Pressure-modulated motor torque of an infusion pump

Abstract

An infusion pump can be configured to adjust a drive motor based on a recognized infusion pressure requirement for quiet and energy-efficient operation of the drive motor. The infusion pump can include an electric motor having a variable output torque based on a current input, a plunger head sensor configured to detect a force between the plunger driver and the plunger of the drug container, and a control module configured to adjust the current input to the electric motor based on the detected force between the plunger driver and the plunger of the drug container. The current input for such an infusion pump can be progressively reduced according to a defined magnitude of the detected force.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 62 / 987,435, filed March 10, 2020, the disclosure of which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to infusion pump systems, and more particularly to systems and methods for adjusting a drive motor of an infusion pump based on detected forces. [Background technology]

[0003] In the medical field, infusion pumps have been used to manage the delivery and administration of predetermined amounts or doses of medications, fluids, fluid-like substances, or infusates (collectively referred to herein as infusates or medications) to patients. Infusion pumps have been used to control the dose and timing of medication, among other parameters. Infusion pumps offer significant advantages over manual administration of infusates by precisely delivering infusates over extended periods of time at rates ranging from 0.01 mL / hour to 1200 mL / hour. Infusion pumps are particularly useful in the treatment of diseases and disorders requiring conventional pharmacological intervention, including cancer, diabetes, vascular disorders, neurological disorders, and metabolic disorders. Infusion pumps also enhance healthcare providers' abilities to deliver anesthesia and manage pain.

[0004] There are many types of infusion pumps, including ambulatory, large volume, patient-controlled analgesia (PCA), elastomeric, syringe, enteral, and insulin pump types. Depending on the specific design and intended use, infusion pumps can be used to administer medications via a variety of delivery methods, including intravenous, intraperitoneal, intra-arterial, intradermal, subcutaneous, and adjacent to nerves, as well as to surgical sites, epidural spaces, or intraarachnoid spaces. Infusion pumps are used in a variety of settings, including hospitals, nursing homes, and other short- and long-term medical facilities, as well as in home care settings.

[0005] As mentioned above, one type of infusion pump, commonly referred to as a syringe pump, mechanically drives a prefilled syringe under microprocessor control to deliver a predetermined amount or dose of medication to a patient via an infusion line or tubing in fluid communication with the prefilled syringe. Syringe pumps typically include a motor that rotates a lead screw. The lead screw in turn activates a plunger driver that pushes (or compresses or otherwise acts in the opposite direction) a plunger in the barrel of a syringe removably attached to the pump. Note that the plunger driver can also move in the reverse direction, e.g., away from the syringe. Thus, pushing the syringe plunger forward forces the infusion fluid out of the syringe, into the tubing of the infusion line, and then into the patient's body. Examples of syringe pumps are disclosed in published PCT application WO2016 / 183349, entitled "High Accuracy Syringe Pumps," and U.S. published patent application 2017 / 0203032, entitled "Method and Apparatus for Overload Protection in Medicament Syringe Pumps," assigned to the assignee of the present disclosure, both of which are incorporated herein by reference in their entireties. As used throughout this disclosure, the term "syringe pump" is intended to generally relate to any device that acts on a syringe to controllably force infusion fluid outward therefrom.

[0006] While such syringe pumps have proven to work very well, there is a desire to continually improve syringe pump systems. In particular, there is a desire to provide a syringe pump that operates quieter and consumes less power than some known pumps. While attempts have been made to produce quieter and more energy-efficient infusion pumps, conventional wisdom has typically involved either mechanically isolating the motor in an effort to produce a quieter pump or using a lower-power motor to produce a quieter and more energy-efficient infusion pump. U.S. Published Patent Application No. 2013 / 0123749, entitled "Drug Delivery Pump Drive Using Linear Piezoelectric Motor" (assigned to Roche Diabetes Care Inc.), discloses one such example of a quieter and more efficient infusion pump, which uses a lower-power linear piezoelectric motor as the drive element.

[0007] While these examples of infusion pumps generally offer quieter operation and lower energy consumption, especially compared to pumps with traditional electric motor-based drives, such pumps can be prone to stalling or otherwise become interrupted at high infusion pressure conditions (e.g., 14-18 psi). Because pressure buildup is not uncommon in various pump operating environments and situations, there is a need to provide more consistent performance with reduced potential for interruption of therapy during infusion. Thus, while it may be desirable to produce quieter and more energy-efficient infusion pumps, the pumps must be large or powerful enough to meet or exceed reliability and dependability standards by providing steady operation over a range of infusion pressures without dramatically stalling or interrupting operation. The present disclosure addresses these concerns. Summary of the Invention

[0008] Embodiments of the present disclosure provide devices and methods that control the power input to a drive motor capable of handling a full range of infusion pressures according to the sensed infusion pressure, thereby allowing the drive motor to operate in a quieter and more energy-efficient manner when the infusion pressure is low enough to allow such operation. For example, in one embodiment, the device and method can use an electric motor with an electrical input of about 0.1 to about 1.0 amperes (A) and can reduce the electrical input based on the detected force between the syringe pump plunger driver and the plunger of the drug container or syringe. In another embodiment, an electric motor with an electrical input of between about 0.175 A and about 0.7 A can be implemented. Thus, in some embodiments, the input current can be significantly reduced under steady-state, normal operating conditions (e.g., infusion pressures below about 8 psi), thereby providing quieter operation and lower energy consumption compared to conventional electric drive systems. Improved energy efficiency may be particularly desirable when operating an infusion pump on battery power.

[0009] One embodiment of the present disclosure provides an infusion pump configured to adjust a current input to a drive motor based on a recognized infusion pressure requirement. The infusion pump includes an electric motor, a force sensor, and a control module. The electric motor can have a variable output torque based on the current input. The force sensor is configured to detect a force between a plunger driver of the pump and a plunger in a medication container. The control module is configured to adjust the current input to the electric motor based on the force detected by the force sensor.

[0010] In one embodiment, the current input to an electric motor in an infusion pump can be incrementally reduced depending on the magnitude of the force detected by the plunger driver sensor. In such an embodiment, the current input can be maintained at the maximum rated power input of the electric motor when the detected force is equal to or greater than approximately 80 N, at approximately 75% of the maximum rated power input of the electric motor when the detected force is less than approximately 80 N, at approximately 50% of the maximum rated power input of the electric motor when the detected force is less than approximately 65 N, and at approximately 25% of the maximum rated power input of the electric motor when the detected force is negligible. In one embodiment, the current input to the electric motor can be reduced according to a nonlinear function of the detected force along a continuous curve.

[0011] Another embodiment of the present disclosure provides a method of operating an infusion pump that includes detecting a force between a plunger driver of the infusion pump and a plunger in a drug container, and adjusting current to an electric drive motor based on the detected force between the plunger driver and the plunger in the drug container.

[0012] In another embodiment, the present disclosure provides an infusion pump configured to modulate a current input to a drive motor based at least in part on a linear speed of a plunger driver of the infusion pump. The infusion pump includes an electric motor, a plunger head sensor, and a control module. The electric motor can have a variable output torque based on the current input. The plunger head sensor is configured to detect a linear speed of the plunger driver during operation as the plunger driver pushes against a medication container like a syringe plunger. The control module is configured to adjust the current input to the electric motor based on the linear speed of the plunger head sensor.

[0013] In another embodiment, the present disclosure provides an infusion pump configured to adjust the current input of a drive motor based on both the force between a plunger driver and a drug container detected by a force sensor and the linear speed of movement of a plunger driver of the infusion pump.

[0014] In one embodiment, the present disclosure provides an infusion pump configured to adjust a current input to a drive motor based on recognized infusion pressure requirements. The infusion pump includes a pump housing defining a syringe receptacle shaped and sized to receive a syringe load, an electric motor having a variable output torque based on the current input, and a syringe drive assembly. The syringe drive assembly includes a lead screw operably coupled to the electric motor, a plunger driver operably coupled to the lead screw and linearly movable in response to rotation of the electric motor, the plunger driver configured to press against a plunger of the syringe, and a force sensor configured to detect a force between the plunger driver and the plunger of the syringe. The infusion pump further includes a control module configured to adjust the current input to the electric motor based on the detected force between the plunger driver and the plunger of the syringe.

[0015] In one embodiment, the present disclosure provides a method of operating an infusion pump, the method including providing, by a control module, a current input to an electric motor of the infusion pump to press a plunger driver of the infusion pump against a plunger of a syringe mounted in the infusion pump, the electric motor including a variable output torque based on the current input, the method further including detecting a force between the plunger driver and the plunger of the syringe using a force sensor, and adjusting, by the control module, the current input to the electric motor based on the detected force between the plunger driver and the plunger of the syringe.

[0016] In an embodiment, the present disclosure provides an infusion pump configured to adjust a current input to a drive motor based on a recognized infusion pressure requirement. The infusion pump includes a pump housing defining a syringe receptacle shaped and sized to receive a syringe load, an electric motor having a variable output torque based on the current input, and a syringe drive assembly. The syringe drive assembly includes a lead screw operably coupled to the electric motor, a plunger driver operably coupled to the lead screw and linearly movable in response to rotation of the electric motor, the plunger driver configured to push against a plunger of the syringe, a force sensor configured to detect a force between the plunger driver and the plunger of the syringe, and a plunger head sensor configured to detect linear movement of the plunger driver. The infusion pump further includes a control module configured to adjust a current input to the electric motor based on a detected force between the plunger driver and the plunger of the syringe, the control module being further configured to adjust a current input to the electric motor based on a linear movement speed of the plunger driver detected by the plunger head sensor, the current input tapering according to a defined magnitude of the detected force, and the maximum rated power input of the drive motor being less than about 1.0 A.

[0017] The above summary is not intended to describe each illustrated embodiment or every embodiment of the present disclosure, the following figures and detailed description more particularly exemplify these embodiments. [Brief explanation of the drawings]

[0018] The present disclosure may be more fully understood from consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying drawings, in which: [Figure 1] FIG. 1 is a front perspective view showing a syringe pump, according to one embodiment. [Figure 2] FIG. 2 is a perspective view of a syringe plunger driver assembly, according to one embodiment. [Figure 3]FIG. 3 is a block diagram illustrating components of a syringe pump, according to one embodiment. [Figure 4] FIG. 4 is a graph illustrating a motor stall curve, an input modulation curve, and a safety factor, according to one embodiment. [Figure 5] FIG. 5 is a graph illustrating noise metric evaluation against flow rate for two different current inputs, according to one embodiment. [Figure 6] FIG. 6 is a flow chart illustrating a method of operating an infusion pump, according to one embodiment. [Figure 7] FIG. 7 is a flow chart illustrating a method of operating an infusion pump, according to one embodiment. [Figure 8] FIG. 8 is a flow chart illustrating a method of operating an infusion pump, according to one embodiment. [Figure 8A] FIG. 8A is another flowchart illustrating a method of operating an infusion pump, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] While embodiments of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments illustrated by way of example in the drawings will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the claims.

[0020] 1 , a syringe pump 100 according to one embodiment of the present disclosure is depicted. Syringe pump 100 can include a housing 102, a user interface 104, a drive assembly (syringe plunger driver assembly) 106, and a drug container receptacle 108. In some embodiments, housing 102 can include a front housing assembly 110 and a rear housing assembly 112 configured to generally form a protective shell that encloses the internal components of syringe pump 100.

[0021] The user interface 104 may include a display screen 114 and a keypad 116. The display screen 114 may be any suitable graphical user interface (GUI) display for use in controlling the syringe pump 100. For example, in one embodiment, the display screen 114 may be a multi-color liquid crystal display (LCD), a dot matrix display, an organic light-emitting diode (OLED) display, and / or any other device capable of visually delivering and / or receiving information. In some embodiments, the display screen 114 may be appropriately sized to allow for the display of medication and / or patient information, infusion delivery parameters, and other information. In one embodiment, the display screen 114 may measure approximately 180 mm by 73 mm, although other display screen sizes are contemplated. In some embodiments, the display screen 114 may be configured to display instructional videos, for example, to assist a caregiver in properly maintaining and using the syringe pump 100. In some embodiments, the display screen may include touchscreen functionality, whereby specific commands and / or instructions may be received by the display screen 114.

[0022] The keypad 116 can be located adjacent to the display screen 114 and can present various buttons and indicator lights. In some embodiments, push buttons requiring physical mechanical actuation can be used on the keypad 116 to receive specific user commands, including on / off power, muting audible alarms, and starting and stopping infusion delivery. Additional or fewer buttons on the keypad 116 are also contemplated. Physical mechanical actuation buttons for primary and redundant purposes improve operator safety and reliability in the event that the touchscreen functionality of the display screen 114 does not function properly or is difficult to operate correctly. Thus, including a user interface 104 with both a display screen 114 and a keypad 116 provides the flexibility and usability of a screen interface and the improved safety and reliability of physical control buttons.

[0023] Drug container receptacle 108 can be defined between a portion of front housing assembly 110 and syringe ledge 118. Drug container receptacle 108 can be configured as an elongated cavity extending across the front of syringe pump 100 configured to accept drug containers (e.g., syringes) of various shapes and sizes when loaded into syringe pump 100. In some embodiments, drug container receptacle 108 can provide syringe pump 100 with a cavity that remains open on the front of syringe pump 100 to allow easy and consistent viewing of the loaded drug containers.

[0024] In some embodiments, the drug container receptacle 108 is located below the display screen 114 of the user interface 104. Locating the drug container receptacle 108 below the user interface 104 can be advantageous because any unintentional fluid leakage from the syringe can naturally flow downward by gravity and away from the user interface 104, thereby avoiding potential damage to the electronic and / or mechanical features of the user interface 104. The drug container receptacle 108 can thus advantageously be somewhat spatially isolated from the rest of the syringe pump 100 in the event that the drug container is damaged or other leakage occurs during loading, unloading, or operation. Furthermore, because the display screen 114 is located above the drug container receptacle 108, the display screen 114 is generally not visually obstructed by the presence of the drug container loaded in the drug container receptacle 108. That is, by positioning display screen 114 above drug container receptacle 108, both the drug container and the display are clearly visible during operation of syringe pump 100.

[0025] In some embodiments, syringe pump 100 can further include a barrel clamping device 120 located within drug container receptacle 108 and / or generally below user interface 104. Barrel clamping device 120 is configured to shift and rotate relative to front housing assembly 110, for example, along an axis generally perpendicular to the axis of drug container receptacle 108, thereby enabling capture of a barrel of a drug container between barrel clamping device 120 and a portion of syringe ledge 118. In some embodiments, barrel clamping device 120 can include a barrel clamp sensor 122 (shown in FIG. 1 ) configured to electronically sense when the barrel of a drug container is captured between barrel clamping device 120 and a portion of syringe ledge 118, and thus when the drug container is loaded into drug container receptacle 108. In some embodiments, barrel clamp sensor 122 may include a linear potentiometer configured to sense the extent to which barrel clamp device 120 is extended or displaced from front housing assembly 110, and thus the approximate diameter of the drug container loaded into drug container receptacle 108. In some embodiments, the sensed approximate diameter of the barrel may be used for characterization of the drug container (or syringe).

[0026] 2, the syringe plunger driver assembly 106 can include a motor 124, a drive train assembly 126, and a plunger driver 128. In one embodiment, the motor 124 can be a stepper motor and encoder configured to rotate in discrete step increments upon application of electrical command pulses. In some embodiments, the motor 124 can be configured to detect motor stall and rotational deceleration below a nominal motor rotational speed.

[0027] Motor 124 can be operably coupled to drive train assembly 126, which can be configured to convert the rotational output of motor 124 into linear motion (or actuation) for use by plunger driver 128. For example, in one embodiment, drive train assembly 126 can include carriage assembly 130, lead screw 132, and drive train chassis 134. During operation, rotation of lead screw 132 (e.g., by motor 124) can shift, translate, or otherwise move carriage assembly 130 relative to drive train chassis 134. In some embodiments, drive train assembly 126 can further include plunger head sensor 136 (e.g., a linear potentiometer) (see FIG. 2 ) configured to determine position data of carriage assembly 130 relative to drive train chassis 134. Plunger driver 128 can be operably coupled to carriage assembly 130 and can include a force sensor 138 configured to sense the magnitude of force acting on the thumb push (or plunger) of a syringe loaded into syringe pump 100. In some embodiments, force sensor 138, plunger head sensor 136, and barrel clamp sensor 122 can collect and utilize data individually or in concert for improved operational characterization.

[0028] 3, a block diagram of a syringe pump 100 is depicted in accordance with one embodiment of the present disclosure. As previously described, the syringe pump 100 may include a user interface 104, which may include a display screen 114 and a keypad 116. The syringe pump 100 may further include a power receptacle 140, a battery 142, a remote administration cord receptacle 144, a USB port 146, an Ethernet connector 148, one or more speakers 150, a controller 152, a motor 124, and a drive train assembly 126.

[0029] Controller 152 can be configured to control the operation of motor 124 and drive train assembly 126. Controller 152, which can be powered by power receptacle 140 and / or battery 142, can include one or more processors and / or memories. In some embodiments, controller 152 is in electrical communication with user interface 104, remote administration cord receptacle 144, USB port 146, and / or Ethernet connector 148 for the purpose of receiving information from and transmitting information to a user of syringe pump 100. In embodiments, controller 152 can be in electrical communication with barrel clamp sensor 122, plunger head sensor 136, and force sensor 138 and can be configured to receive data sensed by sensors 122, 136, and 138 for further processing.

[0030] In one embodiment, data received from sensors 122, 136, and / or 138 may be used by controller 152 to modulate the torque output of motor 124. Modulating the torque output of motor 124 may provide more control over the noise output and energy efficiency of syringe pump 100. A low torque output of motor 124 may be relatively energy efficient and quiet, while a high torque output may promote consistency in injection rate and reduce stalling across a range of injection pressures. For example, in one embodiment, the output of motor 124 may be modulated (e.g., via controller 152) based on the force sensed between plunger driver 128 and the syringe plunger, as measured by force sensor 138. In another embodiment, the output of motor 124 may be modulated (e.g., via controller 152) based on the linear velocity of plunger driver 128, as measured by plunger head sensor 136.

[0031] 4 illustrates a motor stall curve 200 that graphically depicts stall thresholds (e.g., the point at which a motor 124 of a given size will stall) over a range of electrical power inputs and corresponding system pressures. As illustrated, the Y-axis represents the current input to the motor 124 in amperes, and the X-axis represents the pressure, e.g., measured by the force sensor 138, in pounds per square inch. Below the motor stall curve 200, the torque required by the system pressure is greater than the maximum torque that can be generated by the motor 124 at the corresponding electrical input, causing the motor 124 to stall (e.g., stop rotating), resulting in an unstable injection rate (e.g., the motor slows below its nominal speed or stalls intermittently) and / or interrupted injection (e.g., stalls for an extended period of time).

[0032] 4 further illustrates a current input modulation curve 202, according to one embodiment of the present disclosure. Thus, in one embodiment, the current input may be modulated between a minimum of approximately 0.175 A and a maximum of approximately 0.7 A, although other magnitudes of current input are contemplated depending on the size and requirements of the motor 124. The gap on the y-axis between the motor stall curve 200 and the current input modulation curve 202 may represent a safety factor 204, which in embodiments may be configured to increase in magnitude, generally between approximately 0 psi and approximately 18 psi.

[0033] Referring to Table 1 below, the current input may be gradually increased and / or decreased according to a defined force magnitude threshold (or defined range of force magnitude) as detected by force sensor 138. For example, if a negligible amount of force is detected by the sensor of force sensor 138, controller 152 may adjust the current input of motor 124 to approximately 25% of its maximum rated power input (e.g., approximately 0.175 A). If the force detected by force sensor 138 is within a first threshold range (e.g., between greater than approximately 0 N and approximately 64.1 N), controller 152 may adjust the current input of motor 124 to approximately 50% of its maximum rated power input (e.g., approximately 0.35 A). If the force detected by force sensor 138 is within a second threshold range (e.g., between a force greater than approximately 64.1 N and approximately 82.5 N), controller 152 may adjust the current input of motor 124 to approximately 75% of its maximum rated power (e.g., approximately 0.525 A). If the force detected by force sensor 138 is equal to or greater than a third threshold (e.g., a force greater than approximately 82.5 N), controller 152 may adjust the current input of the motor to 100% of its maximum rated power (e.g., approximately 0.7 A). The use of particular current inputs, motor output percentages, and applied forces on force sensor 138 are for illustrative purposes only and should not be considered limiting, as other current inputs, motor output percentages, and forces applied to force sensor 138 are contemplated.

[0034] [Table 1]

[0035] It should be understood that Table 1 is an exemplary list of progressively modulated current inputs. Thus, in some embodiments as shown in Table 1, the current input is progressively modulated in steps (e.g., corresponding to approximately 25%, 50%, 75%, and 100% of predicted motor output) based on estimated infusion pressures (e.g., corresponding to approximately 0 psi, 8 psi, 14 psi, and 18 psi), which may be sensed directly via a fluid pressure sensor (not shown) in contact with the infusate or via force sensor 138. In other embodiments, the current input may be modulated according to a function (linear or nonlinear) of the detected fluid pressure and / or force (e.g., via force sensor 138) between plunger driver 128 and the plunger of a syringe within syringe pump 100.

[0036] In addition to improved power efficiency, reducing the current input to the motor 124 has the effect of reducing the overall noise generated by the motor 124 during infusion and / or therapy procedures over a range of different flow rates. FIG. 5 depicts a noise metric rating curve, graphically illustrating the noise metric rating measured over a range of infusion flow rate outputs. As shown, the Y-axis represents the noise metric (NC) rating, and the X-axis represents the infusion flow rate in milliliters per hour. Thus, as shown, reducing the input current from about 75% to about 50% has the effect of variably reducing the noise metric rating over a range of infusion flow rate outputs.

[0037] In some embodiments, controller 152 may alternately or additionally use input from barrel clamp sensor 122 and / or plunger head sensor 136 in modulating the current input to motor 124. In one embodiment, safety factor 204 may be increased and / or decreased based on the recognized syringe size (e.g., as determined by barrel clamp sensor 122). For example, if it is determined that the infusion will be administered via a relatively large syringe (e.g., a syringe greater than about 20 mL), safety factor 204 may be multiplied by or added to a constant, effectively increasing safety factor 204 in anticipation of larger and potentially more rapid fluctuations in system pressure. Conversely, if it is determined that the infusion will be administered via a relatively small syringe (e.g., a syringe less than about 10 mL), safety factor 204 may be divided by or subtracted from a constant, effectively decreasing safety factor 204 to achieve quieter performance and improved electrical efficiency. Conversely, it is also possible to increase the safety factor for syringes smaller than a certain size and decrease the safety factor for syringes larger than the certain size.

[0038] In one embodiment, the safety factor can be increased and / or decreased based on the sensed movement of the plunger within the syringe (as determined by plunger head sensor 136). For example, if it is determined that the syringe has filled to its maximum capacity (or if syringe pump 100 is in the early stages of an infusion treatment), the safety factor 204 can be multiplied or added by a constant, effectively increasing the safety factor 204. On the other hand, if it is determined that the infusion treatment has continued for a predetermined time and no motor stall has occurred, the safety factor 204 can be divided or subtracted by a constant, effectively decreasing the safety factor 204, resulting in quieter performance and improved electrical efficiency. It is also contemplated that the safety factor 204 can be increased incrementally or continuously as the infusion treatment progresses.

[0039] With reference to the example of Table 1 above and to Figure 6, a flow chart illustrating a method 300 for operating an infusion pump in a quieter and more energy efficient manner in accordance with an embodiment of the present disclosure is shown in Figure 6. At 302, the force (F D ) can be measured (e.g., via force sensor 138). Then, F D may be received by and stored in the memory of the controller 152 for further processing. D can be compared to a first defined force value (F1) (e.g., about 80 N). D If F is greater than or equal to F, then the ideal current input (I) can be set to a first defined current input value (I) (e.g., about 0.7 A) at 306. D If F is less than F1, the method 300 may proceed to 308.

[0040] In 308, F D can be compared to a second defined force value (F2) (e.g., about 65 N). D If F is greater than or equal to F, then I can be set to a second defined current input value (I) (e.g., about 0.5 A) at 310. D If F is less than F2, the method 300 may proceed to 312. At 312, F D can be compared to a third defined force value (F3) (e.g., about 0.1 N). D If F is greater than or equal to F, then I can be set to a third defined current input value (I) (e.g., about 0.3 A) at 314. Alternatively, F D If F is less than F3, the method 300 may proceed to 316. At 316, F D can be compared to a fourth defined force value (F4) (e.g., a negligible force). DIf I is greater than or equal to F4, then I may be set to a fourth defined current input value (I4) (e.g., approximately 0.2 A) at 318. I may be stored in a memory of the controller 152. Once the ideal current input I is set to the defined current input value, the method 300 then proceeds to 320, where the current input to the motor 124 may be set to substantially meet the ideal current input I.

[0041] 7, a flow chart illustrating a method 400 for operating an infusion pump in a quieter and more energy efficient manner is shown in accordance with one embodiment of the present disclosure. At 402, the force (F) between the plunger driver 128 and the plunger of the medication container is measured. D ) can be measured (e.g., via force sensor 138). Then, F D may be received by and stored in the memory of the controller 152 for further processing. D can be compared to a first defined force value (F1) (e.g., about 80 N). D If F is greater than or equal to F, then the ideal current input (I) can be set to a first defined current input value (I) (e.g., about 0.7 A) at 406. D If F is less than F1, the method 400 can proceed to 408.

[0042] In 408, F D can be compared to a second defined force value (F2) (e.g., about 65 N). D If F is greater than or equal to F, then I can be set to a second defined current input value (I) (e.g., about 0.5 A) at 410. D If F is less than F2, the method 400 may proceed to 412. At 412, F D can be compared to a third defined force value (F3) (e.g., about 0.1 N). DIf F is greater than or equal to F, then I can be set to a third defined current input value (I) (e.g., about 0.3 A) at 414. D If F is less than F3, method 400 may proceed to 416. At 416, F D can be compared to a fourth defined force value (F4) (e.g., a negligible force). D If F is greater than or equal to F, then I can be set to a fourth defined current input value (I) (e.g., about 0.2 A) at 418. I can be stored in a memory of the controller 152.

[0043] Method 400 may optionally include blocking operations 420 and 422. If blocking operations 420 and 422 are not included, method 400 may proceed to 424 and set the current input to motor 124 to substantially meet the ideal current input I0.

[0044] In one embodiment, if block operation 420 is included in method 400, the ideal current input can be further adjusted based on the size of the drug container. According to block operation 420, at 426, the drug container size (S D ) (e.g., diameter) can be determined (e.g., via barrel clamp sensor 122). D may be received by and stored in the memory of the controller 152 for further processing. D can be compared with a specified size value (S1). D If I is greater than or equal to S, then I may be multiplied by a first constant (C) at 430. Next, method 400 may proceed to 424, where the current input to motor 124 may be set to substantially meet the ideal current input I. Alternatively, method 400 may proceed to optional blocking operation 422 if it is included in method 400 and has not yet been considered.

[0045] In one embodiment, if block operation 422 is included in method 400, the ideal current input can be further adjusted based on the drug container plunger travel distance. According to block operation 422, at 432, the drug container plunger travel distance (T D ) can be determined (e.g., via plunger head sensor 136). D may be received by and stored in the memory of the controller 152 for further processing. D can be compared with the specified distance traveled (T1). D If I is greater than or equal to T, then I may be divided by a second constant (C) at 436. Method 400 may then proceed to 424, where the current input to motor 124 may be set to substantially meet the ideal current input I. Alternatively, method 400 may proceed to optional blocking operation 420 if blocking operation 420 is included in method 400 and has not yet been considered.

[0046] 8, a flow chart illustrating a method 500 for operating an infusion pump in a quieter and more energy-efficient manner according to one embodiment of the present disclosure is shown. At 502, an ideal current input (I0) can be set to a first defined current input value (I1) (e.g., about 0.7 A or about 100% of its maximum rated power input).

[0047] At 504, the force (F) between the plunger driver 128 and the plunger of the drug container is measured. D ) can be measured (e.g., via force sensor 138). Then, F D may be received by and stored in the memory of the controller 152 for further processing. D can be compared to a first defined force value (F1) (e.g., about 82.5 N). DIf F is less than F, then at 508, the ideal current input (I0) can be set to a second specified current input value (I2) (e.g., about 0.525 A or about 75% of its maximum rated power input). D If F is greater than or equal to F1, the method 500 may return to 502.

[0048] At 510, the force (F) between the plunger driver 128 and the plunger of the drug container is measured. D ) can be detected (e.g., via force sensor 138), and the linear velocity (e.g., ΔT D / Δt) can be detected (e.g., via plunger head sensor 136). D and ΔT D / Δt may be received and stored by the memory of the controller 152 for further processing. D can be compared to a second defined force value (F2) (e.g., about 64.1 N). D If F is less than F2, then at 518, the ideal current input (I0) can be set to a third defined current input value (I3) (e.g., about 0.35 A or about 50% of its maximum rated power input). D If F is greater than or equal to F2, the method 500 may return to 508.

[0049] Furthermore, in 514, F D can be compared to a third defined force value (F3) (e.g., about 30 N). D If F is less than F3, method 500 may proceed to 516. Alternatively, F D If ΔT is greater than or equal to F3, the method 500 may return to 508. At 516, ΔT D / Δt can be compared to a first linear velocity value (LR1) (e.g., about 108 mm / hr). DIf / Δt is less than LR1, then at 518 the ideal current input (I0) can be set to a third defined current input value (I3) (e.g., about 0.35 A or about 50% of its maximum rated current input). D If / Δt is greater than or equal to LR1, method 500 may return to 508. Thus, in some embodiments, the infusion pump may utilize the linear velocity of the plunger as a proxy for the motor rotational velocity, for example, if available motor torque decreases with increasing motor speed.

[0050] FIG. 8A shows an example of the method 500 depicted in FIG.

[0051] It should be understood that the individual steps used in the methods of the present disclosure can be performed in any order and / or simultaneously so long as the disclosure remains operable. Furthermore, it should be understood that the apparatus and methods of the present disclosure can include any number or all of the described embodiments so long as the disclosure remains operable.

[0052] Various embodiments of systems, devices, and methods have been described herein. These embodiments are provided by way of example only and are not intended to limit the scope of the claimed subject matter. Furthermore, it should be understood that various features of the previously described embodiments can be combined in various ways to create numerous additional embodiments. Furthermore, while various materials, dimensions, shapes, configurations, locations, etc. have been described for use with the disclosed embodiments, others than those disclosed may be utilized without departing from the scope of the claimed subject matter.

[0053] Those skilled in the relevant art will recognize that the subject matter herein may be comprised of fewer features than illustrated in any individual embodiment described above. The embodiments described herein are not intended to be an exhaustive representation of the ways in which various features of the subject matter herein can be combined. Thus, the embodiments are not mutually exclusive combinations of features; rather, various embodiments may be comprised of combinations of different individual features selected from different individual embodiments, as would be understood by one of skill in the art. Furthermore, elements described with respect to one embodiment may be implemented in other embodiments even if not described in such embodiment, unless otherwise specified.

[0054] Although a dependent claim may refer to a specific combination with one or more other claims in the claims, other embodiments may also include combinations of the dependent claim with the subject matter of each other dependent claim, or combinations of one or more features with other dependent or independent claims, and such combinations are suggested herein unless it is stated that a specific combination is not intended.

[0055] The incorporation by reference of the above documents is limited so that no subject matter contrary to the express disclosure herein is incorporated. Any incorporation by reference of the above documents is further limited so that no claims contained in the documents are incorporated herein by reference. Any incorporation by reference of the above documents is further limited so that no provisions provided therein are incorporated herein by reference unless expressly included herein.

[0056] For purposes of claim interpretation, it is expressly intended that the provisions of 35 U.S.C. § 112(f) shall not apply unless the specific terms "means for" or "step for" appear in the claim. [Example 1] 1. An infusion pump configured to regulate a current input to a drive motor, comprising: a pump housing defining a syringe receptacle shaped and sized to receive a syringe load; an electric motor having a variable output torque based on said current input; 1. A syringe drive assembly comprising: a lead screw operably coupled to said electric motor; a plunger driver operatively coupled to the lead screw and linearly movable in response to rotation of the electric motor, the plunger driver configured to depress a plunger of the syringe; and a force sensor configured to detect a force between the plunger driver and a plunger of the syringe; a syringe drive assembly including: a control module configured to adjust the current input to the electric motor based on the detected force between the plunger driver and the syringe plunger; An infusion pump comprising: [Example 2] 2. The infusion pump of claim 1, wherein the current input is reduced in a stepwise manner depending on the magnitude of the detected force. [Example 3] 2. The infusion pump of example 1, wherein the current input is maintained at a maximum rated power input when the detected force is greater than or equal to about 80 N. [Example 4] 4. The infusion pump of example 3, wherein the maximum rated power input is about 0.7 A. [Example 5] 2. The infusion pump of example 1, wherein the current input is reduced to about 75% of its maximum rated power input if the detected force is less than about 80 N. [Example 6] 2. The infusion pump of example 1, wherein the current input is reduced to about 50% of its maximum rated power input if the detected force is less than about 65 N. [Example 7] 2. The infusion pump of example 1, wherein the current input is reduced to about 25% of its maximum rated power input if the detected force is negligible. [Example 8] 2. The infusion pump of example 1, wherein the current input is decreased according to a nonlinear function of the detected force along a continuous curve. [Example 9] the syringe drive assembly further comprising a plunger head sensor configured to detect a linear speed of the plunger driver; the control module is further configured to adjust the current input to the electric motor based on the linear velocity of the plunger driver detected by the plunger head sensor. The infusion pump described in Example 1. [Example 10] 1. A method of operating an infusion pump, comprising: a control module providing a current input to an electric motor of the infusion pump to force a plunger driver of the infusion pump against a plunger of a syringe mounted in the infusion pump, the electric motor including a variable output torque based on the current input; detecting a force between the plunger driver and the plunger of the syringe using a force sensor; the control module adjusting the current input to the electric motor based on the detected force between the plunger driver and the plunger of the syringe; A method comprising: [Example 11] Detecting a linear speed of the plunger driver using a plunger head sensor; the control module modulating the current input to the electric motor based on the detected linear velocity of the plunger driver; The method of Example 10, further comprising: [Example 12] 11. The method of example 10, wherein the current input is modulated to a maximum rated power input if the detected force is greater than or equal to about 80 N. [Example 13] 13. The method of claim 12, wherein the maximum rated power input is about 0.7 A. [Example 14] 11. The method of example 10, wherein the current input is modulated to about 75% of its maximum rated power input if the detected force is less than about 80 N. [Example 15] 11. The method of example 10, wherein the current input is modulated to about 50% of its maximum rated power input if the detected force is less than about 65 N. [Example 16] 11. The method of example 10, wherein the current input is modulated to about 25% of its maximum rated power input if the detected force is negligible. [Example 17] 12. The method of example 11, wherein the current input is modulated to about 75% of its maximum rated power input when the detected force is greater than about 30 N and the detected rate of movement is greater than about 108 millimeters per hour. [Example 18] 12. The method of example 11, wherein the current input is modulated to about 50% of its maximum rated power input when the detected force is less than about 64 N and the detected rate of movement is less than about 108 millimeters per hour. [Example 19] 1. An infusion pump configured to regulate a current input to a drive motor, comprising: a pump housing defining a syringe receptacle shaped and sized to receive a syringe load; an electric motor having a variable output torque based on said current input; 1. A syringe drive assembly comprising: a lead screw operably coupled to said electric motor; a plunger driver operatively coupled to the lead screw and linearly movable in response to rotation of the electric motor, the plunger driver configured to depress a plunger of the syringe; a force sensor configured to detect a force between the plunger driver and the plunger of the syringe; and a plunger head sensor configured to detect a linear movement speed of the plunger driver; a syringe drive assembly including: a control module configured to adjust the current input to the electric motor based on the detected force between the plunger driver and the plunger of the syringe, the control module further configured to adjust the current input to the electric motor based on a linear velocity of the plunger driver detected by the plunger head sensor; the current input is progressively reduced according to a defined magnitude of the detected force; the maximum rated power input of the drive motor is less than about 1.0 A; Infusion pump.

Claims

1. 1. An infusion pump configured to regulate a current input to a drive motor, comprising: a pump housing defining a syringe receptacle shaped and sized to receive a syringe load; an electric motor having a variable output torque based on said current input; 1. A syringe drive assembly comprising: a lead screw operably coupled to said electric motor; a plunger driver operatively coupled to the lead screw and linearly movable in response to rotation of the electric motor, the plunger driver configured to depress a plunger of the syringe; and a force sensor configured to detect a force between the plunger driver and a plunger of the syringe; a syringe drive assembly including: a control module configured to adjust the current input to the electric motor based on the detected force between the plunger driver and the syringe plunger; Equipped with reducing the current input stepwise according to the magnitude of the detected force; Infusion pump.

2. The infusion pump of claim 1 , wherein the current input is maintained at a maximum rated power input if the detected force is greater than or equal to 80 N.

3. 3. The infusion pump of claim 2, wherein the maximum rated power input is 0.7 A.

4. 2. The infusion pump of claim 1, wherein the current input is reduced to 75% of its maximum rated power input if the detected force is less than 80 N.

5. 2. The infusion pump of claim 1, wherein the current input is reduced to 50% of its maximum rated power input if the detected force is less than 65 N.

6. 10. The infusion pump of claim 1, wherein the current input is reduced to 25% of its maximum rated power input if the detected force is negligible.

7. 10. The infusion pump of claim 1, wherein the current input is decreased according to a non-linear function of the detected force along a continuous curve.

8. the syringe drive assembly further comprising a plunger head sensor configured to detect a linear speed of the plunger driver; the control module is further configured to adjust the current input to the electric motor based on the linear velocity of the plunger driver detected by the plunger head sensor. The infusion pump of claim 1.

9. 1. A method of operating an infusion pump, comprising: a control module providing a current input to an electric motor of the infusion pump to force a plunger driver of the infusion pump against a plunger of a syringe mounted in the infusion pump, the electric motor including a variable output torque based on the current input; detecting a force between the plunger driver and the plunger of the syringe using a force sensor; the control module adjusting the current input to the electric motor based on the detected force between the plunger driver and the plunger of the syringe; Including, reducing the current input stepwise according to the magnitude of the detected force; method.

10. Detecting a linear speed of the plunger driver using a plunger head sensor; the control module modulating the current input to the electric motor based on the detected linear velocity of the plunger driver; 10. The method of claim 9, further comprising:

11. 10. The method of claim 9, wherein if the detected force is greater than or equal to 80N, the current input is modulated to a maximum rated power input.

12. The method of claim 11 , wherein the maximum rated power input is 0.7 A.

13. 10. The method of claim 9, wherein if the detected force is less than 80N, the current input is modulated to 75% of its maximum rated power input.

14. 10. The method of claim 9, wherein the current input is modulated to 50% of its maximum rated power input if the detected force is less than 65N.

15. 10. The method of claim 9, wherein the current input is modulated to 25% of its maximum rated power input if the detected force is negligible.

16. 11. The method of claim 10, wherein if the detected force is greater than 30 N and the detected speed of movement is greater than 108 mm / hr, the current input is modulated to 75% of its maximum rated power input.

17. 11. The method of claim 10, wherein the current input is modulated to 50% of its maximum rated power input if the detected force is less than 64 N and the detected speed of movement is less than 108 mm / hr.

18. 1. An infusion pump configured to regulate a current input to a drive motor, comprising: a pump housing defining a syringe receptacle shaped and sized to receive a syringe load; an electric motor having a variable output torque based on said current input; 1. A syringe drive assembly comprising: a lead screw operably coupled to said electric motor; a plunger driver operatively coupled to the lead screw and linearly movable in response to rotation of the electric motor, the plunger driver configured to depress a plunger of the syringe; a force sensor configured to detect a force between the plunger driver and the plunger of the syringe; and a plunger head sensor configured to detect a linear movement speed of the plunger driver; a syringe drive assembly including: a control module configured to adjust the current input to the electric motor based on the detected force between the plunger driver and the plunger of the syringe, the control module further configured to adjust the current input to the electric motor based on a linear velocity of the plunger driver detected by the plunger head sensor; the current input is reduced in steps according to the magnitude of the detected force; The maximum rated power input of the drive motor is less than 1.0 A; Infusion pump.

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