Abstract:
An implantable pump system includes: (1) an implantable pump having separate chambers or reservoirs, at least one of which is coupled to the pump so as to allow a programmable rate of delivery of the medication stored in the pump chamber or reservoir, the other chambers or reservoirs of which are at least capable of delivery of a bolus via a pressurized, and potentially independently programmable chamber or pumping mechanism; (2) a patient controller that enables the actuation of the pump so as to administer a bolus or programmed rate of the first, second, third, . . . or nth medication contained in the independent chambers or reservoirs coupled to the pump; and (3) a catheter having two or more reservoir-specific inlet ports directed into respective lumens of the catheter. In one embodiment, the distal tips of the respective lumens may be directed to different sites within the patient&#39;s body, thereby allowing site specific and independent delivery of the medications stored in the respective pump chambers or reservoirs to be administered to different body sites at independently controlled times and rates. In another embodiment, the distal tips of the respective lumens are directed, more or less, to the same body site or tissue region, thereby providing for the independent delivery of multiple medications to the same regions at independently controlled times and rates.

Description:
[0001]    The present application claims the benefit of U.S. Provisional Application Ser. No. 60/284,771, filed Apr. 18, 2001, which application is incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to implantable medical devices, and more particularly to an implantable programmable pump having multiple reservoirs and a multiple lumen catheter through which independent medications may be delivered to a patient at programmed times or upon demand.  
           [0003]    Patients typically require short bursts of independent medications delivered at unique times. Such medications, or drugs, may be delivered via independently accessed reservoirs or may be bolused on demand via a suitable controller. Patients experiencing pain, and receiving medication therefor, may require a short acting, independently-delivered, analgesic rather than an incremental bolus of an admixture or of morphine alone. Spasticity patients may require a burst of pain medications in addition to anti-spasticity medications, or another drug to temporarily increase tone during patient transfers, or other critical times. For example, a cocktail mixture of pain medication in conjunction with another drug that counteracts baclofen for a short period of time may also assist in patient transfers, or other critical times when the patient&#39;s muscles require increased tone.  
           [0004]    U.S. Pat. No. 4,588,394 teaches a totally subcutaneously implantable infusion reservoir and pump system that includes a variable capacity reservoir for receiving and storing fluids containing medications for delivery to a catheter, which catheter directs the medications to a specific infusion location in the body. A pump and valving arrangement is interposed between the reservoir and the catheter to facilitate and control the transfer of the medications from the reservoir to the catheter in a safe and efficient manner. There is no provision for the delivery of multiple medications through the same catheter.  
           [0005]    U.S. Pat. No. 4,449,983 discloses an osmotic device that delivers two beneficial drugs to an environment of use. The device comprises a wall surrounding a lumen divided into a first compartment containing a drug that is separated by a hydrogel partition from a second compartment containing a different drug. An orifice through the wall communicates with the first compartment for delivering drug formulation from the first compartment, and another orifice through the wall communicates with the second compartment for delivering drug formulation from the second compartment. In use, drug formulation is dispensed separately from each compartment by fluid being imbibed through the wall of the device into each compartment at a rate controlled by the permeability of the wall and the osmotic pressure gradient across the wall against the drug formulation in each compartment. A solution is thus produced in each compartment containing drugs. Through the expansion and swelling of the hydrogel, the drug formulation is dispensed through the respective orifices at a controlled and continuous rate over a prolonged period to time. There is no provision for bolus drug delivery over a short period of time, or for programmed rates of delivery.  
           [0006]    U.S. Pat. No. 5,240,713 teaches a dual rate agent delivery device that provides for the controlled delivery of a beneficial agent in a hydrophilic carrier, followed by a continuous and sustained delivery of an agent in a controlled and uniform amount over a prolonged period of time. However, the dual rates are not programmable, but are rather controlled through the physical attributes of the device and osmotic pumping. The U.S. Pat. No. 5,240,713 further provides a comprehensive list of prior art relating to drug delivery devices.  
           [0007]    What is needed is an implantable pump capable of independently delivering multiple medications at independently programmable rates.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention addresses the above and other needs by providing an implantable pump system that includes: (1) in implantable pump having separate chambers or reservoirs, at least one of which is coupled to the pump so as to allow a programmable rate of delivery of the medication stored in the pump chamber or reservoir, the other chambers or reservoirs of which are at least capable of delivery a bolus via a pressurized, and potentially independently programmable chamber or pumping mechanism; (2) a patient controller that enables the actuation of the pump so as to administer a bolus or programmed rate of the first, second, third, . . . or nth medication contained in the independent chambers or reservoirs coupled to the pump; and (3) a catheter having two or more reservoir-specific inlet ports directed into respective lumens of the catheter.  
           [0009]    In one embodiment, the distal tips of the respective lumens may be directed to different sites within the patient&#39;s body, thereby allowing site specific and independent delivery of the medications stored in the respective pump chambers or reservoirs to be administered to different body sites at independently controlled times and rates.  
           [0010]    In another embodiment, the distal tips of the respective lumens are directed, more or less, to the same body site or tissue region, thereby providing for the independent delivery of multiple medications to the same regions at independently controlled times and rates.  
           [0011]    Advantageously the medications administered through use of the implantable pump having multiple chambers and delivery lumens may comprise drugs, biologics, proteins, genetic materials, and any other substance or material which medical personnel may prescribe as being beneficial for the patient to receive.  
           [0012]    An important feature of the present invention is the programmability of the pump, which allows different medications to be delivered through independent lumens at different times and rates. In one embodiment, such programming may be done electronically, based on a clock or different times of the day. In another embodiment, one or more body sensors are coupled with the pump and are adapted to sense various physiological parameters, such as muscle tone, heart rate, respiration rate, blood oxygen saturation, physical activity, temperature, glucose level, and the like. In accordance with the use of such sensor(s), when certain physiological conditions are sensed by the sensor(s), the pump is actuated so as to deliver a programmed amount of one or more medications selected as a function of the sensed physiological condition. For example, if a sudden, fast heart rate is sensed, an appropriate medication may be administered in an attempt to slow the heart rate.  
           [0013]    It is thus a feature of the present invention to provide an a multi-chamber programmable, implantable pump.  
           [0014]    It is a further feature of the invention to provide a multi-lumen catheter for use with such pump through which multiple medications may be independently delivered by the pump. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein:  
         [0016]    [0016]FIG. 1 shows an implantable pump system made in accordance with one embodiment of the invention;  
         [0017]    [0017]FIG. 2 shows an implantable pump system made in accordance with another embodiment of the invention;  
         [0018]    [0018]FIG. 3 is a functional block diagram of the pump system of the present invention;  
         [0019]    [0019]FIG. 3A depicts an alternate embodiment of a multi-lumen catheter that may be used with the invention; and  
         [0020]    [0020]FIG. 4 depicts one method that may be used to refill the independent reservoirs or storage chambers used with the pump system of the present invention.  
         [0021]    Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims.  
         [0023]    Turning first to FIG. 1, a pump system  10  made in accordance with one embodiment of the invention is illustrated. The system  10  includes an implantable pump  12  coupled to a multi-lumen catheter  14 . The pump  12 , which includes multiple chambers or reservoirs, control electronics and a pumping mechanism, all housed within a suitable case, as described in more detail below in conjunction with FIG. 3, along with the multi-lumen catheter  12 , are adapted to be implanted beneath the skin  15  of the patient. Typically, the location where the pump is implanted is in the chest or abdomen area of the patient, but may be implanted in any location in the patient&#39;s body.  
         [0024]    The multi-lumen catheter  14  includes a multiplicity of independent lumens therein, each terminating at a distal tip  16 . For the embodiment shown in FIG. 1, three lumens are employed within the catheter  14 , each having a distal tip  16   a,    16   b  and  16   c  that terminate near the same tissue location. Hence, the embodiment shown in FIG. 1 is particularly adapted for use when one or more medications, e.g., three medications, need to be independently delivered to approximately the same tissue location. The use of three lumens within the multi-lumen catheter  14  is only exemplary, as any number of lumens, e.g., from two to ten lumens, may be employed as circumstances warrant.  
         [0025]    Advantageously, each medication delivered through the multi-lumen catheter  14  may be delivered at its own programmed rate and/or start/stop time. The medications administered through the delivery lumens  16   a,    16   b,    16   c,  . . . may comprise drugs, biologics, proteins, genetic materials, and any other substance or material which medical personnel may prescribe as being beneficial for the patient to receive.  
         [0026]    Programming or control of the implantable pump  12  shown in FIG. 1 is accomplished through the use of an external (non-implanted) control unit  20 . The control unit  20  communicates with the implantable pump  12  via a telecommunications link  22 , which link  22  is represented in FIG. 1 by a wavy arrow. Such link  22  may be of any type known in the art, e.g., a radio frequency (rf) link, an acoustic link, an IR or other optical link, an inductive link, a magnetic link, or the like. Using such link, command words (or other command signals) are sent from the remote control unit  20  to the implantable pump  20  where they are received and acted upon. Such control or command words may control the pump, e.g., turn the pump ON or OFF, or set, i.e., program, various pump parameters used within the pump, e.g., the rate of delivery of a given medication, the time at which delivery of a medication is to commence, the time at which delivery of a medication is to end, and the like.  
         [0027]    Additionally, at least in some embodiments of the invention, the implantable pump  12  sends status signals, e.g., back-telemetry signals, to the remote control unit  20  through the telecommunications link  22 . Such status signals provide information to the remote user, by way of a display included on, or coupled to, the remote unit  20  relative to the performance and status of the pump  20 . Such back-telemetry data indicates, e.g., the state of charge of a battery included as part of the pump, the amount of medication remaining in its multiple reservoirs or chambers, the amount of medication that has been delivered through a given lumen of the catheter during a specified time period, and the like. Back telemetry may also be used, when sensors  18  are employed with the device, e.g., as shown in FIG. 2 described below, to report sensed physiological parameters or other sensor metrics of physiologic conditions, all of which data is telemetered to a remote programmer  20  or other remote device for analysis and/or display. The remote device may also stored such data for subsequent display and/or analysis.  
         [0028]    Next, as seen in FIG. 2, a pump system  10 ′ made in accordance with another embodiment of the invention is shown. Like the system  10  shown in FIG. 1, the system  10 ′ of FIG. 2 includes a programmable implantable pump  12  connected to a multi-lumen catheter  14 . A remote control unit  20  in telecommunicative contact with the pump  12  via a suitable telecommunications link  22  also is included as part of the system  10 ′. The remote control unit  20  is used to control and/or program the implantable pump  12 , as well as to monitor the performance status of the implantable pump  12 , or sensed physiological conditions, as previously described. Unlike the system  10  of FIG. 1, the distal tips  16   a,    16   b,    16   c ,   16   d  of the multiplicity of lumens included within the multi-lumen catheter system  10 ′ of FIG. 2 are adapted to terminate at different distal locations, thereby facilitating the delivery of specific medications to different tissue locations.  
         [0029]    Additionally, unlike the system  10  of FIG. 1, the system  10 ′ of FIG. 2 includes a plurality of sensors  18  that are connected to, or included as an integral part of, the pump  12 . For example, first and second sensors  18   a  and  18   b  are coupled to the pump  12  via a suitable connection cable  19 , while a third sensor  18   m  is mounted within or on the housing of the pump  12 . Such sensors  18   a,    18   b  and  18   c  are adapted to sense a physiological condition of the patient&#39;s body within which the pump unit  12  is implanted, and to respond to such sensed physiological condition in accordance with a preprogrammed protocol. For example, sensor  18   a  may sense the body temperature of the patient, and in response to sensing a high temperature, i.e., a temperature above a preset threshold, the pump  12  may be preprogrammed to deliver a prescribed quantity of a specific medication to the patient aimed to reduce the temperature below the preset threshold. The sensor  18   b,  in a similar manner, may sense the glucose level present in body fluids, and in response to sensing a glucose level that is out of range of predetermined acceptable levels, cause the pump  12  to take appropriate corrective action by delivering an appropriate medication(s) through one or more the lumens of the multi-lumen catheter  14 . The sensor  18   m,  similarly, may sense the physical activity of the patient&#39;s body, and in response to sensing physical activity (i.e., sensing that the patient is active), cause the pump to deliver a first medication, or a first combination of medications, through at least one of the lumens of the multi-lumen catheter  14 ; and in response to not sensing physical activity (i.e., sensing physical inactivity), cause the pump to deliver a second medication, or a second combination of medications, through at least one of the lumens of the multi-lumen catheter.  
         [0030]    The types of physiological parameters that may be sensed by the sensors  18   a,    18   b , . . .  18   m  include, but are not necessarily limited to, muscle tone, heart rate, respiration rate, blood oxygen saturation, tissue impedance, physical activity, body position (e.g., lying, sitting or standing), body temperature, glucose level, and the like. As has been indicated, signals representative of the physiological parameters sensed by the sensors  18   a,    18   b,    18   c , . . .  18   m  may be telemetered to an external device, e.g., to the remote programmer  20 , for storage, display, or analysis.  
         [0031]    Turning next to FIG. 3, a functional block diagram of a representative programmable, implantable pump made in accordance with the present invention is illustrated. It is to be emphasized that that which is shown in FIG. 3 is functional, and not necessarily representative of the actual hardware components that may be used by the implantable pump  12 . Those of skill in the art, given the functional description presented herein, may fashion numerous types of hardware components in order to achieve the functions represented.  
         [0032]    As seen in FIG. 3, the pump  12  includes a multiplicity of chambers, or reservoirs  30   a ,  30   b ,  30   c , . . .  30   n,  wherein desired medications may be stored. Each chamber  30   a ,  30   b ,  30   c , . . .  30   n  has a corresponding lumen  17   a , 17   b , . . .  17   n  in fluid communication therewith. Each lumen terminates at a distal port  16   a ,  16   b , . . .  16   n  (not shown in FIG. 3, but seen in FIGS. 1 and 2) whereat the medication held in the respective chamber  30   a ,  30   b , . . . may be dispensed.  
         [0033]    Each chamber  30   a ,  30   b , . . .  30   n  has a pump mechanism associated therewith that causes the medication stored in the respective chamber to be dispensed through the respective lumen at a programmed rate and/or at a programmed delivery time. By way of functional illustration only, the pump mechanism associated with chambers  30   a  includes a miniature stepping motor M 1  that drives a lead screw  37  passing through an anchored lead nut  35 . A distal end of the lead screw  37  attaches to movable diaphragm  36 , which diaphragm forms one wall of the chamber  30   a.  As the lead screw  37  rotates a fixed rotational amount, under control of the stepper motor M 1 , the distal end of the lead screw, and hence the diaphragm  36 , advances a fixed amount, causing a fixed volume of medication within chamber  30   a  to be dispensed through lumen  17   a.    
         [0034]    In a similar manner, additional miniature stepper motors M 2 , M 3 , . . . Mn, control respective lead screws coupled to movable diaphragms of chambers  30   b ,  30   c  . . .  30   n , thereby allowing controlled volumes of medication stored in chambers  30   b ,  30   c  . . .  30   n  to be dispensed through lumens  17   b , 17   c  . . .  17   n,  respectively.  
         [0035]    The chambers  30   a ,  30   b ,  30   c , . . .  30   n  may be realized using a balloon made from a suitable stretchable material, e.g., silicone rubber or Silastic, and the movable diaphragm  36  may be a wall or plunger that collapses against one side of the balloon, forcing the liquid contents of the balloon, i.e., the medication stored therein, to be dispensed through the respective lumen.  
         [0036]    The stepper motors M 1 , M 2 , M 3 , . . . Mn are controlled by respective driver circuits contained within the pump control circuitry  34 . Such control circuitry includes, in addition to the pump driver circuits, suitable logic circuitry for controlling operation of the pumps in accordance with programmed parameters. The logic circuitry may comprise a state machine and/or a microprocessor. The programmed parameters are stored in suitable memory circuitry, as is known in the art. The parameters that may be stored in the memory circuitry include, for each stepper motor or equivalent pump activation mechanism, dispense start time, dispense stop time, max dispensed volume, and rate.  
         [0037]    Operating power for the pump control circuitry  34  and the stepper motors M 1 , M 2 , M 3  . . . Mn is provided by a suitable battery  38 . The battery  38  may be a primary Lithium Ion battery that has sufficient energy stored therein to power the operation of the pump control circuitry  34  for 3-10 years, or a rechargeable battery, e.g., a rechargeable Lithium Ion battery, as is known in the art.  
         [0038]    A telemetry/recharge circuit  40  allows programming signals and recharge energy to be received from an external remote control/programmer unit  20  or an external charger unit  24 . In one embodiment, the telemetry/recharge circuit  40  includes a coil that is inductively linked with another coil included within the remote control/programmer unit  20  or the remote charger  24 . A carrier signal is coupled from the remote coil to the implanted coil. Energy contained within the carrier signal is used to recharge the battery  38 . Control and/or programming data is transferred to the implantable unit  12  by modulating the carrier signal. Back-telemetry may occur in the same manner, but at a different frequency. Other forms of data/energy transfer may also be employed, as needed or as appropriate.  
         [0039]    One or more physiological sensors  18   a ,  18   b ,  18   c , . . .  18   m  may optionally be used with the implantable pump in order to provide physiological feedback to the pump control circuits in order to control the medication delivery in an appropriate manner. The use of such physiological sensors was described previously in connection with the description of FIG. 2.  
         [0040]    All of the components of the pump  12 , except one or more of the optional sensors  18   a ,  18   b . . .  18   m,  are housed in an implantable housing  31 . The miniature stepper motors M 1 , M 2  . . . Mn may be housed within a separate enclosure  33  included within the housing  31 . The housing  31  is preferably of a size and shape that facilitates its implantation under the skin  15  of a patient. Typically, such shape will comprise a relatively flat case, having rounded corners, much like existing implantable pacemakers or cochlear stimulators.  
         [0041]    An alternative embodiment of a multi-lumen catheter  14 ′ that may be used with the invention is illustrated in FIG. 3A. Such alternative embodiment includes multiple coaxial lumens  17   a ′,  17   b ′,  17   c ′ and  17   d ′. As seen in FIG. 3A, the lumen  17   a ′ has the smallest diameter, and fits within the lumen  17   b ′. The lumen  17   b ′ similarly fits within the lumen  17   c ′, and the lumen  17   c ′ fits within the lumen  17   d ′. Such alternative embodiment of a coaxial multi-lumen catheter  14 ′ may have different volumes associated with each lumen, thereby facilitating the dispensing of different volumes of fluid or other medications at the same time. That is, the actual volume remaining within each lumen  17   a ′,  17   b ′,  17   c ′ or  17   d ′ for delivery of a medication, after subtracting out the volume occupied by the other coaxial lumens, may differ significantly. In contrast, a multi-lumen catheter  14  (seen best in FIG. 4) shows multi-lumens of more or less the same diameter, all contained within the same sheath. Of course, multi-lumens contained within the same sheath could also have different diameters, as needed or desired for a given application.  
         [0042]    Next, with reference to FIG. 4, one technique for refilling the chambers  30   a ,  30   b ,  30   c , . . .  30   n  with a suitable medication is illustrated. For the embodiment contemplated, the case or housing  31  of the implantable pump  12  includes a plurality of windows  42  closed with a suitable septum material  43 . The septum material  43  forms one wall or side of the respective chambers  30   a ,  30   b , . . .  30   n  included within the housing  31 . The windows  42  are positioned so as to lie just under the skin  15  of the patient within whom the pump  12  is implanted. A doctor, or other medical personnel, fills a syringe  50  with medication  52  that is to be placed within one of the chambers  30   a ,  30   b  . . . or  30   n  of the pump. The location of the desired window  42  under the skin  15  is ascertained, e.g., by pushing with a finger or other device. Then, a needle  54  of the syringe  50  is pushed through the skin  15  and through the septum  43  of the desired window  42 , and a specified amount of the medication  52  is injected into the chamber  30   a ,  30   b  . . . or  30   n  by pushing on a plunger  55  of the syringe  50 .  
         [0043]    As described above, it is thus seen that the present invention provides a multi-chamber programmable, implantable pump having a multi-lumen catheter through which multiple medications may be independently delivered to the same or different tissue locations by the pump.  
         [0044]    While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.