. Based on that delivery command, the motor control module512operates the motor532to deliver insulin to the body of the patient to influence the patient's glucose level, and thereby reduce the difference between a subsequently measured glucose level and the target glucose level.

The illustrated control system700includes or otherwise implements a summation block706configured to determine a difference between the target value obtained at input702and the measured value obtained from the sensing arrangement504at input704, for example, by subtracting the target value from the measured value. The output of the summation block706represents the difference between the measured and target values, which is then provided to each of a proportional term path, an integral term path, and a derivative term path. The proportional term path includes a gain block720that multiplies the difference by a proportional gain coefficient, KP, to obtain the proportional term. The integral term path includes an integration block708that integrates the difference and a gain block722that multiplies the integrated difference by an integral gain coefficient, KI, to obtain the integral term. The derivative term path includes a derivative block710that determines the derivative of the difference and a gain block724that multiplies the derivative of the difference by a derivative gain coefficient, KD, to obtain the derivative term. The proportional term, the integral term, and the derivative term are then added or otherwise combined to obtain a delivery command that is utilized to operate the motor at output730. Various implementation details pertaining to closed-loop PID control and determining gain coefficients are described in greater detail in U.S. Pat. No. 7,402,153, which is incorporated by reference.

In one or more exemplary embodiments, the PID gain coefficients are patient-specific and dynamically calculated or otherwise determined prior to entering the closed-loop operating mode based on historical insulin delivery information (e.g., amounts and/or timings of previous dosages, historical correction bolus information, or the like), historical sensor measurement values, historical reference blood glucose measurement values, user-reported or user-input events (e.g., meals, exercise, and the like), and the like. In this regard, one or more patient-specific control parameters (e.g., an insulin sensitivity factor, a daily insulin requirement, an insulin limit, a reference basal rate, a reference fasting glucose, an active insulin action duration, pharmodynamical time constants, or the like) may be utilized to compensate, correct, or otherwise adjust the PID gain coefficients to account for various operating conditions experienced and/or exhibited by the infusion device502. The PID gain coefficients may be maintained by the memory606accessible to the pump control module602. In this regard, the memory606may include a plurality of registers associated with the control parameters for the PID control. For example, a first parameter register may store the target glucose value and be accessed by or otherwise coupled to the summation block706at input702, and similarly, a second parameter register accessed by the proportional gain block720may store the proportional gain coefficient, a third parameter register accessed by the integration gain block722may store the integration gain coefficient, and a fourth parameter register accessed by the derivative gain block724may store the derivative gain coefficient.

In one or more exemplary embodiments, one or more parameters of the closed-loop control system700are automatically adjusted or adapted in a personalized manner to account for potential changes in the patient's glucose level or insulin sensitivity resulting from meals, exercise, or other events or activities. For example, in one or more embodiments, the target glucose value may be decreased in advance of a predicted meal event to achieve an increase in the insulin infusion rate to effectively pre-bolus a meal, and thereby reduce the likelihood of postprandial hyperglycemia. Additionally or alternatively, the time constant or gain coefficient associated with one or more paths of the closed-loop control system700may be adjusted to tune the responsiveness to deviations between the measured glucose value and the target glucose value. For example, based on the particular type of meal being consumed or the particular time of day during which the meal is consumed, the time constant associated with the derivative block710or derivative term path may be adjusted to make the closed-loop control more or less aggressive in response to an increase in the patient's glucose level based on the patient's historical glycemic response to the particular type of meal.

FIG.8depicts an exemplary embodiment of a patient monitoring system800. The patient monitoring system800includes a medical device802that is communicatively coupled to a sensing element804that is inserted into the body of a patient or otherwise worn by the patient to obtain measurement data indicative of a physiological condition in the body of the patient, such as a sensed glucose level. The medical device802is communicatively coupled to a client device806via a communications network810, with the client device806being communicatively coupled to a remote device814via another communications network812. In this regard, the client device806may function as an intermediary for uploading or otherwise providing measurement data from the medical device802to the remote device814. It should be appreciated thatFIG.8depicts a simplified representation of a patient monitoring system800for purposes of explanation and is not intended to limit the subject matter described herein in any way.

In exemplary embodiments, the client device806is realized as a mobile phone, a smartphone, a tablet computer, or other similar mobile electronic device; however, in other embodiments, the client device806may be realized as any sort of electronic device capable of communicating with the medical device802via network810, such as a laptop or notebook computer, a desktop computer, or the like. In exemplary embodiments, the network810is realized as a Bluetooth network, a ZigBee network, or another suitable personal area network. That said, in other embodiments, the network810could be realized as a wireless ad hoc network, a wireless local area network (WLAN), or local area network (LAN). The client device806includes or is coupled to a display device, such as a monitor, screen, or another conventional electronic display, capable of graphically presenting data and/or information pertaining to the physiological condition of the patient. The client device806also includes or is otherwise associated with a user input device, such as a keyboard, a mouse, a touchscreen, or the like, capable of receiving input data and/or other information from the user of the client device806.

In exemplary embodiments, a user, such as the patient, the patient's doctor or another healthcare provider, or the like, manipulates the client device806to execute a client application808that supports communicating with the medical device802via the network810. In this regard, the client application808supports establishing a communications session with the medical device802on the network810and receiving data and/or information from the medical device802via the communications session. The medical device802may similarly execute or otherwise implement a corresponding application or process that supports establishing the communications session with the client application808. The client application808generally represents a software module or another feature that is generated or otherwise implemented by the client device806to support the processes described herein. Accordingly, the client device806generally includes a processing system and a data storage element (or memory) capable of storing programming instructions for execution by the processing system, that, when read and executed, cause processing system to create, generate, or otherwise facilitate the client application808and perform or otherwise support the processes, tasks, operations, and/or functions described herein. Depending on the embodiment, the processing system may be implemented using any suitable processing system and/or device, such as, for example, one or more processor devices, central processing units (CPUs), controllers, microprocessors, microcontrollers, processing cores and/or other hardware computing resources configured to support the operation of the processing system described herein. Similarly, the data storage element or memory may be realized as a random-access memory (RAM), read only memory (ROM), flash memory, magnetic or optical mass storage, or any other suitable non-transitory short or long-term data storage or other computer-readable media, and/or any suitable combination thereof.

In one or more embodiments, the client device806and the medical device802establish an association (or pairing) with one another over the network810to support subsequently establishing a point-to-point or peer-to-peer communications session between the medical device802and the client device806via the network810. For example, in accordance with one embodiment, the network810is realized as a Bluetooth network, wherein the medical device802and the client device806are paired with one another (e.g., by obtaining and storing network identification information for one another) by performing a discovery procedure or another suitable pairing procedure. The pairing information obtained during the discovery procedure allows either of the medical device802or the client device806to initiate the establishment of a secure communications session via the network810.

In one or more exemplary embodiments, the client application808is also configured to store or otherwise maintain an address and/or other identification information for the remote device814on the second network812. In this regard, the second network812may be physically and/or logically distinct from the network810, such as, for example, the Internet, a cellular network, a wide area network (WAN), or the like. The remote device814generally represents a server or other computing device configured to receive and analyze or otherwise monitor measurement data, event log data, and potentially other information obtained for the patient associated with the medical device802. In exemplary embodiments, the remote device814is coupled to a database816configured to store or otherwise maintain data associated with individual patients. In some embodiments, the remote device814may reside at a location that is physically distinct and/or separate from the medical device802and the client device806, such as, for example, at a facility that is owned and/or operated by or otherwise affiliated with a manufacturer of the medical device802. For purposes of explanation, but without limitation, the remote device814may alternatively be referred to herein as a server.

Still referring toFIG.8, the sensing element804generally represents the component of the patient monitoring system800that is configured to generate, produce, or otherwise output one or more electrical signals indicative of a physiological condition that is sensed, measured, or otherwise quantified by the sensing element804. In this regard, the physiological condition of a patient influences a characteristic of the electrical signal output by the sensing element804, such that the characteristic of the output signal corresponds to or is otherwise correlative to the physiological condition that the sensing element804is sensitive to. In exemplary embodiments, the sensing element804is realized as an interstitial glucose sensing element inserted at a location on the body of the patient that generates an output electrical signal having a current (or voltage) associated therewith that is correlative to the interstitial fluid glucose level that is sensed or otherwise measured in the body of the patient by the sensing element804.

The medical device802generally represents the component of the patient monitoring system800that is communicatively coupled to the output of the sensing element804to receive or otherwise obtain the measurement data samples from the sensing element804(e.g., the measured glucose and characteristic impedance values), store or otherwise maintain the measurement data samples, and upload or otherwise transmit the measurement data to the remote device814or server via the client device806. In one or more embodiments, the medical device802is realized as an infusion device102,200,502configured to deliver a fluid, such as insulin, to the body of the patient. That said, in other embodiments, the medical device802could be a standalone sensing or monitoring device separate and independent from an infusion device (e.g., sensing arrangement104,504). It should be noted that althoughFIG.8depicts the medical device802and the sensing element804as separate components, in some embodiments, the medical device802and the sensing element804may be integrated or otherwise combined to provide a unitary device that can be worn by the patient.

In exemplary embodiments, the medical device802includes a control module822, a data storage element824(or memory), and a communications interface826. The control module822generally represents the hardware, circuitry, logic, firmware and/or other component(s) of the medical device802that is coupled to the sensing element804to receive the electrical signals output by the sensing element804and perform or otherwise support various additional tasks, operations, functions and/or processes described herein. Depending on the embodiment, the control module822may be implemented or realized with a general purpose processor device, a microprocessor device, a controller, a microcontroller, a state machine, a content addressable memory, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In some embodiments, the control module822includes an analog-to-digital converter (ADC) or another similar sampling arrangement that samples or otherwise converts an output electrical signal received from the sensing element804into corresponding digital measurement data value. In other embodiments, the sensing element804may incorporate an ADC and output a digital measurement value.

The communications interface826generally represents the hardware, circuitry, logic, firmware and/or other components of the medical device802that are coupled to the control module822for outputting data and/or information from/to the medical device802to/from the client device806. For example, the communications interface826may include or otherwise be coupled to one or more transceiver modules capable of supporting wireless communications between the medical device802and the client device806. In exemplary embodiments, the communications interface826is realized as a Bluetooth transceiver or adapter configured to support Bluetooth Low Energy (BLE) communications.

In exemplary embodiments, the remote device814receives, from the client device806, measurement data values associated with a particular patient (e.g., sensor glucose measurements, acceleration measurements, and the like) that were obtained using the sensing element804, and the remote device814stores or otherwise maintains the historical measurement data in the database816in association with the patient (e.g., using one or more unique patient identifiers). Additionally, the remote device814may also receive, from or via the client device806, meal data or other event log data that may be input or otherwise provided by the patient (e.g., via client application808) and store or otherwise maintain historical meal data and other historical event or activity data associated with the patient in the database816. In this regard, the meal data include, for example, a time or timestamp associated with a particular meal event, a meal type or other information indicative of the content or nutritional characteristics of the meal, and an indication of the size associated with the meal. In exemplary embodiments, the remote device814also receives historical fluid delivery data corresponding to basal or bolus dosages of fluid delivered to the patient by an infusion device102,200,502. For example, the client application808may communicate with an infusion device102,200,502to obtain insulin delivery dosage amounts and corresponding timestamps from the infusion device102,200,502, and then upload the insulin delivery data to the remote device814for storage in association with the particular patient. The remote device814may also receive geolocation data and potentially other contextual data associated with a device802,806from the client device806and/or client application808, and store or otherwise maintain the historical operational context data in association with the particular patient. In this regard, one or more of the devices802,806may include a global positioning system (GPS) receiver or similar modules, components or circuitry capable of outputting or otherwise providing data characterizing the geographic location of the respective device802,806in real-time.

The historical patient data may be analyzed by one or more of the remote device814, the client device806, and/or the medical device802to alter or adjust operation of an infusion device102,200,502to influence fluid delivery in a personalized manner. For example, the patient's historical meal data and corresponding measurement data or other contextual data may be analyzed to predict a future time when the next meal is likely to be consumed by the patient, the likelihood of a future meal event within a specific time period, the likely size or amount of carbohydrates associated with a future meal, the likely type or nutritional content of the future meal, and/or the like. Moreover, the patient's historical measurement data for postprandial periods following historical meal events may be analyzed to model or otherwise characterize the patient's glycemic response to the predicted size and type of meal for the current context (e.g., time of day, day of week, geolocation, etc.). One or more aspects of the infusion device102,200,502that control or regulate insulin delivery may then be modified or adjusted to proactively account for the patient's likely meal activity and glycemic response.

In one or more exemplary embodiments, the remote device814utilizes machine learning to determine which combination of historical sensor glucose measurement data, historical delivery data, historical auxiliary measurement data (e.g., historical acceleration measurement data, historical heart rate measurement data, and/or the like), historical event log data, historical geolocation data, and other historical or contextual data are correlated to or predictive of the occurrence of a particular event, activity, or metric for a particular patient, and then determines a corresponding equation, function, or model for calculating the value of the parameter of interest based on that set of input variables. Thus, the model is capable of characterizing or mapping a particular combination of one or more of the current (or recent) sensor glucose measurement data, auxiliary measurement data, delivery data, geographic location, patient behavior or activities, and the like to a value representative of the current probability or likelihood of a particular event or activity or a current value for a parameter of interest. It should be noted that since each patient's physiological response may vary from the rest of the population, the subset of input variables that are predictive of or correlative for a particular patient may vary from other patients. Additionally, the relative weightings applied to the respective variables of that predictive subset may also vary from other patients who may have common predictive subsets, based on differing correlations between a particular input variable and the historical data for that particular patient. It should be noted that any number of different machine learning techniques may be utilized by the remote device814to determine what input variables are predictive for a current patient of interest, such as, for example, artificial neural networks, genetic programming, support vector machines, Bayesian networks, probabilistic machine learning models, or other Bayesian techniques, fuzzy logic, heuristically derived combinations, or the like.

A medical device of the type described herein can generate various user interface display screens that support different functions and features. For example, an insulin infusion device can generate a home screen that serves as a patient status or monitoring screen, a settings/preferences screen, a bolus delivery control screen, and the like. These and other display screens can present the user with different information, status data, notifications, patient data (e.g., glucose data), and/or other information in any desired arrangement or format.

Non-adjunctive insulin administration requires a sensor glucose (SG) value to be presented for bolus dosage estimation. The SG value should only be presented to the user when it is accurate, reliable, or otherwise trusted. A user may instead choose to use a blood glucose (BG) value from a linked blood glucose meter device (e.g., a blood glucose meter device in wireless or wired communication with the medical device). Given that there are two sources of inputs for therapy, and only one source may be used, the insulin infusion device is suitably configured to clearly indicate which glucose source is being used. To this end, the exemplary embodiment described here is controlled in an appropriate manner to avoid using a current SG value for bolus estimation when it is determined that the quality or reliability of the SG value is not sufficiently high. The exemplary embodiment also safely disambiguates SG from BG, for purposes of bolus estimation and presentation to the user.

The operating methodology described in more detail below is governed by certain rules when handling BG and SG values. For example, when a BG value is provided to the system, that value is displayed on a bolus delivery control screen until the BG value is expired (e.g., after a designated period of time, such as 12 minutes). A unique and visually distinguishable icon is used to indicate that the displayed value is a BG value. If the user fails to make a bolus delivery selection within a predefined period of time (e.g., 12 minutes or any other period of time), the bolus delivery feature will timeout.

In accordance with another operating rule, when an SG value is trusted by the system and there is no recent BG entry, the bolus delivery control screen includes the current SG value with a corresponding icon in a manner that is visually distinguishable from a displayed BG value. The SG value displayed within the bolus delivery screen cannot be modified via the user interface of the insulin infusion device.

In accordance with another operating rule, if there is a sudden spike in SG readings (e.g., the SG increases at a rate that is higher than a predetermined threshold value) that cannot be attributed to carbohydrate ingestion or other physiological processes, the current SG value is assumed to be temporarily unsuitable for non-adjunctive therapy. In that instance, no alert is required, but the SG value is not presented on the bolus delivery control screen, and the SG value is not used to calculate a bolus estimate.

Accordingly, the insulin infusion device supports a user interface associated with fully non-adjunctive bolus estimation. The current SG value is intuitively displayed in the bolus delivery control screen when it is a stable/trusted value. Otherwise, the SG value is removed from the bolus delivery control screen without generating a user alert. If the user desires to administer a manual bolus, then user can provide a BG value to be used for bolus estimation. The display screens and user interface features are designed such that the SG value is clearly disambiguated from the BG value. This avoids user confusion and potential bolus estimation errors.

FIG.9is a flow chart that illustrates an exemplary embodiment of a process900for operating a medical device that regulates delivery of a fluid medication to a user. The process900may be performed by an insulin infusion device of the type described above or any other medical device. The process900receives meter-generated values that are indicative of a physiological characteristic of the user, wherein the generated values are produced in response to operation of an analyte meter device. For the exemplary implementation described here, the medical device is an insulin infusion device, the fluid medication is insulin, the physiological characteristic of interest is blood glucose, and the meter-generated values are BG values obtained from a blood glucose meter device (e.g., a BG fingerstick device) that generates BG measurements from a blood sample taken from the user. Thus, the exemplary embodiment of the process900receives BG values (e.g., once a day, every 12 hours, or as often as desired by the user), either directly from a linked BG meter or via manual data entry by a user or caregiver at the insulin infusion device (task902). The insulin infusion device assumes that recently received BG measurements (whether they are user-entered or received directly from a BG meter device) are accurate and trustworthy.

The process900also obtains sensor-generated values that are indicative of the same physiological characteristic of the user, wherein the sensor-generated values are produced in response to operation of a continuous analyte sensor device. For the exemplary insulin infusion device implementation described here, the sensor-generated values are SG values obtained from a continuous glucose monitor or sensor (or calculated from sensor data obtained from a continuous glucose monitor or sensor) that is worn by the user. Thus, the exemplary embodiment of the process900obtains SG values periodically, e.g., every five minutes, every ten minutes, or any other desired period of time (task904). In some embodiments, tasks902and904are performed independently of one another. For example, task904may be performed more often than task902, or tasks902and904may be performed serially in any order or concurrently.

The process900determines how to use the BG value and/or the SG value for display purposes and for therapy dosage and delivery purposes. To this end, the exemplary embodiment of the process900checks for the presence of a valid BG value, e.g., a valid meter-generated value (query task906). For this particular implementation, a current BG value is deemed to be “valid” until it expires after an expiration time period. The expiration time period may vary from one embodiment to another. For this particular example, BG values have a valid lifespan of only 12 minutes; stale BG values are not used. Thus, if the process900determines that a valid BG value is available (the “Yes” branch of query task906), then the device is controlled in an appropriate manner to operate in a first mode, e.g., as described in further detail with respect toFIG.10below (task908). In accordance with the embodiment described here, the device is operated in the first mode when a valid meter-generated BG value is available, regardless of the availability of a sensor-generated SG value, and regardless of the quality, accuracy, or trustworthiness of the current SG value (if one is available).

FIG.10is a flow chart that illustrates operation of the insulin infusion device in the first mode. The first mode operation process1000depicted inFIG.10can be performed at task908of the process900.

In this example, a “fresh” BG value is assumed to be accurate and trustworthy. Accordingly, the process1000displays the valid BG value on a user monitoring screen of the device (task1002). This BG value remains displayed on the user monitoring screen while it remains valid. Once the BG value expires or is otherwise deemed to be invalid, it is removed from the user monitoring screen (e.g., ceased to be displayed within the user monitoring screen). In some embodiments, the user monitoring screen is a home screen of the insulin infusion device, and the home screen may include additional information if so desired, such as other patient data, status indicators, etc. In this regard,FIG.11is a schematic representation of a user monitoring screen1100on an insulin infusion device, with a current and valid meter-generated BG value1102displayed thereon. The BG value1102can be displayed with a “BG” label1104to make it obvious that the displayed value is indeed a BG value (rather than an SG value). Moreover, the process1000displays the BG value using visually distinguishable characteristics, which may also be used for displaying the “BG” label1104and for displaying the units of the BG value (mg/dL). For example, any one or more of the following visually distinguishable characteristics can be utilized for displaying the BG value: color; font design; font size; font characteristics such as bold, italic, or outlined; animation such as a flashing display or a moving display; fill pattern or stippling; level of transparency; and an accompanying icon (such as a blood drop).

Referring back toFIG.10, the process1000also displays the valid BG value on a therapy delivery control screen of the device (task1004). The BG value remains displayed on the therapy delivery control screen while it remains valid. Once the BG value expires or is otherwise deemed to be invalid, it is removed from the therapy delivery control screen. For this particular embodiment, the therapy delivery control screen is an insulin bolus delivery control screen of the insulin infusion device, and the bolus delivery control screen may include additional information related to an estimated bolus dosage and the operation of the bolus delivery function. In this regard,FIG.12is a schematic representation of a therapy delivery control screen1200on an insulin infusion device, with the current and valid BG value1202displayed thereon. The BG value1202can be displayed with a “BG” label1204to make it obvious that the displayed value is indeed a BG value (rather than an SG value). In addition, the BG value1202can be displayed with a visually distinguishable and contextually relevant icon1206to further indicate that the displayed value is a BG value rather than an SG value. For this example, the icon1206resembles a drop of blood, and the icon1206is colored red.

Notably, the process1000displays the BG value1202using the same (or substantially similar) visually distinguishable characteristics used to display the BG value1102on the user monitoring screen1100. The same visually distinguishable characteristics may also be used for displaying the “BG” label1204and for displaying the units of the BG value (mg/dL). Using the same visually distinguishable characteristics for the BG value across different user interface screens or features makes it easy for the user to interpret and recognize the source of the displayed glucose measurement. Although this description focuses on the user monitoring screen and the therapy delivery control screen, consistent visual characteristics (“look and feel” aspects) can be used across any number of display screens generated by the device.

Referring back toFIG.10, the process1000inhibits the display of any SG value on the user monitoring screen and on the therapy delivery control screen (task1006). In this regard, if a valid BG value is available, then the device relies on that measurement, whether or not a current and accurate SG value is also available. Thus, preventing display of an available SG value under these conditions is intuitive and less confusing for users.

The process1000continues by calculating therapy dosage (if needed) for delivery, based on the valid meter-generated BG value (task1008). For this example, an insulin bolus is calculated at task1008, and the calculated bolus amount is displayed on the therapy delivery control screen. In this regard, the therapy delivery control screen1200shown inFIG.12includes a calculated insulin bolus of 0.8 Units. Thus, the valid BG value serves as an input or parameter for purposes of estimating an appropriate insulin bolus to maintain the user's blood glucose level within a desired target range.

In some embodiments, the calculated bolus amount can be automatically or manually administered. For example, the bolus can be automatically delivered if automatic delivery mode is supported and active. Accordingly, during operation in the first mode, the process1000enables an automatic therapy delivery function of the device (task1010). Consequently, if the user fails to manually administer the calculated bolus amount, the automatic delivery function will take appropriate action to deliver the bolus in a timely manner. To this end, the process1000may automatically control the operation of the device to regulate delivery of the fluid medication (insulin) from the device, in accordance with the calculated therapy dosage (task1012).

Returning toFIG.9and the description of the process900, if a valid BG value is unavailable (the “No” branch of query task906), then the process900checks the current SG value to determine a measure of quality. The quality of the current SG value can be determined or calculated using any appropriate methodology. For example, the current SG value can be compared against historical SG measurements, historical BG measurements, the most recent BG value, or the like. Additionally or alternatively, the quality of the current SG value can be determined using a “self-diagnostic” technique that considers the age of the continuous glucose sensor, SG measurement trends, electrical noise in the raw sensor signals, etc. In accordance with certain embodiments, the process900determines the quality of the SG measurements using the methodology described in more detail below.

Although the quality of SG measurements can be expressed in any suitable manner, the exemplary embodiment of the process900considers “high quality” SG measurements to be the best quality (e.g., above a high-quality threshold) and, therefore, appropriate for purposes of glucose monitoring, for therapy dosage calculation, and for controlling the delivery of therapy. The process900considers “monitor quality” SG measurements to be appropriate for glucose monitoring only, wherein monitor quality SG measurements are less desirable than high quality SG measurements, yet still suitable for certain non-therapy related functions (e.g., below the high-quality threshold and above a low-quality threshold). If the quality of an SG measurement is deemed to be less than monitor quality (e.g., below the low-quality threshold), then that SG value is neither displayed nor used for therapy related functions.

If the process900determines that the current SG value satisfies “high quality” criteria, e.g., quality above the high-quality threshold (the “Yes” branch of query task910), then the device is controlled in an appropriate manner to operate in a second mode (task912). In accordance with the embodiment described here, the device is operated in the second mode when a valid meter-generated BG value is unavailable, and when the current sensor-generated SG value is determined to be of high quality.

FIG.13is a flow chart that illustrates operation of the insulin infusion device in the second mode. The second mode operation process1300depicted inFIG.13can be performed at task912of the process900. The second mode relies on the high quality SG value, which is currently available for use. Accordingly, the process1300displays the current SG value on the user monitoring screen of the device (task1302). This SG value remains displayed on the user monitoring screen until it is refreshed.FIG.14is a schematic representation of a user monitoring screen1400on the insulin infusion device, with the current SG value1402displayed thereon. The SG value1402can be displayed with an “SG” label (not shown) to make it obvious that the displayed value is indeed an SG value (rather than a BG value). The example shown inFIG.14displays glucose trend arrows1404near the displayed SG value1402to indicate whether the user's blood glucose level is increasing or decreasing (e.g., compared to previous glucose level measurements). Moreover, the process1300displays the SG value1402using visually distinguishable characteristics, which may also be used for displaying the “SG” label, the trend arrows1404, and the units of the SG value (mg/dL). The embodiment described here uses color as the visually distinguishable characteristic. In some embodiments, however, any one or more of the following characteristics can be utilized for displaying the SG value: color; font design; font size; font characteristics such as bold, italic, or outlined; animation such as a flashing display or a moving display; fill pattern or stippling; level of transparency; and an accompanying icon. Notably, SG values and BG values are displayed using different visually distinguishable characteristics, such that the user can quickly and easily observe whether the displayed measurement is a BG value or an SG value. For example, BG values and related information can be rendered in a white or yellow font, while SG values and related information can be rendered in an obviously contrasting color, such as blue, cyan, or purple.

Referring back toFIG.13, the process1300also displays the current SG value on the therapy delivery control screen of the device (task1304). The SG value remains displayed on the therapy delivery control screen until it gets refreshed, and it cannot be modified via the user interface of the device.FIG.15is a schematic representation of a therapy delivery control screen1500on an insulin infusion device, with the current (and high quality) SG value1502displayed thereon. The SG value1502can be displayed with an “SG” label1504to make it obvious that the displayed value is indeed an SG value (rather than a BG value). In addition, the SG value1502can be displayed with a visually distinguishable and contextually relevant icon1506to further indicate that the displayed value is an SG value rather than a BG value. For this example, the icon1506resembles a plot or signal waveform, and the icon1506is colored to match the color of the displayed SG value1502.

Notably, the process1300displays the SG value1502using the same (or substantially similar) visually distinguishable characteristics used to display the SG value1402on the user monitoring screen1400. The same visually distinguishable characteristics may also be used for displaying the “SG” label1504and for displaying the units of the SG value (mg/dL). Using the same visually distinguishable characteristics for the SG value across different user interface screens or features makes it easy for the user to interpret and recognize the source of the displayed glucose measurement. Although this description focuses on the user monitoring screen and the therapy delivery control screen, consistent visual characteristics (“look and feel” aspects) can be used across any number of display screens generated by the device.

Referring back toFIG.13, the process1300inhibits the display of any BG value on the user monitoring screen and on the therapy delivery control screen (task1306). In this regard, if a valid BG value is unavailable, then the device only considers a current (e.g., the most recent) and accurate SG value for display purposes.

The process1300continues by calculating therapy dosage (if needed) for delivery, based on the high-quality sensor-generated SG value (task1308). For this example, an insulin bolus is calculated at task1308, and the calculated bolus amount is displayed on the therapy delivery control screen. In this regard, the therapy delivery control screen1500shown inFIG.15includes a calculated insulin bolus of 0.8 Units. Thus, the high quality SG value serves as an input or parameter for purposes of estimating an appropriate insulin bolus to maintain the user's blood glucose level within a desired target range.

In some example, the calculated bolus amount can be manually administered or automatically delivered if automatic delivery mode is supported and active. Accordingly, during operation in the second mode, the process1300enables the automatic therapy delivery function of the device (task1310). Consequently, if the user fails to manually administer the calculated bolus amount, the automatic delivery function will take appropriate action to deliver the bolus in a timely manner. To this end, the process1300may automatically control the operation of the device to regulate delivery of the fluid medication (insulin) from the device, in accordance with the calculated therapy dosage (task1312).

Returning toFIG.9and the description of the process900, if the current SG value does not satisfy the “high quality” criteria (the “No” branch of query task910), but satisfies “monitor quality” criteria (the “Yes” branch of query task914), then the device is controlled in an appropriate manner to operate in a third mode (task916). In accordance with the embodiment described here, the device is operated in the third mode when a valid meter-generated BG value is unavailable, and when the current sensor-generated SG value is determined to be of sufficient quality for user monitoring purposes but potentially unsuitable for calculating therapy dosage.

FIG.16is a flow chart that illustrates operation of the insulin infusion device in the third mode. The third mode operation process1600depicted inFIG.16can be performed at task916of the process900. The third mode relies on the monitor quality SG value, which is currently available for use. Accordingly, the process1600displays the current SG value on the user monitoring screen of the device (task1602). This SG value remains displayed on the user monitoring screen until it is refreshed. The above description of the user monitoring screen1400(seeFIG.14) also applies to this scenario because the monitor quality SG value is displayed in a similar fashion, with the same visually distinguishable characteristics described previously in connection with the exemplary display shown inFIG.14.

While operating in the third mode, the device inhibits the display of the current SG value on the therapy delivery control screen (task1604). In addition, the process1600inhibits the display of any BG value on the therapy delivery control screen (task1606). Instead, the device is operated to display an appropriate message, notification, or indication on the therapy delivery control screen, wherein the displayed content indicates that no suitable measurement of the physiological characteristic of the user is available. For this particular example, the process1600displays a message such as “No Glucose” or “No Glucose Available” on the therapy delivery control screen (task1608).FIG.17is a schematic representation of a therapy delivery control screen1700on an insulin infusion device, with neither a BG value nor an SG value displayed thereon. Instead, the therapy delivery control screen1700includes a “No Glucose” message or field1702that lets the user know that no suitable glucose measurement is available for purposes of calculating an estimated bolus. Consequently, the therapy delivery control screen1700indicates a bolus amount of 0.0 Units under these conditions.

Referring back toFIG.16, the process1600inhibits the use of the current SG value for purposes of calculating therapy dosage for delivery (task1610). Although a monitor quality SG value is suitable for use as a general indicator of the user's glucose level, the process1600assumes that it is potentially unsuitable for use in calculating a precise insulin bolus amount. Accordingly, the process1600operates the device in the third mode to disable the automatic therapy delivery function (task1612). For the embodiment described here, task1612ensures that correction boluses of insulin are not administered while the insulin infusion device is operating in the third mode.

The process1600may continue by prompting the user to obtain a new meter-generated BG value (task1614), which can be used to update the user monitoring screen and the therapy delivery control screen. Moreover, a fresh BG value can be used to calculate an estimated bolus and to reactivate the automatic therapy delivery feature. Additionally or alternatively, the process1600may generate a reminder, message, or notification to prompt the user to check the integrity of the sensor device, to recalibrate the sensor device, to replace the sensor device with a new unit, or the like.

Referring again toFIG.9, if the process900determines that the current SG value does not satisfy the designated “monitor quality” criteria (the “No” branch of query task914), then the process900generates an appropriate alert, message, or notification regarding the need to take some form of corrective action (task918). For example, the device may generate an alert to remind the user to take one or more of the following actions: obtain/enter a new BG value; check the integrity of the currently deployed sensor device; recalibrate the currently deployed sensor device; check the data communication functionality of the currently deployed sensor device; replace the sensor device with a new unit; or the like.

The process900is performed in an ongoing manner that contemplates updating of the BG value and/or the SG value over time. The dashed lines inFIG.9indicate how the process900is repeated as needed to receive and process new BG and SG values.

Automated insulin infusion systems that use feedback from a continuous glucose monitor (CGM) to adjust insulin dosing need to implement safety features to mitigate risk of over-delivery and hypoglycemia under certain glucose sensor conditions. These mitigations may employ one or more of the following technology components: (1) detection and rating of CGM measurement quality for use in automatic insulin dosing; (2) a set of therapy adjustments that are appropriate for each level of sensor quality; (3) a set of system alerts or other user interface (UI) notifications that guide the user to the appropriate action if needed. An example of an insulin infusion system that utilizes a sensor quality metric to adjust therapy delivery modes is described above.

Sensor Quality—A high quality CGM/sensor measurement is needed to realize the full advantages of an automated insulin infusion system to govern basal and bolus insulin deliveries. The sensor quality metric may be determined using known factors that may affect sensor accuracy. Examples of these factors include, without limitation: (1) sensor age that has known correlations to measurement accuracy; (2) measurement noise in the CGM electronics and/or raw sensor signals; (3) a sudden sharp rise or fall in sensor measurement that cannot be attributed to a natural physiological condition.

In accordance with an exemplary embodiment, the sensor quality metric may be mapped onto a scale (e.g., a scale of 1-10, or Low/Medium/High values) that provides different quality grades that can be used to adjust the therapy. The determination of the specific grade should be associated with the potential risk of providing automated therapy given the expected level of sensor error as a result of the underlying condition. For example, transient measurement noise may result in moderate CGM measurement error, so it may correspond to a “medium” sensor quality metric, whereas a sudden, discontinuous jump or drop in a CGM measurement may correspond to a “low” sensor quality metric for purposes of this description.

The sensor quality metric may also depend on characteristics of historical CGM values in a time series. For example, previous CGM values for a moving window of time can be analyzed and compared against the current value. As another example, an average of historical CGM values obtained at or near the same time of day can be analyzed and compared against the current value (obtained at the time of day under analysis). Accordingly, if a sufficient amount of historical values are not available, this condition itself may result in a conservative sensor quality rating until enough historical values are be recorded.

Therapy Adjustments—Once a sensor quality metric is determined, an adjustment to the control algorithm or methodology that governs automated insulin infusion may be necessary to mitigate risks of over or under delivery of insulin. In some embodiments, the specific type of adjustment is dependent on the design of the automated infusion algorithm.

As an example, consider an automated infusion algorithm that uses CGM measurements to make real-time adjustments to basal insulin and provide additional bolus insulin during times of rapidly rising glucose. Furthermore, this algorithm contains a safe fallback delivery mode that provides a constant basal rate for times when the CGM measurement is not available. In such a system, the following cases may be considered for therapy adjustment:

Case 1: “High” CGM/sensor quality metric—The algorithm may use its full authority of basal and bolus insulin based on the CGM measurements.

Case 2: “Medium” CGM/sensor quality metric—Allow only basal insulin delivery to be determined using the CGM but cease or otherwise limit the delivery of bolus insulin.

Case 3: “Low” CGM/sensor quality metric—Ignore the CGM altogether and revert to the safe fallback delivery mode until the sensor quality recovers.

The three cases listed above are representative examples for a hypothetical automated insulin infusion system. A different algorithm design would require therapy adjustments that are matched to the algorithm's dosing rules and/or other factors.

System Alerts and Notifications—System alerts and notifications represent another component to help manage risk while balancing therapy effectiveness and user burden. It is most desirable to maintain acceptable therapy without adding the burden of system alerts that interrupt the user. However, in some cases an alert is necessary to further mitigate risks related to poor CGM quality or to guide the user the action needed to recover optimal therapy.

For example, a particular CGM quality condition may be known to be transient in nature and generally recover without any intervention. In this case it may be appropriate for the system to make the therapy adjustment without notifying the user. However, a condition may be included to notify the user if the CGM quality is not fully recovered after a specified period of time.

As another example, a different CGM quality condition may be known to require a calibration using an external blood glucose measurement to recover. In this case it would be appropriate to alert the user that a CGM calibration is required once this condition occurs.

As mentioned above, the sensor quality metric can be scaled in any desirable manner. In accordance with an exemplary embodiment, the sensor quality metric can be “unknown” or “uncertain” or it can indicate low, medium, or high sensor quality. Table 1 indicates all of the sensor quality metrics for such an implementation, along with their related therapy actions, and system alerts.

FIG.18is a flow chart that illustrates an exemplary embodiment of a process1800for controlling operation of a medical device to regulate therapy actions based on sensor quality. The process1800obtains a current sensor-generated value that is indicative of a physiological characteristic of the user, where the value is produced in response to operation of a continuous analyte sensor device. The embodiment presented here relates to an insulin infusion system that includes or cooperates with a continuous glucose sensor—the physiological characteristic is a glucose level.

The process1800obtains a current SG value from a CGM sensor device (task1802). The process1800calculates, receives, or otherwise obtains a sensor quality metric for the CGM sensor device, where the sensor quality metric indicates accuracy, reliability, and/or trustworthiness of the current sensor-generated SG value (task1804). In accordance with certain embodiments, the sensor quality metric is calculated by the CGM sensor device, which communicates the calculated sensor quality metric to one or more destination devices as needed (for example, the calculated sensor quality metric can be sent from the CGM sensor device to the insulin infusion device, to a glucose monitor device, to a mobile device running a suitably configured mobile app, or the like). Alternatively, or additionally, the sensor quality metric can be calculated by one or more devices other than the CGM sensor device, based on raw sensor signals or information generated at the CGM sensor device. For example, the CGM sensor device can provide its electrical output (such as electrical current values or voltages) to the insulin infusion device, which then calculates the sensor quality metric based on the provided electrical output values.

The process1800continues by adjusting therapy actions of the insulin infusion device in response to the sensor quality metric, to configure a quality-specific operating mode of the insulin infusion device (task1806), as described in more detail below with reference toFIG.20. Thus, therapy-related functions, features, and/or operations of the medical device (the insulin infusion device) are altered based on the calculated sensor quality metric, e.g., high-quality, medium-quality, low-quality, etc. As shown in Table 1, conservative or aggressive insulin therapy options can be enabled/disabled in an ongoing manner, depending on the current state of the sensor quality metric. Moreover, the process1800manages the generation of user alerts at the medical device in response to the calculated sensor quality metric (task1808). In this regard, the process1800controls the insulin infusion device (and/or other user devices) to generate, inhibit, or otherwise regulate user alerts, based on the current state of the sensor quality metric. In some embodiments, task1808manages alerts by generating user alerts when the calculated sensor quality metric satisfies designated alert-generating criteria, and inhibits user alerts when the calculated sensor quality metric fails the designated alert-generating criteria. The alert-generating criteria can be designated to reduce unwanted or annoyance alerts, alarms, and notifications. For example, the alert-generating criteria may inhibit user alerts if the sensor quality metric is “better” than low. As another example, the alert-generating criteria may permit user alerts if the sensor quality metric is low, or if the system determines that the sensor is at its end of life or has lost communication with the medical device. This provides a better user experience with less nuisance alerts and less worrisome notifications.

The process1800continues by regulating delivery of fluid medication (e.g., insulin) from the medical device, in accordance with the current SG value and in accordance with the quality-specific operating mode of the medical device (task1810). In other words, the delivery of the fluid medication is controlled in response to the current sensor quality metric, which determines the quality-specific operating mode to be used, which results in an adjustment of certain specified therapy actions (see Table 1). For this particular implementation, task1810adjusts the therapy actions of the insulin infusion device such that aggressiveness of the insulin delivery therapy is proportional to the quality of the current SG value, as indicated by the calculated sensor quality metric, as described in more detail below with reference toFIG.20. Depending on the particular application and the type of medical device, the therapy actions can be adjusted, controlled, or regulated in a different manner using any desired methodology or algorithm that is driven by values of the sensor quality metric. The process1800can be repeated in an ongoing manner to contemplate updated SG values and their corresponding sensor quality metrics for purposes of adjusting the therapy actions over time.

FIG.19is a block diagram that illustrates the generation of a sensor quality metric in accordance with an exemplary embodiment.FIG.19depicts sensor quality calculation logic1900that calculates the sensor quality metric1902from one or more data inputs. The sensor quality calculation logic1900may reside and be executed at: the CGM sensor device; the insulin infusion device; a user monitoring device; a mobile device; a smart device or appliance; a cloud-based system, device, or service; a computing system or device onboard a vehicle; a tablet, desktop, or portable computer; or the like. Although not always required, the exemplary embodiment presented here calculates the sensor quality metric1902only from information, data, or signals generated by or derived from the continuous analyte sensor device. In other words, the data inputs of the sensor quality calculation logic1900are generated by the sensor device or are derived/calculated from data generated by the sensor device, and no information from external calibrating devices or information from ancillary devices is processed by the sensor quality calculation logic1900to obtain the sensor quality metric1902. In this regard, the continuous analyte sensor device can generate its own sensor quality metric1902in an “isolated” and self-diagnosing manner without relying on any additional information obtained from another device or system. Alternatively, the continuous analyte sensor device can provide its internally produced or calculated information to a compatible destination device, which then computes the sensor quality metric1902using only the information obtained from the sensor device.

In some examples, the data input utilized by the sensor quality calculation logic1900may be chosen to suit the needs and requirements of the particular medical device system, the intended application, and/or the specific embodiment. The example shown inFIG.19processes at least the following data inputs: sensor age data1904; raw sensor signal values1906; and/or historical sensor-generated values1908produced in response to operation of the continuous analyte sensor device. As mentioned above, these three data inputs are generated by the sensor device or are derived from information/data generated by the sensor device.

The sensor age data1904indicates a chronological age, operating life or “runtime” of the sensor device, the amount of time since deployment of the sensor device, or the like. In this regard, the sensor age data1904can be based on the date/time of manufacture, the date/time of initial deployment on the body of the user, the date/time following initialization or warmup of the sensor device following deployment, etc. Preferred implementations base the age of the sensor device on a time immediately following initialization or warmup of the deployed sensor device, which can be determined or marked by the sensor device in certain implementations. The sensor device can keep track of its age and update the sensor age data1904in an ongoing manner over time. Alternatively or additionally, the sensor device can mark and report the initial date/time (following warmup), to enable a destination device to keep track of the sensor age and update the sensor age data1904as time progresses.

The raw sensor signal values1906correspond to the raw signal output of the continuous analyte sensor device, which is produced while the sensor device is monitoring the physiological characteristic of interest. In certain embodiments, the raw sensor signal values1906are electrical current and/or electrical voltage measurements. For the continuous glucose sensor example described here, the raw sensor signal values1906are electrical current readings that are sometimes referred to as “ISIG” values. The raw sensor signal values1906are processed or converted into the monitored analyte levels, such as blood glucose values. To this end, the sensor-generated values1908depicted inFIG.19represent the usable sensor values that are derived from, calculated from, or converted from the raw sensor signal values1906. The methodology described here considers a number of historical sensor-generated values1908as needed to generate the sensor quality metric1902that is associated with the current sensor value.

In certain embodiments, the sensor quality calculation logic1900calculates the sensor quality metric1902based on: the sensor age data1904; measurement noise of the raw signal output of the continuous analyte sensor device; and changes in the sensor-generated values1908that cannot be attributed to a natural physiological condition of the user. The sensor age data1904is considered because accuracy of a newly deployed sensor device usually fluctuates for a short period of time immediately following the initialization or warmup period. Measurement noise in the raw sensor signal values1906can be caused by various conditions, such as physical movement of the sensor device, dislodging of the embedded sensor element, sudden unpredictable changes in physiology, ingress of water or other substances at the sensor site, or the like. The raw sensor signal values1906are usually relatively stable over “long” periods of time such as five minutes. If, however, the sensor quality calculation logic1900detects high variation (measurement noise) in the raw sensor signal values1906, then the corresponding sensor measurements can be designated as low quality. Similarly, if the sensor-generated values1908exhibit sharp changes, spikes, or unrealistic measurements that do not correspond to normal physiological changes or conditions, then the sensor quality calculation logic1900can flag those sensor values as low quality or disregard them.

The sensor quality calculation logic1900may consider any of the input data items individually or in any combination to generate the sensor quality metric1902. As mentioned previously, the sensor quality metric1902can be expressed in any desired format, using any desired range, scale, or domain. For the exemplary embodiment presented here, the sensor quality metric1902is calculated to be a number between 0 and 10 (inclusive), but only four of the available metric values are mapped to the quality states indicated in Table 1: Uncertain; Low; Medium; and High. In other embodiments, more or less than four quality states may be utilized. The sensor quality metric1902is generated and formatted in an appropriate manner for compatibility with a fluid medication delivery device, such that therapy actions of the fluid medication delivery device are adjusted in response to the calculated sensor quality metric.

The sensor quality calculation logic1900performs a method of assessing operational quality of the continuous analyte sensor device, with the sensor quality metric1902serving as an indication of the quality. The sensor quality metric1902can be utilized to regulate, control, or adjust certain functions or features of an associated medical device that regulates the delivery of therapy to a patient. In this regard,FIG.20is a flow chart that illustrates operation of an insulin infusion device in accordance with an exemplary embodiment (process2000) for sensor quality calculation logic1900. The following description of the process2000assumes that the insulin infusion device receives or generates sensor quality metrics with corresponding SG values, as described above. Accordingly, the illustrated embodiment of the process2000begins by processing the current value of the sensor quality metric (task2002). For this particular implementation, the process2000checks whether the sensor quality metric indicates Uncertain quality (query task2004), High quality (query task2012), Medium quality (query task2020), or Low quality (query task2028).

When the sensor quality metric indicates Uncertain quality (the “Yes” branch of query task2004), the process2000adjusts certain therapy actions of the insulin infusion device to configure an operating mode that is appropriate for the Uncertain quality status. More specifically, when the sensor quality metric indicates Uncertain quality, the process2000enables automatic basal insulin delivery by the insulin infusion device (task2006), disables an automatic bolus delivery feature of the insulin infusion device (task2008), and inhibits generation of any user alert related to the current sensor-generated value having Uncertain quality (task2010). The therapy adjustments made for this particular operating mode are appropriate under the assumption that the sensor quality metric will be determined in the near future. Thus, no user alert is generated, but the automatic bolus delivery function is temporarily disabled.

When the sensor quality metric indicates High quality, e.g., the sensor quality metric is greater than or equal to a high threshold value, such as 7 (the “Yes” branch of query task2012), the process2000adjusts certain therapy actions of the insulin infusion device to configure an appropriate high quality operating mode. More specifically, when the sensor quality metric indicates High quality, the process2000enables automatic basal insulin delivery by the insulin infusion device (task2014), enables the automatic bolus delivery feature (task2016), and inhibits generation of any user alert related to the current sensor-generated value having high quality (task2018). The therapy adjustments made for this high quality operating mode are appropriate under the assumption that the sensor device is operating in a normal and accurate manner. To this end, no user alert is generated, and both automatic basal delivery and automatic bolus delivery remain active and enabled.

When the sensor quality metric indicates Medium quality, e.g., the sensor quality metric is between a low threshold value (such as 3) and a high threshold value (such as 7) (the “Yes” branch of query task2020), the process2000adjusts certain therapy actions of the insulin infusion device to configure an appropriate medium quality operating mode. More specifically, when the sensor quality metric indicates Medium quality, the process2000enables automatic basal insulin delivery by the insulin infusion device (task2022), enables a restricted automatic bolus delivery feature (task2024), and inhibits generation of any user alert related to the current sensor-generated value having medium quality (task2026). The therapy adjustments made for this medium quality operating mode are appropriate under the assumption that the sensor device is operating in a manner that can still support a modified automatic bolus delivery function. Accordingly, no user alert is generated and automatic basal delivery remains active. However, the automatic bolus delivery function is modified to be less aggressive than usual. For example, the amount of insulin delivered by the automatic bolus delivery function may be limited or capped by some amount, or the bolus amount that is calculated from the current SG value may be reduced by a certain percentage as a safety factor. As another example, when the sensor quality metric indicates Medium quality, the insulin infusion device may be controlled in a way that places an upper limit on the current SG value for purposes of calculating and administering an automatic bolus. In accordance with certain embodiments, when the sensor quality metric indicates Medium quality, a maximum SG value is utilized for purposes of bolus calculation (e.g., 250 mg/dL)—if the current SG value is higher than the maximum allowable SG value, then the actual SG value is disregarded for purposes of automatic bolus calculation. This methodology reduces the likelihood of delivering too much insulin when the reliability or quality of the continuous glucose sensor device is potentially questionable.

When the sensor quality metric indicates Low quality, e.g., the sensor quality metric is less than or equal to a low threshold value, such as 3 (the “Yes” branch of query task2028), the process2000adjusts certain therapy actions of the insulin infusion device to configure an appropriate low quality operating mode. More specifically, when the sensor quality metric indicates Low quality, the process2000enables a safe basal insulin delivery mode of the insulin infusion device (task2030), disables the automatic bolus delivery feature (task2032), and generates a user alert to prompt the user to take corrective action, such as obtaining a new blood glucose meter value for sensor calibration (task2034). The therapy adjustments made for this low quality operating mode result in conservative insulin therapy. To this end, the normal basal insulin delivery profile for the user may be adjusted to be generally less aggressive, or the basal delivery profile may be adjusted to be a flat profile that merely provides a baseline amount of basal insulin over time. Moreover, automatic bolus delivery is suspended until the sensor quality metric improves.

As outlined above, low aggressiveness in the fluid medication therapy is provided when the sensor quality metric is low (e.g., at or below a low threshold value), medium aggressiveness is provided when the sensor quality metric is medium (e.g., between the low threshold value and a high threshold value), and high aggressiveness is provided when the sensor quality metric is high (e.g., at or above the high threshold value). Depending on the implementation, more or less than three levels of aggressiveness may be supported.

If the sensor quality metric indicates quality worse than Low quality, or indicates an erroneous value, then the process2000may generate an appropriate alert, message, or notification regarding the need to investigate, take corrective action, or the like (task2036). For example, the insulin infusion device may generate an audible alert and display a message that asks the user to check the integrity of the sensor device, recalibrate the sensor device, replace the sensor device, etc.

An iteration of the process2000can be performed as often as needed in an ongoing manner. In some embodiments, the process2000is performed for each new SG value (and its corresponding sensor quality metric).

When implemented in software, firmware, or other form of executable program instructions, various elements of the systems described herein are essentially the code segments or instructions that perform the various tasks. In certain embodiments, the program or code segments are stored in a tangible processor-readable medium, which may include any medium that can store or transfer information. Examples of a non-transitory and processor-readable medium include an electronic circuit, a semiconductor memory device, a ROM, a flash memory, an erasable ROM (EROM), a floppy diskette, a CD-ROM, an optical disk, a hard disk, or the like.

The various tasks performed in connection with a process described herein may be performed by software, hardware, firmware, or any combination thereof. It should be appreciated that a described process may include any number of additional or alternative tasks, the tasks shown in a flow chart representation need not be performed in the illustrated order, and that a described process may be incorporated into a more comprehensive procedure or process having additional functionality not described in detail herein. Moreover, one or more of the illustrated tasks could be omitted from an embodiment of the described process as long as the intended overall functionality remains intact.