Systems, equipment, and methods for detecting blockages using pump operation measurements.

Abstract

A technical solution is provided for monitoring the operation of medical delivery devices, such as infusion pumps, for clogging. This solution employs sensing the pump motor current and monitoring the average motor current difference between the dispensing and suction strokes in the pump cycle. The solution can be implemented alone or in combination with other clogging sensing methods using one or more pump measurement data, such as pump stroke duration, end stop or limit switch activation, and the duration difference between the suction and dispensing strokes, to detect clogging. The pump stroke duration is, for example, the duration of the suction or dispensing stroke in a rotary metering pump or reciprocating pump.

Description

[0001] This application is a divisional application of Chinese patent application No. 201910108210.5, filed on February 3, 2019, entitled "System, apparatus and method for Detecting Blockage Using Pump Operation Measurements". Technical Field

[0002] This invention relates to systems, methods, and apparatus for clogging detection. Exemplary embodiments of the invention relate to clogging detection using pump operating parameters or the activation state of a pump operating monitoring switch to exclude the addition of other pressure sensing components. These parameters are, for example, pump duration (e.g., suction stroke or distribution stroke duration) in a rotary metering pump or reciprocating pump. Pump motor current sensing can also be used to detect clogging in the pump. Background Technology

[0003] Diabetes is a group of diseases characterized by high blood sugar levels caused by the inability of individuals to maintain adequate insulin production when needed. Untreated, diabetes can be dangerous for affected patients and can lead to serious health complications and premature death. However, by utilizing one or more treatment options to help control diabetes, these complications and their risk can be minimized.

[0004] Treatment options for people with diabetes include specialized diets, oral medications, and / or insulin therapy. An effective approach to insulin therapy and diabetes control is infusion therapy or infusion pump therapy using an insulin pump. Insulin pumps can deliver a continuous infusion of insulin to a diabetic patient at varying rates to more closely match the function and behavior of the pancreas in non-diabetic individuals who produce the required insulin. Furthermore, insulin pumps can help a diabetic patient 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 a needle or flexible catheter, through which insulin is infused. Infusion pump therapy offers the advantages of continuous insulin infusion, precise dosing, and programmable delivery schedules.

[0005] Infusion pumps can experience malfunctions or abnormalities, such as leaks, blockages, or air bubbles in the fluid path, without the user necessarily noticing. Detection of malfunctions, such as partial or complete blockages along the fluid path in the infusion pump, is necessary to maintain precisely controlled drug delivery and advise the user to discontinue the faulty infusion device. A typical solution for blockage detection is to place a pressure sensor in the infusion pump system and report a blockage when the pressure exceeds a certain threshold. However, adding a pressure sensor increases system complexity (e.g., mechanical, electrical, and / or software complexity), increases system power consumption, and increases the cost of the infusion pump.

[0006] For medical devices where some or all of their components are disposable for ease of use and cost reduction (e.g., wearable drug delivery pumps), it is undesirable to add other components (e.g., pressure sensors) and increase associated costs and complexity. Therefore, there is a need for accurate blockage detection without adding infusion pump components and without increasing the complexity and cost of the infusion pump itself. Summary of the Invention

[0007] The exemplary embodiments of the present invention overcome the above and other problems and achieve additional advantages.

[0008] One aspect of an exemplary embodiment is to provide an infusion device with integrated blockage sensing, comprising: a pump including: a chamber configured to receive fluid from a reservoir into the chamber, and fluid flowing out of the chamber through the at least one port; and a pumping mechanism configured to control the pumping of a quantity of fluid into the chamber during a suction stroke and to control the dispensing of a quantity of fluid from the chamber during a dispensing stroke; a pump measuring device configured to generate pump measurements associated with at least one of each suction stroke and each dispensing stroke performed by the pump; and a processing device configured to: analyze the pump measurements, the pump measurements including pump measurements for each of a plurality of strokes of at least one of the suction stroke and the dispensing stroke; and determine when the pump measurements include a plurality of pump measurements that satisfy a predetermined metric designated as an indication of blockage.

[0009] According to various aspects of exemplary embodiments of the present invention, the infusion pump with integrated clogging sensing also includes an indicator, and the processing device is configured to operate the indicator as a clogging alarm in response to determining that a plurality of pump measurements meet a predetermined metric.

[0010] According to various aspects of exemplary embodiments of the present invention, the processing device is configured to automatically terminate the operation of the pumping mechanism in response to determining that a plurality of pump measurements meet a predetermined metric.

[0011] According to various aspects of exemplary embodiments 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 predetermined measure is a selected duration shorter than the average of the pump measurements when no blockage occurs in the pump.

[0012] According to various aspects of exemplary embodiments of the present invention, the pump measuring device is an end stop switch on the pump, configured to be activated when the pumping mechanism completes at least one of a suction stroke and a dispensing stroke. The end stop switch is connected to a processing device to determine the duration of each of the at least one of the suction stroke and the dispensing stroke.

[0013] According to various aspects of exemplary embodiments of the present invention, the pump measurement corresponds to the duration of the end stop switch activation state, and the predetermined measure is a selected duration of the end stop switch activation state that is longer than the average value of the pump measurement when no blockage occurs in the pump.

[0014] According to various aspects of exemplary embodiments of the present invention, the infusion device with integrated blockage sensing further includes a current sensing device configured to detect a pumping mechanism current for at least one of a suction stroke and a dispensing stroke of a plurality of pump cycles. Pump measurements correspond to the pumping mechanism current; and the pump measurements include the pumping mechanism current for a selected number of pump cycles among the plurality of pump cycles. A predetermined metric includes an 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, the processing device may be configured to determine, for each of the plurality of pump cycles, an average pumping mechanism current during the suction stroke, an average pumping mechanism current during the dispensing stroke, and a difference between the average pumping mechanism current during the dispensing stroke and the average pumping mechanism current during the suction stroke. The predetermined metric may be a specified value for this difference, exceeding which indicates a blockage.

[0015] According to various aspects of exemplary embodiments of the present invention, the pump measuring device is an end stop switch on the pump, the end stop switch being configured to be activated when the pumping mechanism completes at least one of a suction stroke and a distribution stroke. The end stop switch is connected to a processing device to determine the duration of each of the at least one of the suction stroke and the distribution stroke, such that for a pump measurement value corresponding to the duration of the end stop switch activation state, a predetermined measure is a selected duration of the end stop switch activation state that is longer than the average pump measurement value when no blockage occurs in the pump. The pump measurement value includes at least two of the following: the duration of the end stop switch activation state, the duration of at least one of the suction stroke and the distribution stroke, the time difference between the suction stroke and the distribution stroke, and the difference between the average pumping mechanism current during the distribution stroke and the average pumping mechanism current during the suction stroke. The predetermined measure corresponding to the stroke duration is a selected duration that is shorter than the average stroke duration when no blockage occurs in the pump. The predetermined measure corresponding to the difference between the distribution stroke duration and the suction stroke duration is a selected duration that is larger than the average difference between the stroke durations when no blockage occurs in the pump. The processing unit is configured to analyze pump measurements and determine when the pump measurements include multiple pump measurements that satisfy one of a predetermined metric.

[0016] According to aspects of exemplary embodiments of the present invention, the pump measurement corresponds to the time difference between the suction stroke and the distribution stroke, and a predetermined measure corresponding to the difference in duration of the distribution stroke relative to the duration of the suction stroke is a selected duration greater than the average difference in stroke durations when no blockage occurs in the pump. According to aspects of exemplary embodiments of the present invention, the pump measurement may further include the duration of at least one of the suction stroke and the distribution stroke, and a predetermined measure corresponding to the stroke duration is a selected duration shorter than the average stroke durations 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 corresponding to one of the predetermined measures.

[0017] One aspect of an exemplary embodiment of the present invention is to provide a blockage sensing method for blockage sensing in an infusion pump, comprising: operating a pump including a chamber having at least one port for receiving fluid from a reservoir into the chamber and for fluid to flow out of the chamber through the port; and a pumping mechanism configured to control the intake of a quantity of fluid into the chamber during a suction stroke and to control the dispensing of a quantity of fluid from the chamber during a dispensing stroke; operating a pump measuring device to generate pump measurements associated with at least one of each suction stroke and each dispensing stroke performed by the pump; and analyzing the pump measurements (which include pump measurements for each of a plurality of strokes of at least one of the suction stroke and the dispensing stroke) to determine when the pump measurements include a plurality of pump measurements that satisfy a predetermined metric designated as a blockage indication.

[0018] According to various aspects of exemplary embodiments of the present invention, the blockage sensing method further includes activating an indicator to issue a blockage alarm in response to determining that a plurality of pump measurements meet a predetermined metric.

[0019] According to various aspects of exemplary embodiments of the present invention, the blockage sensing method further includes automatically terminating the operation of the pumping mechanism in response to determining that a plurality of pump measurements meet a predetermined metric.

[0020] According to various aspects of exemplary embodiments of the present invention, the blockage sensing method further includes operating a pump measuring device to generate pump measurements corresponding to the duration of at least one of a suction stroke and a dispensing stroke. For example, the blockage sensing method may use a predetermined metric as a selected duration shorter than the average of pump measurements when no blockage occurs in the pump.

[0021] According to various aspects of exemplary embodiments of the present invention, the blockage sensing method further includes configuring a pump measuring device as an end stop switch on the pump, the end stop switch being activated when the pumping mechanism completes at least one of a suction stroke and a dispensing stroke; and connecting the end stop switch to a processing device configured to analyze signals from the end stop switch to determine the duration of each of the suction stroke and the dispensing stroke.

[0022] According to various aspects of exemplary embodiments of the present invention, the pump measurement corresponds to the duration of the end stop switch activation state, and the predetermined metric is a selected duration of the end stop switch activation state that is greater than the average value of the pump measurement when no blockage occurs in the pump.

[0023] According to aspects of exemplary embodiments of the present invention, a blockage sensing method includes detecting pumping mechanism current for at least one of a suction stroke and a distribution stroke of a plurality of pump cycles. Pump measurements correspond to the pumping mechanism current. The pump measurements include pumping mechanism current for a selected number of pump cycles among the plurality of pump cycles. A predetermined metric includes an average pumping mechanism current exceeding a specified current value, said specified current value being higher than the average pumping mechanism current when no blockage occurs in the pump. For example, analyzing pump measurements may include determining, for each of the plurality of pump cycles, an average pumping mechanism current during the suction stroke, an average pumping mechanism current during the distribution stroke, and a difference between the average pumping mechanism current during the distribution stroke and the average pumping mechanism current during the suction stroke. The predetermined metric is a specified value for this difference, exceeding which indicates a blockage.

[0024] According to various aspects of exemplary embodiments of the present invention, the blockage sensing method further includes configuring a pump measuring device as an end stop switch on the pump, said end stop switch being activated when the pumping mechanism completes at least one of a suction stroke and a distribution stroke, such that for a pump measurement value corresponding to the duration of the end stop switch activation state, a predetermined measure is a selected duration of the end stop switch activation state that is longer than the average pump measurement value when no blockage occurs in the pump. The pump measurement value includes at least two of the following: the duration of the end stop switch activation state, the duration of at least one of the suction stroke and the distribution stroke, the time difference between the suction stroke and the distribution stroke, and the difference between the average pumping mechanism current during the distribution stroke and the average pumping mechanism current during the suction stroke. The predetermined measure corresponding to the stroke duration is a selected duration that is shorter than the average stroke duration when no blockage occurs in the pump. The predetermined measure corresponding to the difference between the distribution stroke duration and the suction stroke duration is a selected duration that is larger than the average difference between the stroke durations when no blockage occurs in the pump. Analyzing the pump measurement value includes determining when the pump measurement value includes a plurality of pump measurement values ​​that satisfy one of the predetermined measures.

[0025] According to aspects of exemplary embodiments of the present invention, the pump measurement corresponds to the time difference between the suction stroke and the distribution stroke, and a predetermined measure corresponding to the difference in the duration of the distribution stroke relative to the duration of the suction stroke is a selected duration greater than the average difference in stroke durations 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 distribution stroke, and a predetermined measure corresponding to the stroke duration is a selected duration shorter than the average stroke durations when no blockage occurs in the pump. Analyzing the pump measurement includes determining when the pump measurement includes multiple pump measurements corresponding to one of the predetermined measures.

[0026] Additional and / or other aspects and advantages of embodiments of the present invention will be set forth in the description below, or will be apparent from the description or may be learned by practice of the invention. The invention may include apparatus and methods for operating having one or more of the foregoing aspects, and / or one or more of the features thereof, and combinations thereof. The invention may include, for example, one or more of the features described in the appended claims and / or combinations of the foregoing aspects. Attached Figure Description

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

[0028] Figure 1 and Figure 2 This is a partial perspective view of an exemplary pump component in an exemplary drug delivery device operating according to a blockage detection algorithm according to an exemplary embodiment of the present invention;

[0029] Figure 3A and 3B They are Figure 1 and Figure 2 A perspective view of the pump components in an exemplary drug delivery device, arranged according to a dispensing preparation phase and a suction preparation phase.

[0030] Figure 3C This is a perspective view of components in an exemplary drug delivery device, including... Figure 1 and Figure 2 Exemplary pump components and related circuitry on printed circuit boards;

[0031] Figure 4 This is a block diagram of components in an exemplary drug delivery device;

[0032] Figure 5A and 5B These are simplified diagrams illustrating the pump durations for multiple suction and multiple dispensing operations of an exemplary drug delivery device under normal operating conditions.

[0033] Figure 6A and 6B These are shown as the methods for generating Figure 5A and Figure 5B However, a simplified diagram of the pump duration for multiple suction and multiple dispensing operations of the same type of drug delivery device under clogging operating conditions;

[0034] Figure 7 This is a flowchart illustrating exemplary operation of an exemplary drug delivery device according to an exemplary embodiment of the present invention, operating according to a blockage detection algorithm employing a travel duration standard;

[0035] Figure 8A and Figure 8B Exemplary end stop or limit switch activation data are depicted during normal and blocked operation of the exemplary pump, respectively;

[0036] Figure 9 This is a flowchart illustrating exemplary operation of an exemplary drug delivery device according to an exemplary embodiment of the present invention, which operates according to a blockage detection algorithm employing an end stop or limit switch activation duration standard;

[0037] Figure 10 Exemplary pump measurement data is depicted, indicating the duration of short dispensing strokes (e.g., when the pump piston cannot move during a blockage).

[0038] Figure 11Exemplary pump measurement data are depicted, indicating the duration of extended end stop or limit switch activation (e.g., when pumping back to the pump reservoir due to blockage).

[0039] Figure 12A , 12B 12C and 12D depict pump measurement data from the respective pumps, indicating the long distribution stroke duration relative to the suction stroke duration (e.g., when leakage occurs due to blockage);

[0040] Figure 13 This is a flowchart illustrating exemplary operation of an exemplary drug delivery device according to a blockage detection algorithm employing a leakage detection standard, based on an exemplary embodiment of the present invention.

[0041] Figure 14 This is a flowchart illustrating exemplary operation of an exemplary drug delivery device according to an exemplary embodiment of the present invention, which operates using a standard combination of blockage detection algorithms;

[0042] Figure 15 This is a schematic diagram of a pump motor of a drug delivery device with a current sensor according to an exemplary embodiment of the present invention;

[0043] Figure 16 This is a flowchart illustrating exemplary operation of an exemplary drug delivery device according to an exemplary embodiment of the present invention, which operates according to a blockage detection algorithm employing a pump motor current standard;

[0044] Figure 17A , 17B 17C, 17D and 17E depict pump measurement data from various exemplary delivery devices, indicating motor current during the distribution stroke before and after blockage;

[0045] Figure 18A , 18B 18C, 18D, and 18E depict the average motor current for selected time periods for each exemplary conveying device; and

[0046] Figure 19 This is a flowchart illustrating exemplary operation of an exemplary drug delivery device according to an exemplary embodiment of the present invention, which operates according to a blockage detection algorithm employing a combination of a standard and a pump motor current standard.

[0047] Throughout the accompanying drawings, the same reference numerals will be understood to denote the same elements, features, and structures. Detailed Implementation

[0048] Reference will now be made in detail to exemplary embodiments of the invention illustrated in the accompanying drawings. These exemplary embodiments described herein are illustrative by way of example and do not limit the scope of the invention.

[0049] Exemplary embodiments can be used with any type of infusion pump that operates by filling a chamber in one stage (e.g., with a liquid medication from a reservoir) and then emptying the fluid from the chamber in another stage (e.g., to a delivery device, such as a cannula deployed in the patient's body). For example, a reciprocating plunger pump or a rotary metering pump can be used. In either case, the piston or plunger retracts from the chamber to draw or aspirate the medication into the chamber and allow the chamber to fill with a certain amount of medication (e.g., from a medication reservoir or cartridge inlet). The piston or plunger is then reinserted into the chamber to dispense or discharge a certain amount of medication from the chamber (e.g., through an outlet) into a fluid path extending between the pump and the cannula in the patient's body.

[0050] For illustrative purposes, reference is made to the exemplary rotary metering pump described in the commonly owned WO 2015 / 157174, the contents of which are incorporated herein by reference in their entirety. Figure 1 , 2 3A, 3B, and 3C, exemplary infusion pumps (e.g., wearable drug delivery devices, such as insulin patch pumps) include a pump assembly 20 connectable to a DC motor and gearbox assembly (not shown) to rotate a sleeve 24 within a pump manifold 22. A helical groove 26 is provided on the sleeve. As the sleeve 24 rotates in one direction and then in the opposite direction, a coupling pin 28 connected to a piston 30 translates along the helical groove to guide the piston 30 in retraction and insertion within the sleeve 24, respectively. The sleeve has an end plug 34. After the aspiration stroke and thus ready for dispensing, as the piston 30 retracts, two seals 32, 36 located at the respective ends of the piston and end plug within the sleeve 24 define a cavity or chamber 38, such as... Figure 3A As shown. Therefore, the volume of chamber 38 varies depending on the degree of retraction of piston 30. In... Figure 3B After the distribution stroke is shown and thus ready for aspiration, when the piston 30 is fully inserted and the seals 32, 36 are substantially in contact with each other, the volume of chamber 38 is negligible or essentially zero. Two ports 44, 46 are provided relative to pump manifold 22, which includes: inlet 44 through which medication can be drawn from pump 64 (… Figure 4 ) storage 70 ( Figure 4 The drug that has been aspirated into chamber 38 (e.g., by retraction of piston 30 during the aspiration phase) flows in; and the drug that has been aspirated into chamber 38 can be dispensed from chamber 38 via the outlet to, for example, a cannula 72 reaching the patient by reinserting piston 30 into chamber 38. Figure 4 In the fluid path of ).

[0051] Continue to refer to Figure 1 , 2 3A, 3B, and 3C, sleeve 24 may be provided with a hole (not shown) aligned with outlet 46 or inlet 44 (i.e., depending on the degree of rotation of sleeve 24 and therefore the degree of translation of piston 30) to allow drug in chamber 38 to flow through a corresponding one of inlets 44, 46. A pump measuring device 78 may be provided. Figure 4 For example, a sleeve rotation limit switch, the pump measuring device has, for example, an interlock 42 located on the sleeve 24 or its end plug 34 and one or more braking devices 40 cooperating with the interlock 42. The interlock 42 can be installed at each end of the manifold 22. When the pump 64 is in the first position, the braking device 40 at the end face of the sleeve 24 is adjacent to the protrusion 48 of the interlock 42, thereby aligning the side hole in the sleeve 24 with the inlet 44 to receive fluid from the reservoir 70 into the chamber 38. Under certain conditions (e.g., back pressure), it is possible that the friction between the piston 30 and the sleeve 24 is sufficient to cause the sleeve 24 to rotate before the piston 30 and the connecting pin 28 reach either end of the spiral groove 26. This can result in an incomplete pumping of liquid volume per stroke. To prevent this from happening, the interlock 42 prevents the sleeve 24 from rotating until the torque exceeds a predetermined threshold, such as Figure 3A As shown. This ensures that the piston 30 rotates fully within the sleeve until the coupling pin reaches the end of the helical groove 26. Once the coupling pin 28 strikes the end of the helical groove 26, the DC motor and gearbox assembly or other type of pump and valve actuator 66 ( Figure 4 Further movement of the sleeve 24 will increase the torque acting on the sleeve 24 beyond a threshold, causing the interlock 42 to bend and allowing the brake 40 to pass over the protrusion 48. Once the sleeve 24 has rotated to orient its side hole together with the insertion tube 72 or outlet 46, the brake 40 moves through the protrusion 48 in the interlock 42, as... Figure 3B As shown. Another sleeve feature 41 may be provided to engage an electrical switch (e.g., an end stop switch 90), which is disposed on the printed circuit board 92 and arranged relative to the sleeve and / or end plug 34, to mate with the pump measuring device 78, such as... Figure 3C (As shown).

[0052] Figure 4 This is an exemplary system diagram showing a system with an infusion pump (e.g., Figure 1 , 2Example components in an exemplary drug delivery device 10 (pumps of types 3A, 3B, and 3C). The drug delivery device 10 may include: an electronics subsystem 52 for controlling the operation of components in a flow control subsystem 54, such as pump 64; and an insertion mechanism 74 for deploying a cannula 72 for insertion into an infusion site on a patient's skin. A power storage subsystem 50 may include a battery 56, for example, for providing power to components in the electronics subsystem 52 and the flow control subsystem 54. The flow control subsystem 54 may include, for example, an optional filling port 68 for filling a reservoir 70 (e.g., filling the reservoir 70 with medication), although the drug delivery device 10 may optionally be shipped from a manufacturer having reservoirs already filled with it. The flow control subsystem 54 also has a metering subsystem 62, which includes pump 64 and pump actuator 66. As described above, pump 64 may have two ports 44, 46 and associated valve subassemblies that control when fluid enters and exits pump chamber 38 via the respective ports 44, 46. One port is inlet 44, through which fluid, such as a liquid medication, flows from reservoir 70 into pump 64 due to suction or pull strokes, for example, the pump acting on pump plunger or piston 30. The other port is outlet 46, through which fluid exits pump chamber 38 and flows to cannula 72 for delivery to patient pump due to pump discharge or push strokes acting on pump plunger or piston 30. Pump actuator 66 may be a DC motor and gearbox assembly or other pump drive mechanism for controlling plunger or piston 30 and other associated pump components, such as sleeve 24, which can rotate relative to the translational movement of pump piston 30. Microcontroller 58 may be provided with an integrated or separate storage device having computer software instructions to activate, for example, rotation of sleeve 24 in a selected direction, translational or axial movement of piston 30 within sleeve 24 for suction or dispensing strokes, and optionally, rotation of sleeve 24 and piston 30 together during valve state changes, as described above in WO 2015 / 157174. As described below, a blockage detection algorithm according to an exemplary embodiment can be provided to the microcontroller 58 to monitor pump measurements and detect when a blockage operation related to the infusion pump occurs.

[0053] Regardless of the type of pump mechanism 64 used to aspirate a controlled volume of drug into and dispense a controlled volume of drug from the pump chamber 38, pump 64 has an expected pump duration associated with it for one or both of the aspiration and dispensing phases or strokes, which can be attributed to pump characteristics. For example, in Figure 1 , 2In the exemplary pump assembly 20 shown in 3A, 3B, and 3C, the pump duration for aspirating medication into and dispensing medication from chamber 38 is affected by pump characteristics such as the internal volume of pump chamber 38, the length or distance of the pump piston stroke, and the characteristics of the port seals located at the inlet and outlet 44, 46. When the pump pressure is within a specified relative normal operating range, the pump duration for filling chamber 38 with a specified amount of fluid (e.g., the desired dose) and dispensing a specified amount of fluid from the chamber can be determined and used as a baseline for monitoring normal operating conditions of pump 64 and for determining when abnormal operating conditions occur, such as due to fluid leakage from the pump chamber or blockage in the pump fluid path, thereby preventing the delivery of a specified amount of fluid (e.g., the desired dose) from the chamber via the dispensing stroke. This may be undesirable because the patient will not receive the required dose.

[0054] As mentioned above, a typical solution for clogging detection is to place an additional pressure sensor in the pump control system and report a clogging when the pressure exceeds a certain threshold. However, adding a pressure sensor has disadvantages such as increased system complexity (e.g., mechanical, electrical, and / or software complexity), increased system power consumption, and / or increased pump cost. These disadvantages are particularly unfavorable for wearable pump designs, where all or part of the pump will be disposable once the reservoir 70 is emptied or the pump 64 has been used for a selected amount of time and / or to deliver a selected amount of medication.

[0055] According to an exemplary embodiment, blockage detection is performed without additional components such as blockage sensors deployed upstream or downstream of pump 64. Once the microcontroller 58 or other processing device used to control pump operation has performed a pump duration measurement for normal operation (e.g., for one or both of the aspiration and dispensing strokes), the microcontroller 58 can be further controlled to determine when the pump duration measurement is outside a specified range of normal operating conditions and thus indicates a blockage, and to generate an indication that a blockage has been detected. Therefore, pump 64 and / or the entire drug delivery system 10 can then be replaced or repaired, thereby ensuring that the patient is receiving the full, intended dose provided under normal operating conditions.

[0056] When measuring pump duration for pump operation, blockage detection can be achieved by adding computer software instructions to the microcontroller 58 or a remote device controlling the drug delivery device 10. This includes monitoring pump duration and determining when a specified pump duration threshold or other criterion for normal pump operation is not met. Therefore, blockage detection is achieved through a software solution without requiring hardware changes to the pump. As described below, there is a clear difference in pump duration between a normal pump and a blocked pump; therefore, the false alarm rate and missed alarm rate are very low. Thus, the blockage detection algorithm constructed according to various aspects of the exemplary embodiments can provide reliable blockage detection results.

[0057] For example, other metrics can be empirically performed for the selected type of pump 64 to determine a pump duration threshold or range, or to indicate blockage. Metrics for a selected type of pump experiencing normal operating pressure can be compared to metrics for a pump of the same type experiencing at least partial or complete blockage. For example, blockage in the downstream path from the blocked pump 64 to its inlet 72 causes the pressure in the fluid path of pump 64 to increase over time. When the pressure in the blocked pump exceeds a threshold, the blocked pump eventually begins to leak. Log files for normal and blocked pumps can be generated to obtain a corresponding history of pump duration information for the suction and / or distribution strokes. However, it should be understood that different pump measurements other than pump duration (i.e., the duration of the suction or distribution stroke) can be used to determine differences in pump operation during normal and blocked operating conditions and to determine thresholds for monitoring pump operation and distinguishing between normal and blocked operating conditions. For example, as described below, the occurrence of blockage can be detected by activating an extended stroke end switch or by distinguishing a significant difference in the corresponding durations of the suction and distribution strokes.

[0058] Reference Figure 5A and 5B The pumping duration of a clogged pump (e.g., an average of about 1.5 seconds) is significantly shorter than the pumping duration of pump 64 under normal operating conditions (e.g., on the order of 3 to 3.5 seconds). This shorter pumping duration is related to the pumping mechanism, which is, for example, as described above... Figure 1 , 2 The piston 30, sleeve 24, interlock 42, and silicon seals on the inlet and outlet 44, 46 are described in 3A, 3B, and 3C. As described above, different types of pumps 64 can be improved by implementing clogging sensing according to exemplary embodiments, and different pump components can contribute to a shortened pump during clogging conditions. Pump 64 can be a rotary metering pump, a reciprocating pump, or other types of pumps that employ the method of drawing or aspirating fluid from an upstream reservoir and then discharging or distributing that fluid to a separate downstream fluid path leading to the patient.

[0059] Referring to the above text Figure 1 , 2 The exemplary infusion pump 64 described in 3A, 3B, and 3C is driven by a piston 30 that translates within an outer plastic sleeve 24. The pump's suction and dispensing strokes relate to the switching of the pump 64 between an upstream and downstream fluid path. As the piston 30 rotates (e.g., via a DC motor and gearbox assembly not shown), it translates through the sleeve 24, guided by a pin 28 on the piston traveling through a helical groove 26 in the sleeve 24. Once the piston 30 has fully translated through the sleeve 24 and completed its fluid suction or dispensing phase, it engages directly with the sleeve 24 via the pin 28 in the slot 26, and the rotation of the piston 30 and the sleeve 24 becomes coupled. This allows the sleeve 24 to rotate between the upstream and downstream fluid paths and activates the stroke-end electrical switch 90 or the pump measuring device 78 (…). Figure 4 This is associated with and located on pump 64 and / or other components in drug delivery device 10. During normal operation, the presence of interlock 42 prevents piston 30 and sleeve 24 from rotating before piston 30 completes its translational movement through sleeve 24. However, if the pressure in the downstream fluid path increases above a threshold, rotation of piston 30 and sleeve 24 couples and allows sleeve 24 to pass under interlock 42 and activates switch 90 (e.g., activated by sleeve feature 41 associated with pump measuring device 78) before piston 30 completes its translational movement through sleeve. This significantly reduces pumping duration (e.g., from 3 to 3.5 seconds during normal conditions to less than 2 seconds during clogging conditions).

[0060] Now refer to Figure 6A and 6B It displays pump duration data from 64 pumps of multiple similar types across multiple pump cycles. For example, log data from 19 pumps that completed 600 cycles is shown, with 10 pumps operating under normal conditions and 9 pumps operating under blocked conditions. Figure 6A and 6B As can be seen, all clogged pumps had a pump duration range of less than 2 seconds. Some pump durations returned to normal, possibly due to pressure release caused by leaks in the manifold area. The significant difference in pump duration between normally operating pumps and those experiencing clogs allows for the use of clog detection algorithms based on pump duration.

[0061] Reference Figure 7An exemplary blockage detection process includes setting pump measurement thresholds or metrics, such as stroke duration thresholds (block 80), where stroke durations above the threshold indicate normal pump operation and stroke durations below the threshold indicate blockage. To set the thresholds, pump measurement data is analyzed. For example, the suction stroke duration and the dispensing stroke duration can be determined by a limit switch or other pump measurement device 78 provided to the pump. Figure 4 To detect. (Refer to...) Figure 1 , 2 In the exemplary pumps described in 3A, 3B, and 3C, a sleeve rotation limit switch or other pump measuring device 78 is used to determine the stroke or pump duration. For example, a microcontroller 58 and other electronic components such as an end stop switch 90 that mate with the sleeve feature 41 can typically be deployed on a printed circuit board (PCB) 92 associated with the pump 64 or delivery device 10. End stop switch activation data can be collected and stored (e.g., via a memory device integrated with the microcontroller 58 or as a separate component on the PCB 92). A blockage detection algorithm can be provided to the microcontroller 58 for processing the end stop switch activation data to determine if a blockage has occurred. According to another exemplary embodiment, the end stop switch activation data can be provided (e.g., wirelessly or via a wired connection) from the pump 64 to another device having a blockage detection algorithm (e.g., a handheld remote control for the pump 64) or to a non-dedicated computing device (e.g., a mobile phone, personal computer (PC), laptop computer, or other portable computing device) equipped with software or an app including the blockage detection algorithm.

[0062] Pump measurement data were obtained for one or more pumps of the same type operating under normal conditions, and pump measurement data were also obtained for one or more pumps of the same type operating under clogging conditions, as in... Figure 5A and 5B as well as Figure 6A and 6B As shown in the diagram. Pump measurement data from these two sets of pumps can be averaged or otherwise summarized or categorized, and then analyzed to determine the degree of difference between pump measurements for a normally operating pump and those for a clogged pump. A threshold or other metric is determined as a numerical value or a range of values ​​with a margin, above which normal pump measurements will not be higher or / or lower than. The numerical value, or range, and / or margin can be specified by the user or determined automatically based on the pump measurement data obtained from the pumps. As mentioned above, pump measurement data is generated and monitored during normal pump activity and therefore is not an additional operation or component that increases pump complexity.

[0063] Continue to refer to Figure 7Once the pump measurement metric (e.g., stroke duration threshold) is set, the microcontroller 58 in the drug delivery device 10 is controlled by a blockage detection algorithm to obtain pump measurement data (e.g., stroke duration data) for the pump (block 81) and compare the stroke duration data during each pump operation phase or operation cycle (e.g., for each pump cycle) with the pump measurement metric (block 82). When the stroke duration data meets the pump measurement metric (e.g., greater than or equal to 2 seconds of Th for pump 64), the pump delivers the drug to the target pump. stroke When the pump is in normal operation (box 84), the pump is confirmed to be operating normally. When the stroke duration data does not meet the pump measurement metric (e.g., below the blockage detection threshold (e.g., less than 2 seconds of Th for pump 64)... stroke If the pump is blocked, it is determined that the normal operating threshold Th is not met. stroke When the counter increments (box 83), referring to box 85, the counter increments when it reaches a selected value (e.g., corresponding to a threshold Th where normal operation is not met). stroke If the counter value (8) for 8 pump cycles is reached, a blockage is detected. The total number of cycles to be reached before indicating a blockage 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 via the blockage detection algorithm to generate an optional indication that a blockage error has been detected (block 86), and automatically stop the operation of the pump and / or drug delivery device 10, and / or generate an optional indication to the user to stop using the pump (block 88). If the counter has not reached the selected counter value after incrementing according to block 83, pump measurement data collection continues according to block 81. Since the blockage detection algorithm is based on pump duration data or other pump measurement data already implemented in the pump, blockage detection is achieved by checking the pump duration or other measurement data in the software against a selected threshold or metric. Therefore, a software-only solution for detecting blockages is provided, requiring no hardware changes.

[0064] Combination Figure 1 , 2The exemplary pump 64 described in 3A, 3B, and 3C uses one or more on / off limit switches to determine the system state at the limits of the rotational stroke. For example, a multi-stage pump (i.e., a pump that draws fluid in one stage to fill a chamber and then discharges the pump chamber in the next stage) may use some type of end stop switch for each stage to detect when the piston and / or sleeve or other pump components reach a predetermined position corresponding to the completion of drawing or dispensing. 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) in addition to the interlock 42 and the sleeve rotational limit switch (e.g., end stop switch) 90. Alternatively, pump 64 may employ one or more optical sensors or encoders with optical switches to determine the position of the pump components at their end stop positions for completing drawing and / or dispensing.

[0065] Therefore, as referenced Figure 7 And as described in an exemplary embodiment of the invention, the time required to fill the chamber and the time required to discharge the required amount of fluid from the chamber are determined, the discharge time for each stroke is measured at least, and an indication indicating that a blockage has been detected is generated when a selected number of discharge times does not exceed a specified amount (e.g., the stroke duration is shortened on a specified number of pump cycles).

[0066] According to another exemplary embodiment, blockage detection is performed by monitoring the duration of activation or triggering of a pump end stop or limit switch, as described below. Figure 9 As described. Capable of being used alone or in combination, such as in combination. Figure 7 The monitoring data described above, which involves monitoring the duration of short pump strokes, is used to process the monitoring data related to the duration of activation or triggering of the detected pump end stop or limit switch in order to determine whether a blockage has occurred in pump 64.

[0067] As described above, during normal operation, the presence of interlock 42 prevents piston 30 and sleeve 24 from rotating before piston 30 completes its translational movement through sleeve 24. However, with the accumulation of pressure in the downstream fluid path (i.e., during blockage), the rotation of piston 30 and sleeve 24 can prematurely couple; that is, sleeve 24 may rotate prematurely before the expected rotation during valve state changes (e.g., during normal pump operation, when sleeve 24 rotates at the end of piston stroke without axial movement to align its side port with the corresponding one of ports 44, 46). This premature rotational coupling of piston 30 and sleeve 24 further allows sleeve 24 to pass under interlock 42 and trigger switch 78 before piston 30 completes its axial translational movement through sleeve. This significantly shortens the pumping duration (e.g., measured as the time period or duration between pump motor start-up and end stop switch signal), as described above. Figure 7 As explained. In addition, another pump operating characteristic that can be monitored for blockage detection is the duration for which the pump measuring device 78 and its associated switch 90 are in an activated or triggered operating mode or otherwise indicate the start of an activated state.

[0068] In some cases, the pump duration in a clogged pump system may remain normal and not decrease as expected; therefore, monitoring another pump measurement parameter or characteristic can improve the accuracy of clog detection. For example, if the pump sleeve 24 rotates prematurely as expected due to a clog in the pump system, the piston can begin to advance and distribute the fluid payload back to the upstream fluid path as soon as the pump sleeve opens to the upstream fluid path (and before the stroke end signal from switch 90). Because the piston 30 and sleeve 24 can rotate across their entire angular position range, the total pump operating time remains constant with and without a clog. On the other hand, since the piston 30 now rotates and translates through sleeve 24 after the sleeve has already rotated in the upstream channel, the end stop switch 90 is now triggered for an extended period of time. Therefore, clog detection may individually include monitoring the activation or triggering of the extended or extended end stop switch, or it may monitor the activation or triggering of the extended or extended end stop switch in addition to monitoring the shortened pump stroke duration according to the exemplary embodiment.

[0069] To further illustrate how a blockage can extend the activation or triggering of the pump measuring device, refer to [reference needed]. Figure 1 , 2 The exemplary pump 64 described in the exemplary embodiments shown in 3A, 3B, and 3C. During normal operation of the pump 64, when the end stop switch 90 is first struck and dragged by the pump sleeve 24 (e.g., by the sleeve feature 41 engaging with the end stop switch 90) and thus triggered, the end stop switch 90 generates a drop in an end stop switch voltage signal from 1.8V to 0V, which is provided to the microcontroller 58. The end stop switch voltage only returns to 1.8V after the switch 90 is released (e.g., by the disengagement of the sleeve feature 41) and the spring returns to center. In some cases, before the piston 30 completes its axial translation and before the end stop switch 90 disengages from the sleeve feature 41, the side opening of the sleeve 24 opens to the upstream fluid path (e.g., aligned with inlet 44), and when the pressure in the upstream fluid path is low, the piston 30 can begin to advance and translate through the sleeve 24, thereby emptying the pump contents into the upstream fluid path while the end stop switch 90 is in an intermediate triggered state. The end result is an activation signal (e.g., voltage drop) of the end stop switch 90 occurring over an extended period. This pump clogging characteristic... Figure 8A and 8B As shown in the figure, Figure 8Aand 8B The normal duration of switch 90 activation (e.g., 0 volts) of less than 0.5 seconds and the extended duration of end stop or limit switch 90 activation (e.g., 0 volts) of nearly 1.5 seconds are shown respectively.

[0070] Several factors can cause some pumps 64 to exhibit shorter total pump durations (e.g., when piston 30 fails to advance), while others may exhibit longer durations of the end stop switch 90 activation signal (e.g., when piston 30 advances in the upstream fluid path). For example, the alignment of switch 90 on PCB 92 with associated pump components (e.g., interlock 42, brake 40, and sleeve feature 41) can allow for some variability in which sleeve angle position the end stop switch 90 is released and therefore when the end stop switch activation signal is generated and provided to microcontroller 58. Additionally, high pressure in the upstream fluid path from a larger insulin reservoir fill volume can prevent piston 30 from advancing in the upstream fluid path (e.g., resulting in a shorter pump duration), while lower pressure in the upstream fluid path from a smaller insulin reservoir fill volume can allow piston 30 to advance in the upstream fluid path (e.g., resulting in a longer or extended end stop or limit switch activation or "trigger" duration).

[0071] Reference Figure 9 An exemplary blockage detection process includes setting a pump measurement threshold or metric, such as a switch activation duration threshold (box 96), where a switch activation duration below the threshold indicates normal pump operation, while a switch activation duration above the threshold indicates blockage. To set the threshold, pump measurement data can be analyzed. For example, multiple identical pumps 64 can be tested under similar blockage conditions to collect pump measurement data that shows a significant increase in duration, such as a voltage drop in the end stop switch signal when the pump is blocked. Figure 1 , 2 In the case of exemplary empirical measurements of pump 64 in 3A, 3B, and 3C, the switch activation duration during blockage is approximately 1.5 seconds, which is comparable to the expected amount of time for piston 30 to fully translate through sleeve 24. Therefore, the blockage detection algorithm can be configured to record the signal duration of end stop switch 90 according to software instructions (e.g., in microcontroller 58) and compare the recorded switch 90 activation duration with a threshold (e.g., Th). switch A comparison (>1.0 second) is performed to determine if a blockage exists. Figure 9As shown in block 98. For example, end stop or pump limit switch activation data can be collected and stored (e.g., via a memory device integrated with microcontroller 58 or implemented as a separate component on PCB 92). A blockage detection algorithm can be provided to microcontroller 58 for processing end stop switch activation data to determine whether a blockage has occurred. According to another exemplary embodiment, end stop switch activation data can be provided (e.g., wirelessly or via wired connection) from pump 64 to another device (e.g., a handheld remote control for pump 64) or a non-dedicated computing device (e.g., a mobile phone, personal computer (PC), laptop computer, or other portable computing device) equipped with software or an app including the blockage detection algorithm. The switch activation duration data of the blocked pump can be averaged or otherwise summarized or categorized and then analyzed to determine the degree of difference between similar pump measurements of a normally operating pump and pump measurements of a blocked pump. Threshold (e.g., Th) switch Other metrics are defined as a single value or a range of values ​​with a margin, such that the pump measurement will not exceed and / or fall below that range. The value, or range, and / or margin can be specified by the user or determined automatically based on pump measurement data obtained from the pump. As mentioned above, pump measurement data (e.g., switch activation duration) are data generated and monitored during normal pump activity, thus eliminating the need for additional components that increase pump complexity.

[0072] Continue to refer Figure 9 Once a pump measurement metric (e.g., a switch activation duration threshold) is set, the microcontroller 58 in the drug delivery device 10 is controlled by a blockage detection algorithm to obtain pump measurement data (e.g., switch activation duration data) for pump 64 (block 97), and compares the switch activation duration data with the pump measurement metric (block 98) during each pump operation phase or operation cycle (e.g., for each pump cycle). When the switch activation duration data meets the pump measurement metric (e.g., Th less than or equal to 1.0 second), the pump activates the pump metric. switch When the switch activation duration data does not meet the pump measurement metric (e.g., a blockage detection threshold Th greater than 0.1 seconds), the pump is confirmed to be operating normally (box 100). switch When this occurs, it indicates that the pump is experiencing a blockage. When the threshold value Th for normal operation is not met... switch When the counter increments (box 99), referring to box 101, the counter increments when it reaches a selected value (e.g., corresponding to a threshold Th where normal operation is not met). switchA blockage is detected when the counter value (8) for 8 pump cycles is reached. The total number of cycles to be reached before indicating a blockage 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 via a blockage detection algorithm to generate an optional indication of a detected blockage error (block 102) and automatically stop operation of the pump 64 and / or the drug delivery device 10, and / or generate an optional indication to the user to stop using the drug delivery device 10 (block 104). If the counter has not reached the selected counter value after incrementing according to block 99, pump measurement data collection continues according to block 97. Since the blockage detection algorithm is based on pump duration data or other pump measurement data already implemented in the pump, blockage detection is achieved by checking the pump duration or other measurement data in the software against a selected threshold or metric. Therefore, a software-only solution for detecting blockages is provided, requiring no hardware changes.

[0073] According to another exemplary embodiment of the present invention, the characteristics of the third pump are monitored to detect blockages in the drug delivery device 10, as described below. Figure 13 As described above. For example, testing of the selected pump 64 under clogging conditions showed that if clogging occurred when the drug delivery device 10 was new, pump 64 tended to have a short stroke duration or a long end-stop duration, as described above in conjunction with... Figure 7 and Figure 9 As described. However, after the pump has undergone many cycles, test data indicates that it tends to leak at the joint area 49 between the manifold seal 47 and the sleeve 24, as... Figure 3B As shown. Excessive leakage after certain pump cycles may be caused by a combination of wear and tear of the seals due to repetitive pumping motion and high internal pressure caused by blockage. In other words, when pump 64 is new and seal 47 is strong enough to tolerate the high pressure introduced by blockage, the pump may exhibit short stroke durations or long end-stop durations (e.g., extended limit switch activation durations) during blockage. However, after certain pump cycles, the seals may become insufficient to withstand the high pressure introduced by blockage, and pump 64 may leak through the weakest link in the downstream fluid path, which could be the seal 49 between manifold 47 and sleeve 24. Because the high internal pressure introduced by blockage forces fluid in pump chamber 38 through the leakage path, the pump motor (not shown) needs to provide more energy to push the fluid through. As a result, the dispensing stroke duration during blockage is longer than during normal operation.

[0074] Figure 12A , 12B 12C and 12D show pumps from the selected type (e.g., reference 12C). Figure 1 , 2Some examples of benchmark clogging tests for pumps 64 described in 3A, 3B and 3C. Figure 12A , 12B 12C and 12D show the long dispensing duration associated with leakage caused by blockage. For the four drug delivery devices 10, Figure 12A , 12B Each curve in 12C and 12D corresponds to a drug delivery device 10. Each drug delivery device 10 is, for example, filled with 300U of fluid and opened 50U for delivery, clamped 2U, and opened 2U. As can be seen from these graphs, when the drug delivery device 10 is clogged, the dispensing stroke duration increases, while the suction stroke duration remains substantially the same. Therefore, this pump characteristic can be used to detect leaks caused by clogging.

[0075] According to one aspect of an exemplary embodiment of the present invention, the blockage detection algorithm described above may employ the pump duration difference between the distribution stroke and the suction stroke. For example, referring to... Figure 13 Box 108 in the diagram can be used to determine the travel difference threshold (Th) as follows. delta ):

[0076] Step 1: At the end of the pre-charge, calculate the average duration difference between the suction stroke and the distribution stroke, defined as:

[0077]

[0078] Where n is the number of strokes used to obtain the average difference. As an example, n = 3 is used for an exemplary embodiment, but it should be understood that this number can vary depending on the specific pump design.

[0079] Step 2: For each pump cycle after pre-charge, collect pump measurement data for pump 64 (e.g., the duration difference between the suction stroke and the distribution stroke) (box 109), and compare the duration difference data with the pump measurement metrics (box 110), for example, as described below:

[0080] 1) Calculate the duration difference: Di = distribution - suction;

[0081] 2) Subtract D0 from Di: D'i = Di - D0; and

[0082] 3) Check if D'i, D'i-1, and D'i-2 are less than a given threshold (e.g., 0.13 seconds). Figure 13 As shown in box 110. If so, normal pump operation can proceed as follows. Figure 13 Continue as shown in box 112. If not, a leak is detected and it can be determined that the pump is experiencing a blockage. When the threshold Th used for normal operation is not met... deltaWhen the counter increments (box 111), referring to box 113, the counter increments when it reaches a selected value (e.g., corresponding to a threshold Th that is not met for normal operation). delta If the counter value (8) of the 8 pump cycles is reached, a blockage is detected and a blockage indication can be generated according to block 114, and pump operation is terminated according to block 116. If the counter has not reached the selected counter value after incrementing according to block 111, pump measurement data collection continues according to block 109. The total number of cycles to be reached before indicating a blockage can be specified, such as 8 consecutive cycles of 8 cycles or within a specified number of cycles (e.g., 20 cycles). Although three consecutive distribution strokes are used in the exemplary embodiment, this number can vary depending on the pump duration over time. Duration difference D 0,1 ,..., x These can be averaged or otherwise aggregated or categorized, and then analyzed to determine the degree of difference between pump measurements of normally operating pumps (e.g., the difference between suction stroke and distribution stroke duration) and pump measurements of clogged pumps, and / or relative to a threshold or other metric. delta The degree of difference.

[0083] According to other exemplary embodiments, in combination Figure 7 The described trip duration standard and / or Figure 9 The described end stop or limit switch activation duration standard, the blockage detection algorithm may include Figure 13 The described leak detection criteria. For example, using clogging detection software provided to the controller of the microcontroller 58 or a separate device associated with the drug delivery device 10, detection can be performed in parallel or serially using all three criteria or only one or a subset of these three criteria. Figure 10 Additional example data for the trip duration standard is shown in [the document], and [it is also shown in the document]. Figure 11 Additional example data for the switch activation duration standard is shown in the figure. (See reference...) Figure 14 The exemplary congestion detection algorithm according to the exemplary embodiment employs, as follows: Figure 7 The aforementioned trip duration standard, such as Figure 9 The aforementioned end stop or limit switch activation duration standard, and such as Figure 13 The combination of the aforementioned leak detection criteria. A counter detecting a blockage is reset or set to 0 (box 120). As shown in box 122, pump cycles are detected (i.e., by using, for example, end stop switches to activate data to detect suction and distribution strokes). Pump measurement data is collected (box 124), such as stroke duration, reference... Figure 9The described end stop duration and the average duration difference between the suction stroke and the distribution stroke during pre-charge. The stroke duration difference is determined (i.e., subtracted from the average duration difference during pre-charge from the duration corresponding to the distribution stroke duration being less than the suction stroke duration) (box 126). If abnormal pump operating conditions are detected (e.g., a shortening of the distribution stroke duration in box 128, e.g., less than 2 seconds of Th...). stroke ), or the activation duration of the end stop switch of block 132 is extended (e.g., greater than 1 second Th). switch ), or the difference in travel duration in box 134 (e.g., a difference greater than 0.13 microseconds in Th). delta If the counter reaches a selected value in box 138 (e.g., counter value 8 corresponding to 8 pump cycles in which a threshold for normal operation is not met), then blockage is detected in box 140, and a blockage indication may be generated and / or pump operation may be terminated, for example. If these blockage conditions are not met, the counter remains cleared (e.g., value 0) in box 134, and the next pump cycle is detected, and relevant pump timing or measurement data are collected according to box 122.

[0084] For example, the above text combined Figure 13 The leak detection criteria described by the blockage detection algorithm are combined with short-stroke duration algorithms (e.g., the above reference). Figure 7 (described in boxes 80 and 82) and the long end stop duration algorithm (e.g., referred to above). Figure 9 The data described in boxes 96 and 98 were applied to baseline blockage data collected from 280 drug delivery devices 10. Table 1 shows the data in unused and used reference data. Figure 13 The comparison between two cases of the leak detection algorithm described in boxes 108 and 110 shows that the leak detection algorithm (e.g., Figure 13 Boxes 108 and 110 in the diagram significantly improve the correct blockage detection rate of the blockage detection algorithm according to an exemplary embodiment of the present invention. However, it slightly increases the false alarm rate.

[0085] Table 1: Blockage Detection and W / O Leakage Detection

[0086]

[0087] Of the 280 drug delivery devices 10, 120 delivered a large dose of 10U before clamping. The manifold seals 49 in these drug delivery devices 10 were used minimally. Table 2 shows a comparison between using and not using a leak detection algorithm for this group of drug delivery devices 10. As can be seen from Table 2, even without adding a leak detection algorithm to a clogging detection algorithm that analyzes stroke duration measurements and / or long end stop duration pump measurements, the clogging detection rate is very high at 88% if the manifold seals 49 are used minimally. These results are consistent with the fact that leaks are primarily caused by wear and tear of the manifold seals after repeated pumping motions.

[0088] Table 2: Blockage detection for subgroups of drug delivery device 10 with and without leak detection (10U large dose before clamping)

[0089]

[0090] Therefore, a leak detection criterion can be implemented in the blockage detection algorithm. Since the algorithm only requires pump duration information to analyze the leak detection criterion, no hardware changes are necessary. The blockage detection algorithm employing the leak detection criterion is improved when implemented in series with a stroke duration criterion and / or an end stop switch activation duration criterion to more completely capture all significant pump behavior during blockage.

[0091] According to yet another exemplary embodiment, the pump motor current is used to detect blockages. Under normal operating conditions, the drug delivery device 10 draws from a reservoir 70 located upstream of the fluid path and dispenses it into a patient located at the end of the downstream fluid path. During the aspiration stroke, the piston opens the pump chamber, allowing fluid from the reservoir to fill the chamber. During the dispensing stroke, the piston closes the pump chamber, pushing the fluid downstream. Figure 3A and 3B An exemplary piston and pump chamber are depicted.

[0092] When the drug delivery device 10 is blocked, the piston cannot evacuate the fluid in the pump chamber downstream. As a result, the pump may 1) retain the fluid in the pump chamber, 2) pump the fluid back to the reservoir, or 3) force the fluid to leak through the pump's manifold seal. Because more energy is required to pump the fluid to any of these three paths, the motor current is higher during the dispensing stroke when a blockage occurs. Therefore, the motor current can be used to detect blockages.

[0093] Figure 15An exemplary device for motor current sensing is shown. A sense resistor 142 is added to the PCB 92 to enable motor current measurement. The voltage drop across the sense resistor 142 is provided to the analog-to-digital converter (ADC) of the microcontroller 58. The microcontroller 58 then calculates the clogging condition and reports a clogging event when, for example, a specified clogging signal is detected. Other components can be used for current sensing to facilitate pump motor current measurement. For example, for a pulse width modulation (PWM) driven motor used as a pump actuator 66, motor current information can be deduced from the PWM data.

[0094] The following refers to Figure 16 Describe an exemplary clogging detection algorithm for each pump cycle. A counter for detecting the clogging condition is cleared or set to a value of 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 by the microcontroller 58 during the suction stroke. Using x in (t), where t is the time referenced to the start time of the stroke, at the end of the suction stroke (e.g., when an end stop signal is detected), the microcontroller 58 can be programmed to determine the average motor current A between 1 second (s) and 2.5 seconds relative to the start time of the motor current as follows in :

[0095] A in = mean[x in (t), 1 second < t < 2.5 seconds].

[0096] It should be understood that other methods for determining the motor current during the pump cycle or the suction stroke or the dispensing stroke can be used.

[0097] 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. Using x out (t), where t is the time referenced to the start time of the stroke, at the end of the dispensing stroke (e.g., when a corresponding end stop signal is detected), the microcontroller 58 can be programmed to determine the average motor current A between 1 second and 2.5 seconds relative to the start time of the motor current as follows out :

[0098] A out = mean[x out (t), 1 second < t < 2.5 seconds].

[0099] Referring to Figure 16 block 156 of

[0100] D = A out -A in .

[0101] If the difference D is greater than the specified threshold Th iDiff (Box 158) then increments the counter (Box 160). Referring to Box 162, when the counter reaches a selected value (e.g., corresponding to a threshold Th where normal operation is not met). iDiff If the counter value (3) for the three pump cycles is incremented, a blockage is detected, and a blockage indication can be generated according to block 164, and pump operation can be terminated. It should be understood that the counter value can be any value other than 3, used to indicate the number of different cycles in which the pump current exceeded a threshold before a blockage was detected. If the counter has not reached the selected counter value (block 162) after incrementing according to block 160, pump measurement data (e.g., motor current) continues to be collected according to block 152. Therefore, if the latest pump cycle and some previous consecutive pump cycles have a D value greater than a given threshold, a blockage is indicated; otherwise, normal pump operation continues.

[0102] Figures 17A to 17E Motor currents during the distribution stroke, measured from five respective exemplary conveying devices 10, are shown before and after the blockage. Figures 17A to 17E This clearly illustrates the distinction between motor current during normal pump strokes and blocked pump strokes, which facilitates the use of motor current-based blockage detection algorithms, such as those described above. Figure 16 The algorithm described.

[0103] Figures 18A to 18E The average motor current is shown from 1 second to 2.5 seconds (i.e., the measurement over a duration of 1–2.5 seconds after the start of the stroke, where t = 0 is the start of the stroke). Similarly, in Figures 18A to 18E There is a clear difference between the congested and normal travel shown. Therefore, the threshold Th can be adjusted. iDiff It is used to detect blockages by averaging motor current.

[0104] Continue to refer to Figure 16 , Figures 17A to 17E ,and Figures 18A to 18E An alternative method could rely solely on the average motor current during the distribution stroke, without depending on the suction stroke. In this case, it would be unnecessary to calculate the average motor current during the suction stroke and D = Aout - Ain. For example, such an alternative algorithm could include determining the motor current during the distribution stroke of the pump cycle. For instance, at the start of the distribution stroke, the microcontroller 58 records the motor current during the distribution stroke. Using x out(t), where t is the time referenced to the start of the stroke, and at the end of the allocated stroke (e.g., when the corresponding end stop signal is detected), the microcontroller 58 can be programmed to determine the average motor current between 1 second and 2.5 seconds relative to the start time of the motor current, as described above. Figure 16 As described. If the average motor current A out Greater than the specified threshold Th Aout The counter increments. When the counter reaches a selected value (e.g., corresponding to a threshold Th where normal operation is not met), the counter continues to increment. Aout When the counter value reaches 3 for 3 pump cycles, a blockage is detected, a blockage indication can be generated, and pump operation can be terminated. It should be understood that the counter value can be any value other than 3, specifying the different number of cycles in which the pump current exceeds a threshold before a blockage is detected. If the counter has not reached the selected counter value after incrementing, pump measurement data (e.g., motor current) continues to be collected. However, as described above... Figure 16 As described, using motor current data from both the suction and distribution strokes may be more robust in terms of sensitivity and accuracy, for example, in blockage detection using motor current.

[0105] Reference Figure 19 In conjunction with other standards used for detecting congestion, congestion detection algorithms can include... Figure 16 The motor current standard is described. For example, according to... Figure 19 The exemplary congestion detection algorithm in the exemplary embodiment of the present invention employs Figure 16 The described motor current standard and Figure 7 The described trip duration standard, such as Figure 9 The aforementioned end stop or limit switch activation duration standard, and such as Figure 13 The aforementioned leak detection criteria. A counter detecting a blockage condition is reset or set to 0 (box 170). As shown in box 172, pump cycles are detected (i.e., by using, for example, end stop switches to activate data to detect suction and distribution strokes). Pump measurement data is collected (box 174), such as stroke duration, reference... Figure 9 The description includes the end stop duration, the average duration difference between the suction and distribution strokes during pre-charge, and the average motor current during each stroke, such as the suction and distribution strokes. The stroke duration difference is determined (i.e., the duration corresponding to the distribution stroke duration minus the suction stroke duration minus the average duration difference during pre-charge) (box 176). The difference D in the average motor current for the distribution stroke compared to the suction stroke is also calculated (box 178). If abnormal pump operating conditions are detected, such as a shortened distribution stroke duration at box 180 (e.g., less than 2 seconds of Th...). stroke), or the activation duration of the end stop switch at box 182 is extended (e.g., greater than 1 second Th). switch ), or the difference in trip duration at box 184 (e.g., a difference greater than 0.13 microseconds), or the difference in trip duration greater than a specified threshold Th at box 186. iDiff The counter increments (block 192) based on the average motor current difference between the distribution stroke and the suction stroke. When the counter reaches a selected value at block 194 (e.g., counter value 8 corresponding to 8 pump cycles in which a threshold for normal operation is not met), a blockage is detected at block 196, and a blockage indication and / or termination of pump operation may be generated, for example. If these blockage conditions are not met, the counter remains zero (e.g., 0 value) at block 190, and the next pump cycle is detected, and the relevant pump timing or measurement data is collected at block 172. It should be understood that one or more of blocks 180, 182, 184, and 186 and their corresponding pump measurement data collection or calculation can be omitted to implement alternative exemplary algorithms employing the remaining blocks 180, 182, 184, and 186. It will be understood by those skilled in the art that the application of the invention is not limited to the construction details and component arrangements set forth in the following description or shown in the drawings.

[0106] The embodiments described herein can have other embodiments and can be practiced or performed in various ways. Moreover, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting. The terms “comprising,” “including,” or “having,” and variations thereof, as used herein, are intended to cover the items listed thereafter and their equivalents, as well as additional items. Unless otherwise limited, the terms “connection,” “link,” and “installation,” and variations thereof, are used broadly and include direct and indirect connections, links, and installations. Furthermore, the terms “connection” and “link,” and variations thereof, are not limited to physical or mechanical connections or links. Additionally, terms such as upper, lower, bottom, and top are relative and are used to aid illustration but are not limiting.

[0107] The exemplary apparatus, systems, and methods employed according to the embodiments shown in the invention can be implemented, at least in part, in digital electronic circuits, analog electronic circuits, or computer hardware, firmware, software, and combinations thereof. For example, these components can be implemented as, for instance, 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 the operation of a data processing apparatus (e.g., a programmable processor, a computer, or a plurality of computers).

[0108] Computer programs can be written in any programming language, including compiled or interpreted languages, and can be deployed in any form, including standalone programs or modules, components, subroutines, or other units suitable for a computing environment. Computer programs can be deployed to execute on a single computer, at a single site, or on multiple computers distributed across multiple sites and interconnected via a communication network. Furthermore, the functional programs, code, and code segments used to implement exemplary embodiments of the present invention can be readily interpreted by programmers in the art to which this invention pertains as being within the scope of the invention. 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 functions (e.g., by manipulating input data and / or generating output data). Method steps can also be executed by devices of exemplary embodiments of the present invention, and the devices of exemplary embodiments of the present invention can be implemented as special-purpose logic circuits, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits).

[0109] The various exemplary logic blocks, modules, and circuits described in conjunction with the embodiments disclosed herein can be implemented or performed using a general-purpose processor, digital signal processor (DSP), ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. 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 also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such construction.

[0110] As an example, processors suitable for executing computer programs include general-purpose and special-purpose microprocessors, as well as any one or more processors in any type of digital computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The basic components of a computer are the processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include, or be operatively coupled to, one or more mass storage devices for receiving data from or transferring data to, such as magnetic disks, magneto-optical disks, or optical disks. Information carriers suitable for implementing computer program instructions and data include all forms of non-volatile memory, which, by way of example, include, for example, semiconductor memory devices such as electrically programmable read-only memory or ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory devices, and data storage disks (e.g., magnetic disks, internal hard disks, or removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks). The processor and memory may be supplemented by or incorporated into special-purpose logic circuitry.

[0111] Those skilled in the art will understand that information and signals can be represented using any of a variety of different techniques and skills. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0112] Those skilled in the art will further appreciate that the various exemplary logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, various exemplary components, blocks, modules, circuits, and steps have been described above in terms of functionality. Whether this functionality is implemented as hardware or software depends on the specific application and design constraints for the system as a whole. Those skilled in the art can implement the described functionality in different ways for each specific application, but these implementation decisions should not be construed as departing from the scope of the invention. Software modules can 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. Exemplary storage media are coupled to a processor so that the processor can read information from and write information to the storage medium. Alternatively, the storage medium can be integrated into the processor. In other words, the processor and storage medium can reside in an integrated circuit or be implemented as discrete components.

[0113] Computer-readable non-transitory media encompasses all types of computer-readable media, including magnetic storage media, optical storage media, flash memory media, and solid-state storage media. It should be understood that software can be installed in and sold with a central processing unit (CPU) device. Alternatively, software can be obtained and loaded into a CPU device, including through physical media or distribution systems, such as from a server owned by the software creator or from a server not owned by the software creator but used by the software creator. For example, the software could be stored on a server for distribution via the Internet.

[0114] The description and accompanying drawings presented above are intended to be illustrative only and are not intended to limit the invention in any way, except as set forth in the appended claims. It should be particularly noted that those skilled in the art can readily combine various technical aspects of the various elements of the various exemplary embodiments described above in a variety of other ways, all of which are considered to be within the scope of the invention.

Claims

1. An infusion device with integrated occlusion sensing, characterized in that, The infusion device includes: A pump, the pump comprising: a chamber having at least one port for receiving fluid from a reservoir into the chamber, and fluid flowing out of the chamber through the at least one port; and a pumping mechanism including a motor and configured to control the pumping of a quantity of fluid into the chamber during a suction stroke and to control the dispensing of a quantity of fluid from the chamber during a dispensing stroke; A pump measuring device, configured to generate pump measurements associated with at least one of each suction stroke and each dispensing stroke performed by the pump; and A processing device configured to: analyze pump measurements, including pump measurements for each of a plurality of strokes for at least one of the suction stroke and the distribution stroke; and determine when the pump measurements include a plurality of pump measurements that satisfy a predetermined metric designated as an indication of blockage. The pump measuring device includes a motor current sensing device configured to detect motor current during the stroke of a pump cycle for multiple pump cycles, the stroke being selected from a suction stroke and a dispensing stroke; The pump measurement value corresponds to the motor current; The pump measurements include motor current for each stroke in a selected number of pump cycles out of the plurality of pump cycles, and the predetermined metric includes the average motor current in strokes exceeding a specified current value, which is higher than the average motor current when no blockage occurs in the pump; and The pump measurement also corresponds to the duration of at least one of the suction stroke and the distribution stroke, and the predetermined measurement is a selected duration longer than the average pump measurement when no blockage occurs in the pump.

2. The infusion device with integrated occlusion sensing according to claim 1, characterized in that, The infusion device also includes an indicator, and the processing device is configured to operate the indicator as a blockage alarm in response to determining that a plurality of pump measurements meet the predetermined metric.

3. The infusion device with integrated occlusion sensing according to claim 1, characterized in that, The processing device is configured to automatically terminate the operation of the pumping mechanism in response to determining that a plurality of pump measurements meet the predetermined metric.

4. The infusion device with integrated occlusion sensing according to claim 1, characterized in that, For multiple distribution strokes, the pump measurement also corresponds to the duration of the distribution stroke.

5. The infusion device with integrated occlusion sensing according to claim 1, characterized in that, The pump measurement also corresponds to the duration of at least one of the suction stroke and the distribution stroke, and the predetermined metric also includes a selected duration shorter than the average of the pump measurements when no blockage occurs in the pump.

6. The infusion device with integrated occlusion sensing according to claim 1, characterized in that, The pump measuring device includes an end stop switch on the pump, the end stop switch being configured to be activated when the pumping mechanism completes at least one of the suction stroke and the dispensing stroke, the end stop 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. The infusion device with integrated occlusion sensing according to claim 6, characterized in that, The pump measurement corresponds to the duration of the end stop switch activation state, and the predetermined metric is a selected duration of the end stop switch activation state that is longer than the average pump measurement when no blockage occurs in the pump.

8. The infusion device with integrated occlusion sensing according to claim 1, characterized in that, The processing device is configured to determine, for each of a plurality of pump cycles, the average motor current of the suction stroke, the average motor current of the distribution stroke, and the difference between the average motor current of the distribution stroke and the average motor current of the suction stroke, and the predetermined metric is a specified value of the difference, wherein a blockage is indicated when the difference exceeds the specified value.

9. The infusion device with integrated occlusion sensing according to claim 8, characterized in that, The pump measuring device includes an end stop switch located on the pump, the end stop switch being configured to be activated when the pumping mechanism completes at least one of the suction stroke and the distribution stroke, the end stop switch being connected to the processing device to determine the duration of each of the at least one of the suction stroke and the distribution stroke, such that for a pump measurement corresponding to the duration of the end stop switch activation state, the predetermined measure is a selected duration of the end stop switch activation state that is longer than the average pump measurement when no blockage occurs in the pump; and The pump measurements include at least two of the following: the duration of the end stop switch activation state; the duration of at least one of the suction stroke and the distribution stroke; the time difference between the suction stroke and the distribution stroke; and the difference between the average motor current of the distribution stroke and the average motor current of the suction stroke. A predetermined metric corresponding to the stroke duration is a selected duration shorter than the average stroke duration when no blockage occurs in the pump, and a predetermined metric corresponding to the difference between the distribution stroke duration and the suction stroke duration is a selected duration greater than the average difference between the stroke durations when no blockage occurs in the pump. The processing device is configured to analyze the pump measurements and determine when the pump measurements include multiple pump measurements corresponding to one of the predetermined metrics.

10. The infusion device with integrated occlusion sensing according to claim 1, characterized in that, The pump measurement corresponds to the time difference between the suction stroke and the distribution stroke, and the predetermined measure corresponding to the difference between the duration of the distribution stroke and the duration of the suction stroke is a selected duration that is greater than the average difference of the stroke durations when no blockage occurs in the pump.

11. The infusion device with integrated occlusion sensing according to claim 8, characterized in that, The pump measurements also include the duration of at least one of the suction stroke and the distribution stroke, and the predetermined metric corresponding to the stroke duration is a selected duration shorter than the average stroke duration when no blockage occurs in the pump. The processing device is configured to analyze the pump measurements and determine when the pump measurements include multiple pump measurements that satisfy one of the predetermined metrics.

12. A blockage sensing method for blockage sensing in a fluid pump, characterized in that, The congestion sensing method includes: An operating pump includes: a chamber having at least one port for receiving fluid from a reservoir into the chamber, and for fluid flowing out of the chamber through the at least one port; and a pumping mechanism including a motor and configured to control the intake of a certain amount of fluid into the chamber during a suction stroke and to control the dispensing of a certain amount of fluid from the chamber during a dispensing stroke. Operate the pump measuring device to generate pump measurement values ​​associated with at least one of each suction stroke and each dispensing stroke performed by the pump; Analyze pump measurements, including pump measurements for each of at least one of the suction stroke and the distribution stroke, to determine when the pump measurements include multiple pump measurements that satisfy a predetermined metric designated as a blockage indication; and Motor current is detected during the stroke of multiple pump cycles, the stroke being selected from the suction stroke and the distribution stroke; The pump measurement value corresponds to the motor current; The pump measurements include motor current for each stroke in a selected number of pump cycles out of the plurality of pump cycles, and the predetermined metric includes an average motor current exceeding a specified current value, which is higher than the average motor current when no blockage occurs in the pump; and The blockage 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 distribution stroke, wherein the predetermined measure is a selected duration longer than the average of the pump measurements when no blockage occurs in the pump.

13. The blockage sensing method according to claim 12, characterized in that, The blockage sensing method further includes: activating an indicator to issue a blockage alarm in response to determining that multiple pump measurements meet the predetermined metric.

14. The blockage sensing method according to claim 12, characterized in that, The blockage sensing method further includes: automatically terminating the operation of the pumping mechanism in response to determining that multiple pump measurements meet the predetermined metric.

15. The blockage sensing method according to claim 12, characterized in that, The blockage sensing method further includes: operating a pump measuring device to generate pump measurements corresponding to the duration of a plurality of distribution strokes.

16. The blockage sensing method according to claim 12, characterized in that, The pump measurement also corresponds to the duration of at least one of the suction stroke and the distribution stroke, and the predetermined metric also includes a selected duration shorter than the average of the pump measurements when there is no blockage in the pump.

17. The blockage sensing method according to claim 12, characterized in that, The blockage sensing method further includes: The pump measuring device is configured as an end stop switch on the pump, which is activated when the pumping mechanism completes at least one of the suction stroke and the distribution stroke. The end stop switch is connected to a processing device configured to analyze signals from the end stop switch to determine the duration of each of the at least one of the suction stroke and the dispensing stroke.

18. The blockage sensing method according to claim 17, characterized in that, The pump measurement corresponds to the duration of the end stop switch activation state, and the predetermined metric is a selected duration of the end stop switch activation state that is longer than the average pump measurement when there is no blockage in the pump.

19. The blockage sensing method according to claim 12, characterized in that, The analysis of pump measurements includes determining the average motor current of the suction stroke, the average motor current of the distribution stroke, and the difference between the average motor current of the distribution stroke and the average motor current of the suction stroke for each of the multiple pump cycles, and the predetermined metric is a specified value for the difference, when the difference exceeds the specified value, indicating a blockage.

20. The blockage sensing method according to claim 19, characterized in that, The blockage sensing method further includes configuring the pump measuring device as an end stop switch on the pump, the end stop switch being activated when the pumping mechanism completes at least one of the suction stroke and the dispensing stroke, such that for the pump measurement corresponding to the duration of the end stop switch activation state, the predetermined measure is a selected duration of the end stop switch activation state that is longer than the average duration of the pump measurement when no blockage occurs in the pump. The pump measurements include at least two of the following: the duration of the end stop switch activation state, the duration of at least one of the suction stroke and the distribution stroke, the time difference between the suction stroke and the distribution stroke, and the difference between the average motor current of the distribution stroke and the average motor current of the suction stroke. A predetermined metric corresponding to the stroke duration is a selected duration shorter than the average stroke duration when no blockage occurs in the pump, and a predetermined metric corresponding to the difference between the distribution stroke duration and the suction stroke duration is a selected duration greater than the average difference between the stroke durations when no blockage occurs in the pump. Analyzing the pump measurements includes determining when the pump measurements include multiple pump measurements that satisfy one of the predetermined metrics.

21. The blockage sensing method according to claim 12, characterized in that, The pump measurement corresponds to the time difference between the suction stroke and the distribution stroke, and the predetermined measure corresponding to the difference between the duration of the distribution stroke and the duration of the suction stroke is a selected duration that is greater than the average difference of the stroke durations when no blockage occurs in the pump.

22. The blockage sensing method according to claim 21, characterized in that, The pump measurements also include the duration of at least one of the suction stroke and the distribution stroke, and the predetermined metric corresponding to the stroke duration is a selected duration shorter than the average stroke duration when no blockage occurs in the pump. Analyzing the pump measurements includes determining when the pump measurements include multiple pump measurements that satisfy one of the predetermined metrics.

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