Patent Publication Number: US-7899544-B2

Title: Access port indicator for implantable medical device

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 10/408,392 filed on Apr. 7, 2003 now U.S. Pat. No. 7,191,011, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Medical devices such as drug infusion pumps are used to treat various ailments and conditions through the delivery of pain medication, anti-spasmatic agents, chemotherapeutic agents, and other pharmaceutical agents. In treating these ailments, the drug infusion pumps can periodically require refilling through a fill access port. In addition, access ports can be provided for bolus injections. 
     Typically, these devices are placed in fatty tissue under the skin. Access to the ports often is obtained by piercing the skin with a needle or syringe and guiding the syringe through the access port. However, many problems arise in locating the access port and accurately inserting the needle. 
     If the needle is inserted in the skin at a location relatively far from the access port, the patient can experience additional pain and tissue damage. This tissue damage can be caused by attempting to stretch the tissue and skin to move the needle into position. Alternately, a patient can be stuck in more than one location in an attempt to find the proper location for accessing the port. This repeated sticking and/or jogging of the needle ultimately causes pain, discomfort and tissue damage to the patient. 
     In addition, attempts to stick the syringe or needle into the access port can cause damage to the needle tip. This damage can scar or core the access port when the needle is inserted or withdrawn, causing a channel or tunnel to be created in the access port. The channel or tunnel can ultimately lead to leaking of pharmaceutical solutions. 
     As such, typical port access systems suffer from deficiencies in indicating a location of the port and allowing easy and accurate access to the port. Many other problems and disadvantages of the prior art will become apparent to one skilled in the art after comparing such prior art with the present invention as described herein. 
     SUMMARY OF THE INVENTION 
     Aspects of the invention are found in an implantable medical device. The implantable medical device such as an implantable drug pump has a port for injecting fluid and a set of energy emitters indicating the location of the port. The device can also have a circuitry coupled to the one or more energy emitters. The energy emitters can be light emitting diodes, edge emitting diodes, or VCSELs, sonic emitters, among emitters. The implantable device can also have a second port and a second set of energy emitters associated with the second port. The second set of energy emitters can emit energy different from that of the first set of the electromagnetic energy emitters. For example, the two sets can display differing colors. The sets of energy emitters can be arranged around the ports in various shapes such as triangles, squares, circles, among others. The ports can be used for bolus injections or refill of reservoirs. 
     The circuitry connected to the energy emitters can be separate from that of the device and can include a coil. The coil can produce a current in response to an electromagnetic or other energy field. The current causes the emitters to illuminate. The circuit can further have a capacitor, which acts as a charge storage. Alternately, the circuit can have a sensor and switch configuration that turns the emitters on and off. 
     Additional aspects of the invention are found in a system for transferring fluid to an implantable device. The system has a syringe, an activation device, and an implantable device. The implantable device has a port and a set of energy emitters indicating the location of the port. The implantable device can also have a second port and a second set of energy emitters indicating the location of the second port. The first and second sets of energy emitters can emit energy of differing wavelengths or colors. The sets of energy emitters can be arranged about their associated port in various configurations including triangles, squares and circles. The system can be used for bolus injections or in refilling a reservoir. 
     Further aspects of the invention are found in a method for indicating a port location. The method includes receiving a signal, and activating energy emitters in response to the signal wherein the energy emitters indicate the location of a port. The method can further include deactivating the emitters to conserve electricity. The step of deactivating can be accomplished by discharging of a capacitor or the opening of a switch, among others. The steps of receiving the signal can include inducing a current in a coil. The method can further include a step of injecting fluid into the port. This injection can take the form of a bolus injection or act to refill a reservoir. 
     As such, an implantable pump, system for transferring fluid to an implantable device, and method for indicating location of a port are described. Other aspects, advantages and novel features of the present invention will become apparent from the detailed description of the invention when considered in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numbers indicate like features and wherein: 
         FIGS. 1 and 2  are schematic diagrams depicting exemplary embodiments of an implantable medical device system, according to the invention; 
         FIGS. 3A ,  3 B,  3 C,  3 D and  3 E are schematic diagrams depicting exemplary arrangements of emitters, according to the invention; 
         FIG. 4  is a schematic diagram depicting an exemplary device, according to the invention; 
         FIGS. 5 ,  6  and  7  are schematic diagrams depicting exemplary circuits for use in the system as seen in  FIGS. 1 and 2 ; and 
         FIGS. 8 and 9  are block flow diagrams depicting exemplary methods for use by the system as seen in  FIGS. 1 and 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Implantable medical devices such as drug infusion pumps are used in various applications to treat various conditions including pain, muscular disorders, and cancer, among others. Periodically, the pumps require refilling. In addition, some pumps permit bolus injections to be administered through an access port. However, problems often arise in locating the ports of medical devices and delivery of materials such as accurately sticking a syringe into the ports. 
     The present invention is directed to a system and method for indicating the location of a port on an implantable medical device, such as a drug infusion pump.  FIG. 1  depicts an exemplary system  10  including an implantable pump  12 , a syringe  14  and an activation device  20 . The implantable pump  12  can have a port  16 . The port  16  can permit bolus injections or be useful in refilling a reservoir. 
     Arranged in proximity to the port can be one or more emitters  18 . Emitters  18  can, for example, emit a visible wavelength of light, indicating the location of the port  16 . Alternately, the emitters  18  can emit various wavelengths of electromagnetic, sonic or other energy, permitting an external device to locate the port. The emitters may take various forms including bulbs, LEDs, VCSELs, EELs, and fiber optic arrangements, among others. However, various emitters and emitter arrangements can be envisioned. 
     The implantable pump  12  can also include circuitry that responds to an activation device  20 . The circuitry can illuminate the emitters  18  for a period of time in response to a signal or the presence of the activation device  20 . In an alternate embodiment, a manipulation mechanism can be include within the pump to activate and/or deactivate the emitters. The circuitry can be separate from or combined with other circuitries within the pump, but various other embodiments can be envisioned. 
       FIG. 2  depicts a placement of the implantable pump  40  in a patient. The placement  30  is shown as a pump  40  located in a fatty tissue  34  below the skin  32  and above the fascia  36  and muscular structure  38 . The pump  40  can be placed in the abdominal region, on the side of the patient, or near the lower back, among others locations. From the pump  40 , a catheter  42  can carry a treatment solution to a treatment location. 
     Periodically, the pump  40  requires refilling through a port  44 . Emitters  46  can project light, electromagnetic or other energy through the skin indicating the location of the port  44 . The port  44  can also be used for injecting a bolus dose. 
     In the exemplary configurations of  FIGS. 1 and 2 , the emitters indicate the location of a port, enabling a user to more accurately insert a syringe through the skin  32  and into the port  44 . In this manner, damage to the port and syringe can be limited and pain and discomfort in the patient can be reduced. 
     The emitters can be arranged in various numbers and shapes to indicate the locations of the ports.  FIGS. 3A ,  3 B,  3 C,  3 D and  3 E indicate various arrangements of emitters for indicating a location of a port. For example,  FIG. 3A  indicates two emitters  54  on opposite sides of the port  52 .  FIG. 3B  depicts a triangular arrangement of three emitters around the port and  FIG. 3C  depicts a cross or square arrangement of four emitters  54  surrounding a port  52 . In an alternate embodiment shown in  FIG. 3D , emitters or a single emitter  56  can be arranged around a port  52  in circular arrangement.  FIG. 3E  shows a further embodiment in which an emitter  60  shines light through a port  58 . Various other arrangements can also be envisioned. 
       FIG. 4  depicts a further embodiment of the system  70 . In this embodiment  70 , a pump  72  directs a treatment solution through catheter  74 . The pump can have two ports  76  and  80 . These ports can serve differing functions. For example, one port  76  can act as a bolus injection port while the other port  80  can act as a refill port. However, various functionalities of various ports can be envisaged. 
     Each port  76  and  80  can have a differing arrangement of emitters. For example, port  76  has a triangular arrangement of three emitters  78 , while port  80  has a linear arrangement of two emitters  82 . Further, the emitters can emit differing energy. For example, the emitters  78  can emit a different color light than emitters  82 . 
     Implantable pumps often have a limited power supply. Sometimes this is mitigated with the use of transcutaneous energy transfer. Energy can be transferred with the use of an electromagnetic field to a coil in the pump. The electromagnetic field can induce a current or voltage within the coil that recharges batteries or provides power to the pump. The light emitters can draw from the same power source or can operate on a second circuitry to avoid draining power from that source used for providing pump functionality. 
       FIG. 5  depicts an exemplary circuitry for operating the emitters. The circuitry  90  includes a coil  92 , a capacitor  94  and one or more emitters  96 . An electromagnetic energy field can be induced about the coil  92  from an external source causing charge to flow. This charge can simultaneously build on capacitor  94  and illuminate the emitters  96 . Once the field is removed from the coil  92 , the capacitor  94  can continue to discharge maintaining, for some period of time, illumination in the emitters  96 . Alternately, a diode can be placed  98  in the circuitry to prevent backflow of current through the coil  92 . In this manner, the emitters  96  can be illuminated on demand for a period of time during which an injection can be made. Subsequently, the capacitor will discharge, allowing the emitters to dim. The separate circuitry prevents taxing of the power source used to pump fluid to the treatment location. 
       FIG. 6  shows an alternate circuit  110 . The circuit includes a coil  112 , a capacitor  114 , a switch  118 , a power source  116 , and an emitter  120 . The power source  116  can be associated with that of the pump or a separate power source for use with the emitter circuitry. An electromagnetic field induced about the coil  112  can cause a charge to flow. This charge can build on capacitor  114  and initiate the flow of current through a switch  118 . For example, the switch  118  can be a transistor. Power from the power source  116  can then flow in a circuit through the emitters  120  causing them to illuminate and indicate the location of a port. Once the electromagnetic field is removed from the coil  112 , the capacitor  114  discharges over time. This discharge maintains the position of the transistor  118 , allowing for the emitter  120  to continue illuminating the location of the port for a period of time after the electromagnetic field is removed from the coil. A diode  122  prevents electricity from reversing through the coil  112 . In this manner, the emitters can be illuminated for a period of time without draining a significant amount of energy from the power source  116 . 
       FIG. 7  depicts a further circuitry  130  for causing a timed illumination of the emitters. A sensor  132  can detect the presence of an activation device. The sensor can activate a timer  134 , which closes a switch  136 . The switch  136  can for example be a transistor. The closing of the switch  136  can direct power from a power source  138  through emitters  140 . Upon expiration of a time, the timer  134  can open the switch  136 , stopping the flow of electricity through the emitters  140 . Alternately, the switch may be opened in response to a signal from the sensor  132 . 
     The sensor  132  can take various forms including a magnetic sensor or a coil, among others. Further, the timer  134  can take various forms including a processor or a timing circuitry, among others. The power source  138  can be a power source of the pump or a separate power source, among others. However, various circuitries can be envisaged to activate or deactivate a emitting source for indicating the location of a port. 
       FIG. 8  depicts an exemplary method for using the indicator system on an implantable pump. The method  170  begins with the activation of the light sources as seen in a block  172 . This activation can be the inducing of current in a coil, alerting a sensor, manipulating a activator, or other method. The emitters can then illuminate, indicating the location of a port. As seen in a block  174 , the port can then be located and a syringe inserted. The fluid can then be injected as seen in block  176 . This injection can function as a bolus injection or act to refill a reservoir. The emitters can then be deactivated as seen in block  178 . This deactivation can take the form of a discharge of a capacitor or the additional activation of a sensor. 
     The pump can act as seen in  FIG. 9 . The method  190  can begin with the receiving of a signal as seen in block  192 . The signal can take the form of an electromagnetic or other energy field induced about a coil. For example, the signal can take the form of a magnet over a sensor or a mechanical manipulation. The implantable pump can then activate the emitters as seen in block  194 . This activation can result in the illumination of the emitters to indicate the location of a port. After a period of time, the emitters can be deactivated as seen in block  196 . This deactivation can take the form of the discharging of a capacitor, additional signaling, or mechanical manipulation of the device, among others. 
     As such, an implantable pump, system for injecting fluid, and method for indicating the location of a port, are described. In view of the above detailed description of the present invention and associated drawings, other modifications and variations will now become apparent to those skilled in the art. It should also be apparent that such other modifications and variations may be effected without departing from the spirit and scope of the present invention as set forth in the claims which follow.