Systems and methods for fluid delivery

Abstract

Systems and methods for fluid delivery are provided.SOLUTION: A system for at least partial closed-loop control of a medical condition is disclosed. The system includes at least one medical fluid pump 14. A medical fluid pump including a sensor for determining the volume of fluid pumped by the pump. Also at least one continuous analyte monitor and a controller 18. The controller is in communication with the medical fluid pump and the at least one continuous analyte monitor. The controller includes a processor. The processor includes instructions for delivery of the medical fluid based at least on data received from the at least one continuous analyte monitor.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application is a continuation of U.S. Provisional Patent Application No. 61 / 097,021, entitled "Systems and Methods for Fluid Delivery (F72)," filed September 15, 2008; U.S. Provisional Patent Application No. 61 / 101,053, entitled "Infusion Pump Assembly with a Switch Assembly (F73)," filed September 29, 2008; U.S. Provisional Patent Application No. 61 / 101,077, entitled "Infusion Pump Assembly with Tubing Storage (F74)," filed September 29, 2008; U.S. Provisional Patent Application No. 61 / 101,105, entitled "Improved Infusion Pump Assembly (F75)," filed September 29, 2008; and U.S. Provisional Patent Application No. 61 / 101,115, entitled "Filling Apparatus and Methods for an Infusion Pump." This is a non-provisional patent application claiming priority to U.S. Provisional Patent Application No. 61 / 141,996 entitled "Acoustic Volume Sensing Methods, Systems and Apparatus (G07)," filed September 28, 2008, and U.S. Provisional Patent Application No. 61 / 141,781 entitled "Split Ring Resonator Antenna Adapted for Use in Wirelessly Controlled Medical Device (G81)," filed December 31, 2008, all of which are incorporated herein by reference in their entireties.

[0002] (Technical field) The present invention relates to fluid delivery, and more particularly to systems and methods for fluid delivery. [Background technology]

[0003] Millions of people live with diabetes. These patients are further commonly classified into one of two types of diabetes: type 1 and type 2. Type 1, historically known as juvenile diabetes, is an autoimmune disease characterized by an inability to secrete insulin. Type 2 is a disease that reduces the ability to respond to insulin and / or produce sufficient insulin. Both types of diabetes are characterized by hyperglycemia. Patients living with type 1 diabetes require daily injections of insulin, a hormone that lowers blood sugar levels, to survive. However, to maintain long-term health, people living with diabetes strive to maintain blood sugar levels as close to "non-diabetic" as possible. However, maintaining healthy blood sugar levels is a very difficult goal to achieve.

[0004] To this end, there have been efforts to design portable devices, such as insulin pumps, for the controlled release of insulin. There are many different forms of insulin available. Most patients using insulin pumps currently use U-100 insulin rapid-acting insulin (e.g., HUMALOG insulin lispro injection or equivalent) in the pump. Insulin pump devices are known to have a reservoir, such as a cartridge, syringe, or bag, and to be electronically controlled. However, the delivery rate must be manually entered by the individual living with diabetes or their caregiver. Therefore, a diabetic patient determines / determines the amount of insulin to be delivered over a given time / period (i.e., "basal" and "bolus" rates / amounts) using information or factors available to the patient, such as blood glucose measurements determined using a blood glucose meter, past data from similar situations, food intended to be eaten or eaten, anticipated or previously completed exercise, and / or stress or illness.

[0005] However, although a diabetic may determine the rate / amount based on one or more of these factors (or additional factors), managing diabetes is not an exact science for many reasons, including, but not limited to, inaccurate methods of insulin delivery, inaccurate blood glucose meters, inability to accurately count carbohydrate intake, inability to determine impending illness, inability to predict the exact effect of exercise, and inability to predict or anticipate the effects of many additional hormones or processes in the body.

[0006] The nature of diabetes management is further complicated by the risk of hypoglycemia, which can be fatal. Moreover, overcalculating the amount of insulin needed can be life-threatening. While the short-term effects of hyperglycemia are not fatal, complications from long-term hyperglycemia are known and include shorter life expectancy, heart attack or stroke, kidney failure, adult blindness, nerve damage, and increased risk of non-traumatic amputation. Therefore, undercalculating the amount of insulin needed can significantly affect quality of life in the long term, as well as lead to fatal complications.

[0007] Thus, there is a need for systems and methods for safely and effectively delivering the right amount of insulin at the right time (i.e., the amount of insulin needed to maintain desired blood glucose levels). Summary of the Invention [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a system for at least partial closed-loop control of a medical condition. The system includes at least one medical fluid pump. The medical fluid pump includes a sensor for determining a volume of fluid delivered by the pump. Also included are at least one continuous analyte monitor and a controller. The controller is in communication with the medical fluid pump and the at least one continuous analyte monitor. The controller includes a processor. The processor includes instructions for delivery of the medical fluid based at least on data received from the at least one continuous analyte monitor.

[0009] Some embodiments of this aspect of the invention include one or more of the following: The sensor further includes an acoustic capacitance sensor; The system further includes a network operations center in communication with the processor; The pump further includes a delivery chamber having an inlet connectable to provide fluid communication with the fluid source and a pump outlet, and a force application assembly adapted to provide a compression stroke to the delivery chamber, the compression stroke forcing fluid from the delivery chamber to the pump outlet while causing restriction of backflow of fluid from the delivery chamber through the inlet; The force application assembly is coupled to the inlet valve actuator and the pump actuator such that the compression stroke actuates and closes an inlet valve coupled between the inlet and the fluid source as the pump actuator forces fluid from the delivery chamber to the pump outlet; The force application assembly includes a monitor for coordinated operation of the valve actuator and the pump actuator, the monitor including at least one shape-memory actuator; At least one of the continuous analyte monitors is a continuous glucose monitor; The system includes at least one accelerometer; and The system includes at least one blood oxygen sensor. The system further includes at least one inertial measurement unit comprising at least one accelerometer and at least one gyroscope. The system includes at least one temperature sensor.

[0010] According to one aspect of the present invention, a method for at least partial closed-loop control of a medical condition is disclosed, the method including receiving glucose data during a time frame or event, comparing the glucose data to previous similar time frames or events, determining an unexpected outcome during the time frame or event, and transmitting a warning signal to indicate the unexpected outcome.

[0011] Some embodiments of this aspect of the invention include one or more of the following: sending the warning signal includes warning a user of the unexpected result; the method further includes prompting the user to input information regarding the unexpected result; the system does not receive information regarding the unexpected result from the user and shuts down the system; shutting down the system includes warning the user of the shutdown through a series of alarms; warning the user of the shutdown through a series of alarms includes warning the user of the shutdown through a series of escalating alarms.

[0012] According to one aspect of the present invention, there is provided a method for at least partial closed-loop control of a medical condition, the method including receiving medical fluid delivery data during a time frame or event, comparing the medical fluid delivery data to previous similar time frames or events, determining an unexpected result during the time frame or event, and transmitting a warning signal to indicate the unexpected result.

[0013] Some embodiments of this aspect of the invention include one or more of the following: sending the warning signal includes warning a user of the unexpected result; the method further includes prompting the user to input information regarding the unexpected result; the system does not receive information regarding the unexpected result from the user and shuts down the system; shutting down the system includes warning the user of the shutdown through a series of alarms; warning the user of the shutdown through a series of alarms includes warning the user of the shutdown through a series of escalating alarms.

[0014] According to one aspect of the present invention, there is provided a method for monitoring the integrity of an analyte sensor, the method including the steps of injecting a volume of an analyte having a predetermined concentration in close proximity to a continuous analyte sensor for the analyte, receiving data from the continuous analyte sensor, and analyzing the data to determine whether the analyte sensor is responsive to the injected volume of analyte.

[0015] Some embodiments of this aspect of the invention include where the analyte is glucose.

[0016] The present invention also provides, for example, the following items. (Item 1) 1. A system for at least partial closed-loop control of a medical condition, the system comprising: at least one medical fluid pump, the medical fluid pump including a sensor for determining a volume of fluid delivered by the pump; at least one continuous analyte monitor; a controller in communication with the medical fluid pump and the at least one continuous analyte monitor, the controller comprising a processor, the processor comprising instructions for delivery of medical fluid based at least on data received from the at least one continuous analyte monitor; A system comprising: (Item 2) Item 10. The system of item 1, wherein the sensor further comprises an acoustic volume sensor. (Item 3) Item 10. The system of item 1, further comprising a network operations center in communication with the processor. (Item 4) The pump a delivery chamber having an inlet connectable to provide fluid communication with a fluid source, and a pump outlet; a force application assembly adapted to provide a compression stroke to the delivery chamber; Furthermore, Item 10. The system of item 1, wherein the compression stroke forces fluid from the delivery chamber to the pump outlet while causing restriction of backflow of fluid from the delivery chamber through the inlet. (Item 5) Item 5. The system of item 4, wherein the force application assembly is coupled to an inlet valve actuator and a pump actuator, such that when the pump actuator forces fluid from the delivery chamber to the pump outlet, the compression stroke actuates and closes an inlet valve coupled between the inlet and the fluid source. (Item 6) Item 6. The system of item 5, wherein the force application assembly further comprises a motor for coordinated movement of the valve actuator and the pump actuator, the motor including at least one shape memory actuator. (Item 7) Item 10. The system of item 1, wherein at least one of the continuous analyte monitors is a continuous glucose monitor. (Item 8) Item 10. The system of item 1, further comprising at least one accelerometer. (Item 9) Item 10. The system of item 1, further comprising at least one blood oxygen sensor. (Item 10) Item 10. The system of item 1, further comprising at least one inertial measurement unit comprising at least one accelerometer and at least one gyroscope. (Item 11) Item 10. The system of item 1, further comprising at least one temperature sensor. (Item 12) 1. A method for at least partial closed-loop control of a medical condition, the method comprising: receiving glucose data during a time period or event; comparing the glucose data to a previous similar time frame or event; determining unexpected results during said time frame or said event; Sending warning signals to indicate unexpected results A method comprising: (Item 13) Item 13. The method of item 12, wherein sending the warning signal further comprises warning a user about the unexpected result. (Item 14) Item 14. The method of item 13, further comprising prompting the user to input information regarding the unexpected result. (Item 15) Item 15. The method of item 14, further comprising the system not receiving information about the unexpected result from the user and shutting down the system. (Item 16) Item 16. The method of item 15, wherein shutting down the system further comprises alerting the user of the shutdown via a series of alarms. (Item 17) 17. The method of claim 16, wherein warning the user of the shutdown via a series of alarms further comprises warning the user of the shutdown via a series of increasing alarms. (Item 18) 1. A method for at least partial closed-loop control of a medical condition, the method comprising: receiving medical fluid delivery data during a time period or event; comparing the medical fluid delivery data with a previous similar time frame or event; determining unexpected results during said time frame or said event; Sending warning signals to indicate unexpected results A method comprising: (Item 19) 20. The method of claim 18, wherein sending a warning signal further comprises warning a user about the unexpected result. (Item 20) 20. The method of claim 19, further comprising prompting the user to input information regarding the unexpected result. (Item 21) 21. The method of claim 20, further comprising the system not receiving information about the unexpected result from the user and shutting down the system. (Item 22) 22. The method of claim 21, wherein shutting down the system further comprises alerting the user of the shutdown via a series of alarms. (Item 23) 23. The method of claim 22, wherein warning the user of the shutdown via a series of alarms further comprises warning the user of the shutdown via a series of increasing alarms. (Item 24) 1. A method for monitoring the integrity of an analyte sensor, the method comprising: injecting a volume of an analyte having a predetermined concentration in close proximity to a continuous analyte sensor for the analyte; receiving data from the continuous analyte sensor; analyzing the data to determine whether the analyte sensor is responsive to the injected volume of the analyte; A method comprising: (Item 25) 25. The method according to item 24, wherein the analyte is glucose. These aspects of the present invention are not intended to be exhaustive, and other features, aspects, and advantages of the present invention will become readily apparent to those skilled in the art when read in conjunction with the appended claims and accompanying drawings. [Brief explanation of the drawings]

[0017] These and other features and advantages of the present invention will be better understood by reading the following detailed description taken in conjunction with the drawings. [Figure 1] FIG. 1 is a schematic diagram of some of the variables used in diabetes management. [Figure 2] FIG. 2 is a schematic diagram of some variables used in various embodiments of the at least partially closed loop method. [Figure 3] FIG. 3 is an illustration of one embodiment of a cannula having depth indicators indicated by different hatches. [Figure 4] FIG. 4 is a diagrammatic representation of an embodiment of the bounded bolus partial closed-loop method. [Figure 5] FIG. 5 is a diagrammatic representation of an embodiment of the bounded basal bolus partial closed loop method. [Figure 6] FIG. 6 is an illustration of one embodiment of the system. [Figure 7] FIG. 7 is a side view of the infusion pump assembly. [Figure 8] 8 is a perspective view of the infusion pump assembly of FIG. 7. FIG. [Figure 9] FIG. 9 is an exploded view of the various components of the infusion pump assembly of FIG. [Figure 10] 10 is a cross-sectional view of the disposable housing assembly of the infusion pump assembly of FIG. 7. FIG. [Figure 11] FIG. 11 is an isometric view of an alternative embodiment of the infusion pump assembly of FIG. [Figure 12] 12 is a top view of the infusion pump assembly of FIG. [Figure 13] 13 is a top view of the infusion pump assembly of FIG. 11. FIG. [Figure 14] Figure 14A is an exploded view of various components of the infusion pump assembly of Figure 16. Figure 14B is an isometric view of a portion of the infusion pump assembly of Figure 11. [Figure 15] 15 is a cross-sectional view of the disposable housing assembly of the infusion pump assembly of FIG. 11. FIG. [Figure 16] FIG. 16 is a diagram of the fluid paths within the infusion pump assembly of FIG. [Figure 17] 17A-17C are diagrams of fluid paths within the infusion pump assembly of FIG. [Figure 18] FIG. 18 is an exploded view of the various components of the infusion pump assembly of FIG. [Figure 19] FIG. 19 is a diagram of a volume sensor assembly contained within an infusion pump assembly. [Figure 20] FIG. 20 is a two-dimensional graph of the performance characteristics of the capacitive sensor assembly of FIG. [Figure 21] FIG. 21 is a two-dimensional graph of the performance characteristics of the capacitive sensor assembly of FIG. [Figure 22] FIG. 22 is a two-dimensional graph of the performance characteristics of the capacitive sensor assembly of FIG. [Figure 23] 23 is a diagram of a volume sensor assembly included within the infusion pump assembly of FIG. [Figure 24] FIG. 24 is a two-dimensional graph of the performance characteristics of the capacitive sensor assembly of FIG. [Figure 25] FIG. 25 is a two-dimensional graph of the performance characteristics of the capacitive sensor assembly of FIG. [Figure 26] 26 is a diagram of a volume sensor assembly included within the infusion pump assembly of FIG. [Figure 27] FIG. 27 is a two-dimensional graph of the performance characteristics of the volume sensor assembly included within the infusion pump assembly of FIG. [Figure 28] FIG. 28 is a two-dimensional graph of the performance characteristics of the volume sensor assembly included within the infusion pump assembly of FIG. [Figure 29] FIG. 29 is a two-dimensional graph of the performance characteristics of the volume sensor assembly included within the infusion pump assembly of FIG. [Figure 30] FIG. 30 is a two-dimensional graph of the performance characteristics of the volume sensor assembly included within the infusion pump assembly of FIG. [Figure 31] FIG. 31 is a two-dimensional graph of the performance characteristics of the volume sensor assembly included within the infusion pump assembly of FIG. [Figure 32] FIG. 32 is a diagram of a control model for a volume sensor assembly included within the infusion pump assembly of FIG. [Figure 33] 33 is a diagram of an electrical control assembly for the volume sensor assembly included within the infusion pump assembly of FIG. [Figure 34] 34 is a diagram of a volume controller of the volume sensor assembly included within the infusion pump assembly of FIG. [Figure 35] FIG. 35 is a diagram of the feed forward controller of the capacity controller of FIG. [Figure 36] 36-37 diagrammatically depict an SMA controller implementation of the capacitance controller of FIG. [Figure 37] 36-37 diagrammatically depict an SMA controller implementation of the capacitance controller of FIG. [Figure 38A] 38A-38B are alternative implementations of an SMA controller. [Figure 38B] 38A-38B are alternative implementations of an SMA controller. [Figure 39] FIG. 39 diagrammatically depicts a multi-processor control configuration that may be included within the infusion pump assembly of FIG. [Figure 40] FIG. 40 is a diagram of a multi-processor control configuration that may be included within the infusion pump assembly of FIG. [Figure 41A] 41A-41B diagrammatically depict multi-processor functionality. [Figure 41B]41A-41B diagrammatically depict multi-processor functionality. [Figure 42] Figure 42 depicts the multi-processor functionality diagrammatically. [Figure 43] Figure 43 depicts the multi-processor functionality diagrammatically. [Figure 44] FIG. 44 diagrammatically depicts a volume sensor assembly that may be included within the infusion pump assembly of FIG. [Figure 45] FIG. 45 is an exemplary schematic diagram of a split ring resonator antenna. [Figure 46] FIG. 46 is an exemplary schematic diagram of a medical device configured to utilize a split ring resonator antenna. [Figure 47] FIG. 47 is an exemplary schematic diagram of a split ring resonator antenna and a transmission line from a medical infusion device. [Figure 48] FIG. 48 is a graph of the return loss of a split ring resonator antenna before contact with human skin. [Figure 48A] FIG. 48A is a graph of the return loss of a split ring resonator antenna during contact with human skin. [Figure 49] FIG. 49 is an exemplary schematic diagram of a split-ring resonator antenna integrated into a device that operates in close proximity to a dielectric material. [Figure 50] FIG. 50 is a schematic diagram of the dimensions of the inner and outer portions of an exemplary embodiment. [Figure 51] FIG. 51 is a graph of the return loss of a non-split ring resonator antenna before contact with human skin. [Figure 52] FIG. 52 is a graph of the return loss of a non-split ring resonator antenna during contact with human skin. [Figure 53A] 53A-53B are examples of a base trajectory and a delivery schedule for that trajectory. [Figure 53B] 53A-53B are examples of a base trajectory and a delivery schedule for that trajectory. [Figure 54A]54A-54B are examples of basal and extended bolus trajectories and delivery schedules for the trajectories. [Figure 54B] 54A-54B are examples of basal and extended bolus trajectories and delivery schedules for the trajectories. [Figure 55A] 55A-55B are examples of basal, extended bolus, and regular bolus trajectories and delivery schedules for the trajectories. [Figure 55B] 55A-55B are examples of basal, extended bolus, and regular bolus trajectories and delivery schedules for the trajectories.

[0018] Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE INVENTION

[0019] Although insulin and diabetes are discussed herein, the present disclosure is not limited to the use of the systems and methods for the treatment of diabetes. The disclosed methods and systems may be used for the delivery of any medical or therapeutic fluid, including but not limited to insulin, for the treatment of medical conditions, including but not limited to diabetes.

[0020] Disclosed herein are methods and systems for closed-loop or partially closed-loop control of diabetes. As explained above, many factors affect the amount of insulin a patient or user needs to maintain an appropriate blood glucose level. The term "appropriate" is used herein to mean a blood glucose level selected by the patient and / or healthcare provider as healthy for the patient. The appropriate blood glucose level for each patient may vary, as may the appropriate blood glucose level for a given patient at a given time. Generally, many healthcare providers recommend maintaining blood glucose levels between 90 and 140 mg / dL. However, depending on the situation, the range may vary. For example, a patient may consider a blood glucose level of 150 mg / dL appropriate before bedtime, but consider the same reading inappropriate before mealtime.

[0021] Referring first to Figure 1, a non-limiting chart of variables used in diabetes management is depicted. These illustrated variables are those currently considered by patients living with diabetes. These variables include blood sugar levels, exercise, illness, food, sleep, and stress.

[0022] Blood glucose levels may be determined by using at least one blood glucose meter, for example, a FREESTYLE blood glucose meter by Abbott Diabetes Care (Alameda, California). Some blood glucose meters may transmit measurements wirelessly to the pump. However, in addition, blood glucose levels may be determined using at least one continuous glucose monitor ("CGM"). In various embodiments, any CGM may be used, for example, a FREESTYLE NAVIGATOR continuous glucose monitoring system from Abbott Diabetes Care (Alameda, California), or similar device. Various CGMs include an analyte sensor worn by the patient that transmits an electrical signal that correlates to interstitial fluid glucose level measurements at predetermined intervals to a handheld or other device.

[0023] Additionally, sensors for the CGM may be any of those described in U.S. Application Publication No. US-2009-0099522, published April 16, 2009, and entitled Microneedle Systems and Apparatus (G34), which is incorporated herein by reference in its entirety.

[0024] Exercise affects people with diabetes differently. Also, depending on the intensity, type of exercise (i.e., aerobic or anaerobic), and duration, a given patient will experience different effects both during and after exercise. In some situations, blood glucose levels may increase during exercise but decrease after exercise. In other situations, the duration and blood glucose-lowering effect may vary.

[0025] Stress can cause elevated blood sugar levels, and the duration and intensity of the stress can produce different results. Similarly, illness can cause elevated blood sugar levels, and the duration and intensity of the illness can produce different results.

[0026] Food includes any item ingested by a patient, including, but not limited to, solids and liquids. Food composition, including fat, protein, and carbohydrates, greatly influences the resulting blood glucose level and the absorption rate of food. The absorption rate may be converted into the rate of increase in blood glucose level. For example, a meal high in fat and carbohydrates may be absorbed at a slower rate, and therefore, increased blood glucose levels may be seen later compared to a meal low in fat. In addition, with respect to carbohydrates, the glycemic index of food greatly influences the rate of change of blood glucose level.

[0027] Various types of insulin may be used together or individually. Long-acting, intermediate-acting, short-acting, and rapid-acting insulin may be used. Examples include HUMALOG, a regular NPH product from Eli Lilly, and NOVALOG from Novo Nordisk, although any insulin may be used. Insulin is also available in various concentrations, such as U-100 and U-400. Various embodiments of the system and method may use various concentrations of insulin.

[0028] Insulin and other biologics / therapeutic and / or medical fluid compounds are not orally active due to poor absorption, hepatic metabolism, or other pharmacokinetic factors. In addition, some therapeutic compounds may be orally absorbed, but may need to be administered frequently, making it difficult for patients to maintain the desired schedule. In these cases, parenteral delivery is often employed or can be employed.

[0029] Effective parenteral routes of insulin and other fluid drug delivery include subcutaneous injection, intramuscular injection, and intravenous (IV) administration, which involve puncturing the skin with a needle or stylet. Many diabetics prefer automated delivery of insulin, which is possible through the use of insulin pumps. These pumps may also be used for subcutaneous delivery of other fluids.

[0030] The pump delivers the therapeutic fluid subcutaneously using a cannula, a tube or needle that is introduced into the subcutaneous area of ​​the skin and remains in the skin for a pre-approved period of time, typically no more than three days. The cannula is fluidly connected to a reservoir of therapeutic fluid. The pump pumps the fluid from the reservoir to the cannula for delivery to the patient.

[0031] Examples of pumps include any known pump, including, but not limited to, U.S. Patent Application Publication No. US-2007-0219480, published September 20, 2007, entitled Patch-Sized Fluid Delivery Systems and Methods (E72); U.S. Patent No. 7,306,578, published December 11, 2007, entitled Loading Mechanism for Infusion Pump (C54); U.S. Patent No. 7,498,563, published March 3, 2009, entitled Optical Displacement Sensor for Infusion Devices (D78); or U.S. Patent Application Publication No. US-2007-0228071, published October 4, 2007, entitled Fluid Delivery Systems and Methods (E70), which are incorporated herein by reference in their entireties.

[0032] Additionally, in some embodiments, fluid delivery pumps that deliver more than one fluid may be used. The pumps described in the aforementioned U.S. Patent Application Publication No. US-2007-0219480, published September 20, 2007, entitled Patch-Sized Fluid Delivery Systems and Methods (E72), the aforementioned U.S. Patent No. 7,306,578, published December 11, 2007, entitled Loading Mechanism for Infusion Pump (C54), the aforementioned U.S. Patent No. 7,498,563, published March 3, 2009, entitled Optical Displacement Sensor for Infusion Devices (D78), or the aforementioned U.S. Patent Application Publication No. US-2007-0228071, published October 4, 2007, entitled Fluid Delivery Systems and Methods (E70), may be slightly modified to incorporate one or more additional reservoirs. These reservoirs may be fluidly connected to the same cannula or to separate cannulas, including any of the above cannulas such as those described in U.S. Patent Application Publication No. US-2009-0099522, published April 16, 2009, entitled Microneedle Systems and Apparatus (G34), which is incorporated herein by reference in its entirety.

[0033] Exemplary embodiments are described in at least U.S. Patent Application Publication No. US-2007-0219480, published September 20, 2007, entitled Patch-Sized Fluid Delivery Systems and Methods (E72); U.S. Patent Application Publication No. US-2007-0228071, published October 4, 2007, entitled Fluid Delivery Systems and Methods (E70); U.S. Patent Application Publication No. US-2007-0219496, published September 20, 2007, entitled Pumping Fluid Delivery Systems and Methods Using Force Application Assembly (E71); and U.S. Patent Application Publication No. US-2007-0219496, published September 20, 2007, entitled Adhesive and Peripheral Systems and Methods for Medical Devices, all of which are incorporated herein by reference in their entireties. No. 12 / 347,985, published December 31, 2008, entitled Infusion Pump Assembly (G75); U.S. Patent Application No. 12 / 347,982, published December 31, 2008, entitled Wearable Pump Assembly (G76); U.S. Patent Application No. 12 / 347,981, published December 31, 2008, entitled Infusion Pump Assembly (G77); and U.S. Patent Application No. 12 / 347,984, published December 31, 2008, entitled Pump Assembly With Switch (G79).

[0034] Specifically, the exemplary embodiment includes a pump having an acoustic capacitance sensor device capable of measuring the volume of fluid pumped by the pump.

[0035] In various embodiments, the system includes at least one continuous analyte sensor, and in some embodiments, at least one continuous glucose monitor ("CGM"), an infusion pump, a fluid pump or medical fluid pump that delivers at least one medical fluid, e.g., insulin, and a controller. In some embodiments, the system additionally includes one or more additional continuous sensors, whether analyte or otherwise. The system components transmit data or are controlled by the controller.

[0036] Referring now to Figure 2, the system controller, or method for determining fluid delivery volume and timing, considers several factors when determining the timing volume of dispensed fluid. The factors presented in Figure 2 are a non-exclusive list of factors the controller may consider. The system and method considers the data to deliver insulin or counter-regulate insulin to maintain a desired blood glucose level.

[0037] The system may use at least one CGM. The CGM includes a glucose sensor (referred to as a "sensor" or "analyte sensor"). In various embodiments, the CGM sensor is introduced and resides in the user's interstitial fluid, located on the body, for example, on the abdomen. The CGM transmits electrical signals at predetermined intervals to a receiver or controller. The receiver or controller correlates these electrical signals to glucose values. In some embodiments, due to safety concerns, a redundant CGM is used to provide more than one interstitial glucose measurement at a given measurement time. In some embodiments, the redundant CGM may be one or more additional CGMs (the same CGM) located on different parts of the patient. In other embodiments, redundancy may be provided by one or more sensors integrated onto a single CGM device, where all of the sensors are introduced at similar locations on the patient, and in some embodiments, the same automatic inserter is used. In some embodiments, the one or more redundant sensors may be sensors introduced at different depths into the patient, for example, if there are four redundant sensors, each sensor is introduced at a different depth into the patient.

[0038] Redundant sensors provide additional safety. Sensor measurements may be sent to a processor, which may use various methods to determine whether or which measurements the system should accept for use in determining the amount of insulin to deliver. For example, the processor may determine whether the values ​​differ by, for example, 6% or more (in other embodiments, the percentage difference may be different and may be determined and / or identified based on one or more calibration techniques). The measurements may then not be used for delivery and recalibration (i.e., by fingerstick) is required. If the processor does not receive a signal from one sensor, the processor may be programmed to ignore that sensor. If all redundant sensors read the same or similar values ​​(again, within a percentage that may be preprogrammed or predetermined), the system can be confident that the values ​​are close to accurate.

[0039] In some embodiments, the redundant sensors may be calibrated differently. For example, one sensor may be calibrated to be more sensitive than the other. In some embodiments, the various sensors are tuned to different dynamic ranges. For example, if two sensors are used, each of the two sensors may be tuned to a different range, with one tuned to be very sensitive to low blood glucose levels and the other tuned to high blood glucose levels. For example, if the low-tuned sensor reads 60 mg / dL, the system knows that the sensor is in the patient and reading. If the high-tuned sensor reads 250 mg / dL, the system may confirm that the sensor is in the patient and reading. In other embodiments, the redundant sensors may be tuned based on time constants, i.e., one sensor reads faster than the next, etc.

[0040] In some embodiments, the patient may alternate the introduction of one or more CGMs so that on a given day there is always a calibrated sensor providing data to the controller / system, hi some embodiments, one or more CGMs are implantable CGMs.

[0041] In various embodiments, the system may include one or more additional sensors that sense various patient symptoms / health or other analytes. The sensed symptoms, in exemplary embodiments, are analytes or other health indicators that affect the patient's insulin needs. The additional sensors may include, but are not limited to, one or more of the following:

[0042] Heart rate sensor, an analyte sensor for one or more hormones; a thermistor to monitor patient temperature; Temperature Sensors for Monitoring Medical Fluid Temperature accelerometer, gyroscope, Inertial Measurement Unit ("IMU"), respiratory rate monitor, Calbox symmetry sensor, Galvanic Skin, Adrenaline sensor, oxygen saturation sensor, hydration sensor, White blood cell count sensor, and / or Signaling hormone sensors.

[0043] Additionally, one or more of the sensors may, in some embodiments, be embodied as a microneedle sensor similar to those described in U.S. Application Publication No. US-2009-0099522, published April 16, 2009, entitled Microneedle Systems and Apparatus (G34), which is incorporated herein by reference in its entirety.

[0044] In some embodiments, the system may include at least one inertial measurement unit (“IMU”). In various embodiments, any type of IMU may be used. In some embodiments, the IMU is a device capable of sensing movement using a combination of sensors. Various IMUs may include, for example, one or more accelerometers and / or one or more gyroscopes to measure orientation relative to gravity, including, but not limited to, sensing type, speed, and direction, using a combination of accelerometers and / or gyroscopes. Data collected from the at least one IMU may be used to determine whether a user is moving. In some embodiments, the collected data may be used to determine whether a user is asleep or has fallen. In other embodiments, the IMU may be used to determine a user's speed and directional change, which may indicate the type of activity the user is engaged in, e.g., running, skiing, playing tennis, etc. Thus, the at least one IMU may be used to determine a user's movement, and the data may be controlled by a controller and used by a processor.

[0045] While the use of at least one IMU to determine a user's movement is described herein, it should be understood that the at least one IMU may be used in conjunction with any one or more of a variety of devices and sensors that determine a user's movement or activity, including, but not limited to, a blood oxygen sensor. In some embodiments, the IMU may be a MICROSTRAIN® 3DM-GX1® by Microstrain, Inc., Williston, VT. In some embodiments, the IMU may be located in the pump or controller, or may be a separate device worn by or on the user. In some embodiments, the IMU used may be a three-axis IMU including an accelerometer and a gyroscope. In some embodiments, the IMU may include three accelerometers and three gyroscopes. These IMUs include outputs for pitch, roll, and yaw. However, these devices may be large and / or heavy and / or have large power requirements. Therefore, in some embodiments, it may be desirable to use an IMU that includes at least one accelerometer and at least one gyroscope.

[0046] In some embodiments, one or more of, but not limited to, a heart rate monitor, a respiration rate monitor, an adrenaline sensor, a thermistor, and / or a hydration sensor may be used to determine if the user is exercising or otherwise stressed or experiencing a condition that may change insulin sensitivity or insulin needs. In some embodiments, a hydration sensor is used to determine if the user may be dehydrated, which may contribute to unexpected glucose data. In some embodiments, a temperature sensor may be used to monitor the temperature of medical fluids, which may include insulin, which may be used to predict unexpected results and / or to alert / warn the user when the temperature is higher or lower than recommended. In various other embodiments, additional sensors may be used. In various embodiments, one or more sensors may be used, and these sensors may be used on the user, in the pump, and / or in the controller, and / or as separate devices, or in combinations thereof.

[0047] The controller also serves as at least one user interface and as a central user interface for the patient / user interface with the CGM / sensor, pump, and control system. For purposes of this specification, the controller may be programmed by the patient, a "user," a caregiver, a healthcare provider, or a combination thereof. However, for purposes of this description, the terms "patient" or "patient / user" or "user" refer to someone who inputs information into the controller or utilizes the controller to provide care to the patient. In an exemplary embodiment, the system controller communicates with various system components via wireless, e.g., radio frequency ("RF") communication and / or other types of remote communication. In an exemplary embodiment, the controller includes a graphical user interface ("GUI") and one or more input devices, e.g., buttons, capacitive sliders, jog wheels, touch screens, keypads, electronic keypads, and any other input device. The controller also includes at least one processor, although in an exemplary embodiment, the controller includes at least two processors, a control processor and a safety processor. These processors may be redundant processors or two different processors that provide redundant processing or check each other's processing.

[0048] Some embodiments of the controller may include at least one "event" or special button, such as a "meal" button, an "exercise" button, and a "bolus" button. In some embodiments, the controller may contain a single "event" button. Pressing or activating this button may bring the user to an event menu, which may include a list of potential events, one or more of which may be customizable by the user.

[0049] For all event buttons, when pressed, these buttons bring the patient / user to a menu or processing logic that allows the patient / user to directly input into the processing logic for, for example, exercise, meal, or bolus. The logic may then query the patient / user to enter additional information, such as how long the exercise is expected to last, how strenuous it is, how much food (i.e., how many carbohydrates), the glycemic index, the fat content, and the protein content of the food. For boluses, the patient / user can enter the bolus volume by using a series of button presses or by using another input device, i.e., a jog wheel, button, or slider, to enter the requested volume of insulin, i.e., insulin units. In some embodiments, the user interface includes many of the same features found on insulin pumps and pump controllers known in the art.

[0050] In exemplary embodiments, the controller also includes a space to receive a "strip reader," e.g., a glucose test strip for use in a "finger stick" or "finger prick" reading, e.g., a patient pricks a finger and uses blood from the finger to apply to the "finger prick." The "strip reader" uses an electrochemical test to determine the glucose level of the blood. The strip reader may be used to calibrate the CGM, to double-check unexpected or abnormal readings, or as a backup to the CGM in case of a CGM failure. In some embodiments, the strip reader may be a separate device, such as a glucose meter. In these embodiments, the glucose meter may receive the finger stick reading wirelessly, or the user may manually enter the reading into the controller.

[0051] The GUI may be a color GUI, a black-on-gray screen, and / or a touch screen, etc. The GUI may additionally accept and / or give voice commands and / or provide magnification on request.

[0052] The controller additionally includes at least one speaker, and in some embodiments, at least one vibration motor. In some embodiments, the controller may include any one or more of the features described in U.S. Application Publication No. US-2008-0198012, published August 21, 2008, and entitled Device and Method for Food Management (F21), which is incorporated herein by reference in its entirety.

[0053] The controller, in some embodiments, acts as a receiver for at least one sensor, including, but not limited to, at least one CGM. As such, the user indicates to the controller when a new sensor is introduced into the body. In some embodiments, the user may additionally input the location of the sensor on the user's body, including, but not limited to, for example, right abdomen, left abdomen, right arm, left arm, right hip, left hip, right foot, left foot, etc. This may be desirable as sensors may function differently in different areas on the body. As the controller records and processes this data, the controller may calibrate the sensor based on past profile information that indicates "lag" and / or "drift" information from the same area of ​​the body.

[0054] The medical fluid pump / infusion pump / insulin pump / fluid pump in various embodiments is used to deliver medical fluids, including insulin, and may include one or more reservoirs for delivering one or more fluids (thus, the various reservoirs may contain the same or different fluids). In some embodiments, the medical pump may deliver more than one type of insulin (e.g., one or more of the types described above). However, in some embodiments, a medical pump including more than one reservoir may be used to deliver insulin and at least one counter-regulatory hormone, such as glucagon. Medical pumps include those disclosed in U.S. Patent Application Publication No. US-2007-0219480, published September 20, 2007, entitled Patch-Sized Fluid Delivery Systems and Methods (E72); U.S. Patent No. 7,306,578, published December 11, 2007, entitled Loading Mechanism for Infusion Pump (C54); U.S. Patent No. 7,498,563, published March 3, 2009, entitled Optical Displacement Sensor for Infusion Devices (D78); U.S. Patent Application Publication No. US-2007-0228071, published October 4, 2007, entitled Fluid Delivery Systems and Methods (E70); and U.S. Patent Application Publication No. US-2007-0228071, published September 20, 2007, entitled Pumping Fluid Delivery Systems and Methods Using Force Application, which are incorporated herein by reference in their entireties. U.S. Patent Application Publication No. US-2007-0219496, entitled "Adhesive and Peripheral Systems and Methods for Medical Devices" (E73), published on September 20, 2007; U.S. Patent Application Publication No. US-2007-0219597, entitled "Infusion Pump Assembly" (G75), published on December 31, 2008;No. 985, U.S. Patent Application No. 12 / 347,982, published December 31, 2008, entitled Wearable Pump Assembly (G76), U.S. Patent Application No. 12 / 347,981, published December 31, 2008, entitled Infusion Pump Assembly (G77), U.S. Patent Application No. 12 / 347,984, published December 31, 2008, entitled Pump Assembly With Switch (G79), U.S. Patent Application Publication No. US-2009-0099522, published April 16, 2009, entitled Microneedle Systems and Apparatus (G34), and U.S. Patent Application No. US-2009-0099522, published April 16, 2009, entitled Infusion Pump The pump may be any of the pumps described in U.S. Patent Application Publication No. US-2009-0099523, entitled "Assembly (G46)," or modifications thereof, that accommodate multiple reservoirs.

[0055] The system may include one or more alarms, including, but not limited to, one or more vibration motors and / or one or more speakers on the controller, and in some embodiments, one or more vibration and / or speaker motors on the medical pump. Some alarms, in some embodiments, may be progressive alarms, i.e., the alarms become progressively louder or more active depending on the alarm type. Alarms may be used to indicate any of a myriad of conditions, including, but not limited to, hyperglycemia, falling or hypoglycemia, blockages, empty or nearly empty reservoirs, removed cannulas, removed sensors, or any other condition of which the patient may wish to be aware.

[0056] In some embodiments, the alarm system may further include a signal amplifier separate from the pump and controller. The amplifier may receive the alarm signal and amplify the alarm. The signal amplifier may, in some embodiments, be a separate device that may receive wireless transmissions from the pump and / or controller. In some embodiments, the signal amplifier may signal another device to automatically trigger, for example, a television or stereo to turn on, a phone to ring, or, in some embodiments, if the alarm is not acknowledged by the patient / user, the signal amplifier may call an emergency services or emergency contact number pre-programmed by the patient / user.

[0057] In some embodiments, the patient / user may select different types of alarms for different events / times. These selections may be pre-programmed (e.g., a night alarm sequence is used if an alarm condition is sensed every night from 6 PM to 6 AM) or may be selected when desired (e.g., before swimming, the patient / user may use a menu to select a "swim alarm," which may be, for example, vibration only). The controller, in exemplary embodiments, may be fully programmable with respect to alarms, such that the patient / user may select an escalating or progressive alarm for some situations and vibration for other situations. Additional alarm conditions that may be programmed by the patient / user include, but are not limited to, conditions required to silence the alarm (e.g., a night alarm silence condition may require a series of inputs to ensure the patient does not turn off the alarm while sleeping without acknowledging the condition).

[0058] The system may use one or more indicators to determine when one or more cannulas have been removed from the patient. In some embodiments, a conductivity sensor may be used to determine whether a cannula has been removed from the patient. In some embodiments, the cannula may include a conductive pad around the cannula, for example, a pad including two electrodes electrically coupled to a central processor. When the cannula is removed, insulin is delivered into the pad, thus changing the conductivity of the pad.

[0059] Referring now to FIG. 3, in some embodiments, the cannula used in the system may be a cannula that includes two or more tubing colors that serve as a visual indicator of removal. For illustrative purposes, the tubing colors are represented by different hatch marks. For example, the tip of the cannula may be red, the middle may be blue, and the ends may be clear tubing. Thus, the patient may determine whether the cannula has been removed from the patient through visual inspection.

[0060] The system may include one or more integrity tests to determine whether one or more CGM sensors have failed or are providing erroneous or inaccurate information. The term "erroneous" or "inaccurate" information may be defined as the percentage difference between the CGM measurement and the fingerstick measurement. The percentage difference may refer to when the CGM measurement is a percentage higher or lower than the fingerstick measurement. In some embodiments, for example, any number higher than a 30% difference between the fingerstick and the CGM may be referred to as "erroneous information" or "inaccurate information." In other embodiments, this percentage may be higher or lower than 30%. In some embodiments, this percentage may vary between the user and the CGM system.

[0061] In some embodiments, a temperature integrity test may be used. Some CGM sensors may experience drift with each degree of temperature excursion. For these CGM sensors, in some embodiments, the system expects a similar percentage and / or proportional drift in the CGM value when the temperature is modulated higher or lower. In some embodiments, the system may prompt the user to perform an initial fingerstick, then encounter a temperature excursion, take a second fingerstick measurement, and note the CGM measurement. This may provide an integrity test for the CGM. In some embodiments, the system may prompt the user in this manner and wait for a temperature excursion (which may be determined by a temperature sensor in the pump or controller), then prompt the user to perform a second fingerstick. The system may then compare the fingerstick measurement with the CGM measurement before and after the temperature excursion. If a particular CGM is expected to experience a temperature excursion but does not, this may be an indicator that the integrity of the CGM system is deteriorating. In these cases, the system notifies the user of the error and discontinues the semi-closed or closed-loop system of control.

[0062] In some embodiments, the system may prompt the user to inject a small amount of glucose into an area under the skin in close proximity to the CGM sensor. The small amount of glucose may be a solution containing a specific concentration of glucose. The system may expect an increase in glucose readings from the CGM shortly after the injection. In some embodiments, if this same test is performed on the same user, and if the solution is the same as that used previously, and if the injection is performed in the same manner and in the same area relative to the sensor as before, the results and profile of the user's response may be in the system, and the system may therefore compare the new results with the old results or an average of the old results. If the CGM reading does not indicate a glucose rate or does not match the old results or an average of the old results within limits, this may be an indicator that the integrity of the CGM system is deteriorating. In these cases, the system notifies the user of the error and discontinues the semi-closed or closed-loop system of control.

[0063] In some embodiments, the system may prompt the user to take a fingerstick measurement on demand. This measurement may be used as a system integrity check and / or to calibrate one or more CGM sensors. For an on-demand fingerstick as an integrity check, if the fingerstick measurement does not confirm the CGM measurement within a certain percentage, this may be an indicator that the integrity of the CGM system is degraded. In these cases, the system notifies the user of the error and discontinues the semi-closed or closed-loop system of control. For an on-demand fingerstick as a calibration, if the fingerstick measurement does not confirm the CGM measurement within a certain percentage, this may be an indicator that the integrity of the CGM system may be degraded. The system may require the user to enter a second fingerstick to confirm the first fingerstick measurement. After the second fingerstick measurement, if the second measurement confirms the first measurement, the system may resume (if the measurement confirms CGM integrity), or if the measurement confirms that integrity may be degraded, the system may notify the user of the error and cease continuing the semi-closed or closed loop system of control.

[0064] In some embodiments, with respect to on-demand fingersticks, if the system requests a fingerstick and the system does not receive a fingerstick measurement within a predetermined amount of time, e.g., 5 or 10 minutes, the system may default to exiting closed-loop or semi-closed-loop mode. This provides additional safety and, in some embodiments, may increase the accuracy of CGM measurements, as the system may require frequent calibration to ensure reliable CGM measurements.

[0065] With respect to the various integrity tests described herein, in some embodiments, rather than sending a system error or alert, in some embodiments, and possibly with any of the integrity checks, the system may determine the percentage difference of the CGM measurement from what is expected and adjust the measurement accordingly.

[0066] In some embodiments, the CGM may provide different or "bad" data when the user is applying pressure to the sensor, for example, by tossing and turning on the sensor while sleeping. In some embodiments, the system may turn the sensor off during these times and may additionally include an indicative alert on the controller screen. In some embodiments, when the controller senses that the user is asleep, the system may shut down, and after a certain amount of time has passed, e.g., 30 minutes, the system may turn the sensor on. If the problem / pressure corrects itself, the system may restart. This may be desirable to allow the user to continue sleeping and perhaps remove pressure from the sensor themselves, rather than waking up during the night. In some embodiments, insulin delivery also stops during shutdown.

[0067] In some embodiments, if the system does not correct itself after an elapsed time, the system will sound an alarm to alert the user that the system has shut down.

[0068] To manage diabetes using at least a partially closed-loop method, the components of the described system may be used to deliver controlled volumes of insulin, and in some embodiments, counter-regulatory hormones, such as glucagon, according to various methods, some of which are described herein. In exemplary embodiments, the control method relies on the use of a system that includes the ability to actively measure the volume of insulin or other fluid actually delivered to the patient (as opposed to measuring the volume of insulin requested by the user or pre-programmed by the user to be delivered), at least one CGM and user interface, and a process containing instructions for at least a partially closed-loop algorithm. As described in more detail above, other sensors and data input models may also be included. However, in some embodiments, pumps that do not actively measure the volume of insulin or other fluid they are actually delivering to the patient may also be used. In these embodiments, an assumption is made that the volume delivered to the patient is the volume requested by the processor (unless or until a mechanical malfunction or blockage is detected).

[0069] 6, a patient 12 is shown wearing a medical fluid pump 14, a sensor device 16, and holding a controller 18. The sensor device 16 may contain one or more CGMs and one or more additional sensors. The sensors transmit data to the controller 18.The medical fluid pump 14 may be implemented using any of the following patent applications: U.S. Patent Application Publication No. US-2007-0219480, published September 20, 2007, entitled Patch-Sized Fluid Delivery Systems and Methods (E72); U.S. Patent Application Publication No. US-2007-0228071, published October 4, 2007, entitled Fluid Delivery Systems and Methods (E70); U.S. Patent Application Publication No. US-2007-0219496, published September 20, 2007, entitled Pumping Fluid Delivery Systems and Methods Using Force Application Assembly (E71); and U.S. Patent Application Publication No. US-2007-0219496, published September 20, 2007, entitled Adhesive and Peripheral Systems and Methods for Medical Devices and Systems (E72), which are incorporated herein by reference in their entireties. U.S. Patent Application Publication No. US-2007-0219597, entitled Infusion Pump Assembly (G75), published on December 31, 2008; U.S. Patent Application Publication No. 12 / 347,985, entitled Infusion Pump Assembly (G75), published on December 31, 2008; U.S. Patent Application No. 12 / 347,982, entitled Wearable Pump Assembly (G76), published on December 31, 2008; U.S. Patent Application No. 12 / 347,981, entitled Infusion Pump Assembly (G77), published on December 31, 2008; U.S. Patent Application No. 12 / 347,984, entitled Pump Assembly With Switch (G79), published on April 16, 2009; No. US-2009-0099522, entitled Infusion Pump Apparatus (G34), and U.S. Patent Application Publication No. US-2009-0099523, published April 16, 2009, entitled Infusion Pump Assembly (G46).The patch pump 14 is controlled by a controller (which in some embodiments may also include a user interface that allows for patient / user control) and transmits information to the controller 18. Thus, the controller receives information about one or more sensors and the pump. In addition, the controller receives input from the user, e.g., events, and may receive manual entry of fingerstick measurements or fingerstick data. Additionally, the controller, in some embodiments, may wirelessly receive information about food or glucose measurements, etc. In some embodiments, the controller includes voice recognition, and thus, in these embodiments, the controller may receive commands via voice.

[0070] The control methods described herein, in exemplary embodiments, may include user calibration of the system. User calibration refers to calibrating the system to the user. This may include, but is not limited to, collecting CGM data at defined times during or after defined events. These may include, but are not limited to, one or more of the examples listed herein.

[0071] The prescribed events may include any events required by the system, such as fasting events, exercise events, meal events, and / or sleep events. The system may prescribe that the user undergo a "fasting event." In some embodiments, this may include prompting the user to fast during a certain period of time. For example, fasting times may include, but are not limited to, between midnight and 10:00 AM, between 9:00 AM and 2:00 PM, between 2:00 PM and 7:00 PM, and between 7:00 PM and midnight. These may correlate to morning fasting, lunch fasting, dinner fasting, and overnight fasting. The system may take periodic measurements during this time to characterize or profile the user. In some embodiments, the system may require and prompt the user to perform fingersticks at certain intervals as a validation of the CGM at this time. These resulting profiles may be used in many ways, including, but not limited to, recommending basal setting changes, identifying abnormalities, and / or recommending basal boundary changes. In some embodiments, the system may recommend or prompt the user to complete a fasting profile several times a year, or if the system identifies anomalies in insulin requirements or CGM data, the system may prompt the user to complete a fasting profile to identify potential issues related to pump, CGM, or controller system integrity, or to identify times or events where the user may want to reconsider boundaries and / or trajectory or rate, etc.

[0072] Other prescribed events may include one or more exercise events. During these events, the user may input the type of exercise being performed. The system may take periodic CGM measurements and prompt for fingerstick verification during the event. Again, similar to fasting events, the system may recommend or prompt the user to complete an exercise profile several times a year, or if the system identifies anomalies in insulin requirements or CGM data, the system may prompt the user to complete an exercise profile to identify potential issues related to pump, CGM, or controller system integrity, or to identify times or events where the user may want to reconsider boundaries and / or trajectory or speed, etc. In some embodiments, the system may prompt or the user may request these events. Also, in some embodiments, many different types of exercise events may occur, including, but not limited to, anaerobic events, long aerobic events, short anaerobic events, long anaerobic events, etc. In this manner, the user may input when they are undertaking any of these events into the system, and the system may therefore collect additional data that may be used to identify recommendations to consider abnormalities and / or boundaries and / or trajectories during these events.

[0073] The eating event may be initiated by a request from the system or the user. The eating event may help the user and / or the system identify the eating event (if the user fails to enter the event into the system, the system itself may recognize the pattern and prompt the user with a question, for example, "Are you eating?"). In some embodiments, more than one type of eating event may be captured, including, for example, but not limited to, breakfast, lunch, dinner, morning snack, afternoon snack, and evening snack. In some embodiments, the system may request the user, for example, to "eat a candy bar." In these embodiments, the user may select a candy bar and enter information about the candy bar into the controller through an input. The user may then choose to initiate the requested calibration. The user may eat the candy bar, and the controller may collect various glucose or other types of data during this time. Thus, the system collects a "profile" of this candy bar that may be used later for the same candy bar and / or for the candy bar at that particular time under the same or similar circumstances. In some embodiments, the system may specify "no exercise" for a non-exercise calibration during the calibration day. In some embodiments, the system may specify that the user will "exercise" and then eat a particular meal. In each case, the user may interact with the controller and input various information, including, but not limited to, the type and duration of the meal and / or the type and / or duration of the exercise.

[0074] In general, patient calibration refers to calibrating the system to any one or more of, but not limited to, the patient's insulin sensitivity, the patient's overall response time (and kinetic profile) to a given insulin, body fat index, glycemic profile to a particular food or type of food, glycemic profile to a particular exercise (both type / severity and duration), current medications, other illnesses, and glycemic profiles to one or more of, but not limited to, night / sleep, illness, work day, school day, exam period, weekend, travel, and the like, i.e., any life situation that the patient may experience frequently enough to help the patient (or caregiver, healthcare provider) to learn the glycemic profile for that experience / situation.

[0075] Once patient calibration for any of the above (or others) is complete, the system may be able to identify unexpected results (i.e., unexpected blood glucose profiles) for any of the calibration types. In some embodiments, the system may alert the patient that one or more calibrations must or should be repeated due to unexpected results.

[0076] The patient / user may program preferences for these alerts, for example, pre-programming the percentage deviation from the expected percentage that will trigger an alert or a given calibration. Thus, the patient / user may limit alerts and recalibrations based on specific / pre-set deviations. The patient / user may also disable alerts. Furthermore, the patient / user may prefer that an alert be triggered when the deviation is 3% overnight, but 10% during stress.

[0077] In some embodiments, the controller may include a menu of calibrations for various situations. In some embodiments, the patient may have the ability to add to and / or customize the calibration menu. If the patient is experiencing any of the situations, the patient may enter this information into the controller so the processor / controller knows to compare measurements and insulin delivery to the calibration. The processor may also store data for each situation and learn from the data, i.e., adjust delivery based on this data.

[0078] In some embodiments, if there is an unexpected result, the user may have an opportunity to explain the deviation / unexpected result. For example, if a patient intended to eat and entered this information into the system but was unable to eat, e.g., changed their mind or forgot, the system, upon reviewing the blood glucose measurements, may determine that the patient's blood glucose level did not rise as expected and therefore may qualify as a deviation from the expected value. The system may alert the patient about the deviation, and the patient may enter (through a menu or otherwise) that the intended meal did not occur.

[0079] In other embodiments, if the user does not enter an event into the system and the system senses a profile similar to an event through CGM or fingerstick data, or a profile indicating an unexpected result may be due to CGM failure, cannula failure, insulin malfunction (e.g., blockage, decreased activity due to temperature or aging, etc.), the system may not change the volume or schedule of insulin delivery; rather, the system may prompt the user to enter additional information, e.g., the event, before rescheduling insulin delivery. For example, if the user does not enter a meal event into the system and the system senses a blood glucose level through CGM or fingerstick data that is atypical for the time of day and / or requires the system to exceed a preprogrammed basal boundary, the system may alert the user that a larger amount of insulin may be required to be delivered than allowed for that time of day, i.e., the volume may exceed a preprogrammed boundary, or there is an indication that delivery will exceed the maximum daily volume. In some embodiments, the user may have an opportunity to enter the event or additional information within a preprogrammed time, e.g., within five minutes, of the alert. The entered information may confirm the blood glucose data, for example, based on a predetermined profile, or if the information does not confirm the blood glucose data, the unexpected blood glucose data may be an indicator that something unexpected and unexpected has occurred and may alert the user and shut down the closed-loop or semi-closed-loop system. In these embodiments, if the user fails to provide information explaining the unexpected blood glucose data, the closed-loop or semi-closed-loop system may shut down.

[0080] In various embodiments, the closed loop and / or semi-closed loop system may not shut down without first notifying the user, i.e., the system does not perform a silent shutdown, e.g., a shutdown without notifying the user before shutting down.

[0081] In some embodiments, as discussed above, the system may prompt the user to inject a small amount of glucose into an area under the skin in close proximity to the CGM sensor. The small amount of glucose may be a solution containing a specific concentration of glucose. The system may expect an increase in glucose readings from the CGM shortly after the injection. In some embodiments, if this same test is performed on the same user, and if the solution is the same as that used previously, and if the injection is performed in the same manner and in the same area relative to the sensor as before, the results and profile of the user's response may be in the system, and the system may then compare the new results with the old results or an average of the old results. However, this procedure may also be used in a user calibration process, in which case the user's resulting glucose profile may be used by the system as a reference for the user's expected response from X grams of fast-acting carbohydrates. This profile, in some embodiments, may be used to recommend a type of snack to the user to treat a predicted or sensed hypoglycemic episode.

[0082] Various control algorithms may be applied to the at least partially closed loop system. In some embodiments, the control algorithms applied are patient / user selected. In some embodiments, the various control algorithms include patient-selected parameters.

[0083] Control algorithms may be turned on or off by the patient / user at any time. Different algorithms may be used at different times and are patient-driven. Thus, in an exemplary embodiment, the patient / user maintains control over the use of a given algorithm, and that algorithm may be disabled at any time.

[0084] Any one or more of the algorithms described below may be used at any time. Although several example algorithms are discussed below, the various embodiments of the system described above may be used in conjunction with any control algorithm desired by the patient / user. Accordingly, additional algorithms may be developed that are easily integrated onto the controller used to at least partially control the delivery of insulin.

[0085] The control algorithm resides on the controller in an exemplary embodiment. However, in some embodiments, the control algorithm may reside on the pump in addition to or instead of the controller. Numerous control algorithms may be accessed by the control system. The control system may receive several patient-specific inputs that may be utilized by any control algorithm. These inputs include patient calibration.

[0086] In some embodiments, the system includes a network operations center (“NOC”). The NOC may be used to coordinate activities and resources. The NOC may communicate with the controller and / or pump via a network connection or wirelessly. The NOC, being remote from the controller / pump, may include greater processing power than the controller or pump and therefore may include adaptive software. In some embodiments, the NOC may include artificial intelligence and / or clinical software. Thus, in these embodiments, the NOC, rather than the pump or controller (or the user's personal computer or “PC”), hosts the clinical software. This may be desirable to prevent software tampering and also to provide a central point for software updates. These updates may be downloaded over the network onto the pump and / or controller and / or the user's PC.

[0087] In some embodiments, the patient / user specifies a "target blood glucose level" or "target blood glucose range" for a range of time or other characterized experience, i.e., including but not limited to one or more of target ranges for exercise, illness, nighttime, before meals, after meals, during meals, etc. These target values ​​may be changed by the patient / user at any time based on permissions given (i.e., in some embodiments, only certain users, i.e., the patient and caregiver, have permission or access to change the target values).

[0088] Using data from one or more sensors along with patient calibration data, the control algorithm serves as a method for controlling the delivery of insulin to the patient.

[0089] One algorithm that may be utilized is a partially closed-loop algorithm. This refers to an algorithm that provides closed-loop control of insulin delivery, but within a "range" or "set of permissions." For example, referring now to FIG. 4, an embodiment of a "bounded bolus" algorithm is shown. In this embodiment, the user specifies a "bolus window," which is the time during which a "bolus" of insulin may be requested to be delivered by the controller. Within the specified bolus window, the controller is only able or only has permission to deliver a certain "bounded" volume of insulin. Interpreted differently, a bounded bolus algorithm prevents delivery of more than a certain volume of insulin during a certain bolus window.

[0090] In some embodiments, if the patient / user determines that a bolus is needed, the patient / user may request a "bounded bolus" algorithm and input duration and volume permissions.

[0091] In some embodiments, the user may specify a "bolus max," which is the maximum bolus volume that the controller may deliver, e.g., 15 units. In some embodiments, the user may specify a "24-hour bolus max," which limits the total volume of bolus insulin delivered in a 24-hour period, e.g., 40 units.

[0092] In various embodiments, one or more of these boundaries may be specified and preprogrammed by the user. In various embodiments, if the controller determines from the blood glucose level that a specific volume should be delivered but that the specific volume exceeds one or more boundaries, the controller may prompt the user to enter additional information or may shut down after alerting the user that one or more boundaries have been met. Another algorithm that may be utilized is a closed-loop bolus algorithm. This refers to the controller's ability to deliver insulin based on patient calibration and information about events and targets, at a time and volume determined by the algorithm. Thus, a closed-loop algorithm uses data from a myriad of sensors or other inputs to determine the appropriate time and volume for insulin delivery.

[0093] Similar to the partially closed-loop bolus algorithm described above, partially closed-loop basal refers to an algorithm that provides closed-loop control of insulin delivery, but within a "range" or "set of permissions." For example, referring now to FIG. 5, an embodiment of a "bounded bolus" algorithm is shown. In this embodiment, the user specifies a "basal window," which is the time during which "basal" insulin may be required to be delivered by the controller. Within the specified basal window, the controller is only able or authorized to deliver a certain "bounded" volume of insulin. Interpreted differently, a bounded basal algorithm prevents delivery of more than a certain volume of insulin during the specified basal window. In some embodiments, the patient / user may have pre-programmed basal rates. In some embodiments, the number of pre-programmed rates may be between 1 and 100. Using a bounded basal algorithm, the patient / user allows the controller to change / vary the basal rate within pre-programmed parameters but over a certain required time frame. For example, the system may be able to increase or decrease the basal rate during a preselected period of time, but the rate will be "bounded," i.e., the system is free to vary the basal rate during the period, but only within a preselected bounded range. The system will not be able to deliver a rate higher or lower than the bounded rate for the preselected period of time.

[0094] In some embodiments of the "bounded" algorithm, the system may recommend to the patient / user that the bounded range be extended. In these embodiments, the patient / user must agree / give permission for the system to deliver beyond the bounded range. In some embodiments, the system may recommend permission to deliver outside the bounded range for a single delivery. In other embodiments, the system may recommend permission to deliver outside the bounded range for a recommended period of time.

[0095] In some embodiments, the user may specify a "basal rate max," which is a basal rate that the controller may deliver, e.g., 2 units per hour. In some embodiments, the user may specify a "24-hour basal max," which limits the total amount of bolus insulin delivered in a 24-hour period, e.g., 40 units.

[0096] In various embodiments, one or more of these boundaries may be specified and pre-programmed by the user. In various embodiments, if the controller determines from the blood glucose level that a certain volume should be delivered but that the certain volume exceeds one or more boundaries, the controller may prompt the user to enter additional information or may shut down after warning the user that one or more boundaries have been met. Another algorithm that may be utilized is a closed-loop basal algorithm. This refers to the controller's ability to deliver insulin based on patient calibration and information about events and targets, at a time and volume determined by the algorithm. Thus, a closed-loop algorithm uses data from a myriad of sensors or other inputs to determine the appropriate time and volume for insulin delivery.

[0097] Another algorithm is a fully closed-loop algorithm. Thus, the system is given full control to determine the time and volume of insulin delivery for both "basal" and "bolus" delivery. Thus, in some embodiments of this algorithm, the system may not distinguish between "basal" and "bolus" delivery; rather, the system delivers insulin based on patient calibration and data received from numerous patient sensors. In some embodiments of the closed-loop algorithm, the system may also accept user input regarding events / experiences and take these inputs into account when calculating delivery time and volume.

[0098] In exemplary embodiments of the systems and methods described herein, if an unexpected result occurs for any algorithm used by the system, the system may automatically shut down. In some embodiments, the system may recommend automatic shutdown but require patient / user confirmation. In other embodiments, the system may employ a method of automatic shutdown that includes notifying the patient / user using a series of escalating alarms, and if the system does not receive confirmation, it will automatically shut down.

[0099] In an exemplary embodiment of the system, the user may pre-program an automatic shutdown procedure if the system does not receive any input from the user for a predetermined interval. For example, if a patient has not taken a fingerstick measurement between 6:00 a.m. and 10:00 a.m., the system may undergo an automatic shutdown procedure. In an exemplary embodiment, these pre-programmed automatic shutdown procedures and time frames may be specified by the patient / user.

[0100] In some embodiments, an automatic shutdown procedure may be triggered if the fingerstick and CGM measurements change by a percentage greater than is acceptable by the system or pre-programmed by the patient / user. Similarly, in some embodiments, an automatic shutdown procedure may be triggered based on data received from any one or more of the sensors used in the system.

[0101] In various embodiments, the closed-loop and / or semi-closed-loop systems detect anomalies, which may include, but are not limited to, unexpected glucose data and / or unexpected insulin requirements, either of which may be an indicator that any one or more of the system components is or has failed and / or that the user is experiencing or is experiencing an unexpected event and / or unexpected results from an event, including, for example, one or more of, but not limited to, a high-carbohydrate meal, a long meal, a long period of exercise, a new exercise, and / or stress. In exemplary embodiments of the semi-closed and / or closed-loop systems disclosed herein, when the system detects an anomaly, the system may shut down.

[0102] In some embodiments, the abnormality may be "good" control. For example, in some embodiments, if the blood glucose data indicates consistent and / or stable blood glucose measurements compared to multiple measurements, this may indicate that one or more CGM sensors have failed or are failing and / or that the blood glucose meter has failed. Thus, unexpected glucose data may not only refer to unexpectedly "high" or unexpectedly "low," but rather to unexpectedly consistent.

[0103] Additionally, in some embodiments, if the glucose data indicates an unexpected hypoglycemic event, this may be an indicator that the insulin pump is experiencing a malfunction or that the user is experiencing an unexpected event (in which case, as discussed above, the system may prompt the user for more information before shutting down).

[0104] In some embodiments, if one or more sensors do not confirm an "event" as indicated by the user or as indicated by the glucose data, this may be an indicator that one or more sensors have failed. Thus, if this is a detected anomaly, the system may shut down.

[0105] In some embodiments, if an abnormality is detected, the controller may prompt the user with a question, for example, "Are you OK?" If the user responds "yes," the system may confirm there is a malfunction and shut down. Alternatively, if the user responds "no," this may indicate that the user is experiencing an unexpected event, such as stress or illness, and the system may shut down. In some embodiments, the system may prompt the user to enter a fingerstick to confirm the CGM data, and in some embodiments, the fingerstick data may be used to calibrate the CGM sensor.

[0106] In some embodiments, as an integrity test or calibration, the system may intentionally not deliver one or more basal deliveries and record the resulting sensor and / or glucose data. This may provide data indicating the effect of each basal delivery on the glucose data, which may be used to optimize therapy. For example, the system may better adjust the basal based on the calibration data from the intentionally not delivered deliveries. This information may also be used to determine insulin sensitivity.

[0107] In exemplary embodiments, if the controller institutes an intentionally non-delivered delivery, the user may be notified prior to the non-delivered delivery, and in some embodiments, the user may be prompted to accept or reject the calibration. In some embodiments, if the user fails to respond within a predetermined time period, the system may not proceed with the calibration.

[0108] In some embodiments, the system may perform an insulin sensitivity test by adding or subtracting a requested basal percentage (based on an algorithm or trajectory). For example, in some embodiments, the system may subtract or add 10% basal over a duration and record at least one sensor data. This may be performed periodically, e.g., monthly, or during various events, e.g., sleep, exercise, etc. These calibrations are saved, and the system may re-reference them to determine insulin sensitivity or identify changes in insulin sensitivity, which in some embodiments may prompt the system to request another calibration. Thus, the system routinely creates a profile that may prompt another calibration or may be used to identify possible unexpected data. In these embodiments, the system routinely optimizes insulin sensitivity factors and basal rates.

[0109] In some embodiments, whether closed-loop or semi-closed-loop control, the system may initialize as an open-loop system and, in some embodiments, gradually convert to a closed-loop or semi-closed-loop system. In some embodiments, open-loop startup may be required to occur for a predetermined amount of time, e.g., three hours, before transitioning to a closed-loop or semi-closed-loop system. In some embodiments, the system may be required to perform a minimum number of calibrations during startup before the transition.

[0110] Once the system is ready to transition, in some embodiments, the transition may be gradual. In some embodiments, the system may deliver a preset basal delivery. In some embodiments, the preset basal delivery may be a percentage less than the average or request for that user at that time, e.g., 10%, 20%, etc. In some embodiments, the preset basal delivery may start at 50% less than request, then progress to 40%, then 30%, until a percentage less than 0% is reached. Thus, at each step, the system may determine whether it is safe to proceed to the next set based on data from at least one glucose sensor, in some embodiments data from additional sensors, and / or fingerstick data.

[0111] In some embodiments, the system analyzes glucose data to determine when an excursion occurs. An excursion may be defined as a glucose measurement that is outside a pre-programmed target range. In some embodiments of the system, many different targets may be pre-programmed by time or event. An excursion may be defined relative to a "time" or an "event." For example, during a meal event, a user's glucose may be expected to rise above a pre-meal target glucose value and then return to a value within the target. Thus, the system may include one target definition for the first 120 minutes after a meal bolus and another definition for 120-180 minutes after the meal bolus.

[0112] In either case, the system may determine the total amount of time per day the user spent “excursion.” This may provide additional data for the user to reassess one or more of the one or more pre-programmed values, including, but not limited to, insulin sensitivity, carbohydrate ratio, target, and / or boundary. In some embodiments, the system may include a “grade” or “rating” of the user’s blood glucose level. The grade or rating may be determined by considering one or more factors, including, but not limited to, average blood glucose level, total amount of time spent within target, total amount of time spent excursion, total amount of time blood glucose level was changing by more than a predetermined percentage, and / or total amount of time spent below target. In some embodiments, one or more of these factors may be weighted more heavily in the grading method, for example, total amount of time spent excursion may be weighted more heavily than total amount of time spent below target. In some embodiments, the grade or rating may be determined by weighting more heavily the total amount of time spent above or below target. In some embodiments, the total amount of time that blood glucose levels have been changing at a rate greater than a predetermined rate may be weighted more heavily than other factors.

[0113] In some embodiments, average blood glucose levels may be correlated with "predicted" A1C levels. For example, if a user has an average blood glucose level of 135 mg / dl over the past 90 days, the system may indicate to the user that this is likely to translate to an A1C level of 6.0%.

[0114] As discussed above, various embodiments of the system may include one or more of a variety of infusion pumps, which are incorporated herein by reference. Below are descriptions of several embodiments of infusion pumps that may be used in some embodiments of the system.

[0115] 7-9 , infusion pump assembly 100 may include a reusable housing assembly 102. Reusable housing assembly 102 may be constructed from any suitable material, such as a hard or rigid plastic, that resists compression. For example, the use of durable materials and parts improves quality and reduces costs by providing a longer-lasting, more durable reusable part and providing greater protection for the components disposed therein.

[0116] Reusable housing assembly 102 may include a mechanical control assembly 104 having a pump assembly 106 and at least one valve assembly 108. Reusable housing assembly 102 may also include an electrical control assembly 110 configured to provide one or more control signals to mechanical control assembly 104 to achieve basal and / or bolus delivery of the infusible fluid to a user. Disposable housing assembly 114 may include valve assembly 108, which may be configured to control the flow of the infusible fluid through the fluid pathways. Reusable housing assembly 102 may also include pump assembly 106, which may be configured to pump the infusible fluid from the fluid pathways to a user.

[0117] Electrical control assembly 110 may monitor and control the amount of infusible fluid that has been and / or is being pumped. For example, electrical control assembly 110 may receive signals from volume sensor assembly 148, calculate the amount of infusible fluid dispensed, and determine whether sufficient infusible fluid has been dispensed based on the dosage required by the user. If sufficient infusible fluid has not been dispensed, electrical control assembly 110 may determine that more sufficient infusible fluid should be dispensed. Electrical control assembly 110 may provide an appropriate signal to mechanical control assembly 104 so that the additional required dosage may be delivered, or so that an additional dosage may be dispensed with the next dosage. Alternatively, if an excessive amount of infusible fluid has been dispensed, electrical control assembly 110 may provide an appropriate signal to mechanical control assembly 104 so that less infusible fluid may be dispensed with the next dosage.

[0118] The mechanical control assembly 104 may include at least one shape memory actuator 112. The pump assembly 106 and / or the valve assembly 108 of the mechanical control assembly 104 may be actuated by at least one shape memory actuator, e.g., a shape memory wire in a wire or spring configuration. The shape memory actuator 112 may be operably connected to and activated by an electrical control assembly 110, which may control the timing and amount of thermal and / or electrical energy used to actuate the mechanical control assembly 104. The shape memory actuator 112 may be, for example, a conductive shape memory alloy wire that changes shape with temperature. The temperature of the shape memory actuator 112 may be changed by a heater or, more conveniently, by the application of electrical energy. The shape memory actuator 112 may be a NITINOL TM Or it may be a shape memory wire constructed of a nickel / titanium alloy, such as FLEXINOL®.

[0119] Infusion pump assembly 100 may include a volume sensor assembly 148 configured to monitor the amount of fluid infused by infusion pump assembly 100. For example, volume sensor assembly 148 may employ, for example, acoustic volume sensing. Acoustic volume measurement techniques are disclosed in DEKA Corporation, the entire disclosure of which is incorporated herein by reference. Nos. 5,575,310 and 5,755,683, assigned to NI Products Limited Partnership, and U.S. Patent Application Publication Nos. US2007 / 0228071A1, US2007 / 0219496A1, US2007 / 0219480A1, and US2007 / 0219597A1. Other alternative techniques for measuring fluid flow may also be used, such as, for example, Doppler-based methods, the use of Hall-effect sensors in combination with vane or flapper valves, the use of strain beams (e.g., associated with a flexible member over a fluid reservoir to sense deflection of the flexible member), the use of capacitive sensing using plates, or thermal time-of-flight methods. One such alternative technique is disclosed in U.S. patent application Ser. No. 11 / 704,899, filed Feb. 9, 2007, entitled "Fluid Delivery Systems and Methods," the entire disclosure of which is incorporated herein by reference. Infusion pump assembly 100 may be configured such that volume measurements produced by volume sensor assembly 148 may be used, through a feedback loop, to measure the amount of infusible fluid infused into the user.

[0120] Infusion pump assembly 100 may further include a disposable housing assembly 114. For example, disposable housing assembly 114 may be configured for a single use or for use over a specified period of time, such as three days, or any other amount of time. Disposable housing assembly 114 may be configured such that any components in infusion pump assembly 100 that come into contact with an infusible fluid are disposed on and / or within disposable housing assembly 114. For example, fluid pathways or channels, including a reservoir, may be positioned within disposable housing assembly 114 and may be configured for a single use or for a specified number of uses before disposal. The disposable nature of disposable housing assembly 114 may improve sanitation of infusion pump assembly 100.

[0121] 10 , disposable housing assembly 114 may be configured to releasably engage reusable housing assembly 102 and includes cavity 116 having reservoir 118 for receiving an infusible fluid (not shown), e.g., insulin. Such releasable engagement may be achieved, for example, by a threaded, twist-lock, or compression-fit arrangement. Disposable housing assembly 114 and / or reusable housing assembly 102 may include an alignment assembly configured to assist in aligning disposable housing assembly 114 and reusable housing assembly 102 for engagement in a particular orientation. Similarly, base node 120 and top node 122 may be used as indicators of alignment and full engagement.

[0122] The cavity 116 may be at least partially formed by and integral with the disposable housing assembly 114. The cavity 116 may include a membrane assembly 124 for at least partially defining a reservoir 118. The reservoir 118 may be further defined by the disposable housing assembly 114, for example, by a recess 126 formed in a base portion 128 of the disposable housing assembly 114. For example, the membrane assembly 124 may be disposed over the recess 126 and attached to the base portion 128, thereby forming the reservoir 118. The membrane assembly 124 may be attached to the base portion 128 by conventional means, such as adhesive, heat sealing, and / or a compression fit, such that a seal 130 is formed between the membrane assembly 124 and the base portion 128. The membrane assembly 124 may be flexible, and the space formed between the membrane assembly 124 and the recess 126 in the base portion 128 may define the reservoir 118. The reservoir 118 may be unpressurized and in fluid communication with a fluid pathway (not shown). The membrane assembly 124 may be at least partially collapsible, and the cavity 116 may include a vent assembly, thereby advantageously preventing a buildup of vacuum within the reservoir 118 as the infusible fluid is delivered from the reservoir 118 to the fluid pathway. In a preferred embodiment, the membrane assembly 124 is fully collapsible, thus allowing for full delivery of the infusible fluid. The cavity 116 may be configured to provide sufficient space to ensure that there is always some void, even when the reservoir 118 is filled with infusible fluid.

[0123] The membranes and reservoirs described herein may be made from materials including, but not limited to, silicone, nitrile, and any other material that has the desired elasticity and properties to function as described herein. Additionally, other structures can serve the same purpose.

[0124] The use of a partially collapsible, non-pressurized reservoir may advantageously prevent the accumulation of air in the reservoir as the fluid in the reservoir is depleted. Air accumulation in a vented reservoir can prevent the escape of fluid from the reservoir, particularly when the system is tilted, such that an air pocket is interposed between the fluid contained in the reservoir and the reservoir's septum. Tilting of the system is expected during normal operation as a wearable device.

[0125] Reservoir 118 may be conventionally sized to hold a sufficient insulin supply for delivery over one or more days. For example, reservoir 118 may hold approximately 1.00 to 3.00 ml of insulin. A 3.00 ml insulin reservoir may approximately correspond to a three-day supply for approximately 90% of potential users. In other embodiments, reservoir 118 may be any size or shape and may be adapted to hold any amount of insulin or other infusible fluid. In some embodiments, the size and shape of cavity 116 and reservoir 118 are related to the type of infusible fluid that cavity 116 and reservoir 118 are adapted to hold.

[0126] Disposable housing assembly 114 may include support member 132 ( FIG. 9 ) configured to prevent accidental compression of reservoir 118. Compression of reservoir 118 may result in an unintended dose of infusible fluid being forced through the fluid pathway and into the user. In a preferred embodiment, reusable housing assembly 102 and disposable housing assembly 114 may be constructed of a rigid material that is not easily compressible. However, as an added precaution, support member 132 may be included within disposable housing assembly 114 to prevent compression of infusion pump assembly 100 and cavity 116 therein. Support member 132 may be a rigid protrusion from base portion 128. For example, support member 132 may be positioned within cavity 116 and may prevent compression of reservoir 118.

[0127] As discussed above, cavity 116 may be configured to provide sufficient space to ensure that there is always some void space, even when reservoir 118 is filled with infusible fluid. Thus, if infusion pump assembly 100 is accidentally compressed, infusible fluid may not be forced through cannula assembly 136.

[0128] Cavity 116 may include a septum assembly 146 ( FIG. 9 ) configured to allow reservoir 118 to be filled with an infusible fluid. Septum assembly 146 may be a conventional septum made of rubber or plastic and may have a one-way fluid valve configured to allow a user to fill reservoir 118 from a syringe or other filling device. In some embodiments, septum 146 may be located on top of membrane assembly 124. In these embodiments, cavity 116 may include a support structure (e.g., support member 132 in FIG. 9 ) to support an area around the backside of the septum to maintain the integrity of the septum seal when a needle is introducing infusible fluid into cavity 116. The support structure may be configured to support the septum while still allowing the introduction of a needle to introduce infusible fluid into cavity 116.

[0129] Infusion pump assembly 100 may include an overfill prevention assembly (not shown), which may, for example, protrude into cavity 116 and may, for example, prevent overfilling of reservoir 118.

[0130] 11-13, there is shown an alternative embodiment infusion pump assembly 500. Similar to pump assemblies 100, 100′, infusion pump assembly 500 may include a reusable housing assembly 502 and a disposable housing assembly 504.

[0131] Similar to reusable housing assembly 402, reusable housing assembly 502 includes a mechanical control assembly (including at least one pump assembly and at least one valve assembly). Reusable housing assembly 502 may also include an electrical control assembly configured to provide control signals to the mechanical control assembly to effect delivery of the infusible fluid to a user. The valve assemblies may be configured to control the flow of the infusible fluid through the fluid pathways, and the pump assemblies may be configured to pump the infusible fluid from the fluid pathways to a user.

[0132] Similar to disposable housing assembly 404, disposable housing assembly 504 may be configured for a single use or for use for a specified period of time, for example, three days, or any other amount of time. Disposable housing assembly 504 may be configured such that any components in infusion pump assembly 500 that come into contact with the infusible fluid are disposed on and / or within disposable housing assembly 504.

[0133] In certain embodiments of this infusion pump assembly, infusion pump assembly 500 may include a switch assembly 506 positioned around the periphery of infusion pump assembly 500. For example, switch assembly 506 may be positioned along a radial edge of infusion pump assembly 500, which may allow for easier use by a user. Switch assembly 506 may be covered with a waterproof membrane and / or an O-ring or other sealing mechanism configured to prevent water penetration into infusion pump assembly 500 may be included on stem 507 of switch assembly 506. However, in some embodiments, switch assembly 506 may include an overmolded rubber button and thus provide functionality as a waterproof seal without the use of a waterproof membrane or O-ring. However, in still other embodiments, the overmolded rubber button may additionally be covered with a waterproof membrane and / or include an O-ring. Reusable housing assembly 502 may include a main body portion 508 (which houses the mechanical and electrical control assemblies described above) and a locking ring assembly 510, which may be configured to rotate around main body portion 508 (in the direction of arrow 512).

[0134] Similar to reusable housing assembly 402 and disposable housing assembly 404, reusable housing assembly 502 may be configured to releasably engage disposable housing assembly 504. Such releasable engagement may be achieved, for example, by a threaded, twist-lock, or compression-fit arrangement. In embodiments in which a twist-lock configuration is utilized, a user of infusion pump assembly 500 may first properly position reusable housing assembly 502 relative to disposable housing assembly 504 and then rotate locking ring assembly 510 (in the direction of arrow 512) to releasably engage reusable housing assembly 502 with disposable housing assembly 404.

[0135] Because locking ring assembly 510 included within infusion pump assembly 500 may be taller than locking ring assembly 410 (i.e., as indicated by arrow 514), locking ring assembly 510 may include a passageway 516 through which button 506 may pass. Thus, when assembling reusable housing assembly 502, locking ring assembly 510 may be installed (in the direction of arrow 518) onto main body portion 508. Once locking ring assembly 510 is installed onto main body portion 508, one or more locking tabs (not shown) may prevent locking ring assembly 510 from being removed from main body portion 508. The portion of switch assembly 506 protruding through passageway 516 may then be pressed (in the direction of arrow 520) into main body portion 508, thus completing the installation of switch assembly 506.

[0136] Although button 506 is shown in various locations on infusion pump assembly 500, button 506 may be located anywhere desired on infusion pump assembly 500 in other embodiments.

[0137] Through the use of locking ring assembly 510, the reusable housing assembly 502 may be properly positioned relative to the disposable housing assembly 504 and then releasably engaged by rotating the locking ring assembly 510, thus eliminating the need to rotate the reusable housing assembly 502 relative to the disposable housing assembly 504. Thus, the reusable housing assembly 502 may be properly aligned with the disposable housing assembly 504 prior to engagement, and such alignment must not be disturbed during the engagement process. The locking ring assembly 510 may include a latching mechanism (not shown) that prevents rotation of the locking ring assembly 510 until the reusable housing assembly 502 and the disposable housing assembly 504 are properly positioned relative to one another. The passageway 516 may be elongated to allow movement of the locking ring 510 around the switch assembly 506.

[0138] 14A-14B and 15-16, various views of infusion pump assembly 500 are shown, which is shown to include reusable housing assembly 502, switch assembly 506, and main body portion 508. As discussed above, main body portion 508 may include multiple components, examples of which include, but are not limited to, volume sensor assembly 148, printed circuit board 600, vibration motor assembly 602, shape memory actuator anchor 604, switch assembly 506, battery 606, antenna assembly 608, pump assembly 106, measurement valve assembly 610, volume sensor valve assembly 612, and reservoir valve assembly 614. For clarity, printed circuit board 600 has been removed from FIG. 14B to allow for visualization of the various components positioned below printed circuit board 600.

[0139] Various electrical components that may be electrically coupled to printed circuit board 600 may include spring-loaded terminals that allow for electrical coupling without the need to solder connections. For example, vibration motor assembly 602 may utilize a pair of spring-loaded terminals (one positive and one negative) that are configured to compress against corresponding conductive pads on printed circuit board 600 when vibration motor assembly 602 is positioned on printed circuit board 600. However, in an exemplary embodiment, vibration motor assembly 602 is soldered directly to the printed circuit board.

[0140] As discussed above, volume sensor assembly 148 may be configured to monitor the amount of fluid infused by infusion pump assembly 500. For example, volume sensor assembly 148 may employ acoustic capacitive sensing, which is the subject of U.S. Patent Nos. 5,575,310 and 5,755,683, assigned to DEKA Products Limited Partnership, and U.S. Patent Publication Nos. US2007 / 0228071A1, US2007 / 0219496A1, US2007 / 0219480A1, and US2007 / 0219597A1, the entire disclosures of which are incorporated herein by reference.

[0141] Vibration motor assembly 602 may be configured to provide a vibration-based signal to a user of infusion pump assembly 500. For example, if the voltage of battery 606 (which powers infusion pump assembly 500) drops below a minimum allowable voltage, vibration motor assembly 602 may vibrate infusion pump assembly 500 to provide a vibration-based signal to a user of infusion pump assembly 500. Shape memory actuator anchor 604 may provide a mounting point for the shape memory actuator (e.g., shape memory actuator 112) described above. As discussed above, shape memory actuator 112 may be, for example, a conductive shape memory alloy wire that changes shape with temperature. The temperature of shape memory actuator 112 may be changed by a heater or, more conveniently, by the application of electrical energy. Thus, one end of shape memory actuator 112 may be rigidly attached (i.e., secured) to shape memory actuator anchor 604, and the other end of shape memory actuator 112 may be applied, for example, to a valve assembly and / or a pump actuator. Thus, by applying electrical energy to shape memory actuator 112, the length of shape memory actuator 112 may be controlled, and thus the valve assemblies and pump actuators to which it is attached may be operated.

[0142] Antenna assembly 608 may be configured, for example, to enable wireless communication between infusion pump assembly 500 and a remote control assembly. As discussed above, the remote control assembly may allow a user to program infusion pump assembly 500, for example, to configure bolus infusion events. As discussed above, infusion pump assembly 500 may include one or more valve assemblies configured to control the flow rate of infusible fluid through a fluid path (within infusion pump assembly 500), and pump assembly 106 may be configured to deliver the infusible fluid from the fluid path to a user. In this particular embodiment of infusion pump assembly 500, infusion pump assembly 500 is shown to include three valve assemblies: a measurement valve assembly 610, a volume sensor valve assembly 612, and a reservoir valve assembly 614.

[0143] As discussed above, and with reference also to FIG. 16 , the infusible fluid may be stored in reservoir 118. To effect delivery of the infusible fluid to a user, processing logic (not shown) included within infusion pump assembly 500 may energize shape memory actuator 112, which may be anchored on one end using shape memory actuator anchor 604. With reference also to FIG. 17A , shape memory actuator 112 may cause actuation of pump assembly 106 and reservoir valve assembly 614. Reservoir valve assembly 614 may include reservoir valve actuator 614A and reservoir valve 614B, and actuation of reservoir valve assembly 614 may cause downward displacement of reservoir valve actuator 614A and closing of reservoir valve 614B, effectively isolating reservoir 118. Further, the pump assembly 106 may include a pump plunger 106A and a pump chamber 106B, and activation of the pump assembly 106 may displace the pump plunger 106A downward into the pump chamber 106B, resulting in displacement of the injectable fluid (in the direction of arrow 616).

[0144] Volume sensor valve assembly 612 may include volume sensor valve actuator 612A and volume sensor valve 612B. Referring also to FIG. 17B , volume sensor valve actuator 612A may be closed via a spring assembly that provides a mechanical force to seal volume sensor valve 612B. However, when pump assembly 106 is activated, if the displaced infusible fluid is of sufficient pressure to overcome the mechanical sealing force of volume sensor valve assembly 612, displacement of infusible fluid occurs in the direction of arrow 618. This may result in filling of volume sensor chamber 620 contained within volume sensor assembly 148. Through the use of speaker assembly 622, port assembly 624, reference microphone 626, spring diaphragm 628, and constant volume microphone 630, volume sensor assembly 148 may determine the volume of infusible fluid contained within volume sensor chamber 620.

[0145] 17C , once the volume of infusible fluid contained within volume sensor chamber 620 has been calculated, shape memory actuator 632 may be energized, resulting in actuation of measurement valve assembly 610, which may include measurement valve actuator 610A and measurement valve 610B. Once actuated, and due to the mechanical energy exerted by spring diaphragm 628 on the infusible fluid within volume sensor chamber 620, the infusible fluid within volume sensor chamber 620 may be displaced (in the direction of arrow 634) through disposable cannula 138 and into the user's body.

[0146] 18 , an exploded view of infusion pump assembly 500 is shown. Shape memory actuator 632 may be secured (on a first end) to shape memory actuator anchor 636. Additionally, the other end of shape memory actuator 632 may be used to provide mechanical energy to valve assembly 638, which may actuate measurement valve assembly 610. Volume sensor assembly spring retainer 642 may properly position volume sensor assembly 148 relative to various other components of infusion pump assembly 500. Valve assembly 638 may be used in conjunction with shape memory actuator 112 to actuate pump plunger 106A. Measurement valve 610B, volume sensor valve 612B, and / or reservoir valve 614B may be self-contained valves configured to allow installation during assembly of infusion pump assembly 500 by pressing the valves upwardly against the underside of main body portion 508.

[0147] As discussed above, infusion pump assembly 100 may include a volume sensor assembly 148 configured to monitor the amount of fluid infused by infusion pump assembly 100. Additionally, as discussed above, infusion pump assembly 100 may be configured such that volume measurements produced by volume sensor assembly 148 may be used to control, via a feedback loop, the amount of infusible fluid infused into the user.

[0148] The following discussion relates to the design and operation of capacitive sensor assembly 148 (shown in simplified form in FIG. 19). For the discussion that follows, the following nomenclature may be used:

[0149] [Table 1] (Derivation of equation for capacitive sensor assembly 148:) (Acoustic capacitance modeling) The pressure and volume of an ideal insulating gas may be related by:

[0150] PV γ =K[EQ#1] where K is a constant defined by the initial conditions of the system.

[0151] EQ#1 can be written in terms of mean pressure P, and volume V, plus small time-dependent disturbances p(t), v(t) as follows:

[0152] (P+p(t))(V+v(t)) γ =K[EQ#2] Differentiating this equation can yield the following:

[0153]

number

[0154]

number

[0155]

number

[0156]

number

[0157]

number

[0158]

number

[0159] Applying the ideal gas law P=ρRT and substituting for pressure can result in the following equation:

[0160]

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[0161]

number

[0162]

number

[0163]

number

[0164] format

[0165]

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[0166]

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[0167]

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[0168]

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[0169]

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[0170]

number

[0171]

number

[0172]

number

[0173]

number

[0174] The difficulty with this relationship is that the complex poles depend on the variable capacitance V2 and the reference capacitance V1. Changes in the mean position of the loudspeakers can introduce errors in the estimated capacitance.

[0175] (Port-to-port transfer function) The relationship between the two capacitances on either side of an acoustic port may be called the port-to-port transfer function. This relationship is:

[0176]

number

[0177] This relationship has the advantage that the pole depends only on the variable capacitance and not on the reference capacitance. However, it has the difficulty that the resonance peak is actually due to an inversion of the zero as a function of the reference capacitance pressure. Therefore, pressure measurements in the reference chamber will have low amplitude near the resonance, potentially increasing measurement noise.

[0178] (Speaker-to-speaker transfer function) Pressure may also be measured from either side of the loudspeaker, this is called the inter-loop transfer function,

[0179]

number

[0180] This transfer function has a set of complex zeros in addition to a set of complex poles.

[0181] Looking at the limit of this transfer function,

[0182]

number

[0183] (Resonance quality factor and peak response) The quality of the resonance is the ratio of stored energy to power loss multiplied by the resonance frequency. For a pure second-order system, the quality factor can be expressed as a function of the damping ratio:

[0184]

number

[0185]

number

[0186]

number

[0187] (Capacity estimation) (Capacity estimation using port-to-port phase) The variable volume (i.e., in the volume sensor chamber 620) may also be estimated using the inter-port phase. The transfer function of the pressure ratio across the resonant ports may be:

[0188]

number

[0189]

number

[0190] The resonant frequency may be determined on a physical system using a number of methods. A phase-locked loop may be employed to determine the 90° phase point, which may correspond to the system's natural frequency. Alternatively, the resonant frequency may be calculated using the phase at any two frequencies.

[0191] The phase φ at a given frequency is given by the following relation:

[0192]

number

[0193] Solving for the value of V2 yields the following equation:

[0194]

number

[0195]

number

[0196] For computational efficiency, the phase does not actually need to be calculated: the ratio of the real and imaginary parts of the resonance (tan φ) is sufficient.

[0197] Rewriting EQ#33 in terms of variable capacitance yields the following equation:

[0198]

number

[0199] The transfer function of a system may be expressed as a rational function of s. The general case is expressed below for a transfer function with nth order numerator and mth order denominator. N and D are the numerator and denominator coefficients, respectively. The equation has been normalized so that the leading coefficient in the denominator is 1.

[0200]

number

[0201]

number

[0202]

number

[0203] y=Xc[EQ#39] where y is k×1, x is k×(m+n−1), and c is (m+n−1)×1. The coefficients may then be found using the least squares method. The error function may be written as:

[0204] e=y-Xc[EQ#40] The function to be minimized is the weighted square of the error function. W is a k×k diagonal matrix.

[0205]

number

[0206]

number

[0207]

number

[0208]

number

[0209]

number

[0210] The coefficients of this transfer function can be found based on the formula found in the previous section:

[0211]

number

[0212] To simplify the algorithm, some of the terms may be combined:

[0213]

number

[0214] To find an expression for D in terms of the complex response vector G and the natural frequency s=jω, X can be separated into its real and imaginary parts.

[0215]

number

[0216]

number

[0217]

number

[0218]

number

[0219]

number

[0220]

number

[0221]

number

[0222]

number

[0223] The determinant can then be calculated for the adjoint matrix using the zero elements in the original array.

[0224]

number

[0225]

number

[0226]

number

[0227]

number

[0228]

number

[0229]

number

[0230] The model fitting error can also be used to detect sensor faults.

[0231] (Alternative solution for second-order systems)

[0232]

number

[0233]

number

[0234]

number

[0235]

number

[0236] The coefficients of this transfer function can be found based on the formula found in the previous section:

[0237]

number

[0238] To simplify the algorithm, some terms may be combined:

[0239]

number

[0240] To find an expression for D in terms of the complex response vector G and the natural frequency s=jω, the partitioned X can be separated into its real and imaginary parts.

[0241]

number

[0242]

number

[0243]

number

[0244]

number

[0245]

number

[0246] Additionally, the total signal variance may be calculated and compared to the variance of a pure tone extracted using a Discrete Fourier Transform (i.e., DFT). This may provide a measure of how much of the signal power comes from noise sources or distortion. This value may then be used to reject and iterate poor measurements.

[0247] (Discrete Fourier Transform Calculation) The signal from the microphone may be sampled synchronously with the output to the speaker assembly 622 so that a fixed number of points N are taken per wavelength. The measured signal at each wavelength point may be summed over an integer number of wavelengths M and stored by the ISR in an array x for processing after all data for that frequency has been collected.

[0248] A DFT may be performed on the data at integer values ​​corresponding to the driving frequency of the speaker. The general formula for the first harmonic of the DFT is:

[0249]

number

[0250]

number

[0251]

number

[0252]

number

[0253]

number

[0254] This can be expressed as follows:

[0255]

number

[0256]

number

[0257] (Calculation of signal variance) The pseudovariance of a signal may be calculated using the following relationship:

[0258]

number

[0259] The sum is approximately

[0260]

number

[0261]

number

[0262] (Calculation of relative microphone response) The relative response (G) of the microphones 626, 630 can be calculated from the complex responses of the individual microphones.

[0263]

number

[0264]

number

[0265]

number

[0266]

number

[0267] The simultaneous equations describing the three-chamber configuration may be as follows:

[0268]

number

[0269]

number

[0270]

number

[0271]

number

[0272]

Number

[0273]

Number

[0274]

Number

[0275] The time delay can be expressed in the Laplace domain as follows.

[0276]

Number

[0277]

Number

[0278] (3-chamber capacitance estimation) The capacitance sensor assembly 148 may also be configured using a third reference capacitance (e.g., reference capacitance 1508, FIG. 26) connected to a separate resonant port (e.g., port 1510, FIG. 26). This configuration may allow for temperature-independent capacitance estimation.

[0279] The simultaneous equations describing the three-chamber configuration may be as follows:

[0280]

number

[0281]

number

[0282]

number

[0283] The volume of the volume sensor chamber 620 can be estimated using the ratio of the natural frequencies of the two resonant ports as follows:

[0284]

number

[0285] (Exponential Capacity Model) Assume that the outflow through the flow resistance is of the form:

[0286]

number

[0287]

number

[0288]

number

[0289]

number

[0290]

number

[0291]

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[0292]

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[0293]

number

[0294]

number

[0295] (implementation details) (end effect) Air resonating in a port (e.g., port assembly 624) may extend into the acoustic volume at the end of each oscillation. The distance the air extends may be estimated based on the basic capacitance sensor assembly equation. For a given acoustic volume, the distance the air extends into the volume may be expressed as a function of pressure and the port cross-sectional area.

[0296]

number

[0297]

number

[0298] Therefore, the air extends approximately 1.9 mm into the acoustic chamber.

[0299] (Sizing of V1 (i.e., fixed capacitance) relative to V2 (i.e., variable capacitance)) Sizing V1 (e.g., fixed capacitance 1500) may require trading off acoustic capacitance with the relative positions of poles and zeros in the transfer function. The transfer functions of both V1 and V2 (e.g., variable capacitance 1502) are shown below versus capacitance displacement of speaker assembly 622:

[0300]

number

[0301] As V1 is increased, the gain may decrease and the speaker may be driven at a higher amplitude to obtain the same sound pressure level. However, increasing V1 may also have the benefit of moving complex zeros in the p1 transfer function toward complex poles. In the limiting case where V1 → ∞, α → 1, there is pole-zero cancellation and a flat response. Thus, increasing V1 reduces both the resonance and the notch in the p1 transfer function, and ω n It may be advantageous to move the p2 pole towards , resulting in less sensitivity to measurement errors when calculating the p2 / p1 transfer function.

[0302] FIG. 27 is a graphical representation of the following equation:

[0303]

number

[0304]

number

[0305]

number

[0306] The demodulation routine can effectively remove noise except at the specific frequency of the demodulation. If the sample frequency is dynamically set to be a fixed multiple of the demodulation frequency, the noise frequencies that can alias down to the demodulation frequency will be a fixed set of harmonics of that fundamental frequency.

[0307] For example, if the sampling frequency is eight times the demodulation frequency, then the noise frequencies that can be aliased down to that frequency are:

[0308]

number

[0309]

number

[0310]

number

[0311]

number

[0312]

number

[0313] However, the measurement may be more susceptible to noise in the temperature measurement: temperature changes during a differential sine wave sweep may result in errors that appear as offsets rather than gain changes.

[0314]

number

[0315] The LM73 temperature sensor may have a published accuracy of + / - 1°C and a resolution of 0.03°C. Additionally, the LM73 temperature sensor appears to consistently have an onset transient of about 0.3°C that takes about five sine sweeps to level off (as shown in Figure 31).

[0316] Because the above-described infusion pump assemblies (e.g., infusion pump assemblies 100, 100', 400, 500) provide discrete delivery of infusible fluid, the above-described infusion pump assemblies may be modeled entirely in the discrete domain (in the manner shown in FIG. 32), which can be summarized in the following equation:

[0317]

number

[0318]

number

[0319] If microphone 626 (i.e., the microphone positioned proximate fixed volume 1500) exhibits an acoustic response and microphone 630 (i.e., the microphone positioned proximate variable volume 1502) does not exhibit an acoustic response, it may be reasonably concluded that disposable housing assembly 114 is not attached to reusable housing assembly 102. Note that a failure of variable volume microphone 630 may also be considered indicative of an unattached disposable housing assembly 114, as a failure of variable volume microphone 630 may result in mid-frequency measurements that are nearly indistinguishable from the microphone response that would be expected when disposable housing assembly 114 is not attached.

[0320] For the discussion that follows, the following nomenclature may be used:

[0321] [Table 2] As part of the demodulation routine employed in each frequency response calculation, minimum and maximum measurements may be calculated for both the fixed capacitance microphone 626 and the variable capacitance microphone 630. The sum of these maximum and minimum values ​​may be calculated over the entire sinusoidal sweep (as discussed above) for both microphone 626 and microphone 630 as follows:

[0322]

number

[0323]

number

[0324]

number

[0325] Thresholding for the above algorithm may be based entirely on numerical evidence. For example, examination of typical minimum / maximum response differences may show that no individual difference is less than 500 ADC counts. Thus, all data examined while the disposable housing assembly 114 is detached from the reusable housing assembly 102 may show all minimum / maximum response differences as being well below 500 ADC counts. Thus, the threshold for δ may be set at T=500.

[0326] Although volume sensor assembly 148 is described above as being utilized within an infusion pump assembly (e.g., infusion pump assembly 100), this is for illustrative purposes only and is not intended to be a limitation of the present disclosure, as other configurations are possible and are considered within the scope of the present disclosure. For example, volume sensor assembly 148 may be used within a process control environment, e.g., to control the amounts of chemicals mixed together. Alternatively, volume sensor assembly 148 may be used within a beverage dispensing system, e.g., to control the amounts of ingredients mixed together.

[0327] While the capacitance sensor assembly 148 has been described above as utilizing a port (e.g., port assembly 624) as a resonator, this is for illustrative purposes only, as other configurations are possible and considered within the scope of the present disclosure. For example, a solid mass (not shown) may be suspended within the port assembly 624 and serve as the resonator for the capacitance sensor assembly 148. Specifically, the resonator mass (not shown) may be suspended on a diaphragm (not shown) that spans the port assembly 624. Alternatively, the diaphragm itself (not shown) may serve as the resonator mass. The natural frequency of the capacitance sensor assembly 148 may be a function of the capacitance of the variable capacitance 1502. Thus, if the natural frequency of the capacitance sensor assembly 148 can be measured, the capacitance of the variable capacitance 1502 may be calculated.

[0328] The natural frequency of the capacitive sensor assembly 148 may be measured in a number of different ways. For example, a time-varying force may be applied to a diaphragm (not shown), and the relationship between the force and the motion of the diaphragm (not shown) may be used to estimate the natural frequency of the capacitive sensor assembly 148. Alternatively, a mass (not shown) may be perturbed and then caused to vibrate. The unforced motion of the mass (not shown) may then be used to calculate the natural frequency of the capacitive sensor assembly 148.

[0329] The force applied to the resonant mass (not shown) may be achieved in a variety of ways, examples of which may include, but are not limited to: · The speaker assembly 622 may generate a time-varying pressure within the fixed volume 1500. · The resonant mass (not shown) may be a piezoelectric material that responds to a time-varying voltage / current. A resonant mass (not shown) may be a voice coil that responds to a time-varying voltage / current.

[0330] The force applied to the resonant mass may be measured in a variety of ways, examples of which may include, but are not limited to: ·Measure pressure in a fixed volume. The resonant mass (not shown) may be a piezoelectric material. A strain gauge may be connected to a diaphragm (not shown) or other structural member supporting a resonating mass (not shown).

[0331] Similarly, the displacement of the resonating mass (not shown) may be measured by measuring the pressure in a variable volume or may be measured directly in a variety of ways, examples of which may include, but are not limited to, the following: Via a piezoelectric sensor. Via a capacitive sensor. Via optical sensors. Via Hall effect sensors. · Via potentiometer (time varying impedance) sensors. Via inductive sensors. Via a Linear Variable Differential Transformer (LVDT).

[0332] Additionally, the resonating mass (not shown) may be integral with either the force-type sensor or the displacement-type sensor (ie, the resonating mass (not shown) may be made of a piezoelectric material).

[0333] The application of force and measurement of displacement may be accomplished by a single device. For example, a piezoelectric material may be used in a resonant mass (not shown), and a time-varying voltage / current may be applied to the piezoelectric material to generate a time-varying force. The resulting voltage / current applied to the piezoelectric material may be measured, and the transfer function between the two may be used to estimate the natural frequency of the capacitive sensor assembly 148.

[0334] As discussed above, the resonant frequency of the volume sensor assembly 148 can be estimated using swept sine wave system identification. Specifically, the above model fitting may allow the resonant frequency of the port assembly to be extracted from the sine wave sweep data, which can then be used to determine the delivered volume. The ideal relationship between resonant frequency and delivered volume can be expressed as follows:

[0335]

number

[0336]

number

[0337]

number

[0338]

number

[0339] Infusion pump assembly 100 may then compare this calculated volume V2 (i.e., representing the actual volume of infusible fluid delivered to the user) with the target volume (i.e., representing the amount of fluid that was to be delivered to the user). For example, assume that infusion pump assembly 100 was to deliver a 0.100 unit basal dose of infusible fluid to the user every 30 minutes. Further assume that upon achieving such delivery, volume sensor assembly 148 indicates a calculated volume V2 of 0.095 units of infusible fluid (i.e., representing the actual volume of infusible fluid delivered to the user).

[0340] When calculating volume V2, infusion pump assembly 100 may first determine the volume of fluid in volume sensor chamber 620 before administration of the dose of infusible fluid and later determine the volume of fluid in volume sensor chamber 620 after administration of the dose of infusible fluid, with the difference between these two measurements indicating volume V2 (i.e., the actual volume of infusible fluid delivered to the user). Thus, V2 is a differential measurement.

[0341] V2 may be the total air space covering the diaphragm in the variable volume chamber. The actual fluid delivery to the patient may be the difference in V2 from when the chamber was full to after the measurement valve was opened and the chamber was emptied. V2 does not have to be directly the delivered volume. For example, the air volume may be measured, and a series of differential measurements may be taken. For an occlusion, a void measurement may be taken, the chamber may be filled, a full measurement may be taken, and then a final measurement may be taken after the outlet valve is opened. Thus, the difference between the first and second measurements may be the volume delivered, and the difference between the second and third measurements is the volume delivered to the patient.

[0342] Thus, electrical control assembly 110 may determine that the delivered infusible fluid is 0.005 units less than desired. In response to this determination, electrical control assembly 110 may provide an appropriate signal to mechanical control assembly 104 so that any additional required dose may be delivered. Alternatively, electrical control assembly 110 may provide an appropriate signal to mechanical control assembly 104 so that the additional dose may be dispensed along with the next dose. Thus, during administration of the next 0.100 unit dose of infusible fluid, the output command to the pump may be modified based on the difference between the target and delivered amount.

[0343] 33, one particular implementation of a control system for controlling the amount of infusible fluid currently being infused based at least in part on the amount of infusible fluid previously administered is shown. Specifically, continuing with the above example, for illustrative purposes, assume that the electrical control assembly 110 requests delivery of a 0.100 unit dose of infusible fluid to a user. Accordingly, the electrical control assembly 110 may provide a target differential volume signal 1600 (identifying a partial basal dose of 0.010 units of infusible fluid per cycle of the shape-memory actuator 112) to the volume controller 1602. Thus, in this particular example, the shape-memory actuator 112 may need to be cycled 10 times to achieve the desired basal dose of 0.100 units of infusible fluid (i.e., 10 cycles × (0.010 units per cycle) = 0.100 units). In turn, the volume controller 1602 may provide an “on-time” signal 1606 to the SMA (i.e., shape-memory actuator) controller 1608. A battery voltage signal 1610 is also provided to the SMA controller 1608 .

[0344] Specifically, shape memory actuator 112 may be controlled by varying the amount of thermal energy (e.g., joules) applied to shape memory actuator 112. Thus, if the voltage level of battery 606 is reduced, the amount of joules applied to shape memory actuator 112 may also be reduced for a defined period of time. Conversely, if the voltage level of battery 606 is increased, the amount of joules applied to shape memory actuator 112 may also be increased for a defined period of time. Thus, by monitoring the voltage level of battery 606 (via battery voltage signal 1610), the type of signal applied to shape memory actuator 112 may be varied to ensure that an appropriate amount of thermal energy is applied to shape memory actuator 112 regardless of the battery voltage level.

[0345] SMA controller 1608 may process “on-time” signal 1606 and battery voltage signal 1610 to determine an appropriate SMA drive signal 1612 to apply to shape-memory actuator 112. One example of SMA drive signal 1612 may be a series of binary pulses, where the amplitude of SMA drive signal 1612 essentially controls the stroke length of shape-memory actuator 112 (and thus pump assembly 106), and the duty cycle of SMA drive signal 1612 essentially controls the stroke rate of shape-memory actuator 112 (and thus pump assembly 106). Furthermore, because SMA drive signal 1612 indicates differential volume (i.e., the volume infused during each cycle of shape-memory actuator 112), SMA drive signal 1612 may be integrated by discrete-time integrator 1614 to generate volume signal 1616, which may indicate the total amount of infusible fluid infused during multiple cycles of shape-memory actuator 112. For example, since it may take 10 cycles of the shape memory actuator 112 (at 0.010 units per cycle) to inject 0.100 units of infusible fluid (as discussed above), the discrete time integrator 1614 may integrate the SMA drive signal 1612 over these 10 cycles to determine the total volume of infusible fluid injected (as represented by the volume signal 1616).

[0346] SMA drive signal 1612 may actuate pump assembly 106, for example, for one cycle, resulting in the filling of volume sensor chamber 620 included within volume sensor assembly 148. Infusion pump assembly 100 may then make a first measurement of the quantity of fluid contained within volume sensor chamber 620 (as discussed above). Further, as discussed above, measurement valve assembly 610 may later be energized, causing all or a portion of the fluid in volume sensor chamber 620 to be delivered to the user. Infusion pump assembly 100 may then make a measurement of the quantity of fluid contained within volume sensor chamber 620 (as explained above) and use these two measurements to determine V2 (i.e., the actual volume of infusible fluid delivered to the user during the current cycle of shape-memory actuator 112). Once determined, V2 (i.e., as represented by signal 1618) may be provided (i.e., fed back) to volume controller 1602 for comparison with a previously received target differential volume.

[0347] Continuing with the example above, in which the differential target volume was 0.010 units of infusible fluid, assume that V2 (i.e., as represented by signal 1618) identifies 0.009 units of infusible fluid as delivered to the user. Accordingly, infusion pump assembly 100 may increase the next differential target volume to 0.011 units to offset the previous 0.001 unit storage. Accordingly, as discussed above, the amplitude and / or duty cycle of SMA drive signal 1612 may be increased when delivering the next basal dose of infusible fluid to the user. This process may be repeated over the remaining nine cycles of shape memory actuator 112 (as discussed above), and discrete-time integrator 1614 may integrate SMA drive signal 1612 (to generate volume signal 1616), which may define the total amount of infusible fluid delivered to the user.

[0348] 34, one possible embodiment of volume controller 1602 is shown. In this particular implementation, volume controller 1602 may include a PI (proportional integrator) controller 1650. Volume controller 1602 may include a feed forward controller 1652 for setting an initial “guess” for “on time” signal 1606. For example, for the situation described above in which target differential volume signal 1600 identifies a partial basal dose of 0.010 units of infusible fluid per cycle of shape memory actuator 112, feed forward controller 1652 may define an initial “on time” of, for example, 1 millisecond. Feed forward controller 1652 may include, for example, a lookup table that defines the initial “on time” based at least in part on target differential volume signal 1600. The capacitance controller 1602 may further include a discrete-time integrator 1654 for integrating the target differential capacitance signal 1600 and a discrete-time integrator 1656 for integrating V2 (ie, as represented by signal 1618).

[0349] 35, one possible embodiment of the feed forward controller 1652 is shown. In this particular implementation, the feed forward controller 1652 may define a constant value signal 1658 and may include an amplifier 1660 (e.g., a unity gain amplifier), the output of which may be summed with the constant value signal 1658 at a summing node 1662. The resulting sum signal (i.e., signal 1664) may be provided as an input signal to, for example, a lookup table 1666, which may be processed to generate an output signal of the feed forward controller 1652.

[0350] As discussed above, the pump assembly 106 may be controlled by the shape memory actuator 112. Additionally, as discussed above, the SMA controller 1608 may process the “on time” signal 1606 and the battery voltage signal 1610 to determine an appropriate SMA drive signal 1612 to apply to the shape memory actuator 112.

[0351] 36-37, one particular implementation of SMA controller 1608 is shown. As discussed above, SMA controller 1608 may be responsive to "on-time" signal 1606 and battery voltage signal 1610 and may provide SMA drive signal 1612 to shape-memory actuator 112. SMA controller 1608 may include a feedback loop (including unit delay 1700), the output of which may be multiplied by battery voltage signal 1610 in multiplier 1702. The output of multiplier 1702 may be amplified, for example, with unity-gain amplifier 1704. The output of amplifier 1704 may be applied to the negative input of summing node 1706 (to which "on-time" signal 1606 is applied). The output of summing node 1706 may be amplified (e.g., via unity-gain amplifier 1708). The SMA controller may also include a feed forward controller 1710 (similar to feed forward controller 1652 of volume controller 1602, see FIG. 35 ) to provide an initial value for SMA drive signal 1612. The output of feed forward controller 1710 may be summed with the output of amplifier 1708 and an integral representation of the output of amplifier 1708 (i.e., signal 1714) at summing node 1712 to form SMA drive signal 1612.

[0352] SMA drive signal 1612 may be provided to a control circuit that effects the application of power to shape memory actuator 112. For example, SMA drive signal 1612 may be applied to a switching assembly 1716, which may selectively apply a current signal 1718 (supplied from battery 606) and / or a fixed signal 1720 to the shape memory actuator. For example, SMA drive signal 1612 may effect the application of energy (supplied from battery 606 via current signal 1718) via switching assembly 1716 in a manner that achieves a duty cycle defined by SMA drive signal 1612. Unit delay 1722 may generate a delayed version of the signal applied to shape memory actuator 112 to form battery voltage signal 1610 (which may be applied to SMA controller 1608).

[0353] When applying power to the shape memory actuator 112, the voltage may be applied for a fixed amount of time at a) a fixed duty cycle with unadjusted voltage, b) a fixed duty cycle with adjusted voltage, c) a variable duty cycle based on a measured current value, d) a variable duty cycle based on a measured voltage value, and e) a variable duty cycle based on the square of the measured voltage value. Alternatively, the voltage may be applied to the shape memory actuator 112 for a variable amount of time based on the measured impedance.

[0354] When applying an unregulated voltage for a fixed amount of time at a fixed duty cycle, inner loop feedback may be used and the shape memory actuator may be driven at a fixed duty cycle and with an on-time determined by the outer capacitance loop.

[0355] When applying an adjusted voltage for a fixed amount of time at a fixed duty cycle, inner loop feedback may not be used and the shape memory actuator 112 may be driven at a fixed duty cycle and with an on-time determined by the outer capacitance loop.

[0356] In a variable constant duty cycle based on measured current values, when applying an unadjusted voltage, the actual current applied to the shape memory actuator 112 may be measured and the duty cycle may be adjusted during operation of the shape memory actuator 112 to maintain the correct average current.

[0357] In a variable constant duty cycle based on a measured voltage value, when applying an unadjusted voltage, the actual voltage applied to the shape memory actuator 112 may be measured and the duty cycle may be adjusted during operation of the shape memory actuator 112 to maintain the correct average voltage.

[0358] In a variable constant duty cycle based on the square of the measured voltage value, when applying an unadjusted voltage, the actual voltage applied to the shape memory actuator 112 may be measured, and the duty cycle may be adjusted during operation of the shape memory actuator 112 to maintain the square of the voltage at a level required to provide the desired level of power to the shape memory actuator 112 (based on the impedance of the shape memory actuator 112).

[0359] Referring also to Figures 38A-38B, other implementations of the SMA controller 1608 are shown. Specifically, Figure 38A is an electrical circuit diagram that may include a microprocessor and various control loops, which may be configured to provide a PWM signal that may open or close a switch assembly. The switch assembly may control the current allowed to flow through the shape memory actuator. A battery may provide current to the shape memory actuator. 114B further discloses a volume controller and an internal shape memory actuator controller. The shape memory actuator controller may provide a PWM signal to the pump, which may be modified based on the battery voltage. This may occur for a fixed on-time, resulting in a volume that may be measured by a volume sensor assembly 148 and fed back to the volume controller.

[0360] In a preferred embodiment, the duty cycle is varied based on the measured battery voltage to provide a fairly consistent power. The duty cycle is adjusted to compensate for a lower battery voltage. Battery voltage may change for two reasons: 1) as the battery discharges, the voltage slowly decreases, and 2) when a load is applied to the battery, its voltage gradually drops due to internal impedance. This occurs in any type of system, and the duty cycle is adjusted to compensate for this, thus mitigating a lower or changing battery voltage. Battery voltage may be measured by a microprocessor. In other systems, 1) the voltage may be regulated (putting a regulator in to maintain the voltage at a stable voltage), or 2) feedback may be based on something else (i.e., motor speed or position, which does not necessarily measure battery voltage).

[0361] Other configurations may be utilized to control the shape memory actuator. For example, A) the shape memory actuator may be controlled at a fixed duty cycle with an unadjusted voltage. As the voltage changes, the repeatability of heating of the shape memory actuator is reduced. B) A fixed duty cycle with an adjusted voltage may be utilized that compensates for changes in battery voltage. However, adjusting the voltage downward is less energy efficient. C) The duty cycle may be varied based on changes in current (which may require more complex measurement circuitry). D) The duty cycle may be changed based on a measured voltage. E) The duty cycle may be changed based on the square of the current or the square of the voltage divided by the resistance. F) The voltage may be applied for a variable amount of time based on a measured impedance (e.g., a Wheatstone gauge (not shown) may be used to measure the impedance). The impedance of the shape memory actuator may be correlated to strain (i.e., how much the SMA moves may be correlated based on its impedance).

[0362] 39 and as discussed above, to improve the safety of infusion pump assembly 100, electrical control assembly 110 may include two separate and distinct microprocessors: supervisor processor 1800 and command processor 1802. Specifically, command processor 1802 may perform the functions discussed above (e.g., generating SMA drive signal 1612) and may control relay / switch assemblies 1804, 1806, which (in this example) control the functionality of shape-memory actuators 112, 632 (respectively). Command processor 1802 may receive feedback from signal conditioner 1808 regarding the state (e.g., voltage level) of the voltage signal applied to shape-memory actuators 112, 632. Command processor 1800 may control relay / switch assembly 1810 independently of relay / switch assemblies 1804, 1806. Thus, when an infusion event is desired, both supervisor processor 1800 and command processor 1802 must agree that the infusion event is proper and both must activate their respective relays / switches. If either supervisor processor 1800 or command processor 1802 fails to activate their respective relays / switches, the infusion event will not occur. Thus, through supervisor processor 1800 and command processor 1802 and the cooperation and simultaneity that must occur, the safety of infusion pump assembly 100 is enhanced.

[0363] The supervisor processor may prevent the command processor from delivering when it should not, and may sound an alarm if the command processor does not deliver when it should. The supervisor processor may also disable the relay / switch assembly if the command processor activates the wrong switch or if the command processor tries to apply power for too long.

[0364] The supervisor processor may perform redundant calculations (i.e., double-check the command processor's calculations) as to how much insulin should be delivered. The command processor may determine the delivery schedule, and the supervisor processor may redundantly check these calculations.

[0365] The supervisor may also keep a profile (delivery profile) redundantly in RAM, so that the command processor may be doing the right calculations, but if there is bad RAM, the command will give wrong results. The supervisor may use a local copy of the base profile, for example, to double-check.

[0366] Supervisors can double-check AVS measurements, look at AVS calculations and apply safety checks. A double-check is performed every time an AVS measurement is taken.

[0367] 40, one or more of supervisor processor 1800 and command processor 1802 may perform diagnostics on various portions of infusion pump assembly 100. For example, voltage dividers 1812, 1814 may be configured to monitor voltages (V1 and V2, respectively), such as those sensed at the distal end of shape-memory actuator 112. Knowing the signals applied to relay / switch assemblies 1804, 1810, the values ​​of voltages V1 and V2 (as shown in exemplary diagnostic table 1816) allow diagnostics to be performed on various components of the circuitry shown in FIG.

[0368] 39-40 , to improve the safety of infusion pump assembly 100, electrical control assembly 110 may include multiple microprocessors (e.g., supervisor processor 1800 and command processor 1802), each of which may be required to interact and operate simultaneously to achieve delivery of a dose of infusible fluid. If the microprocessors fail to interact / operate simultaneously, delivery of the dose of infusible fluid may fail and one or more alarms may be triggered, thus improving the safety and reliability of infusion pump assembly 100.

[0369] A master alarm may be utilized that tracks the volume error over time. Thus, if the sum of the errors becomes too large, the master alarm may be activated, indicating a possible malfunction in the system. Thus, the master alarm may indicate a total volume comparison being made and a discrepancy being noted. A typical value for the discrepancy required to activate the master alarm may be 1.00 milliliters. The master alarm may monitor the sum in a leaky fashion (i.e., the inaccuracy has a horizontal axis of time).

[0370] 41A-41B, one such illustrative example of such interaction between multiple microprocessors during delivery of a dose of infusible fluid is shown. Specifically, command processor 1802 may first determine 1900 the initial volume of infusible fluid in volume sensor chamber 620. Command processor 1802 may then provide 1902 a "pump power request" message to supervisor processor 1800. Upon receiving 1904 the "pump power request" message, supervisor processor 1800 may, for example, energize 1906 relay / switch 1810 (thus energizing shape-memory actuator 112) and send 1908 a "pump power on" message to command processor 1802. Upon receiving 1910 a "pump power on" message, the command processor 1802 may, for example, activate 1912 the pump assembly 106 (by energizing the relay / switch 1804), while the supervisor processor 1800 may, for example, monitor 1914 the operation of the pump assembly 106.

[0371] Once operation of pump assembly 106 is complete, command processor 1802 may provide 1914 a “pump power off” message to supervisor processor 1800. Upon receiving 1916 the “pump power off” message, supervisor processor 1800 may de-energize 1918 relay / switch 1810 and provide 1920 a “pump power off” message to command processor 1802. Upon receiving 1922 the “pump power off” message, command processor 1802 may measure 1924 the volume of infusible fluid pumped by pump assembly 106. This may be accomplished by measuring the current volume of fluid in volume sensor chamber 620 and comparing it to the volume determined above (in step 1900). Once determined 1924, command processor 1802 may provide 1926 a “valve open power request” message to supervisor processor 1800. Upon receiving 1928 the “valve open power requested” message, supervisor processor 1800 may energize 1930 relay / switch 1810 (thus energizing shape memory actuator 632) and may send 1932 a “valve open power on” message to command processor 1802. Upon receiving 1934 the “valve open power on” message, command processor 1802 may, for example, actuate 1936 measurement valve assembly 610 (by energizing relay / switch 1806), while supervisor processor 1800 may, for example, monitor 1938 the actuation of measurement valve assembly 610.

[0372] Once operation of measurement valve assembly 610 is complete, command processor 1802 may provide 1940 a "valve power off" message to supervisor processor 1800. Upon receiving 1942 the "valve power off" message, supervisor processor 1800 may de-energize 1944 relay / switch 1810 and provide 1946 a "valve power off" message to command processor 1802.

[0373] Upon receiving 1948 the "valve power off" message, command processor 1802 may provide 1950 a "valve close power request" message to supervisor processor 1800. Upon receiving 1952 the "valve close power request" message, supervisor processor 1800 may energize 1954 relay / switch 1810 (thus energizing shape-memory actuator 652) and may send 1956 a "power on" message to command processor 1802. Upon receiving 1958 the "power on" message, command processor 1802 may operate 1960 an energizing relay / switch (not shown) configured to energize shape-memory actuator 652, while supervisor processor 1800 may, for example, monitor 1962 the operation of shape-memory actuator 652.

[0374] The shape memory actuator 652 may be secured to a first end using electrical contacts 654. The other end of the shape memory actuator 652 may be connected to a bracket assembly 656. When the shape memory actuator 652 is activated, the shape memory actuator 652 may pull the bracket assembly 656 forward, releasing the valve assembly 634. As such, the measurement valve assembly 610 may be activated via the shape memory actuator 632. Once the measurement valve assembly 610 is activated, the bracket assembly 656 may manually latch the valve assembly 610 in the activated position. Activating the shape memory actuator 652 may pull the bracket assembly 656 forward, releasing the valve assembly 634. Assuming the shape memory actuator 632 is no longer activated, once the bracket assembly 656 releases the valve assembly 634, the measurement valve assembly 610 may be deactivated. Thus, activating the shape memory actuator 652 may deactivate the measurement valve assembly 610.

[0375] Once actuation of shape memory actuator 652 is complete, command processor 1802 may provide 1964 a "power off" message to supervisor processor 1800. Upon receiving 1966 the "power off" message, supervisor processor 1800 may de-energize 1968 relay / switch 1810 and provide 1970 a "power off" message to command processor 1802. Upon receiving 1972 the "power off" message, command processor 1802 may determine 1974 the volume of infusible fluid in volume sensor chamber 620, thus enabling command processor 1802 to compare this measured volume with the volume determined above (in step 1924) to determine the volume of infusible fluid delivered to the user.

[0376] If the amount of infusible fluid delivered to the user 1974 is less than the amount of infusible fluid specified for the basal / bolus infusion event, the above procedure may be repeated (via loop 1976).

[0377] 42, another illustrative example of the interaction between processors 1800, 1802 is shown, this time during the scheduling of a dose of infusible fluid. Command processor 1802 may monitor 2000, 2002 for receipt of a basal scheduling message or a bolus request message (respectively). Upon receipt of either of these messages 2000, 2002, command processor 1802 may set a desired delivery volume 2004 and may provide 2006 a "delivery request" message to supervisor processor 1800. Upon receiving 2008 the "delivery request" message, supervisor processor 1800 may verify 2010 the volume 2004 defined by command processor 1802. Once verified 2010, supervisor processor 1800 may provide 2012 a "delivery accepted" message to command processor 1802. Upon receiving 2014 the "delivery accepted" message, command processor 1802 may update 2016 a controller (e.g., the controller discussed above and illustrated in FIG. 33) and execute delivery of the basal / bolus dose of infusible fluid 2018. Command processor 1808 may monitor and update 2022 the total amount of infusible fluid delivered to the user (as discussed above and illustrated in FIGS. 41A-41B). Once the appropriate amount of infusible fluid has been delivered to the user, command processor 1802 may provide 2024 a "delivery completed" message to supervisor processor 1800. Upon receiving 2026 the "delivery completed" message, supervisor processor 1800 may update 2028 the total amount of infusible fluid delivered to the user. If 2018 the total amount of infusible fluid delivered to the user is less than the amount defined above (in step 2004), the infusion process discussed above may be repeated (via loop 2030).

[0378] Referring also to FIG. 43, there is shown an example of how the supervisor processor 1800 and command processor 1802 may interact while achieving capacitance measurements via the capacitance sensor assembly 148 (as described above).

[0379] Specifically, command processor 1802 may initialize 2050 capacitive sensor assembly 148 and begin collecting 2052 data from capacitive sensor assembly 148, a process that may be repeated for each frequency utilized in the sinusoidal sweep. Each time data is collected for a particular sweep frequency, a data point message may be provided 2054 from command processor 1802, which may be received 2056 by supervisor processor 1800.

[0380] Once data collection 2052 is complete for the entire sinusoidal sweep, command processor 1802 may estimate 2058 the volume of infusible fluid delivered by infusion pump assembly 100. Command processor 1802 may provide 2060 a volume estimate message to supervisor processor 1800. Upon receiving 2062 this volume estimate message, supervisor processor 1800 may check (i.e., verify) 2064 the volume estimate message. Once checked (i.e., verified), supervisor processor 1800 may provide 2066 a verification message to command processor 1802. Once received 2068 from supervisor processor 1800, command processor 1802 may set a measurement state for the dose of infusible fluid delivered by volume sensor assembly 148.

[0381] Blockages and / or leaks can occur anywhere along the fluid delivery path of infusion pump assembly 100.

[0382] 44 , blockages / leaks may occur in the fluid path between reservoir 118 and reservoir valve assembly 614, in the fluid path between reservoir valve assembly 614 and pump assembly 106, in the fluid path between pump assembly 106 and volume sensor valve assembly 612, in the fluid path between volume sensor valve assembly 612 and volume sensor chamber 620, in the fluid path between volume sensor chamber 620 and measurement valve assembly 610, and in the fluid path between measurement valve assembly 610 and the tip of disposable cannula 138. Infusion pump assembly 100 may be configured to implement one or more blockage / leak detection algorithms to detect and locate such blockages / leaks and improve the safety / reliability of infusion pump assembly 100.

[0383] As discussed above, when administering infusible fluid, infusion pump assembly 100 may first determine the volume of infusible fluid in volume sensor chamber 620 before administration of the dose of infusible fluid, and later may determine the volume of infusible fluid in volume sensor chamber 620 after administration of the dose of infusible fluid. By monitoring these values, the occurrence of an occlusion / leak may be detected.

[0384] Occlusion-Complete: When a complete occlusion occurs, the difference between the initial measurement before administration of the dose of infusible fluid and the final measurement after administration of the dose of infusible fluid will be zero (or essentially zero), indicating a large amount of infusible fluid remaining in volume sensor chamber 620. Thus, no fluid may have exited volume sensor chamber 620.

[0385] Specifically, when the tip of the disposable cannula is occluded, the fluid path downstream of volume sensor chamber 620 fills with fluid and eventually becomes pressurized to a level equivalent to the mechanical pressure exerted by spring diaphragm 628. Thus, when measurement valve assembly 610 opens, zero (or essentially zero) fluid is dispensed, and therefore the values ​​of the initial and final measurements (as made by volume sensor assembly 148) are essentially equal.

[0386] Upon detecting the occurrence of such a condition, a total occlusion flag may be set and the infusion pump assembly 100 may, for example, trigger an alarm, thus indicating that the user should seek alternative means for receiving therapy.

[0387] Occlusion Type—Partial: When a partial occlusion occurs, the difference between the initial measurement before administration of the dose of infusible fluid and the final measurement after administration of the dose of infusible fluid indicates that less than a full dose of infusible fluid has been delivered. For example, assume that volume sensor assembly 148 indicates that 0.10 microliters of infusible fluid was present in volume sensor chamber 620 at the end of a particular pump cycle. Further assume that measurement valve assembly 610 is later closed, and pump assembly 106 is later actuated, filling volume sensor chamber 620 with infusible fluid. Further assume that volume sensor assembly 148 determines that volume sensor chamber 620 is now filled with 1.00 microliters of infusible fluid (indicating a pumped volume of 0.90 microliters).

[0388] Thus, upon opening of measurement valve assembly 610, the amount of infusible fluid contained within volume sensor chamber 620 is expected to drop to 0.10 microliters (or reasonably close thereto). However, in the event of a partial occlusion, due to a slower-than-normal flow rate from volume sensor chamber 620, the amount of infusible fluid in volume sensor chamber 620 may only be reduced to 0.40 microliters (indicating a delivered volume of 0.60 microliters). Thus, by monitoring the difference between the pumped volume (0.90 microliters) and the delivered volume (0.60 microliters), the residual volume may be defined, and the occurrence of a partial occlusion may be detected.

[0389] Upon detecting the occurrence of such a condition, a partial occlusion flag may be set and the infusion pump assembly 100 may, for example, trigger an alarm, thus indicating that the user should seek alternative means for receiving therapy. However, because this indicates a partial occlusion (as opposed to a complete occlusion), the issuance of the alarm may be delayed if the partial occlusion may clear on its own.

[0390] Alternatively, infusion pump assembly 100 may calculate the ratio of pump on-time to delivered volume and track it over time by using fast-moving and slow-moving exponential averages of pump on-time. The exponential averages may be tracked, as well as a leak sum integrator. Infusion pump assembly 100 may filter the signal to look for fast changes. The fluid outflow rate and / or residual volume may be monitored. If the residual volume does not change, there may be a complete occlusion. If the residual volume changes, there may be a partial occlusion. As a further alternative, the residual values ​​may be summed. If the number of valve actuations or latch time is changed, the fluid flow rate may be examined, even if pressure builds up in volume sensor assembly 148.

[0391] Fully / Partially Empty Reservoir: When the reservoir 118 is emptying, it becomes more difficult to fill the volume sensor chamber 620 to the desired level. Typically, the pump assembly 106 is capable of pumping 1.0 microliters per millisecond. For example, assume that the “empty” state of the volume sensor chamber 620 is 0.10 microliters and the “full” state of the volume sensor chamber 620 is 1.00 microliters. However, as the reservoir 118 begins to empty, the pump assembly 106 may have more difficulty filling the volume sensor chamber 620 to the “full” state and may consistently miss the target. Thus, during normal operation, it may take the pump assembly 106 one second to fill the volume sensor chamber 620 to the “full” state, and three seconds to fill the volume sensor chamber 620 to the “full” state as the reservoir 118 empties. Ultimately, if reservoir 118 is completely emptied, volume sensor chamber 620 may never achieve a "full" state. Thus, the inability of pump assembly 106 to fill volume sensor chamber 620 to a "full" state may indicate that reservoir 118 is empty. Alternatively, the occurrence of such a state may indicate other conditions (e.g., a malfunction of pump assembly 106, a blockage in the fluid path prior to volume sensor chamber 620). Infusion pump assembly 100 may determine the difference between the "full" state and the actual amount delivered. These differences may be summed and then accounted for once the reservoir condition is addressed.

[0392] Upon detecting the occurrence of such a condition, an empty flag may be set and the infusion pump assembly 100 may, for example, trigger an alarm, thus indicating to the user, for example, that the disposable housing assembly 114 needs to be replaced.

[0393] Additionally, as the reservoir 118 empties, the reservoir 118 may eventually develop a “vacuum” condition, impairing the ability of the pump assembly 106 to deliver fluid to the volume sensor chamber 620. As discussed above, the volume controller 1602 may include a feed forward controller 1652 to set an initial “guess” for the “on-time” signal 1606, where the initial guess is based on a pump calibration curve. For example, for the pump assembly 106 to deliver 0.010 units of infusible fluid, the feed forward controller 1652 may define an initial “on-time” of, for example, 1 millisecond. However, as the reservoir 118 begins to empty, it may take 2 milliseconds to deliver the 0.010 units of infusible fluid due to impaired pump conditions. Furthermore, as the reservoir 118 approaches a completely empty state, it may take 10 milliseconds to deliver the 0.010 units of infusible fluid. Thus, the occurrence of the reservoir 118 approaching an empty state may be detected by monitoring the level at which the actual operation of the pump assembly 106 (e.g., 2 seconds to deliver 0.010 units of infusible fluid) differs from the expected operation of the pump assembly 106 (e.g., 1 second to deliver 0.010 units of infusible fluid).

[0394] Upon detecting the occurrence of such a condition, a reserve flag may be set and the infusion pump assembly 100 may, for example, trigger an alarm, thereby indicating to the user, for example, that the disposable housing assembly 114 needs to be replaced immediately.

[0395] Leak Detection: In the event of a leak in the fluid pathway (e.g., a leaking valve or rupture / perforation), the fluid pathway's ability to hold fluid pressure may be compromised. Therefore, to check for leaks in the fluid pathway, a spill test may be performed in which pump assembly 106 is used to pressurize volume sensor chamber 620. Volume sensor assembly 148 may then perform a first volume measurement (as described above) to determine the volume of infusible fluid in volume sensor chamber 620. Infusion pump assembly 100 may then wait a defined period to allow spillage in the event of a leak. For example, after a 60-second spillage period, volume sensor assembly 148 may perform a second volume measurement (as described above) to determine the volume of infusible fluid in volume sensor chamber 620. If there is no leak, the two volume measurements should be essentially the same. However, in the event of a leak, the second measurement may be less than the first measurement. Additionally, depending on the severity of the leak, pump assembly 106 may be unable to fill volume sensor chamber 620. Typically, a leak check may be performed as part of the delivery of the infusible fluid.

[0396] If the difference between the first volume measurement and the second volume measurement exceeds an acceptable threshold, a leak flag may be set and the infusion pump assembly 100 may, for example, trigger an alarm, thus indicating that the user needs to seek alternative means for receiving therapy.

[0397] Referring to Figures 45 and 46, an exemplary embodiment of a split ring resonator antenna adapted for use in a wirelessly controlled medical device and used in an exemplary embodiment of an infusion pump assembly includes at least one split ring resonator antenna (hereinafter, "SRR antenna") 2508, a wearable electrical circuit such as a wirelessly controlled medical infusion device (hereinafter, "infusion device") 2514 capable of powering the antenna, and a control unit 2522.

[0398] In various embodiments, the SRR antenna 2508 may reside on the surface of a non-conductive substrate 2500, allowing one or more metal layers to resonate at a predetermined frequency. The substrate 2500 may be constructed from standard printed circuit board materials such as flame retardant 2 (FR-2), FR-3, FR-4, FR-5, FR-6, G-10, CEM-1, CEM-2, CEM-3, CEM-4, CEM-5, polyimide, Teflon®, ceramic, or flexible Mylar. The metal resonator comprising the SRR antenna 2508 may be made of two rectangular metal layers 2502, 2504, made of, for example, platinum, iridium, copper, nickel, stainless steel, silver, or other conductive materials. In various other embodiments, the SRR antenna 2508 may contain only one metal resonator.

[0399] In an exemplary embodiment, a gold-plated copper outer layer 2502 surrounds a gold-plated copper inner ring 2504 without physical contact. That is, the inner ring 2504 resides within a cavity 2510 (or opening) formed by the outer layer 2502. The inner ring 2504 may contain gaps or divisions 2506 along its surface, completely separating the material to form an incomplete ring shape. Both metallic resonators 2502, 2504 may reside on the same plane of the substrate 2500. In such a configuration, the outer layer 2502 may be driven, for example, via a transmission line 2512 coupled to the outer layer 2502. Additionally, in various other embodiments, the transmission line 2512 may be coupled to the inner ring 2504.

[0400] Antenna design software, such as AWR Microwave Office, capable of simulating electromagnetic geometry, such as antenna performance, may significantly reduce the time required to produce satisfactory dimensions compared to physically manufacturing and testing an antenna. Thus, using such software, an SRR antenna 2508 may be designed with resonator 2502, 2504 geometries facilitating an operating frequency of 2.4 GHz. FIG. 50 depicts example dimensions of the inner ring 2504 and outer layer 2502, and the positioning of the cavity 2510 in which the inner ring 2504 resides. The distance between the outer layer 2502 and the inner ring 2504 is a constant 0.005 inches along the circumference of the cavity 2510. However, in other embodiments, the distance between the outer layer and the inner ring may vary, and in some embodiments, the operating frequency may change.

[0401] In various embodiments, the SRR antenna 2508 may have dimensions such that it can be classified as electrically small, meaning that the largest dimension of the antenna is much smaller than one wavelength at the operating frequency.

[0402] In various other embodiments, SRR antenna 2508 may be constructed of one or more alternatively shaped metal outer layers, such as circular, pentagonal, octagonal, or hexagonal, surrounding one or more similarly shaped metal inner layers. Additionally, in various other embodiments, one or more metal layers of SRR antenna 2508 may contain gaps in the material, forming imperfect shapes.

[0403] Referring to Figure 48, an SRR antenna 2508 having an exemplary geometry exhibits acceptable return loss and frequency values ​​when placed in contact with human skin. Focusing on the band of interest represented by markers 1 and 2 on the graph as shown in Figure 48, the return loss before contact with human skin is approximately -15 dB while monitoring a frequency band centered at 2.44 GHz. The return loss during contact with human skin remains at a preferred value of approximately -25 dB at the same frequency, as shown in Figure 48A, resulting in approximately 97% transmitted power.

[0404] These results are particularly advantageous when compared to non-split ring resonator antenna types such as the Inverted-F. The return loss of an Inverted-F antenna may exhibit differences when the antenna contacts human skin, resulting in a lower percentage of power being transmitted outward from the antenna. As an example, as shown in FIG. 51, focusing again on the band of interest represented by markers 1 and 2 on the graph, the return loss of the Inverted-F antenna before contact with human skin is approximately -25 dB at frequencies centered at 2.44 GHz. The return loss during contact with human skin is approximately -2 dB at the same frequency, resulting in approximately 37% transmitted power.

[0405] (Integration with wireless medical devices) 50 and 46, one application of the SRR antenna 2508 may be integration into a wearable infusion device 2514 capable of delivering fluid medication to a user / patient 2524. In such an application, the safety of the user / patient depends on the fluid movement between these electrical components, and therefore reliable wireless transmission to and from the control unit 2522 is of great importance.

[0406] The infusion device 2514 may be worn directly on the human body. As an example, such a device may be attached on or above the hip joint in direct contact with the human skin, exposing the SRR antenna 2508 to the risk of unintentional dielectric loading, which would cause a frequency shift in electrical operation. However, in such applications, the electrical properties of the SRR antenna 2508, which reduce the antenna's susceptibility to nearby parasitic objects, are beneficial in reducing or eliminating performance degradation. A control component, such as a control unit 2522 (shown generally in FIG. 49 ), may be paired with the infusion device 2514 and may be designed to transmit and receive wireless signals to and from the infusion device 2514 at a predetermined frequency, such as 2.4 GHz. In an exemplary embodiment, the control unit 2522 serves as the primary user interface through which the patient or a third party may manage insulin delivery. In other embodiments, the infusion device 2514 may utilize an SRR antenna 2508 to communicate with one or more control units 2522.

[0407] In various embodiments, many different wireless communication protocols may be used in conjunction with the SRR antenna 2508, as the protocol and data types transferred are independent of the antenna's electrical characteristics. However, in exemplary embodiments, a bidirectional master / slave means of communication organizes data transfer through the SRR antenna 2508. The control unit 2522 may act as a master by periodically polling the infusion device 2514 or slave for information. In exemplary embodiments, the slave may transmit a signal to the control unit 2522 only when it is polled. However, in other embodiments, the slave may transmit a signal before being polled. Signals transmitted through this system may include, but are not limited to, control, alarm, status, patient treatment profile, treatment log, channel selection and negotiation, handshaking, encryption, and checksum. In some embodiments, transmission through the SRR antenna 2508 may also be stopped during certain infusion operations as an added precaution against electrical disruption of insulin delivery to the patient.

[0408] In an exemplary embodiment, the SRR antenna 2508 may be coupled to a power circuit via one or more pins 2516 on the transmission line 2512. In various other embodiments, the transmission line may comprise a wire, pairs of wires, or other controlled impedance methods that provide a channel through which the SRR antenna 2508 can resonate at a frequency. The transmission line 2512 may be on the surface of the substrate 2500 and may be constructed from the same material as the SRR antenna 2508, such as gold-plated copper. Additionally, a ground plane may be attached to the surface of the substrate opposite the transmission line 2512.

[0409] An electrical circuit coupled to the SRR antenna 2508 may apply an RF signal to the end of the transmission line 2512 nearest the circuit, generating an electromagnetic field throughout the SRR antenna 2508 and propagating from the SRR antenna 2508. The electrical circuit coupled to the SRR antenna 2508 promotes resonance at a predetermined frequency, such as 2.4 GHz. Preferably, both the transmission line 2512 and the SRR antenna 2508 have an impedance of 50 ohms to simplify circuit simulation and characterization. However, in various other embodiments, the transmission line and split-ring resonator antenna may have other impedance values ​​or different resonant frequencies.

[0410] 47 , signal processing components 2518, such as filters, amplifiers, or switches, may be integrated into the transmission line 2512 or may be at some point between the signal source connection pin 2516 and the SRR antenna 2508. In an exemplary embodiment, the signal processing components 2518 are bandpass filters that facilitate desired signal processing, such as allowing only exemplary frequencies to be transmitted to the antenna and rejecting frequencies outside that range. In an exemplary embodiment, a comb bandpass filter 2518 may be included in the transmission line 2512 between the antenna and the signal source. However, in other embodiments, any other signal processing devices may be included, such as, but not limited to, a filter, amplifier, or any other signal processing device known in the art.

[0411] In various embodiments, the SRR antenna 2508 may be constructed from a metal body capable of resonating on a flexible or rigid substrate. As shown in FIG. 46, an exemplary embodiment incorporates a curved SRR antenna on a flexible polyimide substrate 2520. Polyimide may be an exemplary material because it tends to be more flexible than alternative substrates. This configuration may allow for simplified integration into circular devices (such as wirelessly controlled medical infusion device 2514), devices with irregularly shaped external housings, or devices where space conservation is paramount.

[0412] In various embodiments, both the control unit 2522 and the base unit 2514 may incorporate a split SRR antenna 2508. This configuration may be beneficial when the control unit is intended to be handheld in close proximity to human skin, or may be in close proximity to a variety of materials with different dielectric constants.

[0413] In various embodiments, the SRR antenna 2508 may be integrated into a configuration of medical components in which one or more implantable medical devices operating within the human body communicate wirelessly to a handheld, body-mounted, or remote control unit. In an embodiment, both body-mounted and internal wireless devices may utilize the SRR antenna 2508 for wireless communication. Additionally, one or more of the components utilizing the SRR antenna 2508 may be completely surrounded by human skin, tissue, or other dielectric material. As an example, such a configuration may be used in conjunction with a cardiac monitoring / control system, where stability and consistency of wireless data transmission are fundamental concerns.

[0414] In various other embodiments, the SRR antenna 2508 may be integrated into an infusion pump assembly embodiment. In a medical component configuration, one or more electrical sensors positioned on or attached to the human body communicate wirelessly to a remote transceiver unit. As an example, multiple electrodes positioned on the body may be coupled to a wireless unit employing the SRR antenna 2508 for wireless transmission to a remotely located electrocardiogram machine. As an example, a wireless temperature sensor in contact with a person's skin may employ the SRR antenna 2508 for wireless communication to a controller unit for temperature regulation of the room in which the sensor resides.

[0415] The infusion pumps described herein contain a NITINOL, or shape memory alloy, actuated binary valve (measurement valve). This valve is actuated by applying an electric current to the NITINOL wire, which causes the wire to change phase, contract, and actuate the valve. It is desirable to minimize the time that electric current is applied to the NITINOL for many reasons, including, but not limited to, 1) minimizing power consumption, 2) minimizing cycle time, and 3) maximizing the cycle life of the NITINOL. Minimizing power consumption may extend battery life and therefore provide longer pump functionality between recharges. Maximizing the cycle life of the NITINOL extends the life of the reusable portion of the infusion pump and provides longer pump performance. Both of these may be desirable in closed-loop or semi-closed-loop systems as well as open-loop systems.

[0416] Normal operation of the pump involves, among other steps, the following steps: First, an initial volume measurement of the acoustic capacitance sensor chamber is taken using the acoustic capacitance sensor (AVS). Next, fluid is pumped from the reservoir into the AVS chamber using a pulse pump. Another measurement of the full AVS chamber is then taken. Next, the measurement valve is actuated, releasing fluid from the AVS chamber through the tubing set to the user / patient. Finally, a final AVS measurement is taken.

[0417] In various embodiments, the difference between the second and first AVS measurements is the pumped volume, which is the volume pumped into the AVS chamber. The difference between the second and third AVS measurements is the delivered volume, which is the volume delivered to the user / patient. The difference between the pumped volume and the delivered volume is the residual volume, which is the volume remaining in the AVS chamber after actuation of the measurement valve.

[0418] The measurement valve is actuated by allowing current to flow through the valve NITINOL wire at a given duty cycle and on-time. In an exemplary embodiment, the valve may be driven at a nominal 8% duty cycle, adjusted to compensate for supply voltage variations. In an exemplary embodiment, an on-time that is varied to minimize power is used to actuate the valve. However, in other embodiments, similar results may be achieved, for example, by varying the duty cycle instead of the on-time, or by using a combination of the two. The on-time is varied using an algorithm described below.

[0419] When the controller is initialized, the valve on-time t on is initially set to a low value below the minimum on-time required to actuate the valve (approximately 200 ms in some embodiments). Delivery is performed using steps #1 through #5 described above. Once these steps are completed, the following additional steps are taken: the residual volume is calculated, and if the residual volume is not close to 0, it is likely that the valve did not open. In this case, t on is increased (in the exemplary embodiment, t on is increased by a fixed 20 ms per iteration, although in other embodiments the increased on-time may vary), the valve opens, and steps #4 through #7 are repeated until either the residual volume is near zero or the maximum allowable valve on-time is reached.

[0420] The algorithm effectively increases the valve on-time enough (to within the on-time increment) to open the valve. However, it is conceivable that the required on-time may decrease over time or become unusually high during a given delivery. In this case, the valve on-time will increase to compensate, but will then remain high until the controller / algorithm is reset.

[0421] In exemplary embodiments, determining whether the AVS valve has been actuated longer than necessary may not be completed. Thus, in some embodiments, to compensate for this lack of determination, once the valve opens, the residual volume approaches zero, regardless of the extra open time. The valve controller then decreases the valve on-time with each delivery (in the exemplary embodiment, the decrease is 2 ms; however, in other embodiments, this decrease may be by a different amount). This allows the valve on-time to gradually decrease until it is insufficient to open the valve. At that point, the algorithm described above increases the valve on-time by a larger increment (e.g., 20 ms), and the process continues. The result is a control profile of the valve on-time that approaches the minimum required to open the valve. In these embodiments, the system uses a minimal amount of power to actuate the measurement valve. In exemplary embodiments, with reference to the controller described above, the volume sensor assembly monitors the amount of fluid infused by the infusion pump assembly. Thus, after infusion of fluid from the volume sensor chamber, the controller determines whether the infused volume is less than or more than the desired or planned volume for that pulse. The controller may then increase or decrease the volume delivered in a pulse or over a series of pulses. This includes, but is not limited to, the controller adding or subtracting a volume from one or more pulses of the upcoming planned delivery volume over a given period of time. Thus, embodiments of the fluid delivery system include a controller that calculates the volume of infusible fluid to be delivered and also, if necessary, recalculates the upcoming delivery volume based on the volume delivered in a given pulse. This ensures that the desired volume is delivered within a short period of time from a given pulse.

[0422] As discussed above, and referring for purposes of illustration to the delivery of insulin, various delivery volumes may be programmed or demanded at a given time, including, but not limited to, a regular bolus, an extended bolus, a combined bolus (i.e., a percentage of an extended bolus delivered as a regular bolus, followed by the remaining percentage delivered over a desired / demanded or predetermined period), and a basal rate (which in many embodiments may include one or more pre-programmed basal rates per 24 hour period).

[0423] A system for controlling the delivery of an infusible fluid includes a delivery trajectory, i.e., the volume of fluid to be delivered, whether basal, normal bolus, extended bolus, and / or combined bolus, and a schedule, i.e., when the various volumes are delivered. As discussed above, in exemplary embodiments, the controller includes a feedback mechanism. Thus, in some embodiments, the trajectory and delivery schedule may vary based on the volume sensor assembly-measured volume.

[0424] In exemplary embodiments, a constant or near-constant trajectory may be beneficial. A constant trajectory may be desirable for a number of reasons, including, but not limited to, maintaining a constant trajectory to eliminate or mitigate transients. Transients may be introduced into the system based on a mapping of joules applied to the shape memory actuator and the resulting volume delivered or measured by the volume sensor assembly. Over time, the mapping may change. Contributing factors that may change the mapping include, but are not limited to, temperature, reservoir volume, and / or time and use of the shape memory actuator. Therefore, it may be desirable to maintain a near-constant trajectory to eliminate the effects of variables that may be introduced and / or affect the system. Additionally, a constant trajectory creates additional opportunities for the controller to adjust the delivered volume in response to volume sensor assembly measurements.

[0425] In various embodiments of this delivery method and system, a trajectory is calculated based on delivery commands received by the system, which may include, for example, bolus, extended bolus, combined bolus, and basal. The interval between deliveries may be determined based on one or more of the following factors: 1) maximum pulse volume, 2) minimum pulse volume, 3) power consumption, and / or 4) minimum pulse interval. In exemplary embodiments, one or more factors may be considered. In various embodiments, the system determines the trajectory and, operating within the boundaries of the interval factor, determines the interval and volume of fluid delivery that satisfies the desired trajectory, in some embodiments with the preference that each delivery be of equal volume and that delivery be completed with as many equal-volume deliveries as possible (to allow for volume adjustment). Thus, while the interval may vary, in exemplary embodiments, the volume delivered per interval will be constant or close to constant.

[0426] In exemplary embodiments, with respect to bolus delivery, when determining the interval for delivery of the bolus volume, the system may determine a delivery schedule that will deliver the bolus volume as quickly as possible within system preferences (i.e., values ​​that may optimize system performance) and / or system constraints (i.e., minimum and maximum pulses and minimum and maximum intervals). For example, in exemplary embodiments, the system may include a maximum pulse delivery volume of 2.0 microliters and a minimum pulse delivery volume of 0.5 microliters. Additionally, in some embodiments, a minimum pulse interval of 6 minutes may be preferred. Thus, considering the maximum and minimum pulse volumes, along with the minimum interval, the system may determine an optimal schedule of delivery, i.e., the volume of each delivery (preference is for each scheduled volume to be equal) and the interval between each delivery.

[0427] In some embodiments, when determining the number of pulses to be delivered for a bolus volume, the system may adhere to delivering the bolus volume as quickly as possible, taking into account that each scheduled pulse for the bolus delivery is equal. However, in some embodiments, the system may determine the number of pulses to be delivered for a bolus volume by adhering to a set number of pulses, for example, 10. Then, taking this adherence into account, the system may determine the interval and volume of each pulse by dividing the bolus volume by 10. Thereafter, if the resulting delivered volume is less than the minimum delivered volume, for example, 0.5 microliters, the system may determine a schedule based on fewer than 10 pulses. If the resulting delivered volume is greater than the maximum delivered volume, for example, 2.0 microliters, the system may determine a schedule based on more than 10 pulses. Thus, in an exemplary embodiment, the system may adhere to a given number of pulses to deliver the required volume, but may decrease or increase the given number of pulses if the volume is less than the minimum pulse volume or greater than the maximum pulse volume. Note that while exemplary embodiments are described, this is for illustrative purposes only. In other embodiments, the system may have different compliance numbers for the number of pulses and / or differential values ​​for the minimum and maximum pulse volumes. Additionally, the exemplary intervals may also vary, so in some embodiments, the preferred intervals may be less than or greater than 6 minutes.

[0428] As discussed above, in addition to bolus scheduling, other delivery intervals, such as extended bolus, combined bolus, and basal, may also be determined with the desire for equal pulse volumes. Thus, while intervals may vary, as discussed above, the system may include a minimum interval, such as 6 minutes. With regard to basal delivery scheduling, in an exemplary embodiment, the schedule for a given basal rate delivery may be determined by first dividing the hourly rate by the desired interval (e.g., 6 minutes). For example, at a rate of 1 unit per hour (i.e., 10 microliters for U-100 insulin), the schedule may be one delivery of 1.0 microliter every 6 minutes, which is the same as 10 deliveries of 1.0 microliter per hour. As discussed above, in various embodiments, the system may include a volume per pulse maximum and minimum; thus, similar to the example given above with regard to bolus rate scheduling, if a volume minimum or maximum is reached, the number of pulses may be increased or decreased accordingly to maintain equal volumes per pulse. An example of a basal rate trajectory, as well as an example of a delivery schedule for that trajectory, is shown in Figures 53A-53B.

[0429] In addition to the delivery system and method embodiments described herein, if one or more delivery events are desired over a given time interval, i.e., during normal basal delivery, a bolus is requested. This scheduling embodiment is beneficial for many reasons, including, but not limited to, determining the volume attributable to basal and the volume attributable to bolus for purposes of other calculations, such as "insulin on board" calculations. For some embodiments of this exemplary embodiment, when a basal trajectory and scheduled delivery are in progress and a bolus is requested, the system may calculate a bolus schedule and then recalculate the basal schedule. For example, in some cases, for a single pulse, a portion of the pulse volume may be attributable to "bolus" and a portion to "basal," and for a given bolus delivery, with the basal in progress, the pulse may deliver an equivalent volume. Similar delivery schedules may be calculated for long-term boluses delivered in conjunction with the basal rate. Referring now to Figures 54A-54B, examples of basal and long-term bolus trajectories and delivery schedules for those trajectories are shown. The basal and long-term bolus delivery schedules may be determined by considering the time frame for the long-term bolus and the overlap rate for any basal. Unlike a normal bolus, in an exemplary embodiment, it may not be the goal of the system to deliver the long-term bolus "as quickly as possible," but rather it is delivered over a given period of time, given system constraints. Thus, the delivery schedule may be determined by first calculating an optimal schedule for the delivery of the long-term bolus, and then recalculating the basal delivery for the time frame of the long-term bolus, such that the basal and long-term bolus may be delivered in equal volume pulses over the time frame for the long-term bolus.

[0430] 55A-55B, examples of basal, long-term, and regular bolus trajectories and delivery schedules for the trajectories are shown. Combining the above discussion regarding scheduling the delivery of basal, regular, and long-term boluses, when all three are to be delivered during overlapping periods, FIGS. 55A-55B are examples of resulting schedules according to exemplary embodiments. As shown, the basal and long-term boluses may be delivered at a first interval, while the regular bolus may be delivered at a second interval, each of which includes an equivalent delivery volume.

[0431] Referring again to Figures 54A-54B and 55A-55B, it may be seen that even when composite volumes are delivered in single pulses of equal volume over overlapping time windows, the system may distinguish between volumes delivered as "basal" and volumes delivered as "bolus" (including chronic boluses). This distinction may be beneficial in calculating the amount of "on-board" bolus or basal; i.e., the time at which a specific volume of "basal" as opposed to a specific volume of "bolus" was delivered in Figures 54B and 55B allows for a more accurate calculation of insulin on-board, as insulin on-board is a calculation that depends on many factors, including the time and volume of delivery.

[0432] Various embodiments of the system may include various control loop algorithms for closed-loop or semi-closed-loop control methods. In some embodiments, the system includes a reference trajectory. As discussed above, the system follows this trajectory until one or more sensor data determines that the trajectory may be changed. In some embodiments, the trajectory change may be pre-programmed by the user / caregiver or may be governed by boundaries. As discussed above, the trajectory change may occur upon notification to the user, or in some embodiments, upon notification followed by confirmation by the user. In some embodiments, if the trajectory change may be responsive to unexpected results, the system may notify the user before shutting down the system.

[0433] Thus, in various embodiments, the control loop algorithm takes into account a physiological model (which may be adaptive from a reference model), data from at least one sensor, e.g., a CGM system, i.e., data representing interstitial fluid blood glucose levels, and the volume of medical fluid, e.g., insulin delivered, as well as a fingerstick, i.e., representing blood glucose levels.

[0434] In various embodiments, the estimator works in conjunction with the controller, which determines the amount of medical fluid or insulin to deliver based on the estimator's predictions, so that errors in the estimator provide erroneous delivery requests from the controller.

[0435] More importantly, an incorrect amount delivered by the controller (i.e., the controller requests delivery of 0.250 units and actually delivers 0.20 or 0.30 or some other amount higher or lower than the requested amount) alters the effectiveness of the estimator.

[0436] In various embodiments, the estimator interfaces with physiology to establish a "trajectory." The trajectory may be based on several factors and may be continually updated / modified. The trajectory uses CGM data (which may be checked or calibrated by fingerstick as discussed herein) and, in some embodiments, an established normalized or "reference" basal delivery schedule to 1) predict glucose values ​​and 2) determine delivery volume and schedule.

[0437] As discussed above, the trajectory may be constantly updated or changed based on actual CGM or fingerstick data (the fingerstick data may be used to confirm or calibrate the CGM data) and the actual volume of insulin delivered. Thus, in a control loop or semi-control loop system, both the data from the CGM / fingerstick and the actual volume of insulin delivered are important components to the system. If one or both of these values ​​are inaccurate, the system may not function as effectively as desired.

[0438] In some embodiments that use a pre-established or "reference" delivery trajectory, the pre-established trajectory may be referred to as the "outer loop" because the trajectory may include a basic "reference" delivery schedule (volume and time of delivery). The trajectory may be established using one or more constraints of the hardware, including, but not limited to, minimum and / or maximum stroke of the pump, optimal delivery pattern, and / or energy efficiency, i.e., battery life.

[0439] The actual trajectory may be modified in response to detected meals or inputs indicating the presence of factors or "events" that may affect insulin sensitivity, including, but not limited to, one or more inputs (via manual user input or sensor data) indicative of exercise (including duration and level or type), illness, dehydration, sleep, menstruation, and / or stress. Additionally, meals or carbohydrates being consumed by the user are also events that may affect or alter the trajectory. As discussed above, through calibration and profile recording and / or through sensor data, the system may anticipate one or more of these events.

[0440] Using the actual volume delivered as input to the estimator may achieve an accurately filled trajectory. Additionally, using the actual volume delivered may result in a more accurate and precise prediction algorithm. For example, if the controller requests insulin delivery and the actual volume delivered differs from the requested volume or the assumed volume to be delivered, the prediction algorithm may be inaccurate. Therefore, while it is desirable for the trajectory or outer loop itself to be as close to accurate as possible over its duration, even if the trajectory is correct, the trajectory will not be filled if the pump is unable to deliver the desired volume or at the desired time. This is an example of an actual trajectory that differs from the requested trajectory or outer loop.

[0441] Therefore, if the volume delivered by the pump is inaccurate or different from what was requested, the actual delivery versus trajectory may be very different. The inaccurate delivery may be the result of a pump error, an occlusion, and / or an air bubble in the fluid line, or other. In an exemplary embodiment, the system uses an AVS sensor and the methods described herein to accurately and precisely measure the volume of insulin delivered by the pump.

[0442] The ability to accurately and precisely determine the volume of insulin delivered accomplishes many aspects of a control loop system. As a non-limiting example, accurate and precise determination of the volume of insulin delivered feeds into accurate and precise determination of insulin on-board, or "IOB." Accurate estimation or determination of IOB is a factor in 1) accounting for delivery and 2) accurate delivery.

[0443] Also, in various embodiments described herein, accurate measurement of the volume of medical fluid / insulin delivered may enable more accurate and precise recognition of sensor failure or integrity problems of one or more sensors. For example, if the control system assumes that, for one or more CGM sensors, delivery of, say, two units of insulin is requested and the pump delivered two units, and then receives glucose data indicating an unexpected result as discussed above, the system may, in some embodiments, trigger a default shutdown. Thus, the system shuts down based on the “unexpected” CGM data. However, assuming that the pump actually delivered one unit rather than two units, and assuming the glucose data is consistent with one unit delivery, the CGM sensor did not cause an actual unexpected result, but rather a perceived unexpected result based on a lower-than-expected volume of insulin being delivered. Thus, precise and accurate determination of the volume of insulin (or other medical fluid) delivered may provide a more accurate and safer control loop system for the delivery of medical fluid therapy.

[0444] Furthermore, with respect to various embodiments described herein that use an AVS measurement sensor, the presence of blockages, air bubbles, and empty or partially empty reservoirs may be quickly and accurately determined. Again, this provides a more accurate determination of the actual volume of insulin delivered, as well as accurate detection of empty reservoirs, blockages, or air bubbles. Thus, the AVS measurement sensor provides a safer and more accurate control loop system for the delivery of medical fluid therapy. Furthermore, determining the presence of blockages, air bubbles, and empty or partially empty reservoirs may be extremely beneficial to the therapy and safety of the user.

[0445] Accurate determination of the volume of insulin delivered also achieves calibration of the system. Thus, with accurate measurements, the system may be more accurately calibrated and therefore may determine the unexpected outcome of an integrity failure sooner.

[0446] Therefore, various embodiments of the control loop include actual volume and trajectory volume. If the system includes an actual volume that is closest to the trajectory volume, the plasma and ISG estimates will be closer to the truth. This may lead to more accurate insulin sensitivity determination and calculation, as well as more accurate prediction algorithms.

[0447] While the principles of the invention have been described herein, it will be understood by those skilled in the art that this description is made by way of example only and not as a limitation on the scope of the invention. In addition to the exemplary embodiments shown and described herein, other embodiments are contemplated within the scope of the invention. Modifications and substitutions by those skilled in the art are considered to be within the scope of the invention.

Claims

[Claim 1] A system that meets clarity requirements, etc.

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