Abstract:
An infusion device for delivering discrete boluses of medication to a patient, using a mechanically actuated piston. The infusion pump employs a near-field communication system to convey the occurrence of an actuation, the amount of medicament remaining in the pump, and other information to a nearby near-field receiver device. The disclosed drive system and nearer-field communications system provides an infusion device capable of accurately delivering medication and providing a means for tracking and logging data while eliminating the need for a power source within the device, thereby minimizing weight and size.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Ser. No. 61/837,697 filed Jun. 21, 2013, which application is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to infusion devices and more particularly to such devices that enable liquid medicaments to be conveniently and safely self-administered by a patient. 
       BACKGROUND OF THE INVENTION 
       [0003]    Tight control over the delivery of insulin in both type I diabetes (usually juvenile onset) and type II diabetes (usually late adult onset), has been shown to improve the quality of life as well as the general health of these patients. Insulin delivery has been dominated by subcutaneous injections of both long acting insulin to cover the basal needs of the patient and by short acting insulin to compensate for meals and snacks. Recently, the development of electronic, external insulin infusion pumps has allowed the continuous infusion of fast acting insulin for the maintenance of the basal needs as well as the compensatory doses (boluses) for meals and snacks. These infusion systems have shown to improve control of blood glucose levels. However, they suffer the drawbacks of size, cost, and complexity. For example, these pumps are electronically controlled and must be programmed to supply the desired amounts of basal and bolus insulin. This prevents many patients from accepting this technology over the standard subcutaneous injections. 
         [0004]    Hence, there is a need in the art for a convenient form of insulin treatment which does not require significant programming or technical skills to implement to service both basal and bolus needs. Preferably, such a treatment would be carried out by an infusion device that is simple to use and mechanically driven negating the need for batteries and the like. It would also be preferable if the infusion device could be directly attached to the body and not require any electronics to program the delivery rates. The insulin is preferably delivered through a small, thin-walled tubing (cannula) through the skin into the subcutaneous tissue similar to technologies in the prior art. 
         [0005]    While the idea of such a simple insulin delivery device is compelling, many obstacles must be overcome before such a device may become a practical realty. One problem resides in insulin supply. Patients vary greatly on the amount of insulin such a device must carry to provide treatment over a fixed time period of, for example, three days. This is one environment where one size does not fit all. Still further, such devices must be wearable with safety and not subject to possible accidental dosing. Still further, such devices must be capable of delivering an accurately controlled volume of medicament with reliability. Finally, a device that provides means for tracking the number of doses of medication delivered is highly desirable to permit a patient or healthcare provider to ensure that the correct amount of medication is administered over a given period of time. While it is preferred that these devices include all of the forgoing features, it would be further preferred if the cost of manufacturing such a device would be economical enough so as to render the device disposable after use. As will be seen subsequently, the devices and methods described herein address these and other issues. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further features and advantages thereof, may best be understood by making reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify identical elements, and wherein: 
           [0007]      FIG. 1  is a perspective view of a first infusion device embodying certain aspects of the present invention. 
           [0008]      FIG. 2  is a schematic representation of the valves and pump of the device of  FIG. 1 . 
           [0009]      FIG. 3  is an exploded perspective view of the device of  FIG. 1 . 
           [0010]      FIG. 4  shows in perspective view a near-field antenna electrically coupled to an encoder system according to an aspect of the present invention. 
           [0011]      FIG. 5  illustrates in perspective view a geared encoder disc with a ratchet and pawl system for rotating the disc in discrete increments. 
           [0012]      FIG. 6  illustrates an embodiment of the infusion device of the present invention, in perspective view, including the encoder system of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    Referring now to  FIG. 1  it is a perspective view of a first infusion device embodying certain aspects of the present invention. The device  10  generally includes an enclosure  12 , a base  14 , a first actuator control button  16 , and a second actuator control button  18 . 
         [0014]    The enclosure  12 , as will be seen subsequently, is formed by virtue of multiple device layers being brought together. Each layer defines various components of the device such as, for example, a reservoir, fluid conduits, pump chambers, and valve chambers, for example. This form of device construction, in accordance with aspects of the present invention, enables manufacturing economy to an extent rendering the device disposable after use. 
         [0015]    The base  14  preferably includes an adhesive coating to permit the device to be adhered to a patient&#39;s skin. The adhesive coating may originally be covered with a releasable cover that may be pealed off of the base  14  when the patient endeavors to deploy the device  10 . Such arrangements are well known in the art. 
         [0016]    The device  10  may be mated with a previously deployed cannula assembly. However, it is contemplated herein that the various aspects of the present invention may be realized within a device that may be alternatively first adhered to the patient&#39;s skin followed by the deployment of a cannula thereafter. 
         [0017]    The actuator buttons  16  and  18  are placed on opposites sides of the device  10  and directly across from each other. This renders more convenient the concurrent depression of the buttons when the patient wishes to receive a dose of the liquid medicament contained within the device  10 . This arrangement also imposes substantially equal and opposite forces on the device during dosage delivery to prevent the device from being displaced and possibly stripped from the patient. As will be further seen hereinafter, the concurrent depression of the buttons is used to particular advantage. More specifically, the actuator button  16  may serve as a valve control which, when in a first position as shown, establishes a first fluid path between the device reservoir and the device pump to support pump filling, and then, when in a second or depressed position, establishes a second fluid path between the device pump and the device outlet or cannula to permit dosage delivery to the patient. As will be further seen, a linkage between the control actuator buttons  16  and  18  permits actuation of the device pump with the actuator control button  18  only when the second fluid path has been established by the first actuator control button  16 . Hence, the first actuator control button  16  may be considered a safety control. 
         [0018]    Referring now to  FIG. 2 , it is a schematic representation of the valves and pump of the device  10  of  FIG. 1 . As may be seen in  FIG. 2 , the device  10  further includes a fill port  20 , a reservoir  22 , a pump  24 , and the cannula  30 . The device further includes a first valve  32  and a second valve  34 . Fluid conduit  40  provides a fluid connection between the fill port  20  and the reservoir  22 , fluid conduit  42  provides a fluid connection between the reservoir  22  and the first valve  32 , fluid conduit  44  provides a fluid connection between the first valve  32  and the pump  24 , fluid conduit  46  provides a fluid connection between the pump  24  and the second valve  34 , and fluid conduit  48  provides a fluid connection between the second valve  34  and the device outlet  50 . The outlet  50  is arranged to communicate with the cannula  30 . 
         [0019]    It may also be noted that the actuator buttons  16  and  18  are spring loaded by springs  36  and  38 . The springs are provided for returning the actuator buttons to the first position after a dosage is administered. 
         [0020]    The pump  24  of the device  10  comprises a piston pump. The pump  24  includes a pump piston  26  and a pump chamber  28 . In accordance with this embodiment, the actuator control button  18  is directly coupled to and is an extension of the pump piston  26 . 
         [0021]    With further reference to  FIG. 2 , the device additionally includes a first linkage  52  and a second linkage  54 . The first linkage is a toggle linkage between the first valve  32  and the second valve  34 . It is arranged to assure that the second valve  34  does not open until after the first valve  32  is closed. The second linkage  54  is between the first actuator button  16  and the second actuator button  18 . It is arranged to assure that the pump does not pump until after the first valve is closed and the second valve is opened by the first actuator button  16 . 
         [0022]    Still further, the second valve  34  is a safety valve that closes tighter responsive to increased fluid pressure within fluid conduit  46 . This assures that the liquid medicament is not accidentally administered to the patient notwithstanding the inadvertent application of pressure to the reservoir, for example. In applications such as this, it is not uncommon for the reservoir to be formed of flexible material. While this has its advantages, it does present the risk that the reservoir may be accidentally squeezed as it is worn. Because the second valve only closes tighter under such conditions, it is assured that increased accidental reservoir pressure will not cause the fluid medicament to flow to the cannula. 
         [0023]    In operation, the reservoir is first filled through the fill port  20  to a desired level of medicament. In this state, the valves  32  and  34  will be as shown. The first valve  32  will be open and the second valve  34  will be closed. This permits the piston chamber  28  to be filled after the reservoir is filled. The cannula  30  may then be deployed followed by the deployment of the device  10 . In this state, the valves  32  and  34  will still be as shown. The first valve  32  will be open and the second valve  34  will be closed. This permits the pump chamber  28  to be filled through a first fluid path including conduits  42  and  44  as the piston  24  returns to its first position after each applied dose. 
         [0024]    When the patient wishes to receive a dose of medicament, the actuator buttons are concurrently pressed. In accordance with aspects of the present invention, the linkage  52  causes the first valve  32  to close and the second valve  34  to thereafter open. Meanwhile, the second linkage  54  precludes actuation of the pump  24  until the first valve  32  is closed and the second valve  34  is opened by the first actuator button  16 . At this point a second fluid path is established from the pump  24  to the cannula  30  through fluid conduits  46  and  48  and the outlet  50 . The medicament is then administered to the patient through cannula  30 . 
         [0025]    Once the medication dosage is administered, the piston  24 , and thus the actuator button  18 , is returned under the spring pressure of spring  38  to its initial position. During the travel of the piston back to its first position, a given volume of the liquid medicament for the next dosage delivery is drawn from the reservoir into the pump chamber  28  to ready the device for its next dosage delivery. 
         [0026]    Referring now to  FIG. 3 , it is an exploded perspective view of the device of  FIG. 1 . It shows the various component parts of the device. The main component parts include the aforementioned device layers including the base layer  60 , the reservoir membrane or intermediate layer  62 , and the top body layer  64 . The base layer is a substantially rigid unitary structure that defines a first reservoir portion  66 , the pump chamber  28 , and valve sockets  68  and  70  of the first and second valves respectively. The base layer  60  may be formed of plastic, for example. The reservoir membrane layer  62  is received over the reservoir portion  66  to form the reservoir  22  ( FIG. 2 ). A valve seat structure  72  is received over the valve sockets  68  and  70  to form the first and second valves  32  and  34  ( FIG.2 ) respectively. A rocker  74  is placed over the valves seat structure  72  to open and close the valves as will be seen subsequently. The pump actuator button  18  carries the pump piston that is received within the pump chamber  28 . The pump actuator button  18  also carries a cam cylinder  76  with a lock tube  78  therein that form a portion of the second linkage  54  ( FIG. 2 ). The spring  38  returns the actuator button  18  to its first position after each dosage delivery. 
         [0027]    The first actuator control button carries a valve timing cam  80  that rocks the rocker  72 . The button  16  further carries a cam cylinder  82  and a cam pin  84  that is received into the cam cylinder  82 . The spring  36  returns the actuator button  16  to its first position after each dosage delivery. The top body layer  64  forms the top portion of the device enclosure. It receives a planar cap  86  that completes fluid paths  85  partially formed in the top layer  64 . Lastly, a needle  88  is provided that provides fluid coupling from the cannula (not shown) to the outlet of the device  10 . 
         [0028]    The infusion system described herein is capable of delivering discrete doses of medication to the patient with each actuation of the buttons  16  and  18 . Most, if not all, patients may desire a way for their infusion device to record when a dose is delivered. Historical information indicating when a patient received a dose is important in managing chronic conditions and diseases, such as diabetes. Insulin-dependent diabetics, for example, need to know how much insulin they have injected into their body and when, so that they can determine how much insulin they should receive to compensate for meals, etc. 
         [0029]    It has been found that transmitting the occurrence of each dose to a remote device is desirable, as the structure and method for doing so minimizes the number of components that need to be added to the infusion device of  FIGS. 1-3 . A near-field communication (NFC) system, for example, can be used to transmit the occurrence of each dose a short distance. The power supply for this type of transmission system can be in the receiving device, rather than the transmitter which, in this example, is the infusion device. By eliminating the need for a power supply within the infusion device, the weight and size of the device is kept to a minimum, and the shelf-life of the device is not affected by the inclusion of a battery that can discharge over time or require specific storage conditions (temperature, etc.) 
         [0030]      FIG. 4  illustrates an exemplary near-field transmission system  200  that may be added to the presently described infusion device as a means for counting and tracking dosing information via a remote device. The near-field communications (NFC) antenna  210  and associated near-field integrated circuit  220  are inexpensive and highly miniaturized. An inexpensive position encoder is also added to the pump. In this embodiment, the position encoder comprises a moving portion  250  and a stationary portion  240 . The encoder is set to the fully-retracted position when the pump is completely full of medicament. Each time a dose is delivered by the infusion device, the moving portion  250  of the encoder moves relative to the stationary portion  240  of the encoder. 
         [0031]    When the near-field transmission system is placed in proximity to a near-field receiver (not shown), the power necessary to operate the near field integrated circuit  220  is supplied by the receiver via inductive coupling between the receiver and the near-field antenna. While not wishing to be bound by theory, the receiver generates a magnetic field. When the near field antenna  210  is placed within the magnetic field, the magnetic field around the receiver creates a current within the near-field antenna  210 , according to the principle of induction, thereby generating the electricity in the near-field transmitter system  200  to power the near-field integrated circuit  22 . This obviates the need for a power supply to be placed within the infusion device. 
         [0032]    The position of the moving portion  250  of the encoder relative to the stationary portion of the encoder  240  is then transmitted via electrical contacts  230  to the near-field integrated circuit  220 . The near-field integrated circuit  220  processes the signal received via the electrical contacts  230  and the processed signal is transmitted to the remote device via the near-field antenna  210 . 
         [0033]    In the embodiment of the near-field transmitter system  200  of  FIG. 3 , the moving portion  250  of the position encoder may be mechanically linked to the piston actuator button  18  of  FIG. 1  of an infusion device. Thus, each time the piston is actuator to deliver a bolus of medication, the moving portion  250  of the position encoder is advanced relative to the stationary portion  240  of the position encoder. The signal provided to a receiver will reflect the change in position and software running on the receiver can interpret the changed signal as an indication that a bolus was delivered. If the near-field transmitter system  200  is within the magnetic field produced by the receiver at the time of the piston&#39;s actuation, then the receiver may also record the time of the delivery and thus be able to maintain a chronological log of medication deliveries. 
         [0034]    As illustrated in  FIG. 5 , the encoder may also be implemented as a rotary disk. When the user presses the pump&#39;s actuation button  18  to deliver medicament, a pawl-and-ratchet mechanism rotates the encoder disk  300  by one increment. The encoder disk  300  should include means to rotatably secure it within the housing. As illustrated, the encoder disk has a hole  305  to receive a mounting post or other structure known in the art to permit the encoder disk  300  to be held in place while still permitting rotation. Typically, the top cover of the infusion device will inhibit any vertical motion of the encoder disk  300  and the mounting structure need only retain the disk from horizontal movement. 
         [0035]    The encoder disk may also have a series of teeth  290  disposed about its circumference and electrical contacts  265  on its exposed side. An encoder pickup  295  is disposed in proximity to the electrical contacts  265 , but remains fixed relative to the housing of the infusion device, allowing the encoder disk  300  to move relative to the encoder pickup  295 . The encoder disk  300  has electrical contacts  265  imprinted upon its surface. The electrical contacts  265  are arranged such that they open and close electrical circuits with the N electrical pickup contacts that ride on the surface of the encoder disk. The electrical contacts  265  provide a unique binary code for each discrete position of the encoder disk  300 . With N electrical contacts, there are 2 N −1 possible unique binary codes. For example, if the infusion had the capability of being filled with 300 U of insulin and each actuation of the infusion device causes a discrete delivery of 1 U of insulin, the encoder disk must have at least 300 unique positions and 10 (i.e., 1+FLOOR[log 2 (300)+1]) electrical contacts to detect each possible state of the pump. 
         [0036]    NFC technology is often used to identify or prevent counterfeits. The NFC ID in the pump could be programmed with a secure code and encryption scheme that would be unknown to counterfeiters. While this would not prevent the manufacture or use of a counterfeit pump, such a pump could be detected and recognized through encrypted NFC communications. 
         [0037]    The IC could also be factory-programmed with information such as pump date-of-manufacture, batch code, and model number. The pump manufacturer could use this information for inventory control and in forensic investigations. 
         [0038]    The ratchet-and-pawl system shown in  FIG. 5  may include the pawl  255  in mechanical contact with the piston actuation button  18  and spring  38 . The pawl may include an opening for the limiter  260  to be placed such that it limits the movement of the pawl  255  to ensure that the encoder disk  300  is moved only a single increment with each actuation, by the pawl tip  280  biasing against the teeth  290  of the encoder disk  300  when the piston actuation button  18  is depressed. The ratchet ensure that the encoder disk can only rotate in a single direction and may include a ratchet post  275  with a ratchet spring  270  and ratchet arm  285 . The ratchet arm is biased against the teeth  290  of the encoder gear  300  by the ratchet spring  270 . The ratchet spring is attached to or otherwise engaged with the ratchet post  275  for the ratchet spring to bias against. 
         [0039]      FIG. 6  illustrates a manually-activated, mechanical infusion device  400 . Such devices are also described in commonly-assigned U.S. Pat. No. 7,976,500, which is hereby incorporated by reference in its entirety. The encoder disk  300  is rotatably mounted on a top layer 7 of the pump mechanism. An encoder pickup  295  is fixedly mounted over the encoder disk  300 , so that the encoder pickup  295  is able to sense the state of the electrical contacts  265  on the encoder disk  300 . In this embodiment, the actuator button  16  is depressed to permit motion of the actuator button  18 . When actuator button  18  is depressed, a delivery of medication occurs. As well, the pawl  315  biases pawl mechanism  305 , which is limited in movement by the pawl stop post  260 . A ratchet mechanism  310  ensures that the encoder disk  300  cannot rotate in a counter-clockwise direction. The ratchet mechanism may have similar or identical structure to that shown in  FIG. 5 . 
         [0040]    The receiver that supplies power for and receives data from the near field transmitter system of the disclosed embodiments can be a cell phone or other device equipped with a near field receiver. Software on the receiver device may perform numerous functions, such as logging the time of each dose delivered by the pump or to determine the amount of medication remaining in the pump at a given time. 
         [0041]    The system may determine the amount of medicament in the pump in accordance with the following illustrative example. The infusion pump&#39;s encoder and IC remain unpowered until the user wants to determine the medicament remaining in the infusion pump. The user then positions an NFC equipped device, such as a cell phone, within a few centimeters of the infusion pump. The infusion pump&#39;s NFC antenna receives enough electromagnetic energy from the cell phone&#39;s NFC transmitter to power the infusion pump&#39;s IC and the encoder. The IC reads the encoder&#39;s position and wirelessly transmits it to the cell phone, where it will be available for display, recording and further processing. 
         [0042]    The position encoder could be built using a variety of technologies known in the art including resistive, magnetic, LVDT, binary conductive, capacitive, inductive and optical. Encoder technologies could be combined to achieve the best combination of cost, durability, reliability, accuracy and resolution. 
         [0043]    While particular embodiments of the present invention have been shown and described, modifications may be made. For example, instead of manual actuation and spring loaded return of the valves used herein, constructions are possible which perform in a reversed manner by being spring actuated and manually returned. It is therefore intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention as defined by those claims.