Abstract:
A wearable infusion device comprises a reservoir that holds a liquid medicament, an outlet that delivers the liquid medicament to a patient, and a pump that displaces a volume of the liquid medicament to the outlet when actuated. The device further includes a lock-out that disables actuation of the device responsive to a predetermined condition of the device. The lock-out is resettable.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    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. 
         [0002]    Administration of insulin has traditionally been accomplished using a syringe. Recently, needle carrying pen-like devices have also been employed for this purpose. Both forms of insulin administration require the patients to stick themselves each time they inject insulin, often many times a day. Thus, these traditional forms of insulin administration have been a rather pervasive intrusion in the lives and routines of the patients who have had to adopt and employ them. 
         [0003]    More recently, insulin pumps attached by tubing to an infusion set mounted on the patient&#39;s skin have been developed as an alternative form of insulin administration. Such pumps may be controlled by a programmable remote electronic system employing short range radio communication between a control device and electronics that control the pump. While such devices may involve fewer needle sticks, they are expensive to manufacture. They are also complex to operate and cumbersome and awkward to wear. Further, the cost of such devices can be many times the daily expense of using a traditional injection means such as a syringe or an insulin pen. 
         [0004]    Devices of the type mentioned above also require a significant amount of training to control and thus use the devices. Great care in programming the devices is required because the pumps generally carry sufficient insulin to last a few days. Improper programming or general operation of the pumps can result in delivery of an excessive amount insulin which can be very dangerous and even fatal. 
         [0005]    Many patients are also reluctant to wear a pump device because they can be socially awkward. The devices are generally quite noticeable and can be as large as a pager. Adding to their awkwardness is their attachment to the outside of the patients clothes and the need for a catheter like tubing set running from the device to an infusion set located on the patient&#39;s body. Besides being obvious and perhaps embarrassing, wearing such a device can also be a serious impediment to many activities such as swimming, bathing, athletic activities, and many activities such as sun bathing where portions of the patient&#39;s body are necessarily uncovered. 
         [0006]    In view of the above, a more cost effective and simple device has been proposed whereby an injection system is discreetly attached directly to the skin of the patient. The device may be attached to the patient under the patient&#39;s clothing to deliver insulin into the patient by the manual pumping of small doses of insulin out the distal end of a temporarily indwelling cannula that is made a part of the pump device. The cannula may be made a part of the drug delivery device before, during or after the attachment of the drug delivery device to the skin of the patient. The device may be made quite small and, when worn under the clothes, entirely unnoticeable in most social situations. It may still carry sufficient insulin to last a patient several days. It can be colored to blend naturally with the patient&#39;s skin color so as not to be noticeable when the patient&#39;s skin is exposed. As a result, insulin for several days may be carried by the patient discreetly, and conveniently applied in small dosages after only a single needle stick. For a more complete description of devices of this type, reference may be had to co-pending application Ser. No. 11/906,130, filed on Sep. 28, 2007 for DISPOSABLE INFUSION DEVICE WITH DUAL VALVE SYSTEM, which application is owned by the assignee of this application and hereby incorporated herein by reference in its entirety. 
         [0007]    Devices of the type described may be intended for single use. That is, after initial filling of the device reservoir device deployment, and self-administered drug dosing to drug depletion, disposal of the device may be required. In such an event, it would be helpful to have a mechanism built into the device that prevents further use of the device after drug depletion. One solution to achieve this end is fully disclosed and claimed in U.S. co-pending application Ser. No. 11/906,104 filed Sep. 29, 2007 for DISPOSABLE INFUSION DEVICE WITH REUSE LOCK-OUT, which application is owned by the assignee of this invention and incorporated herein by reference in its entirety As taught therein, the dose delivery actuator may be disabled upon operation of the device actuation buttons when the reservoir is empty. Unfortunately, this device disablement may accidentally occur before the device is ever deployed for use. For example, the device disablement may occur by the actuating buttons being accidentally operated prior to the filling of the device reservoir. Such accidental disablement would render the device useless. 
         [0008]    Accordingly, the present invention provides further improvement to the devices disclosed in the above referenced co-pending application. More particularly, the present invention provides for improved patient safety and/or convenience. To that end, the invention provides, an infusion device which includes device disablement upon the reservoir becoming empty while allowing the device disablement to be reset if it occurs prior to the deployment of the device. 
       SUMMARY OF THE INVENTION 
       [0009]    In one embodiment, a wearable infusion device comprises a resettable lock-out. The device includes a reservoir that holds a liquid medicament, an outlet that delivers the liquid medicament to a patient and a pump that displaces a volume of the liquid medicament to the outlet when actuated. The device further includes a lock-out that disables actuation of the device responsive to a predetermined condition of the device. The lock-out is resettable. 
         [0010]    The lock-out is a last dose lock-out The predetermined condition of the device may be that the reservoir is substantially empty. The device may further include a fill port communicating with the reservoir to permit liquid medicament to be introduced into the reservoir. The lock-out is resettable through the fill port. 
         [0011]    The device may further comprise a control that actuates the pump and the lock-out may be arranged to disable the control. 
         [0012]    The lock-out may include a pressure sensor. The predetermined condition may be a reduced pressure such as below ambient pressure, sensed by the pressure sensor. The pump may be arranged to produce the reduced pressure when the reservoir is empty. The pump may be a piston pump. 
         [0013]    The piston pump may be arranged to produce the reduced pressure during a recharge stroke when the reservoir is empty. The device may further include a fill port communicating with the reservoir to permit liquid medicament to be introduced into the reservoir. The reduced pressure is releasable to reset the lock-out by venting the fill port. The fill port may be arranged to communicate with the reservoir to permit liquid medicament to be introduced into the reservoir and the reduced pressure may be releasable to reset the lock-out by venting the fill port and actuating the piston pump through a recharge cycle. The pressure sensor may be disposed between the pump and the reservoir. 
         [0014]    In another embodiment, wearable infusion device comprises a reservoir that holds a liquid medicament, an outlet that delivers the liquid medicament to a patient, and a pump that displaces a volume of the liquid medicament to the outlet when actuated. The device further includes a lock-out including a pressure sensor that disables actuation of the device responsive to the pressure sensor sensing a reduced pressure. The reduced pressure is releasable to reset the lock-out. 
         [0015]    The pump may be arranged to produce the reduced pressure when the reservoir is empty. The pump may be a piston pump. The piston pump may be arranged to produce the reduced pressure during a recharge stroke when the reservoir is empty. 
         [0016]    The device may further include a fill port communicating with the reservoir to permit liquid medicament to be introduced into the reservoir. The reduced pressure may be releasable to reset the lock-out by venting the fill port. 
         [0017]    The may further comprise a fill port communicating with the reservoir to permit liquid medicament to be introduced into the reservoir. The reduced pressure may be releasable to reset the lock-out by venting the fill port and actuating the piston pump through a recharge cycle The pressure sensor may be between the pump and the reservoir. 
         [0018]    In a further embodiment, a wearable infusion device comprises a reservoir that holds a liquid medicament, a fill port permitting a medicament to be introduced into the reservoir, an outlet that delivers the liquid medicament to a patient, and a piston pump that displaces a volume of the liquid medicament to the outlet when actuated. The piston pump is operable through a recharge cycle and produces a reduced pressure during the recharge cycle when the reservoir is empty. The device further includes a lock-out including a pressure sensor that disables actuation of the device responsive to the pressure sensor sensing the reduced pressure. The reduced pressure is releasable through the fill port to reset the lock-out. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    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: 
           [0020]      FIG. 1  is a perspective view of an infusion device embodying the present invention shown without a deployed cannula; 
           [0021]      FIG. 2  is another perspective view of the infusion device of  FIG. 1  shown with a deployed cannula; 
           [0022]      FIG. 3  is an exploded perspective view of the device of  FIG. 1 ; 
           [0023]      FIG. 4  is a sectional view, in perspective, to an enlarged scale, taken along lines  4 - 4  of  FIG. 1 , showing the actuation linkages of the device of  FIG. 1  prior to medicament dosage delivery; 
           [0024]      FIG. 5  is another sectional view, in perspective, to an enlarged scale, taken along lines  5 - 5  of  FIG. 2 , showing the actuation linkage operation of the device of  FIG. 1  during medicament dosage delivery; 
           [0025]      FIG. 6  is another sectional view similar to that of  FIG. 5 , in perspective, to an enlarged scale, showing the actuation linkage operation of the device of  FIG. 1  immediately after dosage delivery; 
           [0026]      FIG. 7  is a schematic representation of the valves and pump of the device of  FIG. 1  between medicament dosage deliveries and during the filling of the pump with the medicament; 
           [0027]      FIG. 8  is another schematic representation of the valves and pump of the device of  FIG. 1  during medicament dosage delivery; 
           [0028]      FIG. 9  is a sectional view, in perspective, to an enlarged scale, showing the configuration of the valves of the device of  FIG. 1  during pump filling and prior to medicament dosage delivery; 
           [0029]      FIG. 10  is another sectional view, in perspective, to an enlarged scale, showing the configuration of the valves of the device of  FIG. 1  during dosage delivery; 
           [0030]      FIG. 11  is a top perspective view of the base of the device of  FIG. 1  illustrating various fluid paths within the device; 
           [0031]      FIG. 12  is a partial bottom plan view of the base of the device of  FIG. 1  to illustrate the interior of a prime indicator according to one embodiment thereof; 
           [0032]      FIG. 13  is a bottom plan view of the base of the device of  FIG. 1  illustrating the prime indicator interior covered by a translucent cover according to the above mentioned prime indicator embodiment; 
           [0033]      FIG. 13A  is a bottom view of the device  110  illustrating a removable non-adhesive layer overlying an adhesive layer on the device base; 
           [0034]      FIG. 14  is a sectional view, in perspective, taken along lines  14   14  of  FIG. 1  of a lock-out according to an embodiment of the device of  FIG. 1  shown prior to an intended dosage delivery; 
           [0035]      FIG. 15  is another sectional view, in perspective, of the lock out shown during a last dosage delivery; 
           [0036]      FIG. 16  is another sectional view in perspective of the lock-out shown after the last dosage delivery; and 
           [0037]      FIG. 17  is a perspective view of the lock-out shown disabling the device after the last dosage delivery. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0038]    Referring now to  FIGS. 1 and 2 , they are perspective views of an infusion device  110  embodying various aspects of the present invention.  FIG. 1  shows the device prior to receiving and thus without a cannula while  FIG. 2  illustrates the device after having received a cannula  130  that has a distal end  131 . As may be seen in both  FIGS. 1 and 2 , the device  110  generally includes an enclosure  112 , a base  114 , a first actuator control button  116 , and a second actuator control button  118 . 
         [0039]    The enclosure  112 , 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 results in a compact design and enables manufacturing economy to an extent that the device is disposable after use. 
         [0040]    The base  114  preferably includes a pad  115  attached to the base  114 . The pad  115  has an adhesive coating  117  on the side thereof opposite the base  114  to permit the device to be adhered to a patient&#39;s skin. The adhesive coating may originally be covered with a releasable cover  292  ( FIG. 13A ) that may be pealed off of the adhesive layer  117  when the patient endeavors to adhere the device  110  to their skin. 
         [0041]    The device  110 , as will be seen herein after is first adhered to the patient&#39;s skin followed by the deployment of the cannula  130  thereafter. However, it is contemplated herein that various aspects of the present invention may be realized within a device that may alternatively be mated with a previously deployed cannula assembly. 
         [0042]    The actuator buttons  116  and  118  are placed on opposites sides of the device  110  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  110 . 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  116  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 distal end of the cannula to permit dosage delivery to the patient. As will be further seen, a linkage between the control actuator buttons  116  and  118  permits actuation of the device pump with the actuator control button  118  only when the second fluid path has been established by the first actuator control button  116 . Hence, the first actuator control button  116  may be considered a safety control. 
         [0043]    The actuator buttons  116  and  118  are preferably arranged to require a complete through of their travel to achieve activation of the device pump and thus dosage delivery. This, together with the sudden release of resistance to actuator advancement creates a snap action that provides an advantage in positively knowing that dosage delivery has occurred and that no less than a full dose has been delivered. For more description regarding this feature, reference may be had to co-pending application Ser. No. 11/906,102, titled DISPOSABLE INFUSION DEVICE WITH SNAP ACTION ACTUATION, which application is owned by the assignee of this application and is incorporated herein by reference in its entirety. 
         [0044]    As may be noted in  FIG. 1 , the device  110  includes a cavity  120  that is arranged to receive a cannula assembly  122  ( FIG. 2 ) from which the cannula  130  extends. When the cannula is deployed, the outlet  124  of the device  110  is placed in fluid communication with the cannula  130  by a cannula carrier  128  of the cannula assembly  122  that carries the cannula. When thus deployed, the cannula  130  extends from the base  114  of the device  110  to beneath the skin of the user. 
         [0045]    As may further be noted in  FIGS. 1 and 2 , the enclosure  112  of the device  110  includes a pair of pockets  140  and  142  on opposite sides of the second actuator button  118 . A similar pair of pockets, not seen in the figure, are also provided on opposite sides of the first actuator button  116 . These pockets are used to receive corresponding projections of a cannula placement assembly for releasably joining the cannula placement assembly to the device  110  to support cannula deployment as will be described subsequently. As will also be seen, upon cannula deployment, the cannula placement assembly is automatically released from the device by the driver projections being forced from the pockets. 
         [0046]    Referring now to  FIG. 3 , it is an exploded perspective view of the device  110  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  160 , a reservoir membrane  162 , an intermediate layer  164  and a top body layer  166 . As may also be seen in  FIG. 3 , the base layer  160  is a substantially rigid unitary structure that defines a first reservoir portion  168 , a pump chamber  170 , and a valve chamber  190  that receives a shuttle bar  200  of a shuttle valve  210 . A reservoir membrane layer  162  is received over the reservoir portion  168  to form an expandable/deflatable reservoir of the device  110 . The base layer  160  may be formed of plastic, for example. The base and the top body layer may be joined together, trapping the intermediate layer there between by any means such as with screws, ultrasonic welding or laser welding. 
         [0047]    The valve chamber  190  is arranged to receive a valve shuttle bar  200  carried by and extending from the first actuator button  116 . A series of O-rings, to be described subsequently, are seated on the shuttle bar  200  to form first, second, and third valves. The actuator button  116  also carries a first linkage portion  240  of the linkage that permits actuation of the device pump with the actuator control button  118  only when the second fluid path has been established by the first actuator control button  116 . The first linkage portion  240  is received within a suitably configured bore  270  formed in the base layer  160  and will be described subsequently. 
         [0048]    The pump actuator button  118  is arranged to be linked to a pump piston  300  and a second linkage portion  340  to interact with the first linkage portion  240 . The pump piston  300  is arranged to be received within the pump chamber  170  and the second linkage portion  340  is arranged to be received within the bore  270  for interacting with the first linkage portion  240 . O-rings are seated on the piston  300  to provide a seal against leakage and to prevent external contaminants from entering the piston chamber. 
         [0049]    The intermediate layer  164  may be a generally resilient member and received on the base layer  160  to cover channels scribed in the base layer as a type of gasket to form fluid channels  380  that serve to conduct the medicament from the reservoir to the device outlet and to the distal end  131  ( FIG. 2 ) of the cannula  130 . Springs  410  are arranged to spring load the actuator buttons  116  and  118  away from each other. 
         [0050]    The reservoir membrane  162  is formed of flexible membrane material and is received over the reservoir portion  168  to form the reservoir of the device  110 . A rigid plate  420  is arranged to be adhered to the reservoir membrane  162  of the reservoir. Because the membrane  162  is flexible, it will move as the reservoir is filled and emptied. The rigid plate  420  will then move with it. The plate  420  includes an eyelet  422  dimensioned to receive an elongated web  424  that forms a part of a medicament level indicator. The web  424  carries an indicator line or feature  426  that may be read through a window  428  of the device top most panel  440 . 
         [0051]    Another component of the device  110  is a translucent window  450  that is received on the underside of the base  160 . As will be seen hereinafter, the window forms a part of a prime indicator It is formed of a transparent material such as glass or transparent plastic and has a roughened surface rendering it translucent. However, when it is covered with or at least wetted by liquid medicament, it is rendered essentially transparent creating a visually obvious condition and, for example, permitting indicia to be seen beneath it indicating that the conduit to the device outlet is primed and ready to deliver fixed doses of medicament when desired. 
         [0052]      FIGS. 4-6  show details of the operation of the linkage that permits actuation of the device pump with the actuator control button  118  only when the second fluid path from the reservoir to the outlet has been established by the first actuator control button  116 . The linkage has been given the general reference character  150 . 
         [0053]    As may be seen  FIG. 4 , the first actuator button  116  has an extension  152  that terminates in a block  154 . The block  154  has a first ramp surface  156  and a second ramp surface  158 . When the device  110  is actuated, the button  116  is concurrently depressed with pump button  118 . It and its extension  152  and block  154  are free to move to the right. As seen in  FIGS. 4 and 5 , the pump actuator button  118  has parallel extensions  250  and  252  which are joined and separated be a rod member  254 . The extensions  250  and  252  are pivotally mounted to pivot about a pivot point  256  Another extension  260  of the pump actuator button  118  spring biases the extensions  250  and  252  as shown in  FIG. 4 . As seen in  FIG. 4 , the extensions  250  and  252  abut an abutment  262  which they must clear to enable the actuator  118  to be moved to the left. As shown in  FIG. 5 , as the button  116  is depressed, its extension  152  moves to the right causing the first ramp surface  156  to engage the rod member  254 . Continued movement of the button causes the rod member  254  to ride up the first ramp surface  156  which in turn causes the extensions  250  and  252  to begin to move slightly to the left and bend upward against the loading of extension  260 . Eventually, the rod member  254  rides up the length of the first ramp  156  and down the second ramp  158  causing the extensions  250  and  252  to clear the abutment  262  and continue their travel to the left until the extensions are received on the opposite side of the abutment as shown in  FIG. 6  The pump button  116  has now been fully depressed to deliver a dose of measured medicament. When the ends of extensions  250  and  252  totally clear the abutment  262 , they will snap behind the abutment  262  as shown in  FIG. 6  and become temporarily locked. Meanwhile, the rod member  254  has traversed all the way down the second ramp surface  158 . The buttons  116  and  118  are now fully depressed. 
         [0054]    Hence, from the above, it may be seen that the pump button  118  could not at first move freely while the first actuator button  116  which operates the valves could. As a result, the pump actuation lags behind the valve actuation. This enables the device outlet to be sealed from the reservoir and the pump connected to the outlet before the pump is permitted to pump any medicament to the outlet. Hence, the device establishes a medicament delivery flow path to the cannula before the pump is able to begin pumping the medicament to the patient. Thus, it is assured that there is never an open unobstructed pathway between the reservoir and the fluid outlet. Also, by assuring that the pump only draws fluid from the reservoir when the pathway to the outlet is sealed off, it is also assured that a precise amount of fluid is moved with each pump cycle. This operation is completely timed by the linkage just described and occurs quickly, appearing to the patient that both actuator buttons are moving at the same rate. 
         [0055]    When the extensions  250  and  252  of the pump button clear the abutment  262 , they become locked in a snap action. This provides positive feedback to the patient that a dosage of medicament was delivered as desired. It also causes a full dose to be delivered. By virtue of the snap action of the pump actuator, only full doses may be administered. 
         [0056]    When the medicament has been delivered, the spring loading of the actuator buttons returns the buttons to their first or initial position. During this time, the same timing provided by the block  154  is used for recharging the pump. More specifically, ramp  158  unlatches the ends of extensions  250  and  252  by lifting rod member  254 . While the extensions  250  and  252  are being lifted by the ramp  158 , the valve control button  116  is returning to the left to cause the outlet to be disconnected from the pump before the reservoir is reconnected to the pump for charging, thus sealing the outlet from both the pump and the reservoir before the reservoir is connected to the pump for recharging. This assures that the pump does not pull medicament from the patient but only from the reservoir As the pump returns, a full dose of the medicament is drawn up into the piston chamber  170  to ready the device for the next dosage delivery 
         [0057]    Referring now to  FIGS. 7 and 8 , they are schematic representations of the valves and pump of the device of  FIG. 1  between medicament dosage filling ( FIG. 7 ) and medicament dosage delivery ( FIG. 8 ). As may be seen in  FIGS. 7 and 8 , the device  110  further includes a reservoir  180 , a pump  172 , and the cannula  130 . The reservoir  180  may be formed as shown in  FIG. 3  by the combination of the device base  160  and the flexible membrane  162 . The device further includes the shuttle valve  210  including shuttle bar  200 . The shuttle bar  200  is shown within the valve chamber  190 . The shuttle bar  200  and O-rings  214  and  216  form a first valve  212 , shuttle bar  200  and O-rings  220  and  222  form a second valve  218  and shuttle bar  200 , O-ring  226  and a bypass channel  186  form a third valve  224 . Although O-rings are used herein to form seals, other types of valve construction may employ forms of seals other than O-rings without departing from the invention. 
         [0058]    The pump piston  300  is within the piston camber  170  to form a piston pump  172 . The actuator control button  118  is directly coupled to and is an extension of the pump piston  300 . It may also be noted that the actuator buttons  116  and  118  are spring loaded by springs  117  and  119 , respectively. The springs are provided for returning the actuator buttons to a first or start position after a dosage is administered. 
         [0059]    A fluid conduit  182  extends between the reservoir  180  and the valve  212 . An annular conduit  192  extends between the O-rings  216  and  226 , and an annular conduit.  194  extends between the O-rings  226  and  220 . A fluid conduit  184  provides a fluid connection between the reservoir  180  and the annular conduits  192  and  194  depending upon the position of the shuttle valve  210 . Also illustrated in  FIG. 7  is the linkage  150  that assures that the shuttle valve  210  is actuated before the piston pump  172  is actuated to provide a dose of medicament. 
         [0060]    In  FIG. 7 , the valves are shown in a first configuration immediately after having returned to their first position following a dosage delivery. After the return of the valves, the linkage  150  permits the pump actuator  118  and piston  300  to return for refilling the pump chamber  170  in ready for the next medicament dosage delivery. During their return, the medicament flows as indicated by arrows  202  from the reservoir  180 , through the conduit  182 , through the annular channel  192 , through conduit  184 , and into the pump chamber  170 . 
         [0061]    As may be noted, when in the first position, the valves  218  and  224  isolate the outlet  124  from both the reservoir  180  and the piston pump  118 . Having two such valves isolate the outlet  124  when the valves are in the first configuration provides an added degree of safety from medicament being inadvertently delivered to the patient between dosage deliveries. For example, this provides additional safety that the liquid medicament is not accidentally administered to the patient notwithstanding the inadvertent application of pressure to the reservoir. 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 valves  218  and  224  isolate the outlet  124  when the valves are in their first configuration, this redundant protection assures that pressure, accidentally applied to the reservoir, will not cause the fluid medicament to flow to the cannula. 
         [0062]    In addition to the linkage  150  preventing return of the piston  300  until after the valves return to their first and start positions, the O-rings on the shuttle bar  200  are also spaced apart to insure that the valves  218  and  224  isolate the outlet  124  from the pump  172  and reservoir  180  before the pump is again connected to the reservoir. The O-ring spacing thus effectively forms a second linkage to assure that the cannula  130  is connected to the pump  172  only when a dosage is to be delivered and that it is never connected to the reservoir  180 . 
         [0063]    In operation, the pump chamber  170  is first filled as the actuator button  118  returns to the first position after having just delivered a medicament dosage. In this state, the shuttle valve  210  is set so that the first valve  212  will be open and the second and third valves  218  and  224  will be closed. This establishes a first fluid path indicated by arrows  202  from the reservoir  180  to the pump chamber  170  to fill the piston pump  172 . When the patient wishes to receive another dose of medicament, the actuator buttons are concurrently pressed. The aforementioned linkages, including linkage  150 , cause the first valve  212  to close and the second and third valves  218  and  224  to thereafter open. Meanwhile, actuation of the pump  172  is precluded until the first valve  212  is closed and the second and third valves  218  and  224  are opened. At this point a second fluid path indicated by arrows  204  is established from the pump chamber  170  to the cannula  130 . The medicament is then administered to the patient through the distal end  131  of cannula  130 . 
         [0064]    Once the medication dosage is administered, the piston  300 , and thus the actuator button  118 , is returned under the spring pressure of spring  119  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  170  as described above to ready the device for its next dosage delivery. 
         [0065]    Referring now to  FIG. 9 , it is a sectional view in perspective showing the valve configuration of the device  110  of  FIG. 1  during medicament filling of the pump chamber  170  immediately after a dosage delivery. Here, it may be clearly seen that the first actuator button  116  is directly coupled to the shuttle bar  200  of the valves  212 ,  218 , and  224 . Above the valves are the conduits from the reservoir, from the pump, and to the cannula. More particularly, the conduit  182  is in fluid communication with the reservoir, the conduit  184  is in fluid communication with the pump, and the conduit  124  is in fluid communication with the cannula. The valves are shown with the first valve  212  opened, communicating reservoir conduit  182  with the pump conduit  184  through channel  192 , the second valve  218  closed and blocking the conduit  124  to the cannula, and the third valve  224  closed and blocking both the reservoir conduit  182  and the pump conduit  184  from the cannula conduit  124 . This permits medicament to flow from the reservoir through conduit  182 , through channel  192 , and to the pump chamber  170  through conduit.  184  as the actuator button  116  returns to its first position. Hence, the pump chamber is filled and ready for the next dosage delivery. 
         [0066]    Referring now to  FIG. 10 , it is a sectional view in perspective similar to that of  FIG. 9  but showing the valve configuration of the device  110  of  FIG. 1  during medicament delivery. Here, the valves are shown with the first valve  212  closed and blocking the reservoir conduit  182 , the second valve  218  opened permitting the outlet conduit  124  to communicate with the annular conduit  194 , and the third valve  224  opened permitting medicament to flow from the annular conduit  192 , through bypass  186 , and to annular conduit  194 . Thus, medicament is permitted to flow from the pump conduit  184 , through annular conduit  192 , through the bypass  186 , through annular conduit  194 , and into the outlet conduit  124  to administer the fixed volume dosage. As previously mentioned, the O-rings defining the first valve  212 , the third valve  224 , and the second valve  218  are spaced apart so that conduit  182  is blocked before conduits  184  and  124  are connected together through the valves  224  and  218 . 
         [0067]      FIG. 11  is a top perspective view of the base  160  of the device  110  of  FIG. 1 . Carried on the base  160  is the intermediate layer  164 . Together, the base  160  and intermediate layer  164  define numerous fluid conduits within the device  110 . One such fluid conduit is designated with reference character  270  in  FIG. 11 . The conduit  270  is within the fluid path that leads to the outlet  124 . It is in the downstream portion of that path and takes a bend at  272  towards the bottom side of the base  160  where it, through an opening  274 , enters a chamber  276  ( FIG. 12 ). The chamber  276  communicates with the device outlet  124  that projects into the aforementioned cavity  120 . When the cannula  130  ( FIG. 13 ) is placed, it extends through an opening  123  in the cavity to beneath the patient&#39;s skin and communicates with the outlet  124  as described herein after. 
         [0068]    The chamber  276  is partly defined by a seal rim  278  which receives a translucent cover  280  ( FIG. 13 ). The top wall of the chamber  276  has an inverted cone shaped surface  282  portion and a tapered portion  284  to the outlet  124 . 
         [0069]    The translucent cover may be formed of transparent plastic wherein the surface that faces the chamber is roughed in a manner that renders the plastic cover translucent. The upper surface of the chamber is preferably coated with indicia which may, for example, be a color, such as blue. When the chamber is empty, the blue indicia will not be readily seen because the rough surface of the cover has rendered the cover translucent. However, when the chamber  276  is filled with a liquid, such as the liquid medicament, the cover  280  will become more transparent allowing the blue indicia to be readily seen. The chamber  276  and cover  280  thus form a prime indicator  286  adjacent the outlet  124 . More particularly, the prime indicator  286  is immediately adjacent the outlet  124  since when the chamber is filled and the indicia readily seen, it will be known that the conduits and cannula are sufficiently prime with medicament to permit a full dosage to he delivered upon the next activation of the device  110 . 
         [0070]    In use, it is contemplated that the reservoir be filled through a fill port  290  on the bottom of the device  110  before the device is deployed on the patient&#39;s skin. After the device is filled, the translucent cover or window  280  may be viewed during device priming. During the priming process, the actuators  116  and  118  may be depressed a number of times until the blue indicia on the top surface portions  282  and  284  of the chamber are seen through the window  280 . This provides an indication to the user that the chamber  276 , and more importantly, the conduits are sufficiently primed and full with medicament to enable actual dosage delivery upon the next actuation of the device  110 . Hence, a prime indicator  286  is provided immediately adjacent the outlet  124 . 
         [0071]    In  FIG. 13A , it may be seen that the removable non-adhesive layer  292 , in accordance with this embodiment, includes two portions, a first portion  293  and a second portion  294 . Each of the first and second layer portions  293  and  294 , respectively, includes a tab  298  and  297  respectively that extend beyond the margins of the device base. This permits the tabs  297  and  298  to be grasped for effortless removal of the removable non-adhesive layer portion  294  and  293 . The layer portion  293  includes cutouts. The cutouts  295  and  296  extend through the pad  115  ( FIG. 2 ) to provide access to the device fill port  290  and the prime indicator window  280 . Hence, as described above, the device  110  may be filled and primed for use before the removable layer portions  293  and  294  are removed for adhering the device to a patient&#39;s skin. 
         [0072]      FIGS. 14-17  are sectional views in perspective of a resettable lock-out  350  according to an embodiment of the present invention. More particularly, as will be seen subsequently, the lock-out  350  is a last dose lock-out that is resettable if the lock-out occurs prior to deployment of the device  110 .  FIG. 14  shows the lock-out  350  prior to an intended dosage delivery. 
         [0073]    When the pump chamber  170  is filled with medicament as the actuator button  118  returns during a recharge stroke after the immediately preceding dosage delivery, medicament flows from the reservoir through a conduit  356  to the pump chamber  170 . A diaphragm chamber  354  is in fluid communication with this flow path from the reservoir to the pump chamber  170 . The diaphragm chamber  354  is defined by a diaphragm  352  formed of flexible membrane material. The diaphragm  352  includes an extension  358  that terminates in a hook portion  360 . The distal end of the hook portion  360  lies within a slot  362 . As long as there is medicament within the diaphragm chamber  354 , the hook portion  360  will remain in the slot  362 . 
         [0074]    The first actuator button  116  includes an extension  364 . The extension  364  includes a slot  366 . When the first actuator button  116  is fully depressed, the slot  366  of the extension  364  will be alignment with the slot  362 . As will be seen subsequently, if there is no medicament within the diaphragm chamber  354  during a pump recharge stroke, the hook enters the slot  366  and remains there to disable the device by locking the actuator buttons. As also shall be seen, this locking arrangement is resettable. 
         [0075]      FIG. 15  shows the lock-out  350  during a normal dosage delivery, such as the dosage delivery before the last dosage delivery. The pump piston  300  has displaced medicament from the pump chamber and the slot  366  is aligned with the slot  362 . The hook portion  360  remains in the slot  362 . 
         [0076]      FIG. 16  shows the lock-out  350  after the dosage delivery before the last dosage delivery. The reservoir and diaphragm chamber  354  are made empty during the recharge stroke of the pump piston  300 . Because the reservoir and diaphragm chamber  354  are empty, a negative pressure within the diaphragm chamber  354  is pulled by the piston  300  as it returns during its last recharge stroke that fills the pump chamber for the last dosage delivery. The negative pressure within the diaphragm chamber  354  causes the diaphragm  352  to be pulled up into the diaphragm chamber  354 . The hook portion  360  is also pulled up with the diaphragm  352  and contacts the underside of the extension  364 . The device  110  is now ready for lock-out during the last dosage delivery. 
         [0077]      FIG. 17  shows the lock-out upon completion of the last dosage delivery. As may be noted, the hook portion  360  is pulled up into the slot  366  of the extension  364 . The capture of the hook portion  360  by the slot  366  precludes the actuator buttons  116  and  118  from returning to their initial positions. Further actuation of the device  110  has been locked-out. 
         [0078]    Upon each recharge cycle, a small negative pressure is caused when the reservoir is not empty. However, this small negative pressure is very small and short lived compared to when the reservoir is empty. Hence, the lock-out will occur when the pressure within the diaphragm chamber  354  is less than a predetermined pressure below ambient pressure. 
         [0079]    As previously mentioned, if the device has not yet been deployed, and lock-out occurs, the lock-out  350  may be reset. To reset the lock out, it is only necessary to release the negative pressure in the diaphragm chamber  354  to return the diaphragm to its original shape for releasing the hook portion  360  from the slot  366 . This may be accomplished by venting the reservoir through the fill port  290  ( FIG. 13A ). 
         [0080]    To that end, the fill port may be packed with a septum formed of a membrane penetrable by a needle, for example. To reset the lock out, such a needle may be used to penetrate the septum within the fill port  290  to admit air or medicament into the reservoir of the device  110 . That air or medicament will flow into the diaphragm chamber  354  to release the pressure within the diaphragm chamber  354 , permitting the diaphragm  352  to return to its original shape and to allow the hook portion  360  to exit the slot  366  and return to the slot  362 . With the last dose lock-out  350  now reset, the reservoir may be filled with medicament and used normally. 
         [0081]    While particular embodiments of the present invention have been shown and described, modifications may be made. 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.