SYSTEM AND METHOD FOR INCORPORATING EXERCISE INTO CLOSED-LOOP DIABETES THERAPY
20200368430 ยท 2020-11-26
Inventors
- Thomas R. Ulrich (Oceanside, CA, US)
- Michael Michaud (San Diego, CA, US)
- Geoffrey A. Kruse (San Diego, CA, US)
- Paul Harris (San Diego, CA, US)
- Garrett Marin (San Diego, CA, US)
Cpc classification
A61M5/1723
HUMAN NECESSITIES
A61M2005/14208
HUMAN NECESSITIES
International classification
Abstract
Disclosed herein are apparatuses and methods that account for exercise in closed loop insulin delivery systems. Rather than increasing a target insulin on board (IOB) as glucose levels rise, which would increase insulin delivery to address the raised glucose levels, when a user indicates that the user will be exercising raised glucose levels are addressed by reducing the target IOB within the closed loop algorithm. By reducing the target IOB, the algorithm responds less aggressively to pre-exercise food, and does not build up the IOB that can cause dangerously low glucose levels once the exercise also begins lowering glucose levels.
Claims
1. A system for closed loop diabetes therapy as described herein. a pump mechanism configured to facilitate delivery of insulin to a user; a user interface; a communications device adapted to receive glucose levels from a continuous glucose monitor; a processor functionally linked to the pump mechanism, the user interface and the communications device, the processor configured to: calculate and deliver insulin doses to the user based on a closed loop insulin delivery algorithm, the closed loop insulin delivery algorithm including an outer glucose loop that compares glucose levels from the continuous glucose monitor to a glucose target to determine an insulin on board target for the user and an inner insulin on board loop that compares an estimated insulin on board for the user to the insulin on board target to determine an insulin on board error used to calculate insulin doses configured to maintain the insulin on board of the user at the insulin on board target and the glucose levels of the user at the glucose level target; receive an indication that the user will be exercising; activate an exercise mode for the closed loop insulin delivery algorithm in response to the indication that the user will be exercising, the exercise mode modifying the inner insulin on board loop of the closed loop delivery algorithm that calculates insulin doses to maintain the insulin on board of the user at the insulin on board target; and calculate and deliver insulin doses to the user based on glucose levels from the continuous glucose monitor according to the exercise mode of the closed loop insulin delivery algorithm following the indication that the user will be exercising.
2. The system of claim 1, where the exercise mode modifies the inner glucose loop of the closed loop delivery algorithm by modifying the insulin on board error of the inner glucose loop.
3. The system of claim 2, wherein the insulin on board error is modified by applying a temporary constant to the insulin on board target to reduce the insulin on board target.
4. The system of claim 2, wherein the exercise mode modifies the inner on board error of the closed loop delivery algorithm by increasing an insulin action time used in calculating the estimated insulin on board for the user used to determine the insulin on board error.
5. The system of claim 1, wherein the exercise mode modifies the inner glucose loop of the closed loop delivery algorithm by modifying a stored basal rate for the user used in calculating the insulin doses to maintain the insulin on board target for the user.
6. The system of claim 1, wherein the indication that the user is exercising is received through the user interface.
7. The system of claim 1, wherein the processor is configured calculate and deliver insulin doses to the user based on glucose levels from the continuous glucose monitor according to the exercise mode of the closed loop insulin delivery algorithm for a predetermined time following the indication that the user will be exercising.
8. The system of claim 7, wherein the predetermined time is received through the user interface.
9. The system of claim 1, wherein the pump mechanism, user interface and processor are part of an ambulatory infusion pump.
10. The system of claim 1, wherein the user interface and processor are part of a remote control device for remotely controlling an ambulatory infusion pump including the pump mechanism.
11. A method of closed loop diabetes therapy, comprising: receiving glucose levels of a user from a continuous glucose monitor; calculating insulin doses to the user based on a closed loop insulin delivery algorithm, the closed loop insulin delivery algorithm including an outer glucose loop that compares glucose levels from the continuous glucose monitor to a glucose target to determine an insulin on board target for the user and an inner insulin on board loop that compares an estimated insulin on board for the user to the insulin on board target to determine an insulin on board error used to calculate insulin doses configured to maintain the insulin on board of the user at the insulin on board target and the glucose levels of the user at the glucose level target; delivering the calculating insulin doses to the user with a pump mechanism; receiving an indication that the user will be exercising; activating an exercise mode for the closed loop insulin delivery algorithm in response to the indication that the user will be exercising, the exercise mode modifying the inner insulin on board loop of the closed loop delivery algorithm that calculates insulin doses to maintain the insulin on board of the user at the insulin on board target; and calculating and delivering insulin doses to the user based on glucose levels from the continuous glucose monitor according to the exercise mode of the closed loop insulin delivery algorithm following the indication that the user will be exercising.
12. The method of claim 11, where the exercise mode modifies the inner glucose loop of the closed loop delivery algorithm by modifying the insulin on board error of the inner glucose loop.
13. The method of claim 12, wherein the insulin on board error is modified by applying a temporary constant to the insulin on board target to reduce the insulin on board target.
14. The method of claim 12, wherein the exercise mode modifies the inner on board error of the closed loop delivery algorithm by increasing an insulin action time used in calculating the estimated insulin on board for the user used to determine the insulin on board error.
15. The method of claim 11, wherein the exercise mode modifies the inner glucose loop of the closed loop delivery algorithm by modifying a stored basal rate for the user used in calculating the insulin doses to maintain the insulin on board target for the user.
16. The method of claim 11, further comprising receiving the indication that the user is exercising through a user interface.
17. The method of claim 11, wherein insulin doses are calculated and delivered to the user based on glucose levels from the continuous glucose monitor according to the exercise mode for a predetermined time following the indication that the user will be exercising.
18. The method of claim 17, further comprising receiving the predetermined time through a user interface.
19. The method of claim 11, wherein the pump mechanism is part of an ambulatory infusion pump that calculates the insulin doses.
20. The method of claim 11, wherein the user interface and processor are part of a remote control device for remotely controlling an ambulatory infusion pump including the pump mechanism.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:
[0013]
[0014]
[0015]
[0016]
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[0020]
[0021]
[0022] While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention.
[0024]
[0025] In one embodiment, the medical device can be an ambulatory insulin pump configured to deliver insulin to a patient. Further details regarding such pump devices can be found in U.S. Pat. No. 8,287,495, which is incorporated herein by reference in its entirety. In other embodiments, the medical device can be an infusion pump configured to deliver one or more additional or other medicaments to a patient.
[0026]
[0027]
[0028] In one embodiment, pump 102 includes a processor that controls operations of the pump and, in some embodiments, may receive commands from a separate device for control of operations of the pump. Such a separate device can include, for example, a dedicated remote control or a smartphone or other consumer electronic device executing an application configured to enable the device to transmit operating commands to the processor of pump 102. In some embodiments, processor can also transmit information to one or more separate devices, such as information pertaining to device parameters, alarms, reminders, pump status, etc. In one embodiment pump 102 does not include a display but may include one or more indicator lights 174 and/or one or more input buttons 172. Pump 102 can also incorporate any or all of the features described with respect to pump 12 in
[0029] Pump 12 or 102 can interface directly or indirectly (via, e.g., a smartphone or other device) with a glucose meter, such as a blood glucose meter (BGM) or a continuous glucose monitor (CGM). Referring to
[0030] In an embodiment of a pump-CGM system having a pump 12, 102 that communicates with a CGM and that integrates CGM data and pump data as described herein, the CGM can automatically transmit the glucose data to the pump. The pump can then automatically determine therapy parameters and deliver medicament based on the data. Such an automatic pump-CGM system for insulin delivery can be referred to as an automated insulin delivery (AID) or an artificial pancreas system that provides closed-loop therapy to the patient to approximate or even mimic the natural functions of a healthy pancreas. In such a system, insulin doses are calculated based on the CGM readings (that may or may not be automatically transmitted to the pump) and are automatically delivered to the patient at least in part based on the CGM reading(s). In various embodiments, doses can be delivered as automated correction boluses and/or automated increases or decreases to a basal rate. Insulin doses can also be administered based on current glucose levels and/or predicted future glucoses levels based on current and past glucose levels.
[0031] For example, if the CGM indicates that the user has a high blood glucose level or hyperglycemia, the system can automatically calculate an insulin dose necessary to reduce the user's blood glucose level below a threshold level or to a target level and automatically deliver the dose. Alternatively, the system can automatically suggest a change in therapy upon receiving the CGM data such as an increased insulin basal rate or delivery of a bolus, but can require the user to accept the suggested change prior to delivery rather than automatically delivering the therapy adjustments.
[0032] If the CGM data indicates that the user has a low blood glucose level or hypoglycemia, the system can, for example, automatically reduce a basal rate, suggest to the user to reduce a basal rate, automatically deliver or suggest that the user initiate the delivery of an amount of a substance such as, e.g., a hormone (glucagon) to raise the concentration of glucose in the blood, automatically suggest that the user, e.g., ingest carbohydrates and/or take other actions and/or make other suggestions as may be appropriate to address the hypoglycemic condition, singly or in any desired combination or sequence. Such determination can be made by the infusion pump providing therapy or by a separate device that transmits therapy parameters to the infusion pump. In some embodiments, multiple medicaments can be employed in such a system as, for example, a first medicament, e.g., insulin, that lowers blood glucose levels and a second medicament, e.g., glucagon, that raises blood glucose levels.
[0033] As with other parameters related to therapy, such thresholds and target values can be stored in memory located in the pump or, if not located in the pump, stored in a separate location and accessible by the pump processor (e.g., cloud storage, a smartphone, a CGM, a dedicated controller, a computer, etc., any of which is accessible via a network connection). The pump processor can periodically and/or continually execute instructions for a checking function that accesses these data in memory, compares them with data received from the CGM and acts accordingly to adjust therapy. In further embodiments, rather than the pump determining the therapy parameters, the parameters can be determined by a separate device and transmitted to the pump for execution. In such embodiments, a separate device such as the CGM or a device in communication with the CGM, such as, for example, a smartphone, dedicated controller, electronic tablet, computer, etc. can include a processor programmed to calculate therapy parameters based on the CGM data that then instruct the pump to provide therapy according to the calculated parameters.
[0034] A schematic representation of a control algorithm for automatically adjusting insulin delivery based on CGM data is depicted in
[0035] The estimated IOB level determined at step 206 is then taken as the command (cmdIOB) for the inner loop and based on a difference of an IOB feedback value (fdbkIOB) and the cmdIOB set point at step 208, an IOB error value (errIOB) is determined. At step 210, the errIOB value is multiplied by a constant k2 (relating to insulin-dependent glucose uptake in the body) and an estimate of the total daily insulin (TDI) of the user. This adjusts the errIOB to be proportional to the constant and the user's total daily intake of insulin. At step 212, a limiter function is applied to the value calculated at step 210. The limiter function prevents the calculated amount from being larger or smaller than preset limits. The result is an insulin amount dU, which is the amount by which the user's stored basal rate should be modified. The insulin delivery rate for the user for the next closed loop interval is therefore calculated by modifying the user's stored basal rate profile by the dU value at step 214.
[0036] After the dose is calculated, it can be delivered to the user at step 216 and can also be used to update the estimated TDI for the user at step 218. The dose can also be used to update the estimated IOB level for the user at step 220 by comparing the actual insulin delivered to the programmed basal rate. The updated estimated IOB then becomes the new fdbkIOB for the IOB comparison at step 208. When new CGM values are received from the CGM, an estimated true CGM can be determined based on various factors such as, for example, the calibration status of the CGM sensor, and the estimated true CGM value then becomes the new fdbkGLUCOSE value for the outer loop comparison with cmdGLUCOSE at step 204. The algorithm then proceeds through to calculate a new estimated IOB and to the inner IOB loop for calculation of an insulin dose as described above. In one embodiment, a new CGM value is received every 5 minutes and therefore the algorithm executes as set forth above every 5 minutes.
[0037] Applicant has determined that the difficulties in accounting for exercise in such closed loop controls are caused by the estimated IOB. For example, when the user consumes food the algorithm increases the estimated IOB in response to the increase in insulin delivered to address rising blood glucose, and that increased estimated IOB can cause blood glucose to go low during exercise. For example, for an individual with a total daily insulin (TDI) of 50 units, the algorithm of
[0038] In some embodiments, a user will indicate to the system that the user will be exercising, such as, for example, by selecting to enter an exercise mode through a user interface of a pump, remote control, etc. In other embodiments, the system can automatically determine that the user is exercising. In some embodiments, the system can make this determination based on information from one or more additional devices, such as, for example, a fitness or health monitoring device or application. The system may remain in exercise mode for a predetermined time that can be determined in various ways. For example, a user may enter or select an amount of time that the user will exercise or starting time and an ending time for exercise. The user may also be able to disable or close the exercise mode following the exercise through a user interface of a pump, remote control etc. In embodiments that automatically determine when the user is exercising based on information from one or more additional devices, the system can automatically determine when the user has stopped exercising based on the information from the one or more additional devices.
[0039]
[0040] A second potential modification to the algorithm of
[0041] It should further be noted that be increasing the estimated IOB the above embodiments provide a further safeguard against a manual bolus administered during exercise mode causing an unsafe drop in glucose. Manual boluses during closed loop mode take into account the estimated IOB in the system and only dose as needed to increase the current estimated IOB to match the amount requested in the bolus. Therefore, by increasing the estimated IOB the amount of insulin delivered in any given bolus request is necessarily reduced, which decreases the risk of the bolus in conjunction with exercise causing a dangerously low level of glucose.
[0042] A third potential modification to the algorithm of
[0043] Each of these three proposed modifications to the basal increase control algorithm of
[0044] In addition, in some embodiments the number of modifications employed could also be a key aspect of accounting for exercise based on the intensity of the exercise. For example, in setting standard pre-sets for handling exercise, there can be multiple combinations of values such that for light workouts, for example, only one of the options is used, while for heavy workouts, for example, all options are used and may be used with more extreme constant values.
TABLE-US-00001 TABLE 1 Potential Exercise Schemes IOB Setpoint Lengthening Insulin Temporary Exercise Reduction Duration Time Rate Intensity (FIG. 6) (FIG. 7) (FIG. 8) Mild N/A (K2 = 1) 6 Hours N/A (K3 = 1) Moderate K2 = 75% 6 Hours N/A (K3 = 1) 60 Minute K2 = 55% 6 Hours K3 = 80% workout at the gym 5K Race K2 = 40% 6 Hours K3 = 20% Marathon K2 = 20% 6 Hours K3 = 0
[0045] As depicted above, different settings can be prescribed for different levels of exercise including mild exercise, moderate exercise and intense exercise. More intense exercise can further be broken down into various levels including, for example, specific exercise activities such as a 60 minute workout, a 5K race and a marathon. In this embodiment, for mild exercise the algorithm is adjusted only to include the lengthening insulin duration time aspect of the disclosure whereas for moderate exercise both the IOB set-point reduction and lengthening insulin duration time aspects are incorporated. For the more intense types of exercise, all three aspects can be incorporated, with the k.sub.2 and k.sub.3 constants decreasing as the exercise intensity increases. It should be noted that Table 1 depicts one exemplary embodiment and that which and how many adjustments are applied to a given type and/or intensity of exercise can vary.
[0046] Although embodiments described herein may be discussed in the context of the controlled delivery of insulin, delivery of other medicaments, singly or in combination with one another or with insulin, including, for example, glucagon, pramlintide, etc., as well as other applications are also contemplated. Device and method embodiments discussed herein may be used for pain medication, chemotherapy, iron chelation, immunoglobulin treatment, dextrose or saline IV delivery, treatment of various conditions including, e.g., pulmonary hypertension, or any other suitable indication or application. Non-medical applications are also contemplated.
[0047] Also incorporated herein by reference in their entirety are commonly owned U.S. Pat. Nos. 6,999,854; 8,133,197; 8,287,495; 8,408,421 8,448,824; 8,573,027; 8,650,937; 8,986,523; 9,173,998; 9,180,242; 9,180,243; 9,238,100; 9,242,043; 9,335,910; 9,381,271; 9,421,329; 9,486,171; 9,486,571; 9,492,608; 9,503,526; 9,555,186; 9,565,718; 9,603,995; 9,669,160; 9,715,327; 9,737,656; 9,750,871; 9,867,937; 9,867,953; 9,940,441; 9,993,595; 10,016,561; 10,201,656; 10,279,105; 10,279,106; 10,279,107; 10,357,603; 10,357,606; 10,492,141; 10/541,987; and 10,569,016. commonly owned U.S. Patent Publication Nos. 2009/0287180; 2012/0123230; 2013/0053816; 2014/0276423; 2014/0276569; 2014/0276570; 2018/0021514; 2018/0071454; 2019/0240398; 2019/0307952; 2019/0365997 and 2020/0114076 and commonly owned U.S. patent application Ser. Nos. 16/507,146; 16/725,278; 16/725,337; 16/793,662 and 16/830,415.
[0048] With regard to the above detailed description, like reference numerals used therein may refer to like elements that may have the same or similar dimensions, materials, and configurations. While particular forms of embodiments have been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the embodiments herein. Accordingly, it is not intended that the invention be limited by the forgoing detailed description.
[0049] The entirety of each patent, patent application, publication, and document referenced herein is hereby incorporated by reference. Citation of the above patents, patent applications, publications and documents is not an admission that any of the foregoing is pertinent prior art, nor does it constitute any admission as to the contents or date of these documents.
[0050] Modifications may be made to the foregoing embodiments without departing from the basic aspects of the technology. Although the technology may have been described in substantial detail with reference to one or more specific embodiments, changes may be made to the embodiments specifically disclosed in this application, yet these modifications and improvements are within the scope and spirit of the technology. The technology illustratively described herein may suitably be practiced in the absence of any element(s) not specifically disclosed herein. The terms and expressions which have been employed are used as terms of description and not of limitation and use of such terms and expressions do not exclude any equivalents of the features shown and described or portions thereof and various modifications are possible within the scope of the technology claimed. Although the present technology has been specifically disclosed by representative embodiments and optional features, modification and variation of the concepts herein disclosed may be made, and such modifications and variations may be considered within the scope of this technology.