System, device, and method for blockage detection using pump operation measurement

Abstract

To provide a blockage detection system.SOLUTION: An injection device includes: a fluid chamber; a pump for controlling a suction dispensation stroke; a measuring device for generating a pump measurement value of each stroke; and a processing device for analyzing a plurality of pump measurement values of each stroke. The measuring device includes a current sensing device for detecting a pumping mechanism current in the stroke of a pumping cycle. The pump measurement value corresponds to the pumping mechanism current, and includes a pumping mechanism current of a plurality of selected pump cycles. A predetermined metric includes an average pumping mechanism current exceeding a designated current value higher than a pumping mechanism current average value with no blockage in the pump. The pump measurement value further corresponds to duration of the stroke, and the predetermined metric is selected duration longer than an average value of the pump measurement value with no blockage in the pump. The injection device includes integrated blockage sensing.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to systems, methods, and devices for occlusion detection. Exemplary embodiments of the invention relate to occlusion detection using pump operation parameters such as pump duration (e.g., aspiration stroke duration or dispense stroke duration) in rotary metering or reciprocating pumps, or pump operation monitoring switch actuation, to eliminate the need to add additional pressure sensing components. Pump motor current sensing may also be used to detect occlusion conditions in the pump. [Background technology]

[0002] Diabetes is a group of diseases characterized by high levels of blood sugar resulting from the inability of diabetic patients to maintain adequate levels of insulin production when needed.Diabetes can be dangerous to affected patients if it is not treated, which can lead to serious health complications and early death.However, such complications can be minimized by utilizing one or more treatment options to help control diabetes and reduce the risk of complications.

[0003] Treatment options for diabetic patients include special diets, oral medications, and / or insulin therapy. An effective method of insulin therapy and diabetes management is infusion therapy or infusion pump therapy, in which an insulin pump is used. Insulin pumps can provide continuous infusion of insulin to diabetic patients at various rates to more closely match the function and behavior of a properly functioning pancreas in a non-diabetic person that produces the required insulin, and the insulin pump can help diabetic patients maintain their blood glucose levels within a target range based on their individual needs. Infusion pump therapy requires an infusion cannula, typically in the form of an infusion needle or flexible catheter, that pierces the diabetic patient's skin and through which the insulin is infused. Infusion pump therapy offers the advantages of continuous infusion of insulin, precise dosing, and programmable delivery schedules.

[0004] Anomalies or faults, such as leaks, blockages, or the presence of air bubbles in the fluid path, may occur within an infusion pump and may not necessarily be perceptible to the user. Detection of faults, such as partial or complete blockages along the fluid path within the infusion pump, may be desirable to maintain precisely controlled drug delivery and advise the user to discontinue use of the improperly operating infusion device. A common solution to blockage detection is to place a pressure sensor within the infusion pump system and report a blockage when the pressure exceeds a certain threshold. However, adding a pressure sensor increases system complexity (e.g., increases mechanical complexity, electrical complexity, and / or software complexity), increases system power consumption, and increases the cost of the infusion pump.

[0005] For medical devices such as wearable drug delivery pumps, where some or all of the components are disposable for ease of use and cost effectiveness, it is undesirable to add another component, such as a pressure sensor, and the associated increased cost and complexity to the medical device. Thus, there is a need for accurate occlusion detection without adding infusion pump components, thereby increasing infusion pump complexity and cost. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2015 / 157174 Brochure Summary of the Invention [Means for solving the problem]

[0007] The above and other problems are overcome, and additional advantages are realized, by exemplary embodiments of the present invention.

[0008] It is an aspect of an exemplary embodiment to provide an infusion device with integrated occlusion sensing comprising: a pump comprising a chamber configured with at least one port for receiving fluid from a reservoir into the chamber and through which the fluid flows out of the chamber; and a pumping mechanism configured to control the intake of a predetermined amount of fluid into the chamber during an aspiration stroke and to control the dispense of a predetermined amount of fluid from the chamber during a dispense stroke; a pump measurement device configured to generate pump measurements of at least one of each aspiration stroke performed by the pump and each dispense stroke performed by the pump; and a processing device configured to analyze the pump measurements, including pump measurements for each of a plurality of the at least one of the aspiration strokes and the dispense strokes, and to determine when the pump measurements include a plurality of pump measurements that satisfy a predetermined metric specified as an indication of an occlusion.

[0009] In accordance with an aspect of an exemplary embodiment of the present invention, the infusion pump with integrated occlusion sensing further comprises an indicator, the processing device configured to operate the indicator as an occlusion alert in response to a determination that the plurality of pump measurements satisfy a predefined metric.

[0010] In accordance with an aspect of the exemplary embodiment of the present invention, the processing device is configured to automatically terminate operation of the pumping mechanism in response to a determination that the plurality of pump measurements satisfy a predefined metric.

[0011] According to aspects of an exemplary embodiment of the present invention, the pump measurements correspond to a duration of at least one of an aspiration stroke and a dispense stroke, and the predefined metric is a selected duration that is shorter than an average value of the pump measurements when no occlusion occurs within the pump.

[0012] According to an aspect of an exemplary embodiment of the present invention, the pump measurement device is an end stop switch on the pump configured to be actuated when the pumping mechanism completes at least one of an aspiration stroke and a dispense stroke, the end stop switch being connected to a processing device for determining the duration of each of the at least one of the aspiration stroke and the dispense stroke.

[0013] In accordance with aspects of an exemplary embodiment of the present invention, the pump measurements correspond to a duration of end stop switch actuation, and the predefined metric is a selected duration for end stop switch actuation that is longer than an average value of the pump measurements when no occlusion occurs within the pump.

[0014] According to aspects of an exemplary embodiment of the present invention, the infusion device with integrated occlusion sensing further comprises a current sensing device configured to detect a pumping mechanism current for a plurality of pump cycles during at least one of an aspiration stroke and a dispense stroke of such pump cycle. The pump measurements correspond to the pumping mechanism current, the pump measurements including the pumping mechanism current for a selected number of the plurality of pump cycles. The predefined metric includes an average pumping mechanism current exceeding a specified current value that is higher than an average value of the pumping mechanism current when no occlusion occurs in the pump. For example, the processing device can be configured to determine, for each of the plurality of pump cycles, an average pumping mechanism current of the aspiration stroke, and an average pumping mechanism current of the dispense stroke, and a difference between the average pumping mechanism current of the dispense stroke and the average pumping mechanism current of the aspiration stroke. The predefined metric can be a specified value for the difference that, when exceeded, indicates an occlusion.

[0015] According to aspects of an exemplary embodiment of the present invention, the pump measurement device is an end stop switch on the pump configured to be actuated when the pumping mechanism completes at least one of an aspiration stroke and a dispense stroke. The end stop switch is connected to a processing device to determine a duration of each of at least one of the aspiration stroke and the dispense stroke such that for a pump measurement corresponding to a duration of the end stop switch actuation, a predefined metric is a selected duration for the end stop switch actuation that is longer than an average value of the pump measurement when no occlusion occurs in the pump. The pump measurement includes at least two of the end stop switch actuation duration, the duration of at least one of the aspiration stroke and the dispense stroke, the time difference between the aspiration stroke and the dispense stroke, and the difference between an average pumping mechanism current of the dispense stroke and an average pumping mechanism current of the aspiration stroke. The predefined metric corresponding to the stroke duration is a selected duration that is shorter than an average value of the stroke duration when no occlusion occurs in the pump. The predefined metric corresponding to the dispense stroke duration difference relative to the aspiration stroke duration is a selected duration that is greater than an average value of the stroke duration difference when no occlusion occurs in the pump. The processing device is configured to analyze the pump measurements, including when the pump measurements include a plurality of pump measurements that satisfy corresponding ones of the predefined metrics.

[0016] According to aspects of an exemplary embodiment of the present invention, the pump measurements correspond to a time difference between an aspiration stroke and a dispense stroke, and a predefined metric corresponding to a dispense stroke duration difference relative to an aspiration stroke duration is a selected duration that is greater than an average value of the stroke duration difference when no occlusion occurs in the pump. According to aspects of an exemplary embodiment of the present invention, the pump measurements may also include a duration of at least one of the aspiration stroke and the dispense stroke, and the predefined metric corresponding to the stroke duration is a selected duration that is less than an average value of the stroke duration when no occlusion occurs in the pump. The processing device is configured to analyze the pump measurements and determine when the pump measurements include a plurality of pump measurements that satisfy a corresponding one of the predefined metrics.

[0017] It is an aspect of an exemplary embodiment of the present invention to provide a method of occlusion sensing in an infusion pump comprising operating a pump including a chamber configured with at least one port for receiving fluid from a reservoir into the chamber and through which fluid flows out of the chamber, and a pumping mechanism configured to control the intake of a predetermined amount of fluid into the chamber during an aspiration stroke and to control the dispense of a predetermined amount of fluid from the chamber during a dispense stroke; operating a pump measurement device to generate pump measurements of at least one of each aspiration stroke performed by the pump and each dispense stroke performed by the pump; and analyzing the pump measurements including the pump measurements for each of a plurality of the at least one of the aspiration strokes and the dispense strokes to determine when the pump measurements include a plurality of pump measurements that satisfy a predefined metric designated as an indicator of an occlusion.

[0018] In accordance with aspects of an exemplary embodiment of the present invention, the method of occlusion sensing further includes activating an indicator occlusion alert in response to determining that the plurality of pump measurements satisfy a predefined metric.

[0019] In accordance with aspects of an exemplary embodiment of the present invention, the method of occlusion sensing further includes automatically terminating operation of the pumping mechanism in response to a determination that the plurality of pump measurements satisfy a predefined metric.

[0020] According to aspects of an exemplary embodiment of the present invention, the method of occlusion sensing further includes operating a pump measurement device to generate a pump measurement corresponding to a duration of at least one of an aspiration stroke and a dispense stroke. For example, the method of occlusion sensing may use a predefined metric as a selected duration that is less than an average value of the pump measurements when no occlusion occurs in the pump.

[0021] According to aspects of an exemplary embodiment of the invention, the method of occlusion sensing further includes configuring the pump measurement device as an end-stop switch on the pump that is activated when the pumping mechanism completes at least one of an aspiration stroke and a dispense stroke, and connecting the end-stop switch to a processing device configured to analyze a signal from the end-stop switch to determine a duration of each of the at least one of the aspiration stroke and the dispense stroke.

[0022] In accordance with aspects of an exemplary embodiment of the present invention, the pump measurements correspond to a duration of end stop switch actuation, and the predefined metric is a selected duration for end stop switch actuation that is longer than an average value of the pump measurements when no occlusion occurs within the pump.

[0023] According to aspects of an exemplary embodiment of the invention, a method of occlusion sensing includes detecting a pumping mechanism current for a plurality of pump cycles during at least one of an aspiration stroke and a dispense stroke of such pump cycle. The pump measurements correspond to the pumping mechanism current. The pump measurements include the pumping mechanism current for a selected number of the plurality of pump cycles. The predefined metric includes an average pumping mechanism current exceeding a specified current value that is higher than an average value of the pumping mechanism current when no occlusion occurs in the pump. For example, analyzing the pump measurements may include determining, for each of the plurality of pump cycles, an average pumping mechanism current for an aspiration stroke, and an average pumping mechanism current for a dispense stroke, and a difference between the average pumping mechanism current for the dispense stroke and the average pumping mechanism current for the aspiration stroke. The predefined metric is a specified value for the difference that, when exceeded, indicates an occlusion.

[0024] According to aspects of an exemplary embodiment of the present invention, the method of occlusion sensing further includes configuring the pump measurement device as an end stop switch on the pump that is actuated when the pumping mechanism completes at least one of an aspiration stroke and a dispense stroke such that for pump measurements corresponding to a duration of the end stop switch actuation, the predefined metric is a selected duration for the end stop switch actuation that is longer than an average value of the pump measurements when no occlusion occurs in the pump. The pump measurements include at least two of the end stop switch actuation duration, the duration of at least one of the aspiration stroke and the dispense stroke, the time difference between the aspiration stroke and the dispense stroke, and the difference between an average pumping mechanism current of the dispense stroke and an average pumping mechanism current of the aspiration stroke. The predefined metric corresponding to the stroke duration is a selected duration that is shorter than an average value of the stroke duration when no occlusion occurs in the pump, and the predefined metric corresponding to the dispense stroke duration difference relative to the aspiration stroke duration is a selected duration that is greater than an average value of the stroke duration difference when no occlusion occurs in the pump. Analyzing the pump measurements includes determining when the pump measurements include a plurality of pump measurements that satisfy a corresponding one of the predefined metric.

[0025] According to aspects of an exemplary embodiment of the present invention, the pump measurements correspond to a time difference between an aspiration stroke and a dispense stroke, and a predefined metric corresponding to a dispense stroke duration difference relative to an aspiration stroke duration is a selected duration that is greater than an average value of the stroke duration difference when no occlusion occurs in the pump. The pump measurements may also include a duration of at least one of the aspiration stroke and the dispense stroke, and the predefined metric corresponding to the stroke duration is a selected duration that is less than an average value of the stroke duration when no occlusion occurs in the pump. Analyzing the pump measurements includes determining when the pump measurements include a plurality of pump measurements that satisfy a corresponding one of the predefined metrics.

[0026] Additional and / or other aspects and advantages of embodiments of the invention will be set forth in or will be apparent from the description that follows, or may be learned by practice of the invention. The invention may comprise a device and a method for operating the same having one or more of the above-described aspects and / or one or more of the features, and combinations thereof. The invention may comprise, for example, one or more of the features recited in the appended claims and / or combinations of the above-described aspects. [Brief description of the drawings]

[0027] The above and / or other aspects and advantages of embodiments of the present invention will be more readily appreciated from the following detailed description taken in conjunction with the accompanying drawings.

[0028] [Figure 1] 1 is a partial perspective view of an exemplary pump component within an exemplary drug delivery device operating according to an occlusion detection algorithm in accordance with an exemplary embodiment of the present invention. [Diagram 2] 1 is a partial perspective view of an exemplary pump component within an exemplary drug delivery device operating according to an occlusion detection algorithm in accordance with an exemplary embodiment of the present invention. [Figure 3A] 3 is a perspective view of the pump components of FIGS. 1 and 2 in an exemplary drug delivery device arranged according to a ready-to-dispense stage of operation. FIG. [Figure 3B] FIG. 3 is a perspective view of the pump components of FIGS. 1 and 2 in an exemplary drug delivery device arranged according to a ready-to-inhale stage of operation. [Figure 3C] FIG. 3 is a perspective view of components within an exemplary drug delivery device comprising the exemplary pump components of FIGS. 1 and 2 and associated electronic circuitry on a printed circuit board. [Figure 4] FIG. 1 is a block diagram of components within an exemplary drug delivery device. [Figure 5A]FIG. 13 illustrates pump duration times for multiple aspiration operations of an exemplary drug delivery device under normal operating conditions. [Figure 5B] FIG. 13 illustrates pump duration times for multiple dispense operations of an exemplary drug delivery device under normal operating conditions. [Figure 6A] FIG. 5C illustrates pump duration times for multiple aspiration strokes of the same type of drug delivery device used to generate FIGS. 5A and 5B but under occluded operating conditions. [Figure 6B] FIG. 5C illustrates pump duration times for multiple dispensing operations of the same type of drug delivery device used to generate FIGS. 5A and 5B but under occluded operating conditions. [Figure 7] 13 is a flow diagram of an example operation of an example drug delivery device operating according to an occlusion detection algorithm using stroke duration criterion in accordance with an example embodiment of the present invention. [Figure 8A] 1 is a graph illustrating exemplary end stop or limit switch actuation data during normal operation of an exemplary pump. [Figure 8B] 1 is a graph illustrating exemplary end stop or limit switch actuation data during occluded operation of an exemplary pump. [Figure 9] 13 is a flow diagram of an example operation of an example drug delivery device operating according to an occlusion detection algorithm using an end stop or limit switch actuation duration criterion in accordance with an example embodiment of the present invention. [Figure 10] 13 is a graph illustrating exemplary pump measurement data showing short dispense stalk durations (e.g., when the pump piston cannot move during an occlusion). [Figure 11] 13 is a graph illustrating exemplary pump measurement data illustrating extended end stop or limit switch actuation duration (eg, when an occlusion causes pumping back into the pump reservoir). [Figure 12A]13 is a graph showing pump measurement data from each pump showing long dispense stroke duration (eg, when leakage occurs due to blockage) versus aspiration stroke duration. [Figure 12B] 13 is a graph showing pump measurement data from each pump showing long dispense stroke duration (eg, when leakage occurs due to blockage) versus aspiration stroke duration. [Figure 12C] 13 is a graph showing pump measurement data from each pump showing long dispense stroke duration (eg, when leakage occurs due to blockage) versus aspiration stroke duration. [Figure 12D] 13 is a graph showing pump measurement data from each pump showing long dispense stroke duration (eg, when leakage occurs due to blockage) versus aspiration stroke duration. [Figure 13] 1 is a flow diagram of an example operation of an example drug delivery device operating according to an occlusion detection algorithm using leak detection criteria in accordance with an example embodiment of the present invention. [Figure 14] 13 is a flow diagram of an example operation of an example drug delivery device operating according to an occlusion detection algorithm using a combination of criteria in accordance with an example embodiment of the present invention. [Figure 15] 1 is a schematic diagram of a drug delivery device pump motor having a current sensor according to an exemplary embodiment of the present invention. [Figure 16] 11 is a flow diagram of an example operation of an example drug delivery device operating according to an occlusion detection algorithm using a pump motor current reference in accordance with an example embodiment of the present invention. [Figure 17A] 11A-11C are graphs depicting pump measurement data from respective exemplary delivery devices showing motor current during a dispense stroke before and after occlusion. [Figure 17B] 11A-11C are graphs depicting pump measurement data from respective exemplary delivery devices showing motor current during a dispense stroke before and after occlusion. [Figure 17C]11A-11C are graphs depicting pump measurement data from respective exemplary delivery devices showing motor current during a dispense stroke before and after occlusion. [Figure 17D] 11A-11C are graphs depicting pump measurement data from respective exemplary delivery devices showing motor current during a dispense stroke before and after occlusion. [Figure 17E] 11A-11C are graphs depicting pump measurement data from respective exemplary delivery devices showing motor current during a dispense stroke before and after occlusion. [Figure 18A] 11 is a graph showing average motor current for selected time periods for each exemplary delivery device. [Figure 18B] 11 is a graph showing average motor current for selected time periods for each exemplary delivery device. [Figure 18C] 11 is a graph showing average motor current for selected time periods for each exemplary delivery device. [Figure 18D] 11 is a graph showing average motor current for selected time periods for each exemplary delivery device. [Figure 18E] 11 is a graph showing average motor current for selected time periods for each exemplary delivery device. [Figure 19] 11 is a flow diagram of an example operation of an example drug delivery device operating according to an occlusion detection algorithm using a combination of criteria with a pump motor current criterion in accordance with an example embodiment of the present invention.

[0029] Throughout the drawing figures, like reference numbers will be understood to refer to like elements, features, and structures. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Reference will now be made in detail to the exemplary embodiments of the invention, which are illustrated in the accompanying drawings, in which the exemplary embodiments described herein are by way of illustration, rather than by way of limitation, of the invention.

[0031] Exemplary embodiments may be used with any type of infusion pump that functions on the principle of filling a chamber (e.g., with liquid drug from a reservoir) in one stage and then draining fluid from the chamber (e.g., into a delivery device such as a cannula deployed in a patient) in another stage. For example, a reciprocating plunger type pump or a rotary metering type pump can be used. In either case, the piston or plunger is retracted from the chamber to aspirate or draw drug into the chamber and allow the chamber to fill with a predetermined amount of drug (e.g., from a drug reservoir or cartridge into an inlet port). The piston or plunger is then reinserted into the chamber to dispense or expel the predetermined amount of drug from the chamber (e.g., via an outlet port) into a fluid path extending between the pump and a cannula in the patient.

[0032] For illustrative purposes, reference is made to the rotary metered-dose type pump described in commonly owned U.S. Patent Application Publication No. 2009 / 0133999, the contents of which are incorporated herein by reference in their entirety. With reference to Figures 1, 2, 3A, 3B, and 3C, an exemplary infusion pump (e.g., a wearable drug delivery device such as an insulin patch pump) includes a pump assembly 20 connectable to a DC motor and gearbox assembly (not shown) to rotate a sleeve 24 within a pump manifold 22. A helical groove 26 is provided on the sleeve. A coupling pin 28 connected to a piston 30 translates along the helical groove to guide the retraction and insertion of the piston 30 within the sleeve 24, respectively, as the sleeve 24 rotates in one direction and then the opposite direction. The sleeve has an end plug 34. The two seals 32, 36 on each end of the piston and end plug inside the sleeve 24 define a cavity or chamber 38 when the piston 30 is retracted following a suction stroke, as shown in FIG. 3A, and thus ready to dispense. Thus, the volume of the chamber 38 varies depending on the degree of retraction of the piston 30. As shown in FIG. 3B, when the piston 30 is fully inserted and the seals 32, 36 are in substantial contact with one another following a dispensing stroke, and thus ready to aspirate, the volume of the chamber 38 is negligible or essentially zero. Two ports 44, 46 are provided to the pump manifold 22, including an inlet port 44 through which drug can flow from a reservoir 70 (FIG. 4) for the pump 64 (FIG. 4), and an outlet port 46 through which drug drawn into the chamber 38 (e.g., by retraction of the piston 30 during the suction stage of operation) can be dispensed from the chamber 38, for example, from a fluid path to a cannula 72 (FIG. 4) in the patient, upon reinsertion of the piston 30 into the chamber 38.

[0033] 1, 2, 3A, 3B, and 3C, the sleeve 24 may include an aperture (not shown) that aligns with the outlet port 46 or the inlet port 44 to allow flow of drug in the chamber 38 through a corresponding one of the ports 44, 46 (i.e., depending on the degree of rotation of the sleeve 24 and thus the degree of translation of the piston 30). For example, a pump metering device 78 (FIG. 4) such as a sleeve rotary limit switch having an interlock 42 and one or more detents 40 on the sleeve 24 or its end plug 34 that cooperate with the interlock 42 may be provided. The interlock 42 may be attached to the manifold 22 at each end thereof. When the pump 64 is in a first position whereby a side hole in the sleeve 24 is aligned with the inlet port 44 to receive fluid from the reservoir 70 into the chamber 38, the detents 40 on the end face of the sleeve 24 abut the ridges 48 of the interlock 42. Under certain conditions, such as back pressure, it is possible that friction between the piston 30 and sleeve 24 may be sufficient to rotate the sleeve 24 before the piston 30 and coupling pin 28 reach both ends of the helical groove 26. This may result in an incomplete amount of liquid being pumped with each stroke. To prevent this situation, the interlock 42 prevents the sleeve 24 from rotating until the torque passes a predefined threshold, as shown in FIG. 3A. This ensures that the piston 30 rotates completely within the sleeve until the coupling pin reaches the end of the helical groove 26. Once the coupling pin 28 hits the end of the helical groove 26, further movement by a DC motor and gearbox assembly or other type of pump and valve actuator 66 (FIG. 4) increases the torque on the sleeve 24 beyond the threshold, bending the interlock 42 and forcing the detent 40 past the ridge 48. Upon completion of rotation of sleeve 24 such that its side hole is oriented with cannula 72 or exit port 46, detent 40 moves over bump 48 in interlock 42, as shown in FIG. 3B.Another sleeve feature may be provided for engaging an electrical switch (e.g., an end stop switch 90 provided on a printed circuit board 92 and disposed relative to the sleeve and / or end plug 34 to cooperate with the pump measurement device 78, as shown in FIG. 3C).

[0034] FIG. 4 is an exemplary system diagram illustrating exemplary components in an exemplary drug delivery device 10 having an infusion pump, such as the pumps of FIGS. 1, 2, 3A, 3B, and 3C. The drug delivery device 10 can include an electronics subsystem 52 for controlling the operation of components in a fluidics subsystem 54, such as a pump 64 and an insertion mechanism 74 for deploying a cannula 72 for insertion into an infusion site on a patient's skin. The power storage subsystem 50 can include, for example, a battery 56 for providing power to the components in the electronics subsystem 52 and the fluidics subsystem 54. The fluidics subsystem 54 can include, for example, an optional fill port 68 for filling the reservoir 70 (e.g., with a drug), although the drug delivery device 10 can optionally be shipped from manufacture with its reservoir already filled. The fluidics subsystem 54 also has a metering subsystem 62 that includes a pump 64 and a pump actuator 66. As explained above, the pump 64 can have two ports 44, 46 and associated valve subassemblies that control when fluid enters and leaves the pump chamber 38 through the respective ports 44, 46. One of the ports is an inlet port 44 through which fluid, such as a liquid medication, flows from a reservoir 70 into the pump 64 as a result of a pump suction or pull stroke on the pump plunger or piston 30. The other port is an outlet port 46 through which fluid flows out of the pump chamber 38 towards the cannula 72 for administration to the patient pump as a result of a pump release or push stroke on the pump plunger or piston 30. The pump actuator 66 can be a DC motor and gearbox assembly or other pump drive mechanism for controlling the plunger or piston 30 and other associated pump components such as the sleeve 24, which may rotate relative to the translational movement of the pump piston 30.The microcontroller 58 may include an integrated or separate memory device having computer software instructions for actuating, for example, the rotation of the sleeve 24 in a selected direction, the translational or axial movement of the piston 30 within the sleeve 24 for an aspiration or dispense stroke, and, optionally, the rotation of the sleeve 24 and piston 30 together during valve state changes, as described in the above-referenced '617 patent. As described below, an occlusion detection algorithm according to an exemplary embodiment can be provided to the microcontroller 58 to monitor pump measurements and detect when an occlusion operating condition occurs for the infusion pump.

[0035] Regardless of the type of pump mechanism 64 used to aspirate a controlled amount of drug into and dispense a controlled amount of drug from the pump chamber 38, the pump 64 has associated with it an expected pump duration for one or both of the aspiration and dispense stages or strokes that can be attributed to pump characteristics. For example, in the exemplary pump assembly 20 shown in Figures 1, 2, 3A, 3B, and 3C, the pump duration for aspirating drug into and dispensing drug from the chamber 38 is affected by pump characteristics such as the internal volume of the pump chamber 38, the length or distance of the pump piston stroke, the characteristics of the port seals provided at the inlet and output ports 44, 46, etc. When the pump pressure is within a specified relative normal range for operation, the pump duration to fill chamber 38 with a specified amount of fluid (e.g., a desired dose) and expel a specified amount of fluid from the chamber can be determined and used as a baseline for monitoring pump 64 under normal operating conditions to determine when an abnormal operating condition occurs due to leakage of fluid from the pump chamber or a blockage in the pump fluid path whereby in either scenario the specified amount of fluid (e.g., a desired dose) cannot be delivered from the chamber via a dispense stroke. This can be undesirable as the patient would not receive the desired dose.

[0036] As mentioned above, a common solution for occlusion detection is to place an additional pressure sensor in the pump control system and report an occlusion when the pressure rises above a certain threshold. However, adding a pressure sensor has the disadvantage of increasing system complexity (e.g., mechanical complexity, electrical complexity, and / or software complexity), increasing system power consumption, and / or increasing pump costs. These disadvantages may be particularly detrimental to wearable pump designs where all or part of the pump is intended to be disposable once the reservoir 70 is emptied or the pump 64 has been used for a selected amount of time and / or to deliver a selected amount of drug.

[0037] According to an exemplary embodiment, occlusion detection is accomplished without additional components, such as occlusion sensors deployed upstream or downstream of pump 64. When microcontroller 58 or other processing device for controlling pump operation already performs pump duration measurements for normal operation, such as for one or both of the aspiration and dispense strokes, microcontroller 58 is further controllable to determine when the pump duration measurements fall outside of a specified range for normal operating conditions and thus indicate an occlusion, and generate an indication of the detected occlusion. Thus, pump 64 and / or the entire drug delivery device 10 can then be replaced or repaired, thereby ensuring that the patient is receiving the full intended dose provided under normal operating conditions.

[0038] When pump duration measurements are implemented for pump operation, occlusion detection can be achieved by adding operations such as monitoring pump duration and determining when a specified pump duration threshold or other criteria for normal pump operation conditions is not met to the computer software instructions of the microcontroller 58, or a remote device controlling the drug delivery device 10. Thus, occlusion detection is implemented via a software solution and no hardware changes to the pump are required. As explained below, a clear difference in pump duration exists between a normal pump and an occluded pump. Thus, the false alarm rate and error rate are extremely low. Thus, an occlusion detection algorithm configured according to aspects of an exemplary embodiment can provide a reliable occlusion detection result.

[0039] Determining the pump duration threshold or range of values ​​or other metrics indicative of blockage can be performed empirically, for example, for a selected type of pump 64. The metrics for a selected type of pump experiencing normal operating pressures can be compared to metrics for the same type of pump except it is experiencing at least partial or complete blockage. For example, a blockage in the downstream path from a blocked pump 64 to its cannula 72 will increase pressure in the fluid path of the pump 64 over time. When the pressure in the blocked pump exceeds a threshold, the blocked pump will eventually begin to leak. Log files of normal and blocked pumps can be generated to capture a history of their respective pump duration information for aspirate and / or dispense strokes. However, it should be understood that different pump measurements other than pump duration (i.e., duration of aspirate or dispense stroke) can be used to determine differences in pump operation during normal and blocked operating conditions, as well as to determine thresholds for monitoring pump operation and distinguishing between normal and blocked operating conditions. For example, as described below, a long stroke switch activation termination or a significant difference in the respective durations of the aspirate and dispense strokes can be used to detect the occurrence of an occlusion.

[0040] 5A and 5B, the pump duration of the pump that experienced an occlusion (e.g., about 1.5 seconds on average) is significantly shorter than the pump duration of the pump 64 when it is operating under normal conditions (e.g., on the order of 3-3.5 seconds), and the phenomenon of shorter pumping duration is related to the pumping mechanisms, such as the piston 30, sleeve 24, interlock 42, and silicone seals on the inlet and outlet ports 44, 46, described above in connection with FIGS. 1, 2, 3A, 3B, and 3C. As described above, different types of pumps 64 can be improved by implementing occlusion sensing according to exemplary embodiments, and different pump components can contribute to a shortened pump during an occlusion condition. The pump 64 can be a rotary metering type pump or a reciprocating type pump, or other type of pump that uses drawing or aspirating fluid from an upstream reservoir and then expelling or dispensing the fluid into a separate downstream fluid path leading to the patient.

[0041] With reference to the exemplary infusion pump 64 described above in connection with FIGS. 1, 2, 3A, 3B, and 3C, the pump's suction and dispensing strokes, driven by the translation of the piston 30 within the outer plastic sleeve 24, are associated with switching of the pump 64 between the upstream and downstream fluid paths. As the piston 30 is rotated (e.g., by a DC motor and gearbox assembly, not shown), the piston 30 translates through the sleeve 24 guided by the progression of the pin 28 on the piston through a helical slot 26 in the sleeve 24. Once the piston 30 has fully translated through the sleeve 24 and completed its suction or dispensing stage of fluid, it engages the sleeve 24 directly via the pin 28 in the slot 26, coupling the rotation of the piston 30 and the sleeve 24. This allows the sleeve 24 to rotate between the upstream and downstream fluid paths and actuate an end of stroke electrical switch 90 or other component provided on the pump 64 and / or within the drug delivery device 10, associated with a pump measurement device 78 (FIG. 4). During normal operation, the presence of interlock 42 prevents the piston 30 and sleeve 24 rotations from coupling before the piston 30 completes its translation through the sleeve 24. However, if pressure in the downstream fluid path increases above a threshold, the piston 30 and sleeve 24 rotations couple, allowing the sleeve 24 to pass under interlock 42 and activate switch 90 (e.g., via sleeve feature 41 associated with pump measurement device 78) before the piston 30 completes its translation through the sleeve. This reduces pump duration significantly (e.g., from between 3 to 3.5 seconds during normal conditions to less than 2 seconds during occluded conditions).

[0042] Reference is now made to Figures 6A and 6B, which show pump duration data from multiple similar type pumps 64 over multiple pump cycles. For example, log data from 19 pumps that completed 600 complete cycles are shown, with 10 of the pumps operating under normal conditions and 9 of the pumps operating under occluded conditions. It can be seen from Figures 6A and 6B that all of the occluded pumps have sections of pump duration less than 2 seconds. Some pump durations returned to normal, which may be due to a release of pressure from leaking in the manifold area. The apparent difference in pump duration between normally operating pumps and pumps that experienced occlusion allows for the use of an occlusion detection algorithm based on pump duration.

[0043] With reference to FIG. 7, an exemplary occlusion detection process includes setting a pump measurement threshold or metric, such as a stroke duration threshold (block 80), where a stroke duration above the threshold indicates normal pump operation and a stroke duration below the threshold indicates an occlusion. To set the threshold, pump measurement data is analyzed. For example, aspiration stroke duration and dispense stroke duration can be detected by a limit switch or other pump measurement device 78 (FIG. 4) provided in the pump. In the exemplary pump described with reference to FIGS. 1, 2, 3A, 3B, and 3C, the stroke or pump duration is determined using a sleeve rotation limit switch or other pump measurement device 78. For example, the microcontroller 58 and other electronic components, such as an end stop switch 90 that cooperates with the sleeve feature 41, can be deployed on a printed circuit board (PCB) 92 generally associated with the pump 64 or delivery device 10. End stop switch actuation data can be collected and stored (e.g., via a memory device integrated with the microcontroller 58 or embodied as a separate component on the PCB 92). The microcontroller 58 can include an occlusion detection algorithm for processing the endstop switch actuation data to determine if an occlusion has occurred. According to another exemplary embodiment, the endstop switch actuation data can be provided (e.g., wirelessly or via a wireline connection) from the pump 64 to another device having an occlusion detection algorithm, such as a handheld remote controller for the pump 64 or a non-dedicated computing device (e.g., a mobile phone, a personal computer (PC), a laptop computing device, or other portable computing device) that includes software or an app that includes the occlusion detection algorithm.

[0044] Pump measurement data is obtained for one or more of the same type of pumps operating under normal conditions and for one or more of the same type of pumps operating under occluded conditions, as shown above in Figures 5A and 5B and 6A and 6B. The pump measurement data for these two groups of pumps can be averaged or summarized or categorized and then analyzed to determine the degree of difference between the pump measurements for the normally operating pumps and the occluded pumps. A threshold or other metric is determined to be above and / or below a value or range of values ​​within a margin that does not include the normal pump measurements. The value or range of values ​​and / or margin can be specified by a user or can be automatically determined based on the pump measurement data obtained from the pump. As explained above, the pump measurement data is generated and monitored during the course of normal pump activity and is therefore data that does not require additional components that increase the complexity of the pump, not added operations.

[0045] 7, once the pump measurement metric (e.g., stroke duration threshold) is set, the microcontroller 58 in the drug delivery device 10 is controlled by the occlusion detection algorithm to obtain pump measurement data (e.g., stroke duration data) for the pump (block 81) and compare the stroke duration data to the pump measurement metric during various pump stages or cycles of operation for each pump cycle, etc. (block 82). stroke If the stroke duration data fails to meet a pump measurement metric (e.g., falls below an occlusion detection threshold (e.g., a Th of 2 seconds for pump 64), then the pump is determined to be operating normally (block 84). stroke When the counter is greater than or equal to the threshold Th for normal operation, the pump is determined to be experiencing a blockage condition.stroke is not met, is incremented (block 83). Referring to block 85, the counter is incremented to a selected value (e.g., a threshold value Th for normal operation). stroke An occlusion is detected when the counter reaches a counter value of 8, which corresponds to 8 pump cycles where the counter value is not met. The total number of cycles the selected number of cycles is reached before an occlusion is indicated can be specified, such as 8 consecutive cycles of 8 cycles, or within a specified number of cycles (e.g., 20 cycles). The microcontroller 58 can be configured by the occlusion detection algorithm to generate an optional indication of a detected occlusion error (block 86) and to automatically cease operation of the pump and / or drug delivery device 10 and / or to generate an optional indication to the user to cease using the pump (block 88). If the counter has not yet reached the selected counter value after being incremented per block 83, pump measurement data continues to be collected per block 81. Since the occlusion detection algorithm is based on pump duration or other pump measurement data already implemented in the pump, occlusion detection is accomplished by checking the pump duration or other measurement data in the software against a selected threshold or metric. Thus, a software-only solution is provided for detected occlusion, obviating the need for hardware modifications.

[0046] The exemplary pump 64 described in connection with Figures 1, 2, 3A, 3B, and 3C uses one or more on / off limit switches to determine the state of the system at the limits of rotational travel. For example, a multi-stage pump (i.e., a pump that aspirates fluid to fill a chamber during one stage and then discharges the pump chamber in the next stage) may use some type of end-stop switch for each stage to detect when the piston and / or sleeve or other pump components reach a predefined position corresponding to a full aspiration or dispense position. However, it should be understood that different mechanisms or other pump measurement devices 78 can be used to determine pump measurements (e.g., pump duration) other than the interlock 42 and sleeve rotation limit switch (e.g., end-stop switch) 90. Alternatively, the pump 64 may use one or more optical sensors or encoders with optical switches to determine the position of the pump components at their respective end-stop positions for full aspiration and / or dispense.

[0047] Thus, with reference to FIG. 7 and in accordance with an exemplary embodiment of the invention, as described, a determination of the time required to fill the chamber and the time required to expel a desired amount of fluid from the chamber is performed, the expel time of at least each stroke is measured, and further, when a selected number of expel times fail to exceed a specified amount (e.g., stroke duration shortens over a specified number of pump cycles), an indication is generated to indicate that an occlusion has been detected.

[0048] According to another exemplary embodiment, occlusion detection is performed by monitoring the duration of actuation or triggering of a pump end stop or limit switch, as described below with reference to Figure 9. Processing monitored data related to the detected duration of actuation or triggering of a pump end stop or limit switch to determine if an occlusion in pump 64 has occurred can be performed alone or in combination with monitoring for short pump stroke durations, as described above with reference to Figure 7.

[0049] As explained above, during normal operation, the presence of interlock 42 prevents piston 30 and sleeve 24 rotation from coupling before piston 30 completes its translation through sleeve 24. However, when pressure in the downstream fluid path increases (i.e., during occlusion), piston 30 and sleeve 24 rotation can couple early. That is, sleeve 24 rotates early before the intended rotation during a valve state change, e.g., when sleeve 24 rotates without axial motion at the end of a full piston stroke to align its side ports with corresponding ones of ports 44, 46 during normal operation of the pump. This early rotational coupling of piston 30 and sleeve 24 then allows sleeve 24 to pass under interlock 42 and trigger switch 78 before piston 30 completes its axial translation through the sleeve. This significantly reduces pump duration (e.g., measured as the time period or duration between pump motor activation and end stop switch signal), as explained above in connection with FIG. 7. Additionally, another pump operating characteristic that may be monitored for occlusion detection is the duration that the pump measurement device 78 and its associated switch 90 are in an actuated or triggered mode of operation or indicate the beginning of an actuated state.

[0050] In some instances, pump duration in an occluded pump system may remain normal and may not decrease as expected. Thus, monitoring for another pump measurement parameter or characteristic increases occlusion detection accuracy. For example, while the pump sleeve 24 rotates early as expected due to an occlusion in the pump system, the piston may begin to advance and dispense the fluid payload into the upstream fluid path as soon as the pump sleeve opens to the upstream fluid path (and prior to the end-of-stroke signal from the switch 90). Since both the piston 30 and the sleeve 24 can rotate through their full range of angular positions, the total pump operation time remains constant both with and without occlusion. Meanwhile, now the end-stop switch 90 has been triggered for an extended period of time as the piston 30 is rotating and translating through the sleeve 24 after the sleeve has rotated on the upstream channel. Thus, occlusion detection may include monitoring or triggering for a long or extended end-stop of limit switch actuation separately or in addition to monitoring for a shortened pump stroke duration according to an exemplary embodiment.

[0051] To further illustrate how actuation or triggering of the pump measurement device may be delayed as a result of an occlusion, reference is made to an exemplary pump 64 described by the exemplary embodiment shown in Figures 1, 2, 3A, 3B, and 3C. During normal pump 64 operation, when the end stop switch 90 is initially struck and dragged by the pump sleeve 24 (e.g., via the sleeve feature 41 engaging the end stop switch 90), and thus triggered, the end stop switch 90 causes a drop in its end stop switch voltage signal provided to the microcontroller 58 from 1.8V to 0V. Only when the switch 90 is released (e.g., by disengaging the sleeve feature 41) and springs back to center does it reset the end stop switch voltage back to 1.8V. In some examples, when the side port of the sleeve 24 opens into the upstream fluid path (e.g., aligned with the input port 44), before the piston 30 completes its axial translation and before the end stop switch 90 is disengaged by the sleeve feature 41, and when the pressure in the upstream fluid path is low, the piston 30 can begin to advance and translate through the sleeve 24, draining the pump contents into the upstream fluid path while the end stop switch 90 is in the mid-trigger state. The net result is that an end stop switch 90 actuation signal (e.g., voltage drop) occurs for an extended period of time. This pump occlusion characteristic is illustrated in Figures 8A and 8B, which show a typical duration of switch 90 actuation (e.g., 0 volts) of less than 0.5 seconds and an extended end stop or limit switch 90 actuation (e.g., 0 volts) of approximately 1.5 seconds, respectively.

[0052] There are several reasons why some pumps 64 may exhibit a shorter overall pump duration (e.g., piston 30 fails to advance) while some pumps 64 may exhibit an increased end stop switch 90 actuation signal duration (e.g., as piston 30 advances on the upstream fluid path). For example, alignment of switch 90 on PCB 92 with associated pump components (e.g., interlock 42, detents 40, and sleeve features 41) may allow some variability in which sleeve angular position releases end stop switch 90 and thus when the end stop switch actuation signal is generated and provided to microcontroller 58. Additionally, high pressure in the upstream fluid path from a larger insulin reservoir fill volume may prevent piston 30 from advancing on the upstream fluid path (e.g., resulting in a shorter pump duration), while lower pressure in the upstream fluid path from a lower insulin reservoir fill volume may allow piston 30 to advance on the upstream fluid path (e.g., resulting in a longer or extended end stop or limit switch actuation or "trigger" duration).

[0053] 9, an exemplary occlusion detection process includes setting a pump measurement threshold or metric, such as a switch actuation duration threshold (block 96), where a switch actuation duration below the threshold indicates normal pump operation and a switch actuation duration above the threshold indicates an occlusion. To set the threshold, pump measurement data can be analyzed. For example, several identical pumps 64 can be tested with similar occlusion conditions to collect pump measurement data related to an indicated significant increase in the duration of a pump measurement parameter, such as an end-stop switch signal voltage drop, when the pump is occluded. In the case of an exemplary empirical measurement for the pump 64 in FIGS. 1, 2, 3A, 3B, and 3C, the switch actuation duration during occlusion was measured to be approximately 1.5 seconds, which corresponds to the expected amount of time for the piston 30 to fully translate through the sleeve 24. Thus, the occlusion detection algorithm logs the end-stop switch 90 signal duration according to software instructions (e.g., in the microcontroller 58) and compares the logged switch 90 actuation duration to a threshold (e.g., Th switch>1.0 seconds) to determine whether an occlusion is present or absent, as shown in block 98 of FIG. 9 . End stop switch actuation data or pump limit switch actuation data can be collected and stored (e.g., via a memory device integrated with the microcontroller 58 or implemented as a separate component on the PCB 92). The microcontroller 58 can include an occlusion detection algorithm for processing the end stop switch actuation data to determine if an occlusion has occurred. According to another exemplary embodiment, the end stop switch actuation data can be provided (e.g., wirelessly or via a wireline connection) from the pump 64 to another device having an occlusion detection algorithm, such as a handheld remote controller for the pump 64 or a non-dedicated computing device (e.g., a mobile phone, personal computer (PC), laptop computing device, or other portable computing device) that includes software or an app that includes an occlusion sensing algorithm. The switch actuation duration data for the occluded pump can be averaged or summarized or categorized and then analyzed to determine the degree of difference between similar pump measurements for a normally operating pump and the pump measurements for the occluded pump. A threshold (e.g., Th switch ,) or other metrics are determined to be above and / or below a value or range of values ​​within a margin that normal pump measurements do not fall within. The value or range of values ​​and / or margins can be specified by a user or can be determined automatically based on pump measurement data obtained from the pump. As discussed above, pump measurement data such as switch actuation duration is generated and monitored during the course of normal pump activity and thus is data that does not require additional components that increase the complexity of the pump.

[0054] 9, once the pump measurement metric (e.g., switch actuation duration threshold) is set, the microcontroller 58 within the drug delivery device 10 is controlled by the occlusion detection algorithm to obtain pump measurement data (e.g., switch actuation duration data) for the pump 64 (block 97) and compare the switch actuation duration data to the pump measurement metric during various pump stages or cycles of operation for each pump cycle, etc. (block 98). switch If the switch actuation duration data fails to satisfy a pump measurement metric (e.g., an occlusion detection threshold Th of 1.0 seconds), the pump is determined to be operating normally (block 100). switch When the counter is greater than the threshold Th for normal operation, the pump is determined to be experiencing a blockage condition. switch is not satisfied, the counter is incremented (block 99). Referring to block 101, the counter is incremented to a selected value (e.g., Th for normal operation). switchAn occlusion is then detected when the counter reaches a counter value of 8, which corresponds to 8 pump cycles where the counter value is not met. The total number of cycles the selected number of cycles is reached before an occlusion is indicated can be specified, such as 8 consecutive cycles of 8 cycles, or within a specified number of cycles (e.g., 20 cycles). The microcontroller 58 can be configured by the occlusion detection algorithm to generate an optional indication of a detected occlusion error (block 102), automatically cease operation of the pump 64 and / or the drug delivery device 10, and / or generate an optional indication to the user to cease using the drug delivery device 10 (block 104). If the selected counter value has not yet been reached after the counter has been incremented per block 99, pump measurement data continues to be collected per block 97. Since the occlusion detection algorithm is based on pump duration data or other pump measurement data already implemented in the pump, occlusion detection is accomplished by checking the pump duration or other measurement data in the software against a selected threshold or metric. Thus, a software-only solution is provided for detected occlusion, obviating the need for hardware modifications.

[0055] According to another exemplary embodiment of the present invention, a third pump characteristic is monitored to detect blockages in the drug delivery device 10, as described below in connection with FIG. 13. For example, testing a selected pump 64 under blockage conditions revealed that if blockages occur when the drug delivery device 10 was new, the pump 64 tended to have short stroke durations or long end stop durations, as described above in connection with FIG. 7 and FIG. 9, respectively. However, after the pump went through many cycles, the testing data showed that it tended to leak at the joint area 49 between the manifold seal 47 and the sleeve 24, as shown in FIG. 3B. The reason there was excessive leakage after certain pump cycles was likely a combination of seal wear and tear caused by repetitive pumping motion and high internal pressure caused by blockage. In other words, when the pump 64 was new and the seal 47 was strong enough to tolerate the high pressures brought about by blockages, the pump likely exhibited short stroke durations or long end stop durations (e.g., long limit switch actuation durations) during blockages. However, after several pump cycles, the seals are not strong enough to tolerate the high pressures caused by the occlusion, and the pump 64 may leak through the weakest link in the downstream fluid path, which may be the seal 49 between the manifold 47 and the sleeve 24. Because the fluid in the pump chamber 38 is forced through the leak path by the high internal pressure caused by the occlusion, the pump motor (not shown) is required to provide more energy to push the fluid out. As a result, the dispense stroke duration during the occlusion is longer than in normal operation.

[0056] 12A, 12B, 12C, and 12D show some examples from bench occlusion testing of selected types of pumps, such as pump 64, described with reference to FIGS. 1, 2, 3A, 3B, and 3C. FIGS. 12A, 12B, 12C, and 12D show long dispense durations associated with leakage caused by occlusion. For four drug delivery devices 10, each plot in FIGS. 12A, 12B, 12C, and 12D corresponds to one drug delivery device 10. Each drug delivery device 10 was filled with, for example, 300 U fluid and delivered with 50 U open, 2 U clamped, and 2 U open. From these plots, it can be seen that when the drug delivery device 10 is occluded, the dispense stroke duration increases, but the aspiration stroke duration remains relatively the same. Thus, this pump characteristic can be used to detect leakage caused by occlusion.

[0057] In accordance with aspects of an exemplary embodiment of the present invention, the occlusion detection algorithm described above may use the pump duration difference between the dispense stroke and the aspiration stroke. For example, referring to block 108 of FIG. 13, a stroke difference threshold (Th delta ) can be determined as follows:

[0058] Step 1: At the end of loading,

[0059]

number

[0060] Calculate the average duration difference between the aspirate and dispense strokes, defined as:

[0061] where n is the number of strokes used to obtain the average difference. By way of example, n=3 is used for the exemplary embodiment, but it should be understood that this number may vary depending on the specific pump design.

[0062] Step 2: For each pump cycle after loading, collect pump measurement data (e.g., the duration difference between the aspiration and dispense strokes) for the pump 64 (block 109) and compare the duration difference data to pump measurement metrics (block 110), e.g., as follows:

[0063] 1) Calculate the duration difference: Di = Dispense - Aspirate

[0064] 2) Subtract D0 from Di: D'i = Di - D0

[0065] 3) As shown in block 110 of FIG. 13, check whether D'i, D'i-1, and D'i-2 are less than a given threshold (e.g., 0.13 seconds). If yes, normal pump operation may continue per block 112 of FIG. 13. If not, a leak may be detected and the pump may be determined to be experiencing a clogged condition. The counter is counted up to the threshold Th for normal operation. delta is not satisfied, the counter is incremented (block 111). Referring to block 113, the counter is incremented to a selected value (e.g., Th for normal operation). delta When the counter reaches a counter value of 8 (corresponding to 8 pump cycles where D is not satisfied), an occlusion is detected, an occlusion indicator can be generated per block 114, and pump operation can be terminated per block 116. If the counter has not yet reached the selected counter value after being incremented per block 111, pump measurement data continues to be collected per block 109. The total number of cycles that the selected number of cycles is reached before an occlusion is indicated can be specified, such as 8 consecutive cycles of 8 cycles, or within a specified number of cycles (e.g., 20 cycles). In an exemplary embodiment, three consecutive dispense strokes are used, but this number may vary over time depending on variations in pump duration. Duration difference D 0,1,…,xare averaged or summarized or categorized and then a threshold or other metric Th between the pump measurements for normally operating pumps and the pump measurements for blocked pumps is determined. delta The measurements can be analyzed to determine the extent of the difference (eg, aspiration stroke and dispense stroke duration difference) with respect to the time course of the measurements.

[0066] The occlusion detection algorithm may include the leak detection criteria described with FIG. 13 in combination with the stroke duration criteria described with FIG. 7 and / or the end stop or limit switch actuation duration criteria described with FIG. 9 according to other exemplary embodiments. For example, detection using all three of the criteria or only a single criterion or a subset of these three criteria can be performed in parallel or sequentially using occlusion detection software provided to the microcontroller 58 or to a controller of a separate device associated with the drug delivery device 10. Additional exemplary data for the stroke duration criteria is shown in FIG. 10 and additional exemplary data for the switch actuation duration criteria is shown in FIG. 11. Referring to FIG. 14, an exemplary occlusion detection algorithm according to an exemplary embodiment uses a combination of the stroke duration criteria described with FIG. 7, the end stop or limit switch actuation duration criteria described with FIG. 9, and the leak detection criteria described with FIG. 13. The counter for the detected occlusion condition is cleared or set to a zero value (block 120). As shown in block 122, pump cycles are detected (i.e., aspiration and dispense strokes are detected, for example, using endstop switch actuation data). Pump measurement data, such as stroke duration, endstop duration, and average duration difference between aspiration and dispense strokes during loading, as described with reference to FIG. 9, are collected (block 124). The stroke duration difference is determined (i.e., subtract the average duration difference during loading from the duration corresponding to the dispense stroke duration being shorter than the aspiration stroke duration (block 126). The dispense stroke duration reduction (e.g., a Th of 2 seconds) per block 128 is calculated. stroke (shorter than 1 second), or an end stop switch activation duration extension per block 132 (e.g., Th switch ), or stroke duration difference per block 134 (e.g., Th deltaIf an abnormal pump operation condition is detected, such as an abnormal pump operation condition (e.g., a difference greater than 0.01, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83

[0067] For example, the leak detection criteria described above with the occlusion detection algorithm in connection with FIG. 13 was applied to bench occlusion data collected from 280 drug delivery devices 10 in combination with a short stroke duration algorithm (e.g., described above with respect to blocks 80 and 82 of FIG. 7) and a long endstop duration algorithm (e.g., described above with respect to blocks 96 and 98 of FIG. 9). Table 1 shows a comparison without and with the leak detection algorithm described with respect to blocks 108 and 110 of FIG. 13. It can be seen that the leak detection algorithm (e.g., blocks 108 and 110 of FIG. 13) significantly improved the detection rate of proper occlusion by the occlusion detection algorithm according to an exemplary embodiment of the present invention. However, it slightly increases the false positive rate.

[0068] [Table 1]

[0069] Of the 280 drug delivery devices 10, there were 120 that delivered a 10U bolus prior to clamping. The manifold seals 49 in these drug delivery devices 10 were minimally used. Table 2 shows a comparison of this group of drug delivery devices 10 without and with a leak detection algorithm. From Table 2, it can be seen that when the manifold seals 49 were minimally used, the occlusion detection rate was extremely high, 88%, even without the leak detection algorithm added to the occlusion detection algorithm using stroke duration measurements and / or analysis of long end stop duration pump measurements. These results are consistent with leaks being caused in large part by wear and tear of the manifold seals after repetitive pumping motions.

[0070] [Table 2]

[0071] Thus, the leak detection criteria can be implemented within the occlusion detection algorithm. No hardware modifications are required since the algorithm only requires pump duration information to analyze the leak detection criteria. The occlusion detection algorithm using the leak detection criteria is improved when implemented with the stroke duration criterion and / or the end stop switch actuation duration criterion to more completely capture all significant pump behavior during occlusion.

[0072] According to yet another exemplary embodiment, the pump motor current is used to detect occlusion. Under normal functioning conditions, the drug delivery device 10 aspirates from a reservoir 70 at the upstream of the fluid path and dispenses into the patient's body at the end of the downstream fluid path. During the aspirating stroke, the piston opens the pump chamber, which allows fluid from the reservoir to fill the chamber. During the dispensing stroke, the piston closes the pump chamber, which pushes the fluid downstream. Figures 3A and 3B show an exemplary piston and pump chamber.

[0073] When the drug delivery device 10 is occluded, the piston cannot vent the fluid inside the pump chamber downstream. As a result, the pump can 1) retain the fluid in the pump chamber, 2) pump the fluid to a reservoir, or 3) the fluid can be forced to leak through the pump's manifold seal. Because it takes more energy to pump the fluid to any of these three paths, the motor current is higher during the dispense stroke when an occlusion occurs. Thus, the motor current can be used to detect an occlusion.

[0074] 15 shows an exemplary apparatus for motor current sensing. A sensing resistor 142 is added to the PCB 92 to enable motor current measurement. The voltage drop across the sensing resistor 142 is provided to an analog-to-digital converter (ADC) of the microcontroller 58. An occlusion condition is then calculated by the microcontroller 58, and an occlusion event is reported by the microcontroller 58, for example, when a specified occlusion signature is detected. Other components can be used for current sensing to facilitate pump motor current measurement. For example, in the case of a pulse-width modulated (PWM) driven motor used as the pump actuator 66, motor current information can be extrapolated from the PWM data.

[0075] An exemplary occlusion detection algorithm for each pump cycle is described below with reference to FIG. 16. A counter for detected occlusion conditions is cleared or set to a zero value (block 150). The motor current is determined during the suction stroke of the pump cycle (block 152). For example, at the start of the suction stroke, the motor current is recorded via the microcontroller 58 during the suction stroke. in Using (t), where t is a time referring to the start of this stroke, at the end of the suction stroke (e.g., when an end-stop signal is detected), the microcontroller 58 calculates the average motor current A as follows: inIt is programmable to be determined between 1 second and 2.5 seconds with respect to the start of the motor current. A in =mean[x in (t), 1 second < t < 2.5 seconds]

[0076] It should be understood that other methods of determining the motor current during the pump cycle or the suction stroke or the dispensing stroke can also be used.

[0077] The motor current is also determined during the dispensing stroke of the pump cycle (block 154). For example, at the start of the dispensing stroke, the microcontroller 58 records the motor current during the dispensing stroke. x out (t) is used, where t is the time referring to the start of this stroke. However, at the end of the dispensing stroke (for example, when the corresponding end stop signal is detected), the microcontroller 58, as follows, the average motor current A out It is programmable to be determined between 1 second and 2.5 seconds with respect to the start of the motor current. A out =mean[x out (t), 1 second < t < 2.5 seconds]

[0078] Referring to block 156 of FIG. 16, the microcontroller 58 is configured to calculate the motor current difference (D) between the suction stroke and the dispensing stroke represented by D, where D = A out -A in is.

[0079] When the difference (D) is greater than the specified threshold Th iDiff (block 158), the counter is incremented (block 160). Referring to block 162, when the counter reaches the selected value (for example, the threshold Th for normal operation iDiffWhen the counter reaches a counter value of 3, corresponding to 3 pump cycles where D is not met, an occlusion is detected, an occlusion indicator can be generated per block 164, and pump operation can be terminated. It should be understood that the counter value can be other than 3 to specify a different number of cycles that the pump current exceeds the threshold before an occlusion is indicated as detected. If the counter has not yet reached the selected counter value after being incremented per block 160 (block 162), pump measurement data (e.g., motor current) continues to be collected per block 152. Thus, if the maximum pump cycle and several consecutive previous pump cycles have a D value greater than the given threshold, an occlusion is indicated. Otherwise, normal operation of the pump continues.

[0080] Figures 17A-17E each show the motor current during pre- and post-occlusion dispense strokes measured from five respective exemplary delivery devices 10. Figures 17A-17E show a clear difference in motor current between a normal and an occluded pump stroke, facilitating the use of an occlusion detection algorithm based on motor current, such as the algorithm described above in connection with Figure 16.

[0081] 18A through 18E show the average motor current from 1 second to 2.5 seconds (i.e., measured over a duration of 1 to 2.5 seconds after the stroke begins, where t=0 is the start of the stroke), respectively. Again, there is a clear difference between the occluded strokes shown in FIGS. 18A through 18E and normal strokes. Thus, the occlusion occurs when the threshold Th iDiff can be detected by applying

[0082] With continued reference to Figures 16, 17A-17E, and 18A-18E, an alternative approach may rely only on the average motor current for the dispense stroke and not the aspiration stroke, in which case the calculation of the average motor current for the aspiration stroke and D = Aout-Ain would not be required. For example, such an alternative algorithm may include the following operations: The motor current is determined during the dispense stroke of the pump cycle. For example, at the start of the dispense stroke, microcontroller 58 records the motor current during the dispense stroke. x out (t), where t is a time referring to the beginning of this stroke, at the end of the dispense stroke (e.g., when the corresponding end stop signal is detected), the microcontroller 58 will calculate the average motor current A, as described above in connection with FIG. out can be programmed to determine the average motor current A between 1 and 2.5 seconds relative to the start of the motor current. out is the specified threshold Th Aout If the counter is greater than a selected value (e.g., Th for normal operation), the counter is incremented. Aout When the counter reaches a counter value of 3, corresponding to 3 pump cycles where the threshold is not met, an occlusion is detected, an occlusion indication can be generated, and pump operation can be terminated. It should be understood that the counter value can be other than 3 to specify a different number of cycles where the pump current exceeds a threshold before an occlusion is indicated as detected. If, after the counter has been incremented, the selected counter value has not yet been reached, pump measurement data (e.g., motor current) continues to be collected. Using motor current data from both the aspiration and dispense strokes, as described above in conjunction with FIG. 16, however, may be more robust in terms of, for example, sensitivity and accuracy of occlusion detection using motor current.

[0083] With reference to FIG. 19, the occlusion detection algorithm may include the motor current criteria described with FIG. 16 in combination with other criteria used to detect an occlusion. For example, the exemplary occlusion detection algorithm according to the exemplary embodiment in FIG. 19 uses a combination of the motor current criteria described with FIG. 16 with the stroke duration criteria described with FIG. 7, the end-stop switch actuation duration criteria or the limit switch actuation duration criteria described with FIG. 9, and the leak detection criteria described with FIG. 13. A counter for a detected occlusion condition is cleared or set to a zero value (block 170). As shown in block 172, a pump cycle is detected (i.e., an aspiration stroke and a dispense stroke are detected, for example, using end-stop switch actuation data). Pump measurement data is collected (block 174), such as stroke duration, end-stop duration, and the average duration difference between the aspiration stroke and the dispense stroke during loading, and the average motor current during each of the aspiration stroke and the dispense stroke, as described with reference to FIG. 9. The stroke duration difference is determined (i.e., subtract the average duration difference during loading from the duration corresponding to the dispense stroke duration being shorter than the aspiration stroke duration (block 176). The difference in average motor current (D) for the dispense stroke compared to the aspiration stroke is also calculated (block 178). The dispense stroke duration reduction (e.g., 2 seconds Th stroke (shorter than 1 second), or an end stop switch activation duration extension per block 182 (e.g., Th switch ), or stroke duration difference per block 184 (e.g., Th delta (difference greater than Th) or a specified threshold value per block 186 iDiffIf an abnormal pump operating condition is detected, such as a difference in average motor current between dispense and aspiration strokes greater than ., a counter is incremented (block 192). When the counter reaches a selected value per block 194 (e.g., a counter value of 8 corresponding to 8 pump cycles where the threshold for normal operation is not met), for example, an occlusion is detected per block 196 and an occlusion indication can be generated and / or pump operation can be terminated. If none of these occlusion conditions are met, the counter remains cleared (e.g., a 0 value) per block 190, the next pump cycle is detected, and associated pump timing or measurement data is collected per block 172. It should be understood that one or more of blocks 180, 182, 184, and 186 and their corresponding pump measurement data collection or calculation can be omitted to achieve an alternative exemplary algorithm using the remaining ones of blocks 180, 182, 184, and 186. Those skilled in the art will appreciate that the present disclosure is not limited in its application to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings.

[0084] The embodiments herein are capable of other embodiments and can be implemented or performed in various ways. It will also be understood that the phraseology and terminology used herein is for the purpose of description and should not be considered limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and their equivalents as well as additional items. Unless otherwise limited, the terms "connected," "coupled," and "attached" and variations thereof herein are used broadly to encompass direct and indirect connections, couplings, and attachments. Furthermore, the terms "connected" and "coupled" and variations thereof are not limited to physical or mechanical connections or couplings. Furthermore, terms such as above, below, below, and top are relative and are used to aid in the description and are not limiting.

[0085] Components of the exemplary devices, systems, and methods used in accordance with the illustrated embodiments of the invention may be implemented at least partly in digital electronic circuitry, analog electronic circuitry, or in computer hardware, firmware, software, or combinations of these. These components may be implemented as a computer program product, such as a computer program, program code, or computer instructions tangibly embodied in an information carrier or machine-readable storage device for execution by, or to control the operation of, a data processing apparatus, such as a programmable processor, a computer, or multiple computers.

[0086] The computer program may be written in any type of programming language, including compiled or interpreted languages, and may be deployed in any type, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. The computer program may be deployed to be executed on one computer, or on multiple computers at one site, or distributed across multiple sites and interconnected by a communication network. Also, functional programs, codes, and code segments for achieving the exemplary embodiments of the present invention may be readily interpreted as being within the scope of the present invention by a programmer skilled in the art to which the present invention pertains. Method steps associated with the exemplary embodiments of the present invention may be executed by one or more programmable processors that execute computer programs, codes, or instructions to perform functions (e.g., by acting on input data and / or generating output). For example, the method steps may also be executed by special purpose logic circuitry, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), as which the apparatus of the exemplary embodiments of the present invention may be implemented.

[0087] The various example logic blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in association with a DSP core, or any other such configuration.

[0088] Processors suitable for executing computer programs include, by way of example, both general purpose and special purpose microprocessors, and any one or more processors of any kind of digital computer. In general, a processor will receive instructions and data from a read-only memory or a random access memory, or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. In general, a computer will also include one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, or will be operatively coupled to receive data from or transfer data to them, or both. Information carriers suitable for embodying computer program instructions and data include, by way of example, semiconductor memory devices, such as electrically programmable read-only memories or ROMs (EPROMs), electrically erasable programmable ROMs (EEPROMs), flash memory devices, and non-volatile memories of any type, including data storage disks (e.g., magnetic disks, internal hard disks, or removable disks, magneto-optical disks, and CD-ROM disks, and DVD-ROM disks). The processor and memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0089] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0090] Those skilled in the art will further appreciate that the various exemplary logic blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability of hardware and software, the various exemplary components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in various ways for each particular application, and such implementation decisions should not be interpreted as causing a departure from the scope of the present invention. The software modules may reside in a random access memory (RAM), flash memory, ROM, EPROM, EEPROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, such that the processor can read information from and write information to the storage medium. Alternatively, the storage medium may be integral to the processor. In other words, the processor and the storage medium may reside within an integrated circuit or may be implemented as discrete components.

[0091] The non-transitory computer-readable medium includes any type of computer-readable medium, including magnetic storage media, optical storage media, flash media, and solid-state storage media. It should be understood that the software can be installed in and sold with a central processing unit (CPU) device. Alternatively, the software can be obtained and loaded into the CPU device, including obtaining the software through a physical medium or a distributed system, including, for example, from a server owned by the software creator or from a server used but not owned by the software creator. The software can be stored on a server, for example, for distribution over the Internet.

[0092] The description and figures presented above are intended as examples only and are not intended to limit the present invention in any manner except as set forth in the following claims. It is specifically noted that those skilled in the art can easily combine various technical aspects of the various elements of the various exemplary embodiments described above in numerous other ways, all of which are considered to be within the scope of the present invention.

Claims

1. a pump comprising a chamber configured with at least one port for receiving fluid from a reservoir into the chamber and for fluid to flow out of the chamber, and a pumping mechanism configured to control the aspiration of a predetermined amount of the fluid into the chamber during an aspiration stroke and to control the dispensing of a predetermined amount of fluid from the chamber during a dispense stroke; a pump measurement device configured to generate a pump measurement of at least one of each dispense stroke performed by the pump and each aspiration stroke performed by the pump; a processing device configured to analyze pump measurements, including the pump measurements for each of a plurality of the at least one of the aspiration stroke and the dispense stroke, and determine when the pump measurements include a plurality of the pump measurements that satisfy a predefined metric designated as an indicator of an occlusion; Equipped with the pump measurement device comprises a current sensing device configured to detect a pumping mechanism current for a plurality of pump cycles during at least one of the aspiration stroke and the dispense stroke of such pump cycle; the pump measurement corresponds to the pumping mechanism current; the pump measurements include the pumping mechanism current for a selected number of the plurality of pump cycles, and the predefined metric includes an average pumping mechanism current exceeding a specified current value that is higher than an average value of the pumping mechanism current when no occlusion occurs in the pump; the pump measurements further correspond to a duration of at least one of the aspiration stroke and the dispense stroke, the predefined metric further comprising a selected duration that is greater than an average value of the pump measurements when no occlusion occurs within the pump; The processing device is further configured to determine, for each of a plurality of pump cycles, an average pumping mechanism current of the aspiration stroke, and an average pumping mechanism current of the dispense stroke, and a difference between the average pumping mechanism current of the dispense stroke and the average pumping mechanism current of the aspiration stroke, the predefined metric further including a designated value for the difference that, when exceeded, indicates an occlusion. An infusion device with integrated occlusion sensing.

2. The infusion device with integrated occlusion sensing of claim 1 , further comprising an indicator, wherein the processing device is configured to operate the indicator as an occlusion alert in response to a determination that a plurality of the pump measurements satisfy the predefined metric.

3. The infusion device with integrated occlusion sensing of claim 1 , wherein the processing device is configured to automatically terminate operation of the pumping mechanism in response to a determination that a plurality of the pump measurements satisfy the predefined metric.

4. 2. The infusion device with integrated occlusion sensing of claim 1, wherein the pump measurement further corresponds to a duration of a dispense stroke in a plurality of the dispense strokes.

5. 2. The infusion device with integrated occlusion sensing of claim 1, wherein the pump measurements further correspond to the duration of at least one of the aspiration stroke and the dispense stroke, and the predetermined metric is a selected duration that is shorter than an average value of the pump measurements when no occlusion occurs in the pump.

6. 2. The infusion device with integrated occlusion sensing of claim 1, wherein the pump measurement device comprises an end stop switch on the pump configured to be activated when the pumping mechanism completes the at least one of the aspiration stroke and the dispense stroke, the end stop switch connected to the processing device to determine the duration of each of the at least one of the aspiration stroke and the dispense stroke.

7. The infusion device with integrated occlusion sensing of claim 6, wherein the pump measurements correspond to a duration of endstop switch actuation, and the predefined metric further includes a selected duration for endstop switch actuation that is longer than an average value of the pump measurements when no occlusion occurs in the pump.

8. the pump measurement device comprises an end stop switch on the pump configured to be actuated when the pumping mechanism completes the at least one of the aspiration stroke and the dispense stroke, the end stop switch being connected to the processing device for determining a duration of each of the at least one of the aspiration stroke and the dispense stroke, such that for pump measurements corresponding to a duration of an end stop switch actuation, the predefined metric further comprises a selected duration for an end stop switch actuation that is longer than an average value of the pump measurements when no occlusion occurs in the pump; the pump measurements include at least two of the end stop switch actuation duration, the duration of the at least one of the aspiration stroke and the dispense stroke, the time difference between the aspiration stroke and the dispense stroke, and the difference between the average pumping mechanism current of the dispense stroke and the average pumping mechanism current of the aspiration stroke, the predefined metric corresponding to a stroke duration is a selected duration that is shorter than an average value of the stroke duration when no occlusion occurs in the pump, and the predefined metric corresponding to a dispense stroke duration difference relative to aspiration stroke duration is a selected duration that is greater than an average value of the stroke duration difference when no occlusion occurs in the pump, and the processing device is configured to analyze the pump measurements and determine when the pump measurements include a plurality of the pump measurements that satisfy corresponding ones of the predefined metrics.

10. The infusion device with integrated occlusion sensing of claim 1.

9. 2. The infusion device with integrated occlusion sensing of claim 1, wherein the pump measurement corresponds to a time difference between the aspiration stroke and the dispense stroke, and the predetermined metric corresponding to a dispense stroke duration difference relative to aspiration stroke duration is a selected duration that is greater than an average value of the stroke duration difference when no occlusion occurs in the pump.

10. 2. The infusion device with integrated occlusion sensing of claim 1, wherein the pump measurements also include a duration of at least one of the aspiration stroke and the dispense stroke, and the predefined metric corresponding to the stroke duration is a selected duration that is shorter than an average value of the stroke duration when no occlusion occurs in the pump, and the processing device is configured to analyze the pump measurements and determine when the pump measurements include a plurality of the pump measurements that satisfy corresponding ones of the predefined metrics.

11. operating a pump comprising a chamber configured with at least one port for receiving fluid from a reservoir into the chamber and for fluid to flow out of the chamber, and a pumping mechanism configured to control the intake of a predetermined amount of the fluid into the chamber during an aspiration stroke and to control the dispensing of a predetermined amount of the fluid from the chamber during a dispense stroke; operating a pump measurement device to generate a pump measurement of at least one of each aspiration stroke performed by the pump and each dispense stroke performed by the pump; analyzing pump measurements, including the pump measurements for each of a plurality of the at least one of the aspiration stroke and the dispense stroke, to determine when the pump measurements include a plurality of the pump measurements that satisfy a predefined metric designated as an indicator of an occlusion; detecting a pumping mechanism current for a plurality of such pump cycles during at least one of the aspiration stroke and the dispense stroke of a pump cycle; the pump measurement corresponds to the pumping mechanism current; the pump measurements include the pumping mechanism current for a selected number of the plurality of pump cycles, and the predefined metric includes an average pumping mechanism current exceeding a specified current value that is higher than an average value of the pumping mechanism current when no occlusion occurs in the pump; operating the pump measurement device to generate pump measurements corresponding to a duration of at least one of the aspiration stroke and the dispense stroke, the predefined metric further comprising a selected duration that is greater than an average value of the pump measurements when no occlusions are occurring in the pump; Analyzing the pump measurements includes determining, for each of a plurality of pump cycles, an average pumping mechanism current of the aspiration stroke, an average pumping mechanism current of the dispense stroke, and a difference between the average pumping mechanism current of the dispense stroke and the average pumping mechanism current of the aspiration stroke, the predefined metric further including a designated value for the difference that, when exceeded, indicates an occlusion. A method for occlusion sensing in an infusion pump.

12. The method of occlusion sensing of claim 11, further comprising activating an indicator occlusion alert in response to a determination that a plurality of the pump measurements satisfy the predefined metric.

13. 12. The method of occlusion sensing of claim 11, further comprising automatically terminating operation of the pumping mechanism in response to a determination that a plurality of the pump measurements satisfy the predefined metric.

14. 12. The method of occlusion sensing of claim 11, further comprising operating the pump measurement device to generate pump measurements corresponding to durations of dispense strokes in a plurality of the dispense strokes.

15. 12. The method of occlusion sensing of claim 11, further comprising the step of: the pump measurement further corresponds to a duration of at least one of the aspiration stroke and the dispense stroke, and the predetermined metric is configured as a selected duration that is shorter than an average value of the pump measurement when no occlusion occurs in the pump.

16. configuring the pump measurement device as an end stop switch on the pump that is activated when the pumping mechanism completes the at least one of the aspiration stroke and the dispense stroke; connecting the end stop switch to a processing device configured to analyze a signal from the end stop switch to determine a duration of each of the at least one of the aspiration stroke and the dispense stroke; 12. The method of occlusion sensing of claim 11, further comprising:

17. 17. The method of occlusion sensing of claim 16, wherein the pump measurements correspond to a duration of an end-stop switch actuation, and the predefined metric further includes a selected duration for an end-stop switch actuation that is longer than an average value of the pump measurements when no occlusion occurs in the pump.

18. configuring the pump measurement device as an end stop switch on the pump that is activated when the pumping mechanism completes at least one of the aspiration stroke and the dispense stroke, such that for the pump measurements corresponding to durations of end stop switch activation, the predefined metric further includes a selected duration for end stop switch activation that is longer than an average value of the pump measurements when no occlusion occurs in the pump; 12. The method of claim 11, wherein the pump measurements include at least two of the end stop switch actuation duration, the duration of the at least one of the aspiration stroke and the dispense stroke, the time difference between the aspiration stroke and the dispense stroke, and the difference between the average pumping mechanism current of the dispense stroke and the average pumping mechanism current of the aspiration stroke, the predefined metric corresponding to stroke duration is a selected duration that is less than an average value of the stroke duration when no occlusion occurs in the pump, and the predefined metric corresponding to dispense stroke duration difference relative to aspiration stroke duration is a selected duration that is greater than an average value of the stroke duration difference when no occlusion occurs in the pump, and analyzing the pump measurements includes determining when the pump measurements include a plurality of the pump measurements that satisfy a corresponding one of the predefined metrics.

19. 12. The method of occlusion sensing of claim 11, wherein the pump measurement corresponds to a time difference between the aspiration stroke and the dispense stroke, and the predetermined metric corresponding to aspiration stroke duration difference relative to dispense stroke duration is a selected duration that is greater than an average value of the stroke duration difference when no occlusion occurs in the pump.

20. 20. The method of occlusion sensing of claim 19, wherein the pump measurements also include a duration of at least one of the aspiration stroke and the dispense stroke, the predefined metric corresponding to the stroke duration being a selected duration that is shorter than an average value of the stroke duration when no occlusion occurs in the pump, and analyzing the pump measurements includes determining when the pump measurements include a plurality of the pump measurements that satisfy a corresponding one of the predefined metrics.

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