System, apparatus, 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 a system, method, and apparatus for blockage detection. Exemplary embodiments of the present invention relate to blockage detection using pump operating parameters such as pump duration (e.g., suction stroke duration or dispensing stroke duration) or pump operation monitoring switch activation in a rotary metering pump or reciprocating pump, in order to eliminate the need for additional pressure sensing components. Pump motor current sensing may also be used to detect blockage conditions within the pump. [Background technology]

[0002] Diabetes is a group of diseases characterized by high blood glucose levels resulting from the inability of diabetic patients to maintain adequate insulin production when needed. If left untreated, diabetes can be dangerous for those affected, potentially leading to serious health complications and premature death. However, such complications can be minimized by utilizing one or more treatment options to control diabetes and reduce the risk of complications.

[0003] Treatment options for patients with diabetes include specialized diets, oral medications, and / or insulin therapy. An effective method of insulin therapy and diabetes management is infusion therapy, or infusion pump therapy, through which an insulin pump is used. Insulin pumps can provide continuous insulin infusion to diabetic patients at varying rates to better match the function and behavior of a properly functioning pancreas in a non-diabetic person, producing the insulin needed. Insulin pumps 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, through which insulin is infused after puncturing the skin of the diabetic patient. Infusion pump therapy offers the advantages of continuous insulin infusion, precise administration, and a programmable delivery schedule.

[0004] Anomalies or malfunctions, such as leaks, blockages, or the presence of air bubbles in the fluid pathway, can occur within an infusion pump and may not always be perceptible to the user. Detecting malfunctions, such as partial or complete blockages along the fluid pathway within the infusion pump, is desirable to maintain precisely controlled drug delivery and to advise the user to discontinue the use of a malfunctioning infusion device. A common solution for blockage detection is to place a pressure sensor within the infusion pump system that reports a blockage when the pressure exceeds a certain threshold. However, adding a pressure sensor increases the complexity of the system (e.g., 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, if some or all of the components are disposable for ease of use and cost-effectiveness, adding another component, such as a pressure sensor, and the associated increased cost and complexity to the medical device is undesirable. Therefore, there is a need for accurate blockage detection without adding infusion pump components and thereby increasing the complexity and cost of the infusion pump. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2015 / 157174 Brochure [Overview of the Initiative] [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] An example embodiment provides an infusion device with integrated occlusion sensing, comprising: a pump comprising: a chamber configured to receive fluid from a reservoir into a chamber and having at least one port through which the fluid flows out of the chamber; a pump configured to control the suction of a predetermined amount of fluid into the chamber during an suction stroke and the dispensing of a predetermined amount of fluid from the chamber during a dispensing stroke; a pump measuring device configured to generate at least one pump measurement for each suction stroke and each dispensing stroke performed by the pump; and a processing device configured to analyze the pump measurement, including the pump measurement for each of a plurality of at least one of the suction strokes and dispensing strokes, and to determine when the pump measurement includes a plurality of pump measurements that satisfy a predetermined metric designated as an indicator of occlusion.

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

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

[0011] According to an aspect of an exemplary embodiment of the present invention, the pump measurement corresponds to the duration of at least one of the suction stroke and the dispensing stroke, and the predefined metric is a selected duration shorter than the average value of the pump measurements when no occlusion occurs in 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 the suction stroke and the dispensing stroke. The end-stop switch is connected to the processing device to determine the duration of each of at least one of the suction stroke and the dispensing stroke.

[0013] According to an aspect of an exemplary embodiment of the present invention, the pump measurement corresponds to the duration of the end-stop switch actuation, and the predefined metric is a selected duration for end-stop switch actuation longer than the average value of the pump measurements when no occlusion occurs in the pump.

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

[0015] According to an exemplary embodiment of the present invention, the pump measuring device is an endstop switch on a pump, configured to activate when the pumping mechanism completes at least one of a suction stroke and a dispensing stroke. The endstop switch is connected to a processing device to determine the duration of each of the at least one of the suction stroke and dispensing stroke, such that a default metric is a selected duration for endstop switch activation that is longer than the average value of the pump measurements when no blockage occurs in the pump, with respect to a pump measurement corresponding to the duration of endstop switch activation. The pump measurement includes at least two of the following: the duration of endstop switch activation, the duration of at least one of the suction stroke and dispensing stroke, the time difference between the suction stroke and the dispensing stroke, and the difference between the average pumping mechanism current for the dispensing stroke and the average pumping mechanism current for the suction stroke. The default metric corresponding to the stroke duration is a selected duration that is shorter than the average value of the stroke duration when no blockage occurs in the pump. The default metric corresponding to the dispensing stroke duration difference relative to the suction stroke duration is a selected duration that is greater than the average value of the stroke duration difference when no blockage occurs in the pump. The processing device is configured to analyze and determine when the pump measurement includes multiple pump measurements that satisfy the corresponding values ​​of a predetermined metric.

[0016] According to an exemplary embodiment of the present invention, the pump measurement corresponds to the time difference between the suction stroke and the dispensing stroke, and the default metric corresponding to the dispensing stroke duration difference relative to the suction stroke duration is a selected duration greater than the average value of the stroke duration difference when no blockage occurs in the pump. According to an exemplary embodiment of the present invention, the pump measurement may also include the duration of at least one of the suction stroke and the dispensing stroke, and the default metric corresponding to the stroke duration is a selected duration shorter than the average value of the stroke duration when no blockage occurs in the pump. The processing device is configured to analyze the pump measurement and determine when the pump measurement includes a plurality of pump measurements that satisfy the corresponding default metric.

[0017] Providing a method for sensing occlusion in an injection pump is an exemplary embodiment of the present invention, which includes operating a pump comprising a chamber configured to receive fluid from a reservoir into a chamber and through which the fluid flows out of the chamber, and a pumping mechanism configured to control the suction of a predetermined amount of fluid into the chamber during an suction stroke and the dispensing of a predetermined amount of fluid from the chamber during a dispensing stroke; operating a pump measuring device to generate at least one pump measurement for each suction stroke and each dispensing stroke performed by the pump; and analyzing the pump measurement, including the pump measurement for each of the multiple pump measurements for at least one of the suction stroke and dispensing stroke, to determine when the pump measurement includes a plurality of pump measurements that satisfy a predetermined metric designated as an indicator of occlusion.

[0018] According to an exemplary embodiment of the present invention, the blockage sensing method further includes activating an indicator blockage alert in response to a determination that multiple pump measurements satisfy a predetermined metric.

[0019] According to an exemplary embodiment of the present invention, the blockage sensing method further includes automatically terminating the operation of the pumping mechanism in response to a determination that a plurality of pump measurements satisfy a predetermined metric.

[0020] According to an exemplary embodiment of the present invention, the occlusion sensing method further includes operating a pump measuring device to generate a pump measurement value corresponding to the duration of at least one of the suction stroke and the dispensing stroke. For example, the occlusion sensing method can use a default metric as a selected duration shorter than the average value of the pump measurement values ​​when no occlusion occurs in the pump.

[0021] According to an exemplary embodiment of the present invention, the method for occlusion sensing further includes configuring a pump measuring device as an endstop switch on a pump, which is activated when the pumping mechanism completes at least one of a suction stroke and a dispensing stroke, and connecting the endstop switch to a processing device configured to analyze the signal from the endstop switch to determine the duration of each of the at least one of the suction stroke and the dispensing stroke.

[0022] According to an exemplary embodiment of the present invention, the pump measurement corresponds to the duration of end-stop switch activation, and the default metric is a selected duration for end-stop switch activation that is longer than the average value of the pump measurement when no blockage occurs in the pump.

[0023] According to an exemplary embodiment of the present invention, a method for sensing blockages includes detecting pumping mechanism currents for a plurality of such pump cycles during at least one of the suction stroke and dispensing stroke of the pump cycle. The pump measurement corresponds to the pumping mechanism current. The pump measurement includes the pumping mechanism current for a selected number of plurality of pump cycles. A default metric includes the average pumping mechanism current exceeding a specified current value, which is higher than the average pumping mechanism current when no blockage occurs in the pump. For example, analyzing the pump measurement may include determining, for each of the plurality of pump cycles, the average pumping mechanism current for the suction stroke, the average pumping mechanism current for the dispensing stroke, and the difference between the average pumping mechanism current for the dispensing stroke and the average pumping mechanism current for the suction stroke. The default metric is a specified value for the difference, which, when exceeded, indicates a blockage.

[0024] According to an exemplary embodiment of the present invention, the method for sensing blockages further includes configuring a pump measuring device as an end-stop switch on the pump that is activated when at least one of a suction stroke and a dispensing stroke is completed, such that a default metric for a pump measurement corresponding to the duration of end-stop switch activation is a selected duration for end-stop switch activation that is longer than the average value of pump measurements when no blockage occurs in the pump. The pump measurement includes at least two of the following: the duration of end-stop switch activation, the duration of at least one of the suction stroke and dispensing stroke, the time difference between the suction stroke and the dispensing stroke, and the difference between the average pumping mechanism current for the dispensing stroke and the average pumping mechanism current for the suction stroke. The default metric corresponding to the stroke duration is a selected duration that is shorter than the average value of stroke durations when no blockage occurs in the pump, and the default metric corresponding to the dispensing stroke duration difference relative to the suction stroke duration is a selected duration that is greater than the average value of stroke duration differences when no blockage occurs in the pump. Analyzing the pump measurement includes determining when the pump measurement includes a plurality of pump measurements that satisfy the corresponding default metric.

[0025] According to an exemplary embodiment of the present invention, the pump measurement corresponds to the time difference between the suction stroke and the dispensing stroke, and the default metric corresponding to the dispensing stroke duration difference relative to the suction stroke duration is a selected duration greater than the average value of the stroke duration difference when no blockage occurs in the pump. The pump measurement may also include the duration of at least one of the suction stroke and the dispensing stroke, and the default metric corresponding to the stroke duration is a selected duration shorter than the average value of the stroke duration when no blockage occurs in the pump. Analyzing the pump measurement involves determining when the pump measurement includes multiple pump measurements that satisfy the corresponding default metric.

[0026] Additional and / or other embodiments and advantages of the present invention are described in the following description, will become apparent therefrom, or may be learned through the practice of the present invention. The present invention may comprise a device and a method for operating it, having one or more of the above embodiments and / or one or more of the features and / or a combination thereof. The present invention may comprise, for example, one or more of the features described in the appended claims and / or a combination of the above embodiments. [Brief explanation of the drawing]

[0027] The above and / or other embodiments and advantages of the present invention will be more readily apparent from the following detailed description, which is taken into account in conjunction with the accompanying drawings.

[0028] [Figure 1] This is a partial perspective view of an exemplary pump component in an exemplary drug delivery device operating according to an occlusion detection algorithm according to an exemplary embodiment of the present invention. [Figure 2] This is a partial perspective view of an exemplary pump component in an exemplary drug delivery device operating according to an occlusion detection algorithm according to an exemplary embodiment of the present invention. [Figure 3A] Figures 1 and 2 show perspective views of the pump components within an exemplary drug delivery device, arranged according to a readily dispensable stage of operation. [Figure 3B] Figures 1 and 2 show perspective views of the pump components within an exemplary drug delivery device, arranged according to the immediately aspirable stages of operation. [Figure 3C] Figures 1 and 2 are perspective views of components within an exemplary drug delivery device, comprising exemplary pump components and associated electronic circuits on a printed circuit board. [Figure 4] This is a block diagram of components within an exemplary drug delivery device. [Figure 5A]This figure shows the pump duration for multiple aspiration operations of an exemplary drug delivery device under normal operating conditions. [Figure 5B] This figure shows the pump duration for multiple dispensing operations of an exemplary drug delivery device under normal operating conditions. [Figure 6A] Figures 5A and 5B are used to generate the pump duration for multiple aspiration operations of the same type of drug delivery device under obstructed operating conditions. [Figure 6B] Figures 5A and 5B are used to generate the pump duration for multiple dispensing operations of the same type of drug delivery device under obstructed operating conditions. [Figure 7] This is an exemplary flowchart illustrating the operation of an exemplary drug delivery device operating according to an exemplary embodiment of the present invention, which operates in accordance with an occlusion detection algorithm using a stroke duration criterion. [Figure 8A] This graph shows exemplary endstop or limit switch activation data during the normal operation of an exemplary pump. [Figure 8B] This graph shows exemplary endstop or limit switch activation data during the operation of an exemplary pump under blockage. [Figure 9] This is an exemplary flowchart of the operation of an exemplary drug delivery device that operates according to an occlusion detection algorithm using an endstop or limit switch activation duration criterion, according to an exemplary embodiment of the present invention. [Figure 10] This graph shows exemplary pump measurement data illustrating short dispensing stalk durations (for example, when the pump piston cannot move due to occlusion). [Figure 11] This graph shows exemplary pump measurement data illustrating the extended endstop or limit switch activation duration (for example, when pumping back to the pump reservoir occurs due to blockage). [Figure 12A]This graph shows pump measurement data from each pump, illustrating the ratio of the duration of a long dispensing stroke to the duration of a suction stroke (for example, when leakage occurs due to obstruction). [Figure 12B] This graph shows pump measurement data from each pump, illustrating the ratio of the duration of a long dispensing stroke to the duration of a suction stroke (for example, when leakage occurs due to obstruction). [Figure 12C] This graph shows pump measurement data from each pump, illustrating the ratio of the duration of a long dispensing stroke to the duration of a suction stroke (for example, when leakage occurs due to obstruction). [Figure 12D] This graph shows pump measurement data from each pump, illustrating the ratio of the duration of a long dispensing stroke to the duration of a suction stroke (for example, when leakage occurs due to obstruction). [Figure 13] This is an exemplary flowchart illustrating the operation of an exemplary drug delivery device operating according to an exemplary embodiment of the present invention, in accordance with an obstruction detection algorithm using a leak detection criterion. [Figure 14] This is an exemplary flowchart illustrating the operation of an exemplary drug delivery device that operates according to an obstruction detection algorithm using a combination of criteria, as described in an exemplary embodiment of the present invention. [Figure 15] This 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] This is an exemplary flowchart illustrating the operation of an exemplary drug delivery device that operates according to an exemplary embodiment of the present invention, in accordance with an obstruction detection algorithm using a pump motor current reference. [Figure 17A] This graph shows pump measurement data from each exemplary delivery device, illustrating the motor current during the dispensing stroke before and after occlusion. [Figure 17B] This graph shows pump measurement data from each exemplary delivery device, illustrating the motor current during the dispensing stroke before and after occlusion. [Figure 17C]This graph shows pump measurement data from each exemplary delivery device, illustrating the motor current during the dispensing stroke before and after occlusion. [Figure 17D] This graph shows pump measurement data from each exemplary delivery device, illustrating the motor current during the dispensing stroke before and after occlusion. [Figure 17E] This graph shows pump measurement data from each exemplary delivery device, illustrating the motor current during the dispensing stroke before and after occlusion. [Figure 18A] This graph shows the average motor current for a selected time period for each exemplary delivery device. [Figure 18B] This graph shows the average motor current for a selected time period for each exemplary delivery device. [Figure 18C] This graph shows the average motor current for a selected time period for each exemplary delivery device. [Figure 18D] This graph shows the average motor current for a selected time period for each exemplary delivery device. [Figure 18E] This graph shows the average motor current for a selected time period for each exemplary delivery device. [Figure 19] This is an exemplary flowchart of the operation of an exemplary drug delivery device that operates according to an exemplary embodiment of the present invention, in accordance with an obstruction detection algorithm that uses a combination of criteria with a pump motor current reference.

[0029] Throughout the drawings, similar reference numbers will be understood to refer to similar elements, features, and structures. [Modes for carrying out the invention]

[0030] Next, references to exemplary embodiments of the invention, shown in the accompanying drawings, will be made in detail. The exemplary embodiments described herein are illustrative, rather than limiting, the invention by reference to the drawings.

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

[0032] For illustrative purposes, references are made to a rotary metering pump described in Patent Document 1, owned by the rights holder of this application, the contents of which are incorporated herein by reference in their entirety. Referring 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) comprises a pump assembly 20 connectable to a DC motor and gearbox assembly (not shown) for rotating 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 as the sleeve 24 rotates in one direction and then in the opposite direction, respectively. The sleeve has an end plug 34. Two seals 32, 36 on the respective ends of the piston and end plug inside the sleeve 24 define a cavity or chamber 38 when the piston 30 is retracted following the suction stroke, as shown in Figure 3A, and therefore immediately ready for dispensing. Thus, the volume of the chamber 38 changes depending on the degree of retraction of the piston 30. When the piston 30 is fully inserted and the seals 32, 36 are substantially in contact with each other following the dispensing stroke and therefore immediately ready for suction, as shown in Figure 3B, the volume of the chamber 38 is negligible or essentially zero. Two ports 44, 46 are provided on the pump manifold 22, including an inlet port 44 through which the drug can flow from the reservoir 70 (Figure 4) for the pump 64 (Figure 4), and an outlet port 46 through which the drug drawn into the chamber 38 (for example by the retraction of the piston 30 during the suction stage of operation) can be dispensed from the chamber 38 to a cannula 72 (Figure 4) in the patient, for example from a fluid pathway, by reinsertion of the piston 30 into the chamber 38.

[0033] Continuing to refer to Figures 1, 2, 3A, 3B, and 3C, the sleeve 24 may be provided with an aperture (not shown) that aligns with the outlet port 46 or the inlet port 44 (i.e., depending on the degree of rotation of the sleeve 24 and therefore the degree of translation of the piston 30) to allow the drug in the chamber 38 to flow through the corresponding port of one of the ports 44, 46. A pump measuring device 78 (Figure 4), such as a sleeve rotation limiting switch, may be provided, for example, having an interlock 42 and one or more stoppers 40 or end plugs 34 on the sleeve 24 that cooperate with the interlock 42. The interlock 42 may be mounted on the manifold 22 at each end thereof. When the pump 64 is in a first position, thereby the side holes in the sleeve 24 are aligned with the inlet port 44 to receive fluid from the reservoir 70 into the chamber 38, the stoppers 40 on the end face of the sleeve 24 are adjacent to the protrusions 48 of the interlock 42. Under certain conditions, such as back pressure, the friction between the piston 30 and the sleeve 24 can be sufficient to rotate the sleeve 24 before the piston 30 and coupling pin 28 reach both ends of the helical groove 26. This can result in an incomplete amount of fluid being pumped with each stroke. To prevent this situation, the interlock 42 prevents the sleeve 24 from rotating until the torque passes a predetermined threshold, as shown in Figure 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 the DC motor and gearbox assembly or other types of pump and valve actuators 66 (Figure 4) increases the torque on the sleeve 24 beyond the threshold, causing the interlock 42 to bend and the retaining pin 40 to pass through the ridge 48. When the rotation of the sleeve 24 is complete, such that its side hole is directed toward the cannula 72 or the exit port 46, the stopper 40 moves over the protrusion 48 in the interlock 42, as shown in Figure 3B.Another sleeve feature may be provided for engaging with an electrical switch (for example, an endstop switch 90 provided on a printed circuit board 92 and positioned relative to the sleeve and / or end plug 34 to cooperate with the pump measuring device 78, as shown in Figure 3C).

[0034] Figure 4 is an exemplary system diagram showing exemplary components within an exemplary drug delivery device 10 having an infusion pump, such as the pumps in Figures 1, 2, 3A, 3B, and 3C. The drug delivery device 10 may include an electronics subsystem 52 for controlling the operation of components within a fluid engineering subsystem 54, such as a pump 64 and an insertion mechanism 74 for deploying a cannula 72 for insertion into an injection site on the patient's skin. A power storage subsystem 50 may include, for example, a battery 56 for supplying power to the electronics subsystem 52 and components within the fluid engineering subsystem 54. The fluid engineering subsystem 54 may include, for example, an optional filling port 68 for filling the reservoir 70 (for example, with drug), although the drug delivery device 10 with its reservoir already filled is optionally shippable from manufacture. The fluid engineering subsystem 54 also has a metering subsystem 62 comprising a pump 64 and a pump actuator 66. As described above, the pump 64 may have two ports 44, 46 and associated valve subassemblies that control when fluid enters and exits the pump chamber 38 through the respective ports 44, 46. One of the ports is an inlet port 44 through which fluid, such as liquid medication, flows from the reservoir 70 to 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 from the pump chamber 38 toward the cannula 72 for administration to the patient pump as a result of a pump discharge or push stroke on the pump plunger or piston 30. The pump actuator 66 may 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 a sleeve 24 that can rotate relative to the translational movement of the pump piston 30.The microcontroller 58 may include, for example, an integrated or separate memory device having computer software instructions for operating the rotation of the sleeve 24 in a selected direction, the translational or axial movement of the piston 30 within the sleeve 24 for a suction stroke or dispensing stroke, and optionally, the joint rotation of the sleeve 24 and piston 30 during a valve state change, as described in Patent Document 1 referenced above. 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 the pump chamber 38 and to dispense a controlled amount of drug from the pump chamber, the pump 64 associates the expected pump duration with one or both of the aspiration and dispensing stages or strokes, which may be due to the pump characteristics. For example, in the exemplary pump assembly 20 shown in Figures 1, 2, 3A, 3B, and 3C, the pump duration for aspirating the drug into the chamber and dispensing the drug from the chamber 38 is influenced by pump characteristics such as the internal volume of the pump chamber 38, the length or distance of the pump piston stroke, and the characteristics of the port seals provided at the inlet and output ports 44, 46. When the pump pressure is within the specified relative normal range for operation, the pump duration for filling chamber 38 with a specified amount of fluid (e.g., a desired dose) and releasing the specified amount of fluid from the chamber can be determined and used as a baseline for monitoring pump 64 under normal operating conditions and determining when abnormal operating conditions occur, such as fluid leakage from the pump chamber or blockage in the pump fluid path that prevents the specified amount of fluid (e.g., a desired dose) from being delivered from the chamber via the dispensing stroke in either scenario. This can be undesirable as the patient does not receive the desired dose.

[0036] As mentioned above, a common solution for blockage detection is to place an additional pressure sensor within the pump control system to report a blockage when the pressure exceeds a certain threshold. However, adding a pressure sensor has the disadvantages of increasing the complexity of the system (e.g., mechanical complexity, electrical complexity, and / or software complexity), increasing system power consumption, and / or increasing pump costs. These disadvantages can be particularly unfavorable for wearable pump designs in which all or part of the pump is intended to be disposable once the reservoir 70 is emptied or the pump 64 is 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 achieved without additional components such as occlusion sensors deployed upstream or downstream of the pump 64. When the microcontroller 58 or other processing device for controlling pump operation has already performed pump duration measurements for normal operation, such as for one or both of the aspiration and dispensing strokes, the microcontroller 58 is further controllable to determine when the pump duration measurement falls outside a specified range of normal operating conditions and thus indicates an occlusion, and to generate a marker for the detected occlusion. Thus, the pump 64 and / or the entire drug delivery device 10 can then be replaced or repaired, thereby ensuring that the patient receives the well-intended dose provided under normal operating conditions.

[0038] When pump duration measurement is performed 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 are 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 performed via a software solution and no hardware changes to the pump are required. As described below, a clear difference in pump duration exists between a normal pump and an occluded pump. Therefore, the false alarm rate and error rate are extremely low. Thus, an occlusion detection algorithm configured in accordance with the exemplary embodiment is capable of providing reliable occlusion detection results.

[0039] Determining a pump duration threshold or range of values ​​or other metrics indicating occlusion is empirically feasible, for example, for a selected type of pump 64. The metrics for a selected type of pump to experience normal operating pressure are comparable to metrics for the same type of pump, except that it is experiencing at least partial or complete occlusion. For example, occlusion in the downstream path from a occluded pump 64 to its cannula 72 increases the pressure in the fluid path of pump 64 over time. When the pressure in the occluded pump exceeds a threshold, the occluded pump eventually begins to leak. Log files for normal and occluded pumps can be generated to obtain a history of their respective pump duration information for suction strokes and / or dispensing strokes. However, it should be understood that different pump measurements other than pump duration (i.e., duration of suction or dispensing strokes) can be used to determine the difference in pump operation under normal and occluded operating conditions, as well as to monitor pump operation and determine thresholds for distinguishing between normal and occluded operating conditions. For example, as described below, the termination of long-term stroke switch operation or significant differences in the duration of the suction stroke and dispensing stroke can be used to detect the occurrence of obstruction.

[0040] Referring to Figures 5A and 5B, the pump duration of a pump experiencing occlusion (e.g., approximately 1.5 seconds on average) is considerably shorter than the pump duration of pump 64 when it is operating under normal conditions (e.g., approximately 3-3.5 seconds). This phenomenon of shorter pumping duration is related to the pumping mechanism, such as the piston 30, sleeve 24, interlock 42, and silicone seals on the inlet and outlet ports 44, 46, as described above in relation to Figures 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 the shortened pump during occlusion conditions. Pump 64 can be a rotary metering type pump or a reciprocating type pump, or other types of pumps that use drawing or aspirating fluid from an upstream reservoir and then releasing or dispensing that fluid into a separate downstream fluid path leading to a patient.

[0041] Referring to the exemplary infusion pump 64 described above in relation to Figures 1, 2, 3A, 3B, and 3C, the suction and dispensing strokes of the pump, driven by the translation of a piston 30 within an outer plastic sleeve 24, are related to the switching of the pump 64 between the upstream and downstream fluid paths. When the piston 30 is rotated (for example, by a DC motor and gearbox assembly not shown), the piston 30 translates through the sleeve 24, guided by the progression of a pin 28 on the piston through a helical slot 26 within the sleeve 24. When the piston 30 has fully translated through the sleeve 24 and completed its suction or dispensing stage of the fluid, it engages directly with the sleeve 24 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 to actuate the ends or other components of a stroke electric switch 90 provided on the pump 64 and / or within the drug delivery device 10, which is associated with a pump measuring device 78 (Figure 4). During normal operation, the presence of the interlock 42 prevents the rotations of the piston 30 and sleeve 24 from coupling before the piston 30 completes its translation through the sleeve 24. However, if the pressure in the downstream fluid path increases above a threshold, the rotations of the piston 30 and sleeve 24 will coupling, allowing the sleeve 24 to pass under the interlock 42 and activate the switch 90 (for example, via the sleeve feature 41 associated with the pump measuring device 78) before the piston 30 completes its translation through the sleeve. This significantly reduces the pump duration (for example, from between 3 and 3.5 seconds under normal conditions to less than 2 seconds under occluded conditions).

[0042] Next, references are made to Figures 6A and 6B, which show pump duration data from several similar type pumps 64 across multiple pump cycles. For example, log data is shown from 19 pumps that completed 600 cycles, with 10 pumps operating under normal conditions and 9 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 the release of pressure from leaks in the manifold area. The clear difference in pump duration between normally operating pumps and pumps that experienced occlusion allows for the use of a pump duration-based occlusion detection algorithm.

[0043] Referring to Figure 7, an exemplary blockage detection process includes setting a pump measurement threshold or metric (block 80), such as a stroke duration threshold, where a stroke duration above the threshold indicates normal pump operation, and a stroke duration below the threshold indicates blockage. Pump measurement data is analyzed to set the threshold. For example, suction stroke duration and dispensing stroke duration can be detected by a limiting switch or other pump measurement device 78 provided to the pump (Figure 4). In the exemplary pump described with reference to Figures 1, 2, 3A, 3B, and 3C, the stroke or pump duration is determined using a sleeve rotation limiting switch or other pump measurement device 78. For example, other electronic components, such as an endstop switch 90 cooperating with a microcontroller 58 and sleeve feature 41, can generally be deployed on a printed circuit board (PCB) 92 associated with the pump 64 or delivery device 10. Endstop switch operation data can be collected and stored (for example, via a memory device integrated with the microcontroller 58 or implemented as a separate component on the PCB 92). The microcontroller 58 may include an obstruction detection algorithm for processing endstop switch actuation data to determine whether an obstruction has occurred. According to another exemplary embodiment, the endstop switch actuation data can be provided from the pump 64 to another device having an obstruction 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), which includes software or an app that includes the obstruction detection algorithm (e.g., wirelessly or via a wireline connection).

[0044] Pump measurement data is acquired for one or more pumps of the same type operating under normal conditions and for one or more pumps of the same type operating under occluded conditions, as shown in Figures 5A and 5B and 6A and 6B above. The pump measurement data for these two groups of pumps is averaged, summarized, or categorized and then analyzed to determine the degree of difference between the pump measurements for normally operating pumps and the pump measurements for occluded pumps. Thresholds or other metrics are determined to be above and / or below values ​​or ranges of values ​​within a margin into which normal pump measurements do not fall. The values ​​or ranges of values, and / or margins, can be specified by the user or can be automatically determined based on the pump measurement data acquired from the pumps. As described above, 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, rather than additional operation.

[0045] Continuing to refer to Figure 7, once a pump measurement metric (e.g., stroke duration threshold) is set, the microcontroller 58 in the drug delivery device 10 is controlled by an occlusion detection algorithm to acquire pump measurement data (e.g., stroke duration data) for the pump (block 81) and compare the stroke duration data with the pump measurement metric during various pump stages or cycles of operation for each pump cycle, etc. (block 82). stroke When the stroke duration data is greater than or equal to the blockage detection threshold (e.g., 2 seconds for pump 64), the pump is determined to be operating normally (block 84). stroke When the counter is smaller than the threshold Th for normal operation, the pump is determined to be experiencing a blockage condition.stroke If the condition is not met, it is incremented (block 83). Referring to block 85, the counter is set to a selected value (for example, the threshold Th for normal operation). stroke An obstruction is detected when the counter reaches a value of 8 (corresponding to 8 pump cycles that do not satisfy the condition). The total number of cycles to which a selected number of cycles are reached before an obstruction 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 obstruction detection algorithm to generate an optional indicator for detected obstruction errors (block 86), an optional indicator for the user to automatically stop the operation of the pump and / or drug delivery device 10, and / or to stop 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 obstruction detection algorithm is based on pump duration or other pump measurement data already performed within the pump, obstruction detection is achieved 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 obstructions, eliminating the need for hardware changes.

[0046] An exemplary pump 64 described in relation to Figures 1, 2, 3A, 3B, and 3C uses one or more on / off limiting switches to determine the state of the system in limiting rotational progress. For example, a multistage pump (i.e., a pump that draws fluid to fill a chamber in one stage and then discharges the pump chamber in the next stage) can use some type of end-stop switch for each stage to detect when the piston and / or sleeve or other pump components reach a predetermined position corresponding to the full suction or dispensing position. However, it should be understood that different mechanisms or other pump measuring devices 78 may be used to determine pump measurements (e.g., pump duration) other than the interlock 42 and sleeve rotation limiting switches (e.g., end-stop switches) 90. Alternatively, the pump 64 can 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 suction and / or dispensing.

[0047] Accordingly, as described by an exemplary embodiment of the present invention with reference to Figure 7, a determination is made of the time required to fill the chamber and the time required to discharge a desired amount of fluid from the chamber, the discharge time for at least each stroke is measured, and further, when a selected number of discharge times fail to exceed a specified amount (for example, the stroke duration is shortened over a specified number of pump cycles), a signal is generated to indicate that an obstruction has been detected.

[0048] According to another exemplary embodiment, blockage detection is performed by monitoring the duration of activation or triggering of the pump endstop or limit switch, as described below with reference to Figure 9. Processing the monitored data related to the detected duration of activation or triggering of the pump endstop or limit switch to determine whether a blockage has occurred in the pump 64 can be done alone or in combination with monitoring with respect to short pump stroke durations, as described above with reference to Figure 7.

[0049] As described above, during normal operation, the presence of the interlock 42 prevents the rotations of the piston 30 and sleeve 24 from coupling before the piston 30 completes its translation through the sleeve 24. However, if the pressure in the downstream fluid path increases (i.e., during occlusion), the rotations of the piston 30 and sleeve 24 can coupling prematurely. That is, the sleeve 24 rotates prematurely before the intended rotation during a valve state change, for example, when the sleeve 24 rotates without axial motion to align its lateral port with the corresponding port of one of the ports 44, 46 during normal operation of the pump, at the end of the full piston stroke. This premature coupling of rotations of the piston 30 and sleeve 24 then allows the sleeve 24 to pass under the interlock 42 and trigger the switch 78 before the piston 30 completes its axial translation through the sleeve. This significantly shortens the pump duration (measured, for example, as the time period or duration between pump motor start and end-stop switch signal), as described above in relation to Figure 7. Furthermore, another pump operating characteristic that can be monitored with respect to blockage detection is the duration that the pump measuring device 78 and its associated switch 90 indicate that the operation is in an operating mode or trigger mode or that the operating state has begun.

[0050] In some examples, the pump duration in a blocked pump system may remain normal and may not decrease as expected. Therefore, monitoring of other pump measurement parameters or characteristics increases the accuracy of blockage detection. For example, while the pump sleeve 24 rotates prematurely as expected due to a blockage in the pump system, and as soon as the pump sleeve opens to the upstream fluid path (and before the stroke end signal from switch 90), the piston can begin to move forward and begin dispensing the fluid payload into the upstream fluid path. Since both the piston 30 and the sleeve 24 can rotate through the entire range of their angular positions, the total pump operating time remains constant both with and without blockage. On the other hand, since the piston 30 is now rotating after the sleeve has rotated over the upstream channel and is translating through the sleeve 24, the endstop switch 90 is now triggered over an extended period of time. Therefore, blockage detection may include monitoring or triggering the limit switch activation for a long-term or extended endstop, separately from, or in addition to, monitoring for the shortened pump stroke duration according to the exemplary embodiment.

[0051] To further illustrate how much the operation or triggering of the pump measuring device may be delayed as a result of blockage, references are made to an exemplary pump 64 illustrated by the exemplary embodiments shown in Figures 1, 2, 3A, 3B, and 3C. During normal pump 64 operation, when the endstop switch 90 is first struck, dragged, and thus triggered by the pump sleeve 24 (e.g., via the sleeve feature 41 that engages with the endstop switch 90), the endstop switch 90 causes a drop in its endstop switch voltage signal from 1.8V to 0V, which is provided to the microcontroller 58. The endstop switch voltage returns to 1.8V only when the switch 90 is released (e.g., by disengaging the sleeve feature 41) and springs back to its center. In some examples, when the lateral port of the sleeve 24 opens to the upstream fluid path (for example, aligned with the input port 44), before the piston 30 completes its axial translation, before the endstop switch 90 is disengaged by the sleeve feature 41, and when the pressure in the upstream fluid path is low, the piston 30 may begin to move forward through the sleeve 24 and translate, allowing the pump contents to open to the upstream fluid path while the endstop switch 90 is in a triggered intermediate state. The net result is that an endstop switch 90 activation signal (e.g., voltage drop) occurs over an extended period of time. This pump occlusion characteristic is shown in Figures 8A and 8B, which illustrate the normal duration of switch 90 activation (e.g., 0 volts) of less than 0.5 seconds and the extended endstop or limit switch 90 activation (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., the piston 30 fails to advance), while others may exhibit an increased duration of the endstop switch 90 activation signal (e.g., when the piston 30 advances on the upstream fluid path). For example, the alignment of the switch 90 on the PCB 92 with related pump components (e.g., the interlock 42, the retainer 40, and the sleeve feature 41) may allow some variability in which sleeve angle position releases the endstop switch 90 and therefore when the endstop switch activation signal is generated and provided to the microcontroller 58. Additionally, higher pressure in the upstream fluid path from a larger insulin reservoir filling volume may prevent the 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 filling volume may allow the piston 30 to advance on the upstream fluid path (e.g., resulting in a longer or extended endstop or limit switch activation or "trigger" duration).

[0053] Referring to Figure 9, the exemplary blockage detection process includes setting a threshold or metric for pump measurements, 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 blockage. Pump measurement data is analyzable to set the threshold. For example, several identical pumps 64 can be examined with similar blockage conditions to collect pump measurement data related to the indicated significant increase in the duration of pump measurement parameters, such as the endstop switch signal voltage drop, when the pump is blocked. In the case of exemplary empirical measurements for pump 64 in Figures 1, 2, 3A, 3B, and 3C, the switch actuation duration during blockage 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 blockage detection algorithm logs the endstop switch 90 signal duration according to software instructions (e.g., in a microcontroller 58) and sets the logged switch actuation duration to a threshold (e.g., Th switchCompared to >1.0 seconds, it can be configured to determine whether or not a blockage is present, as shown in block 98 of Figure 9. Endstop switch actuation data or pump limit switch actuation data can be collected and stored (for example, via a memory device integrated with the microcontroller 58 or implemented as a separate component on PCB 92). The microcontroller 58 may include a blockage detection algorithm for processing the endstop switch actuation data to determine whether a blockage has occurred. According to another exemplary embodiment, endstop switch actuation data can be provided from the pump 64 to another device having a blockage 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), which includes software or an app with a blockage sensing algorithm (e.g., wirelessly or via a wireline connection). Switch actuation duration data for a blocked 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 pump measurements for a blocked pump. Threshold (e.g., Th switch , or other metrics are determined to be above and / or below a value or range of value within a margin in which normal pump measurements do not fall. The value or range of value, and / or margin can be specified by the user or can be automatically determined based on pump measurement data obtained from the pump. As described above, pump measurement data such as switch operation duration 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.

[0054] Continuing to refer to FIG. 9, when a pump measurement metric (e.g., a switch actuation duration threshold) is set, the microcontroller 58 within the drug delivery device 10 acquires pump measurement data (e.g., switch actuation duration data) for the pump 64 (block 97) and compares the switch actuation duration data to the pump measurement metric during various pump stages or cycles of operation, such as for each pump cycle (block 98), and is controlled by an occlusion detection algorithm. When the switch actuation duration data meets (e.g., is less than or equal to) the pump measurement metric (e.g., Th of 1.0 second), the pump is determined to be operating normally (block 100). When the switch actuation duration data fails to meet the pump measurement metric (e.g., is greater than the occlusion detection threshold Th of 1.0 second), the pump is determined to be experiencing an occlusion condition. The counter is incremented (block 99) when a threshold Th for normal operation is not met. Referring to block 101, when the counter reaches a selected value (e.g., Th for normal operation switch ), the pump is determined to be operating normally. switch ), the pump is determined to be experiencing an occlusion condition. The counter is incremented (block 99) when a threshold Th for normal operation switch is not met. Referring to block 101, when the counter reaches a selected value (e.g., Th for normal operation switchA blockage is detected when the counter reaches a value of 8 (corresponding to 8 pump cycles that do not satisfy the condition). The total number of cycles to which a selected number of cycles are reached before a blockage 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 blockage detection algorithm to generate an optional indicator for detected blockage errors (block 102), an optional indicator for the user to automatically stop the operation of the pump 64 and / or the drug delivery device 10, and / or to stop using the drug delivery device 10 (block 104). If the counter has not yet reached the selected counter value after being incremented per block 99, pump measurement data continues to be collected per block 97. Since the blockage detection algorithm is based on pump duration data or other pump measurement data already performed within the pump, blockage detection is achieved 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 blockages, eliminating the need for hardware changes.

[0055] According to another exemplary embodiment of the present invention, a third pump characteristic is monitored to detect blockages within the drug delivery device 10, as described below in relation to Figure 13. For example, inspecting a selected pump 64 under blockage conditions revealed that when blockages occur when the drug delivery device 10 is new, the pump 64 tends to have short stroke durations or long endstop durations, respectively, as described above in relation to Figures 7 and 9. However, after the pump has experienced many cycles, inspection data showed that it tended to leak in the joint area 49 between the manifold seal 47 and the sleeve 24, as shown in Figure 3B. The reason for the excessive leakage after a certain number of 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 is new and the seal 47 is strong enough to withstand the high pressures caused by blockage, the pump will likely exhibit short stroke durations or long endstop durations (e.g., long limit switch activation durations) during blockage. However, after several pump cycles, the seal may not be strong enough to withstand the high pressure caused by the blockage, and the pump 64 may leak through the weakest connection in the downstream fluid path, which may be the seal 49 between the manifold 47 and the sleeve 24. Since the fluid in the pump chamber 38 is forced through the leak path by the high internal pressure caused by the blockage, the pump motor (not shown) needs to provide more energy to push the fluid out. As a result, the duration of the dispensing stroke during blockage is longer than in normal operation.

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

[0057] According to an exemplary embodiment of the present invention, the blockage detection algorithm described above can utilize the difference in pump duration between the dispensing stroke and the suction stroke. For example, referring to block 108 of Figure 13, the stroke difference threshold (Th delta ) can be determined as follows:

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

[0059]

number

[0060] The average duration difference between the aspiration stroke and the dispensing stroke is calculated, as defined below.

[0061] Here, n is the number of strokes used to obtain the average difference. For 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 for pump 64 (e.g., the duration difference between the suction stroke and the dispensing stroke) (block 109), and compare the duration difference data with the pump measurement metric, for example, as follows (block 110):

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

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

[0065] 3) As shown in block 110 of Figure 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 can continue per block 112 of Figure 13. Otherwise, a leak may be detected and it may be determined that the pump is experiencing a blockage condition. The counter sets the threshold Th for normal operation. delta If the condition is not met, it is incremented (block 111). Referring to block 113, the counter is set to a selected value (for example, Th for normal operation). delta When the counter reaches a value of 8 (corresponding to 8 pump cycles that do not satisfy the condition), an obstruction is detected, an obstruction indicator can be generated per block 114, and pump operation can be terminated per block 116. If the counter has been incremented per block 111 but has not yet reached the selected counter value, pump measurement data continues to be collected per block 109. The total number of cycles to which the selected number of cycles are reached before an obstruction 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 the exemplary embodiment, three consecutive dispensing strokes are used, but this number may change over time depending on variations in pump duration. Duration difference D 0,1,…,xThe values ​​are then averaged, summarized, or categorized, and then compared between pump measurements for a normally functioning pump and pump measurements for a blocked pump, and / or a threshold or other metric. delta It is possible to analyze the degree of the difference (e.g., the difference in aspiration stroke duration and dispensing stroke duration) in relation to these factors.

[0066] The blockage detection algorithm may, according to other exemplary embodiments, include a leak detection criterion as described with Figure 13, in combination with the stroke duration criterion as described with Figure 7 and / or the endstop or limit switch activation duration criterion as described with Figure 9. For example, detection using all three of the criteria, a single criterion, or a subset of these three criteria can be performed in parallel or sequentially using blockage 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 criterion is shown in Figure 10, and additional exemplary data for the switch activation duration criterion is shown in Figure 11. Referring to Figure 14, the exemplary blockage detection algorithm according to an exemplary embodiment uses a combination of the stroke duration criterion as described with Figure 7, the endstop or limit switch activation duration criterion as described with Figure 9, and the leak detection criterion as described with Figure 13. A counter for detected blockage conditions is cleared or set to a value of 0 (block 120). As shown in block 122, the pump cycle is detected (i.e., the suction stroke and dispensing stroke are detected, for example, using endstop switch activation data). Pump measurement data such as stroke duration, endstop duration, and the average duration difference between the suction stroke and dispensing stroke during loading are collected, as described with reference to Figure 9 (block 124). The stroke duration difference is determined (i.e., the average duration difference during loading is subtracted from the duration corresponding to a dispensing stroke duration that is shorter than the suction stroke duration) (block 126). Dispensing stroke duration reduction per block 128 (e.g., 2 seconds Th stroke (shorter than) or extension of the endstop switch actuation duration per block 132 (for example, 1 second Th switch (larger than), or the stroke duration difference per block 134 (for example, 0.13 microseconds of Th deltaIf abnormal pump operating conditions are detected, such as a difference greater than , the counter is incremented (block 136). When the counter reaches a value selected per block 138 (for example, a counter value of 8 corresponding to 8 pump cycles in which the threshold for normal operation is not met), for example, a blockage is detected per block 114, a blockage indicator can be generated, and / or the pump operation can be terminated. If none of these blockage conditions are met, the counter remains cleared per block 134 (for example, a value of 0), the next pump cycle is detected, and the relevant pump timing or measurement data is collected per block 122.

[0067] For example, the leak detection criteria described above in relation to the occlusion detection algorithm in connection with Figure 13 were applied to bench occlusion data collected from 280 drug delivery devices 10 in combination with a short stroke duration algorithm (for example, described above with respect to blocks 80 and 82 in Figure 7) and a long endstop duration algorithm (for example, described above with respect to blocks 96 and 98 in Figure 9). Table 1 shows a comparison of the case with and without the leak detection algorithm described in relation to blocks 108 and 110 in Figure 13. It can be seen that the leak detection algorithm (for example, blocks 108 and 110 in Figure 13) significantly improved the detection rate of appropriate occlusions by the occlusion detection algorithm according to the 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, 120 delivered a 10U bolus before clamping. The manifold seals 49 in these drug delivery devices 10 were used minimally. Table 2 shows a comparison of this group of drug delivery devices 10 with and without a leak detection algorithm. From Table 2, it can be seen that when the manifold seals 49 were used minimally, the occlusion detection rate was extremely high at 88%, even without a leak detection algorithm added to the occlusion detection algorithm using analysis of stroke duration measurements and / or long endstop duration pump measurements. These results are consistent with the conclusion that leaks are largely caused by wear and tear of the manifold seals after repetitive pumping motions.

[0070] [Table 2]

[0071] Therefore, leak detection criteria can be implemented within a blockage detection algorithm. Since this algorithm requires only pump duration information to analyze the leak detection criteria, no hardware modifications are necessary. A blockage detection algorithm using leak detection criteria is improved when implemented in conjunction with stroke duration criteria and / or end-stop switch activation duration criteria to more completely capture all significant pump behavior during blockage.

[0072] In yet another exemplary embodiment, the pump motor current is used to detect blockages. Under normal operating conditions, the drug delivery device 10 draws fluid from a reservoir 70 located upstream of the fluid pathway and dispenses it into the patient's body at the downstream end of the fluid pathway. During the draw stroke, the piston opens the pump chamber, which allows the fluid from the reservoir to fill the chamber. During the dispense stroke, the piston closes the pump chamber, which pushes the fluid downstream. Figures 3A and 3B show exemplary pistons and pump chambers.

[0073] When the drug delivery device 10 is blocked, the piston cannot release the fluid inside the pump chamber downstream. As a result, the pump may 1) hold the fluid in the pump chamber, 2) pump the fluid to the reservoir, or 3) force the fluid to leak through the pump's manifold seal. Since pumping the fluid through any of these three paths requires more energy, the motor current is higher during the dispensing stroke when a blockage occurs. Therefore, the motor current can be used to detect a blockage.

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

[0075] An exemplary blockage detection algorithm for each pump cycle is described below with reference to Figure 16. A counter for detected blockage conditions is cleared or set to 0 (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 the time referring to the start of this stroke, but at the end of the suction stroke (for example, when the endstop signal is detected), the microcontroller 58 sets 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] <s 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. At the end of the dispensing stroke (for example, when the corresponding end stop signal is detected), the microcontroller 58, as follows, calculates 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] [[ID=z8]]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] If the difference (D) is greater than the specified threshold Th iDiff , 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 iDiffA blockage is detected when the counter value reaches 3 (corresponding to 3 pump cycles where the condition is not met), and a blockage indicator can be generated per block 164, at which point the pump operation can be terminated. It should be understood that the counter value can be a value other than 3 to specify a different number of cycles in which the pump current exceeds the threshold before it is indicated that a blockage has been detected. If the counter has been incremented per block 160 and has not yet reached the selected counter value (block 162), pump measurement data (e.g., motor current) continues to be collected per block 152. Thus, a blockage is indicated if the longest pump cycle and several consecutive previous pump cycles have a D value greater than a given threshold. Otherwise, normal pump operation continues.

[0080] Figures 17A to 17E show the motor currents during dispensing strokes before and after occlusion, measured from five respective exemplary delivery devices 10. Figures 17A to 17E show the clear difference in motor current between a normal pump stroke and an occluded pump stroke, facilitating the use of motor current-based occlusion detection algorithms, such as the algorithm described above in relation to Figure 16.

[0081] Figures 18A to 18E show the average motor current from 1 second to 2.5 seconds, respectively (i.e., measured over a duration of 1 to 2.5 seconds after the stroke has started, where t=0 is the start of the stroke). Here again, there is a clear difference between the blocked stroke and the normal stroke shown in Figures 18A to 18E. Therefore, the blocked stroke is above the threshold Th iDiff This can be detected by applying it to the average motor current.

[0082] Continuing to refer to Figures 16, 17A to 17E, and 18A to 18E, the alternative method may rely only on the average motor current for the dispensing stroke and not on the suction stroke, in which case the calculation of the average motor current for the suction stroke and D=Aout-Ain would not be necessary. For example, such an alternative algorithm may include the following operation: The motor current is determined during the dispensing stroke of the pump cycle. For example, at the start of the dispensing stroke, the microcontroller 58 records the motor current during the dispensing stroke. out Using (t), where t is the time referring to the start of this stroke, but at the end of the dispensing stroke (for example, when the corresponding endstop signal is detected), the microcontroller 58 will use the average motor current A as described above in relation to Figure 16. out It can be programmed to determine the average motor current A between 1 and 2.5 seconds after the start of the motor current. out The specified threshold Th Aout If it is greater than, the counter is incremented. The counter is set to a selected value (for example, Th for normal operation). Aout When the counter value reaches 3 (corresponding to 3 pump cycles where the condition is not met), an obstruction is detected, an obstruction indicator can be generated, and the pump operation can be terminated. It should be understood that the counter value can be a value other than 3 to specify a different number of cycles in which the pump current exceeds the threshold before an obstruction is indicated. If the counter has been incremented and has not yet reached the selected counter value, pump measurement data (e.g., motor current) continues to be collected. Using motor current data from both the suction and dispensing strokes, as described above with Figure 16, may, however, be more robust in terms of the sensitivity and accuracy of obstruction detection using motor current, for example.

[0083] Referring to Figure 19, the blockage detection algorithm may include the motor current criterion described with Figure 16 in combination with other criteria used to detect the blockage. For example, the exemplary blockage detection algorithm in the exemplary embodiment in Figure 19 uses a combination of the motor current criterion described with Figure 16, with the stroke duration criterion described with Figure 7, the endstop switch activation duration criterion or limit switch activation duration criterion described with Figure 9, and the leak detection criterion described with Figure 13. A counter for the detected blockage condition is cleared or set to a value of 0 (block 170). The pump cycle is detected as shown in block 172 (i.e., the suction stroke and dispensing stroke are detected, for example, using endstop switch activation data). Pump measurement data is collected, such as the stroke duration, endstop duration, and the average duration difference between the suction stroke and dispensing stroke during loading, as well as the average motor current in each of the suction stroke and dispensing stroke, as described with reference to Figure 9 (block 174). The stroke duration difference is determined (i.e., subtract the average duration difference during loading from the duration corresponding to a dispensing stroke duration that is shorter than the aspiration stroke duration (block 176)). The difference in average motor current for the dispensing stroke compared to the aspiration stroke (D) is also calculated (block 178). Block 180 shows the dispensing stroke duration reduction per block (e.g., 2 seconds Th stroke (shorter than) or extension of the endstop switch actuation duration per block 182 (for example, 1 second Th switch (larger than), or stroke duration difference per block 184 (for example, 0.13 microseconds of Th delta (A difference greater than) or a specified threshold Th per block 186 iDiffIf an abnormal pump operating condition is detected, such as the difference in average motor current between the dispensing stroke and the suction stroke being greater than 0, the counter is incremented (block 192). When the counter reaches a selected value per block 194 (for example, a counter value of 8 corresponding to 8 pump cycles in which the threshold for normal operation is not met), for example, an obstruction is detected per block 196, an obstruction indicator can be generated, and / or the pump operation can be terminated. If none of these obstruction conditions are met, the counter remains cleared per block 190 (e.g., a value of 0), the next pump cycle is detected, and the relevant 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 are optional to achieve alternative exemplary algorithms using the remaining blocks 180, 182, 184, and 186. Those skilled in the art will understand that, with respect to its application, this disclosure is not limited to the structural and arrangement details of the components described in the following description or shown in the drawings.

[0084] The embodiments described herein are subject to other possible embodiments and can be implemented or performed in various ways. It will also be understood that the language and terminology used herein are for illustrative purposes only and should not be considered limiting. The use of “includes,” “equipped with,” or “has” and their variations herein means to include the items listed thereafter and their equivalents, as well as additional items. Unless otherwise limited, the terms “connected,” “joined,” and “attached” and their variations herein are used broadly and include direct and indirect connection, joining, and attachment. Furthermore, the terms “connected” and “joined” and their variations are not limited to physical or mechanical connection or joining. Additionally, terms such as “above,” “below,” “bottom,” and “upper” are relative and are used to aid in explanation, not limiting.

[0085] The components of the exemplary devices, systems, and methods used in the described embodiments of the present invention can be implemented at least in part within digital electronic circuits, analog electronic circuits, or within computer hardware, firmware, software, or a combination thereof. These components can be implemented as computer program products, such as computer programs, program code, or computer instructions, tangibly embodied in an information carrier or machine-readable storage device for execution by or control of a data processing device, such as a programmable processor, a computer, or multiple computers.

[0086] Computer programs can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as standalone programs or as modules, components, subroutines, or other units suitable for use in a computing environment. Computer programs can be deployed to run on one computer or on multiple computers at one site, or distributed across multiple sites and interconnected by a communication network. Furthermore, functional programs, code, and code segments for achieving exemplary embodiments of the present invention can be readily interpreted as being within the scope of the invention by a programmer skilled in the art to which the invention relates. Method steps associated with exemplary embodiments of the present invention can be executed by one or more programmable processors that execute computer programs, code, or instructions to perform a function (for example, by acting on input data and / or producing an output). For example, method steps can also be executed by special-purpose logic circuits, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits), and as such, the apparatus of exemplary embodiments of the present invention can be implemented.

[0087] Various exemplary logic blocks, modules, and circuits described in relation to embodiments disclosed herein may be implemented or run with general-purpose processors, digital signal processors (DSPs), ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors related to a DSP core, or any other such configuration.

[0088] Processors suitable for executing computer programs include, for example, both general-purpose microprocessors and special-purpose microprocessors, and any one or more processors in any type of digital computer. Generally, a processor will receive instructions and data from read-only memory or random-access memory or both. Essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, 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 operablely coupled to receive data from or transfer data to them, or both. Suitable information carriers for embodying computer program instructions and data include, for example, semiconductor memory devices, such as electrically programmable read-only memory i.e., ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory devices, and all forms of non-volatile memory, 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). Processors and memory can be supplemented by or incorporated into special-purpose logic circuits.

[0089] Those skilled in the art will understand that information and signals can be represented using any of the various different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the above description may be represented by voltage, electric current, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any combination thereof.

[0090] Those skilled in the art will further understand that various exemplary logic blocks, modules, circuits, and algorithmic steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. To clearly demonstrate this hardware and software compatibility, various exemplary components, blocks, modules, circuits, and steps have been described above in general terms with respect to their functions. Whether such functions are implemented as hardware or as software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art will understand that the described functions may be implemented in various forms for each specific application, but such implementation decisions should not be construed as causing a departure from the scope of the invention. Software modules may reside in random access memory (RAM), flash memory, ROM, EPROM, EEPROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. The exemplary storage medium may be coupled to a processor, and such a processor may read information from and write information to the storage medium. Alternatively, the storage medium may be integrated with the processor. In other words, the processor and storage medium may reside within an integrated circuit or may be implemented as discrete components.

[0091] Computer-readable non-temporary media include all types of computer-readable media, including magnetic storage media, optical storage media, flash media, and solid-state storage media. It should be understood that software is installed within a central processing unit (CPU) device and is available for sale in conjunction with it. Alternatively, software can be retrieved and loaded into a CPU device, including obtaining the software through physical media or distributed systems, such as from a server owned by the software creator or from a server used by a server not owned by the software creator. Software can also be stored on servers for distribution over the internet, for example.

[0092] The descriptions and figures presented above are intended to be illustrative only and are not intended to limit the invention by any means other than those described in the following claims. It should be noted that those skilled in the art will readily be able to combine various technical aspects of various elements of the various exemplary embodiments described above in numerous other forms, all of which are considered to fall within the scope of the invention.

Claims

1. A pump comprising: a chamber configured to receive fluid from a reservoir into a chamber and to have at least one port for fluid to flow out of the chamber; and a pumping mechanism configured to control the suction of a predetermined amount of the fluid into the chamber during a suction stroke and to control the dispensing of a predetermined amount of the fluid from the chamber during a dispensing stroke; A pump measuring device configured to generate a pump measurement value for at least one of the dispensing strokes performed by the pump and the suction strokes performed by the pump, A processing device configured to analyze pump measurements, including the pump measurements for each of the at least one plurality of the suction stroke and the dispensing stroke, and to determine when the pump measurements include a plurality of the pump measurements that satisfy a predetermined metric designated as an indicator of occlusion. Equipped with, The pump measuring device comprises a current sensing device configured to detect pumping mechanism currents for a plurality of such pump cycles between at least one of the suction stroke and the dispensing stroke of the pump cycle. The pump measurement value corresponds to the pumping mechanism current, The pump measurement includes the pumping mechanism current for a selected number of the multiple pump cycles, and the default metric includes the average pumping mechanism current exceeding a specified current value that is higher than the average value of the pumping mechanism current when no blockage occurs in the pump. The pump measurement further corresponds to the duration of at least one of the suction stroke and the dispensing stroke, and the default metric further includes a selected duration that is longer than the average value of the pump measurement when no blockage occurs in the pump. The processing device is further configured to determine, for each of a plurality of pump cycles, the average pumping mechanism current for the suction stroke, the average pumping mechanism current for the dispensing stroke, and the difference between the average pumping mechanism current for the dispensing stroke and the average pumping mechanism current for the suction stroke, wherein the default metric further includes a specified value for the difference, when exceeded, indicating occlusion. An injection device with integrated occlusion sensing.

2. An infusion device having integrated occlusion sensing according to claim 1, further comprising an indicator, wherein the processing device is configured to activate the indicator as an occlusion alert in response to a determination that a plurality of the pump measurements satisfy the predetermined metric.

3. An injection device having an integrated blockage sensing according to claim 1, wherein the processing device is configured to automatically terminate the operation of the pumping mechanism in response to a determination that a plurality of the pump measurements satisfy the predetermined metric.

4. The pump measurement value further corresponds to the duration of the dispensing stroke in a plurality of dispensing strokes, an infusion device having integrated occlusion sensing according to claim 1.

5. An infusion device having integrated occlusion sensing according to claim 1, wherein the pump measurement further corresponds to the duration of at least one of the suction stroke and the dispensing stroke, and the default metric is a selected duration shorter than the average value of the pump measurement when no occlusion occurs in the pump.

6. Infusion device having integrated occlusion sensing according to claim 1, wherein the pump measuring device comprises an endstop switch on the pump configured to be activated when the pumping mechanism completes at least one of the suction stroke and the dispensing stroke, the endstop switch being connected to the processing device to determine the duration of each of the at least one of the suction stroke and the dispensing stroke.

7. An infusion device having integrated occlusion sensing according to claim 6, further comprising a selected duration for endstop switch activation, wherein the pump measurement corresponds to the duration of endstop switch activation, and the default metric is longer than the average value of the pump measurement when no occlusion occurs in the pump.

8. The pump measuring device comprises an endstop switch on the pump configured to be activated when the pumping mechanism completes at least one of the suction stroke and the dispensing stroke, and the endstop switch is connected to the processing device to determine the duration of each of the at least one of the suction stroke and the dispensing stroke, such that the default metric for the endstop switch activation further includes a selected duration for the endstop switch activation that is longer than the average value of the pump measurements when no blockage occurs in the pump. The pump measurement includes at least two of the following: the duration of the endstop switch operation; the duration of at least one of the aspiration stroke and the dispensing stroke; the time difference between the aspiration stroke and the dispensing stroke; and the difference between the average pumping mechanism current of the dispensing stroke and the average pumping mechanism current of the aspiration stroke, wherein the default metric corresponding to the stroke duration is a selected duration shorter than the average value of the stroke duration when no blockage occurs in the pump; and the default metric corresponding to the dispensing stroke duration difference relative to the aspiration stroke duration is a selected duration greater than the average value of the stroke duration difference when no blockage occurs in the pump; and the processing device is configured to analyze the pump measurement and determine when the pump measurement includes a plurality of the pump measurement that satisfy the corresponding default metric. An injection device having an integrated occlusion sensing as described in claim 1.

9. An infusion device having integrated occlusion sensing according to claim 1, wherein the pump measurement corresponds to the time difference between the suction stroke and the dispensing stroke, and the default metric corresponding to the dispensing stroke duration difference relative to the suction stroke duration is a selected duration greater than the average value of the stroke duration difference when no occlusion occurs in the pump.

10. An infusion device having integrated occlusion sensing according to claim 1, wherein the pump measurement also includes the duration of at least one of the suction stroke and the dispensing stroke, the default metric corresponding to the stroke duration is a selected duration shorter than the average value of the stroke duration when no occlusion occurs in the pump, and the processing device is configured to analyze the pump measurement and determine when the pump measurement includes a plurality of the pump measurements that satisfy the corresponding default metric.

11. The steps of operating a pump comprising a chamber configured to receive fluid from a reservoir into the chamber and to have at least one port for fluid to flow out of the chamber, and a pumping mechanism configured to control the suction of a predetermined amount of the fluid into the chamber during a suction stroke and to control the dispensing of a predetermined amount of the fluid from the chamber during a dispensing stroke, The steps include operating a pump measuring device to generate a pump measurement value for at least one of the suction strokes performed by the pump and each dispensing stroke performed by the pump, The steps include analyzing the pump measurement, which includes the pump measurement for each of the at least one of the pump measurement for the suction stroke and the dispensing stroke, in order to determine when the pump measurement includes a plurality of the pump measurement that satisfy a predetermined metric designated as an indicator of occlusion, The step includes detecting a pumping mechanism current for a plurality of such pump cycles during at least one of the suction stroke and the dispensing stroke of the pump cycle, The pump measurement value corresponds to the pumping mechanism current, The pump measurement includes the pumping mechanism current for a selected number of the multiple pump cycles, and the default metric includes the average pumping mechanism current exceeding a specified current value that is higher than the average value of the pumping mechanism current when no blockage occurs in the pump. The pump measuring device is operated to generate a pump measurement corresponding to the duration of at least one of the suction stroke and the dispensing stroke, the default metric further comprising a selected duration longer than the average value of the pump measurement when no blockage occurs in the pump, The step of analyzing pump measurements includes, for each of a plurality of pump cycles, determining the average pumping mechanism current for the suction stroke, the average pumping mechanism current for the dispensing stroke, and the difference between the average pumping mechanism current for the dispensing stroke and the average pumping mechanism current for the suction stroke, wherein the default metric further includes a specified value for the difference, when exceeded, indicating occlusion. A method for detecting blockages in an injection pump.

12. The method for sensing blockages according to claim 11, further comprising the step of activating an indicator blockage alert in response to a determination that a plurality of the pump measurements satisfy the predetermined metric.

13. The method for detecting blockages according to claim 11, further comprising the step of automatically terminating the operation of the pumping mechanism in response to a determination that a plurality of the pump measurements satisfy the predetermined metric.

14. The method for occlusion sensing according to claim 11, further comprising the step of operating the pump measuring device to generate pump measurement values ​​corresponding to the duration of the dispensing strokes in a plurality of dispensing strokes.

15. The method for sensing an obstruction according to claim 11, further comprising the step that the pump measurement value further corresponds to the duration of at least one of the suction stroke and the dispensing stroke, and the default metric is configured as a selected duration shorter than the average value of the pump measurement values ​​when no obstruction occurs in the pump.

16. The steps include configuring the pump measuring device as an end-stop switch on the pump that is activated when the pumping mechanism completes at least one of the suction stroke and the dispensing stroke, The steps include connecting the endstop switch to a processing device configured to analyze the signal from the endstop switch in order to determine the duration of each of the at least one of the aspiration stroke and the dispensing stroke; The method for occlusion sensing according to claim 11, further comprising:

17. The method for sensing blockages according to claim 16, further comprising a selected duration for endstop switch activation, wherein the pump measurement corresponds to the duration of endstop switch activation, and the default metric is longer than the average value of the pump measurement when no blockage occurs in the pump.

18. The pumping mechanism further includes the step of configuring the pump measuring device as an end-stop switch on the pump that is activated when at least one of the suction stroke and the dispensing stroke is completed, such that the default metric further includes a selected duration for end-stop switch activation, where the default metric is longer than the average value of the pump measurements when no blockage occurs in the pump. The method for sensing blockages according to claim 11, wherein the pump measurement includes at least two of the following: the duration of the endstop switch operation; the duration of at least one of the suction stroke and the dispensing stroke; the time difference between the suction stroke and the dispensing stroke; and the difference between the average pumping mechanism current of the dispensing stroke and the average pumping mechanism current of the suction stroke, wherein the default metric corresponding to the stroke duration is a selected duration shorter than the average value of the stroke duration when no blockage occurs in the pump; and the default metric corresponding to the dispensing stroke duration difference relative to the suction stroke duration is a selected duration greater than the average value of the stroke duration difference when no blockage occurs in the pump, and the step of analyzing the pump measurement includes determining when the pump measurement includes a plurality of the pump measurement that satisfy the corresponding default metric.

19. The method for sensing an obstruction according to claim 11, wherein the pump measurement corresponds to the time difference between the suction stroke and the dispensing stroke, and the default metric corresponding to the dispensing stroke duration difference relative to the suction stroke duration is a selected duration that is greater than the average value of the stroke duration difference when no obstruction occurs in the pump.

20. The method for sensing an obstruction according to claim 19, wherein the pump measurement also includes the duration of at least one of the suction stroke and the dispensing stroke, the default metric corresponding to the stroke duration is a selected duration shorter than the average value of the stroke duration when no obstruction occurs in the pump, and the step of analyzing the pump measurement includes determining when the pump measurement includes a plurality of the pump measurement that satisfy the corresponding default metric.

21. A method for sensing blockage in an injection pump, A step of operating a pump comprising: a chamber that receives fluid from a reservoir into the chamber and has at least one port through which the fluid flows out of the chamber; and a pump mechanism configured to operate for a plurality of pump cycles, each of which pump cycles includes at least a dispensing stroke, and controlling the dispensing of a certain amount of the fluid from the chamber during the dispensing stroke of each of the plurality of pump cycles; The steps include: operating a pump stroke measuring device to generate pump stroke measurements related to the dispensing stroke in each of the plurality of pump cycles; The steps include detecting the pumping mechanism current during the dispensing stroke in each of the plurality of pump cycles, A step of using a processing device to analyze pump measurements, including the pump stroke measurement and the pumping mechanism current, for each pump cycle of the plurality of pump cycles, and determining when the pump stroke measurement and the pumping mechanism current for the dispensing stroke satisfy a predetermined metric and a second predetermined metric, respectively, which are designated as indicators of blockage. An obstruction sensing method, further including the following.

22. The blockage sensing method according to claim 21, further comprising the step of automatically terminating the operation of the pump mechanism in response to a determination that the selected number of pump stroke measurements and the pumping mechanism current of the dispensing strokes satisfy the predetermined metric and the second predetermined metric, respectively.

23. The blockage sensing method according to claim 21, further comprising the step of incrementing a counter whenever the analysis of the pump measurement values ​​determines that one of the dispensing strokes in each of the plurality of pump cycles satisfies at least one of the predetermined metric and the second predetermined metric.

24. The blockage sensing method according to claim 23, further comprising the step of the counter having a specified threshold count, and automatically terminating the operation of the pumping mechanism in response to a determination that the counter has reached the specified threshold count.

25. The occlusion sensing method according to claim 24, wherein the threshold count corresponds to a value of 2 or more.

26. The blockage sensing method according to claim 21, wherein the step of analyzing the pump measurement value including the pumping mechanism current includes the step of determining an average pumping mechanism current corresponding to the average of the values ​​of the pumping mechanism current over time corresponding to at least a portion of the dispensing stroke.

27. The occlusion sensing method according to claim 21, wherein the predetermined metric corresponds to the duration of a specified time.

28. The blockage sensing method according to claim 21, wherein the second predetermined metric is a specified current value.

29. The blockage sensing method according to claim 28, wherein the second predetermined metric includes a specified current value that is higher than the average value of the pumping mechanism current when no blockage occurs in the pump.

30. The blockage sensing method according to claim 21, wherein the step of operating the pump stroke measuring device includes operating one or more pump stroke measuring components selected from an interlock located on the pump with respect to a limit switch provided on the pump mechanism, one or more optical sensors, and an encoder having an optical switch located on the pump with respect to the pump mechanism, to determine the position of the pump mechanism during at least one of drawing the fluid into the chamber and dispensing the fluid from the chamber.

31. The blockage sensing method according to claim 30, wherein the step of operating the pump stroke measuring device further includes providing the output from one or more pump stroke measuring components to the processing device to determine the duration of at least one of the dispensing stroke and the pump cycle.

32. The obstruction sensing method according to claim 21, wherein the pump stroke measuring device is an endstop switch on the pump configured to be activated when the pump mechanism completes at least one of the dispensing stroke and the pump cycle, and further comprises the step of providing the output from the endstop switch to the processing device to determine the duration of each of the at least one of the dispensing stroke and the pump cycle.

33. The obstruction sensing method according to claim 32, wherein the pump stroke measurement corresponds to the duration of operation of the end stop switch, and the predetermined metric is a selected duration of operation of the end stop switch that is longer than the average value of the pump stroke measurement when no obstruction occurs in the pump.

34. The step of operating the pump includes the step of operating a motor associated with the pump mechanism and the step of detecting a voltage on a sensing resistor provided in the pump to detect the motor current, The steps include: digitizing the detected voltage and generating a digitized voltage output to be provided to the processing device; The steps include: operating the processing device to calculate the pumping mechanism current from the digitized voltage output; The occlusion sensing method according to claim 21, further comprising:

35. The blockage sensing method according to claim 21, wherein the step of operating the pump includes the step of operating a pulse-width modulation (PWM) drive motor associated with the pump mechanism, and the step of detecting the pumping mechanism current includes the step of providing PWM data to the processing device and the step of operating the processing device to determine the pumping mechanism current from the PWM data.

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