FIELD OF THE INVENTION
The present invention relates to electrokinetic pumps useful for medical applications.
BACKGROUND OF THE INVENTION
In many diagnostic and therapeutic medical applications (including drug delivery and analyte sampling/monitoring), precise transport of a drug, blood and/or other bio-fluid is important. However, with most conventional diagnostic and therapeutic medical systems, precise movement of large and small aqueous volumes of drugs and other bio-fluids is difficult to achieve. This difficulty arises because conventional systems employ mechanical components to effect fluid transport and delivery. Modification of such systems, to enable highly precise movement of small and large aqueous volumes of a solution containing biomaterials, would be impractical, as the complexity of such systems would make their manufacture expensive, time consuming and labor intensive. Further, such modification is likely to result in systems that are too large for many intended applications.
Presently, electrokinetic (“EK”) or electro-osmotic manipulations of fluids represent the state-of-the art in controlled, high precision, small volume fluid transport and handling. Electro-osmosis involves the application of an electric potential to an electrolyte, in contact with a dielectric surface, to produce a net flow of the electrolyte.
While electro-osmosis has found widespread and wide ranging applications in chemical analysis (e.g., high-speed liquid chromatography and other chemical separation procedures), its medical applications, such as for drug delivery and analyte sampling, have been limited, despite its advantages over conventional, mechanical approaches. Design challenges, including gas generation in the EK pump fluid, insufficient hydraulic pressure generation, and chemical degradation of the transported material caused by an applied electrical field, need to be overcome. When configured for non-medical use, these drawbacks do not pose major issues because the consequences are minimal, unlike in medical applications.
One potentially useful medical application of such electro-osmosis technology is in the design and manufacture of infusion pumps for the delivery of agents such as drugs to a wearer of the pump.
Accordingly, the present invention is directed to low-cost, high precision, reliable and compact EK pumps and systems adapted for medical applications, including, but not limited to, drug delivery and/or analyte sampling.
SUMMARY OF THE INVENTION
The present invention generally provides methods and devices for delivering an infusion liquid using an electrokinetic infusion pump. In one embodiment, an electrokinetic infusion pump is provided which includes an infusion housing having an infusion reservoir. The infusion reservoir has an infusion outlet and is capable of containing an infusion liquid. A plunger is movably coupled to the infusion housing and is adapted to be manually displaced relative to the infusion housing to load the infusion reservoir with infusion liquid. A movable partition can be disposed within the infusion housing and has a first surface in communication with an electrokinetic solution and a second surface, isolated from the first surface, in communication with the infusion reservoir. The electrokinetic infusion pump further includes an electrokinetic engine integrated within the plunger and adapted to selectively apply electric potential across an electrokinetic porous media to cause the electrokinetic solution within the electrokinetic engine to displace the movable partition to effect delivery of at least a portion of the infusion liquid through the infusion outlet.
In one exemplary embodiment, the movable partition can form part of a displacement piston that is adapted to be slidably disposed within the infusion housing to form, with an inner surface of the displacement piston, an adjustable receiving reservoir which is fluidly isolated from the infusion reservoir and capable of containing an electrokinetic solution. The adjustable receiving reservoir can be formed by a chamber extending within the displacement piston. The plunger can be in the form of a generally elongate member having a forward piston extending from a distal portion of an outer plunger housing.
The electrokinetic infusion pump can also include other features, including a fixed supply reservoir effective to contain an electrokinetic solution and having a first electrode in communication therewith and a fixed receiving chamber being capable of receiving a volume of the electrokinetic solution from the fixed supply reservoir and having a second electrode in communication therewith. The electrokinetic porous media is disposed between the fixed supply reservoir and the fixed receiving chamber. The infusion pump can also include an inner channel formed in the forward piston and providing a fluid communication pathway between the adjustable receiving reservoir and a fixed receiving chamber. The forward piston can be adapted to slidably mate within the chamber extending within the displacement piston.
The application of electric potential across the porous media can be effective to cause electrokinetic solution in the fixed supply chamber to flow through the porous media, into the fixed receiving chamber, through the inner channel of the forward piston and into the adjustable receiving chamber, causing a distally directed force to be placed on the displacement piston. This results in distal movement of the movable partition which will effect dispensing of at least a portion of the infusion liquid through the infusion outlet.
In one exemplary embodiment, the diameter of the adjustable receiving chamber (D1) can be less then the diameter of the fixed supply reservoir (D2) to allow for a larger volume of infusion liquid to be displaced than the volume of electrokinetic solution that is displaced within the electrokinetic engine. In one embodiment, the ratio of (D1/D2)2 defines an amplification factor and the amplification factor is greater than 1 and, for example, can be about 4.
The electrokinetic infusion pump can also include a latch disposed on a portion of the plunger. The latch is selectively movable between a latched condition in which it is coupled to the displacement piston to allow movement of the displacement piston and the movable partition with movement of the plunger, and an unlatched condition in which it is uncoupled from the displacement piston to permit movement of the displacement piston and the movable partition independent of the plunger. The latched condition allows for loading of the infusion liquid into the infusion reservoir, and the unlatched condition allows for delivery of at least a portion of the infusion liquid through the infusion outlet when an electric potential is applied across the porous media to cause the electrokinetic solution within the electrokinetic engine to displace the movable partition.
In one embodiment of the invention, the plunger can include a knob disposed on a proximal end thereof. The knob is adapted for grasping by a user to enable rotational and longitudinal movement of the plunger. In one exemplary embodiment, a surface of the outer plunger housing includes an axial groove formed along at least a portion of the length thereof and a perimeter groove extending transversely from a distal portion of the axial groove. The perimeter groove is angled towards a proximal end of the outer plunger housing. The infusion housing can include a surface feature slidably disposed within the axial and perimeter grooves of the outer plunger housing. The knob disposed on the plunger is adapted to move the plunger proximally to fill the infusion reservoir with infusion liquid, and the plunger is adapted to move proximally until the surface feature reaches the distal end of the axial groove. The knob is able to be rotated to cause the surface feature to travel along the perimeter groove to allow at least a portion of the infusion liquid to be delivered through the infusion outlet to prime the infusion pump. A first locking feature provided on the infusion housing can irreversibly engage a second locking features provided on the plunger to lock the plunger to the infusion housing.
In another exemplary embodiment of the invention, an electrokinetic infusion pump is provided that includes a base capable of being attached to a patient, and an electrokinetic engine infusion module adapted to selectively apply an electric potential across an electrokinetic porous media. This causes an electrokinetic solution within the module to displace a movable partition disposed adjacent to a deformable infusion reservoir that is adapted to contain an infusion liquid to effect delivery of at least a portion of the infusion liquid through an infusion outlet. The module can be adapted to be detachably coupled to the base. The electrokinetic infusion pump further includes a controller configured to control the application of electric potential across the electrokinetic porous media and adapted to be detachably coupled to the base.
The base can attach to a patient in a variety of way. For example, the base can be attachable to the patient using an adhesive, or the base can include a clip to enable attachment of the base to an article of clothing worn by a user. In one embodiment, the controller can be integrated with the electrokinetic engine infusion module, or the controller can be separate from the electrokinetic engine infusion module. The infusion pump can further include a battery disposed within the controller, or disposed within the electrokinetic engine infusion module. Further, the infusion outlet can include a needle or plastic cannula that extends through an opening in the base, or the infusion outlet can include a catheter extending from a portion of the infusion pump.
In one embodiment, the electrokinetic porous media can separate a collapsible supply chamber containing an electrokinetic solution and an expandable receiving chamber within the electrokinetic engine such that electrokinetic solution is able to flow from the supply chamber through the porous media and into the expandable receiving chamber when a voltage is applied to the electrokinetic solution infusion module. The transfer of the electrokinetic solution from the collapsible supply chamber can be effective to expand the expandable receiving chamber such that the expandable receiving chamber applies a compressive force to the deformable infusion reservoir to effect delivery of the infusion liquid.
Methods for delivering an infusion liquid using an electrokinetic infusion pump is also provided, and in one embodiment, the method can include priming the infusion liquid housed in an infusion reservoir of the electrokinetic pump to displace air in an infusion pump outlet and an infusion tubing. To dispense infusion liquid from the infusion pump, an electric potential, such as a voltage, can be applied across an electrokinetic porous media using a first and second electrode disposed on either side of the porous media. The electrical potential causes an electrokinetic solution to flow through the porous media from a first chamber containing the electrokinetic solution to a second chamber. As the second chamber fills with the electrokinetic solution, a movable partition is displaced and puts pressure on the infusion reservoir, causing infusion liquid to be delivered through the infusion outlet and into a user.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
FIGS. 1A and 1B are schematic illustrations of an electrokinetic infusion pump with closed loop control according to an embodiment of the present invention;
FIG. 2 is an illustration of an electrokinetic infusion pump coupled with a vial containing infusion liquid;
FIG. 3 is an illustration of a low profile electrokinetic infusion pump according to another exemplary embodiment of the present invention;
FIG. 4 is an illustration of the electrokinetic infusion pump and pump controller of FIG. 3 after the electrokinetic infusion pump has been filled with infusion liquid, connected to an infusion tube, and inserted into the pump controller;
FIG. 5 is an illustration of an electrokinetic infusion pump according to another embodiment of the present invention, and includes an electrokinetic engine and an infusion module.
FIG. 6 is a cross-sectional illustration of the electrokinetic infusion pump of FIG. 5;
FIG. 7 is an exploded view of the electrokinetic infusion pump of FIG. 5;
FIG. 8 is an illustration of an electrokinetic engine subassembly, as used in the electrokinetic infusion pump of FIG. 5;
FIG. 9 is an illustration of a piston/engine subassembly, as used in the electrokinetic infusion pump of FIG. 5;
FIG. 10 is a perspective view of an infusion housing, as used in the electrokinetic infusion pump of FIG. 5;
FIG. 11 is another perspective view of an infusion housing, as used in the electrokinetic infusion pump of FIG. 5;
FIG. 12 is a perspective view of an engine housing, as used in the electrokinetic infusion pump of FIG. 5;
FIG. 13 is another perspective view of an engine housing, as used in the electrokinetic infusion pump of FIG. 5;
FIG. 14 is a perspective view of a displacement piston, as used in the electrokinetic infusion pump of FIG. 5;
FIG. 15 is another perspective view of a displacement piston, as used in the electrokinetic infusion pump of FIG. 5;
FIGS. 16 through 29 are a series of drawings that illustrate operation of the electrokinetic infusion pump of FIG. 5.
FIG. 30 is an illustration of an electrokinetic infusion pump according to another embodiment of the present invention, and includes an electrokinetic engine and infusion module, and was used to generate basal and bolus delivery of infusion liquid;
FIG. 31 is a graphical illustration of basal delivery shot size as a function of time using the electrokinetic infusion pump illustrated in FIG. 30;
FIG. 32 is a graphical illustration of bolus delivery shot size as a function of time using the electrokinetic infusion pump illustrated in FIG. 30;
FIG. 33 is an illustration of an electrokinetic infusion pump with closed loop control according to an additional embodiment of the present invention;
FIG. 34 is an illustration of a magnetic linear position sensor as can be used in an electrokinetic infusion pump with closed loop control according to an embodiment of the present invention;
FIGS. 35 and 36 illustrate portions of an electrokinetic infusion pump with closed loop control according to an embodiment of the present invention, including an electrokinetic engine, an infusion module, a magnetostrictive waveguide, and a position sensor control circuit;
FIG. 37 is a block diagram of a circuit that can be used in an electrokinetic infusion pump with closed loop control according to an additional embodiment of the present invention;
FIG. 38 is a block diagram of a sensor signal processing circuit that can be used in an electrokinetic infusion pump with closed loop control according to an additional embodiment of the present invention;
FIG. 39 is an illustration of an electrokinetic infusion pump with closed loop control according to an embodiment of the present invention. The electrokinetic infusion pump with closed loop control illustrated in FIG. 39 includes an electrokinetic engine and infusion module, and was used to generate basal and bolus delivery of infusion liquid;
FIG. 40 is a graph showing the performance of the electrokinetic infusion pump with closed loop control illustrated in FIG. 39 in both basal and bolus modes;
FIG. 41 is a flow diagram illustrating a method of detecting occlusions in an electrokinetic infusion pump with closed loop control according to an additional embodiment of the present invention;
FIG. 42 is a graph illustrating back pressure in an electrokinetic infusion pump with closed loop control according to an embodiment of the present invention;
FIG. 43 is a graph illustrating the position of a moveable partition as a function of time when an occlusion occurs in an electrokinetic infusion pump with closed loop control according to an embodiment of the present invention;
FIGS. 44A, 44B, and 44C illustrate a low profile electrokinetic infusion pump according to an additional embodiment of the present invention. In FIG. 44A, the combined electrokinetic engine/infusion module is in an initial state, ready to draw infusion liquid from a vial. In FIG. 44B, the combined electrokinetic engine/infusion module illustrated in FIG. 44A is connected to a vial, and partially filled with infusion liquid. In FIG. 44C, the combined electrokinetic engine/infusion module illustrated in FIG. 44B is connected to an infusion line, and is dispensing infusion liquid;
FIGS. 45A, 45B, and 45C are illustrations of a low profile electrokinetic infusion pump according to an additional embodiment of the present invention. The low profile electrokinetic infusion pump illustrated in FIGS. 45A, 45B, and 45C include a combined electrokinetic engine/infusion module, and a controller. In FIG. 45A, the combined electrokinetic engine/infusion module and controller are detached. In FIG. 45B, the combined electrokinetic engine/infusion module and controller are attached. In FIG. 45C, the combined electrokinetic engine/infusion module and controller are attached, and an infusion reservoir outlet is protruding from the combined electrokinetic engine/infusion module;
FIGS. 46A and 46B are cross sectional illustrations the low profile electrokinetic infusion pump illustrated in FIGS. 45A, 45B, and 45C;
FIG. 47 is an illustration of the low profile electrokinetic infusion pump illustrated in FIGS. 45A, 45B, 45C, 46A, and 46B with an alternative infusion reservoir outlet and mounting clip;
FIG. 48 is an illustration of the low profile electrokinetic infusion pump illustrated in FIGS. 4A, 4B, 4C, 5A, 5B and 6 attached to a user by way of an adhesive. In FIG. 48, the low profile electrokinetic infusion pump is in wireless communication with a remote controller;
FIG. 49 is an illustration of the low profile electrokinetic infusion pump illustrated in FIGS. 4A, 4B, 4C, 5A, 5B, 6, and 7 attached to a user by way of a mounting clip and belt. In FIG. 49, the low profile electrokinetic infusion pump is in wireless communication with a remote controller, and an infusion line connects the user to the infusion reservoir outlet;
FIG. 50 illustrates a perspective view of a mounting plate adapted to attach to a user and coupled to an electrokinetic infusion pump;
FIG. 51 illustrates the mounting plate as shown in FIG. 50 with the electrokinetic infusion pump uncoupled therefrom;
FIG. 52 illustrates another exemplary embodiment of a mounting plate adapted to attach to a user that includes a hole therethrough adapted to be positioned over an infusion tip disposed in the user;
FIG. 53 is a perspective view of the mounting plate shown in FIG. 52;
FIG. 54 illustrates another exemplary embodiment of a mounting plate and an electrokinetic infusion pump which are coupled together using a tubing;
FIG. 55 is a cross-sectional view of an assembly adapted to allow a user to adjust the depth of a needle and cannula;
FIG. 56 illustrates the assembly shown in FIG. 55 where the needle and the cannula are at a first position corresponding to a first depth;
FIG. 57 illustrates the assembly shown in FIG. 55 where the needle and the cannula are at a second position corresponding to a second depth;
FIG. 58 illustrates the assembly shown in FIG. 55 where the needle and the cannula are at a third position corresponding to a third depth;
FIG. 59 illustrates a needle inserter assembly as used with the assembly shown in FIG. 55;
FIG. 60A illustrates a cannula having a flange at a proximal end thereof;
FIG. 60B illustrates a cannula having a flared proximal end;
FIG. 60C illustrates a cannula having an extended flange at a proximal end thereof;
FIG. 60D illustrates a cannula having a squared flange at a proximal end thereof;
FIG. 61 illustrates a top septum and septum cap for use with the assembly shown in FIG. 55;
FIG. 62 illustrates a bottom septum and septum cap for use with the assembly shown in FIG. 55;
FIG. 63 is an illustration of an exemplary embodiment of an infusion pump that allows a user to modify the configuration and showing the infusion pump attached to a user in various stages of assembly;
FIG. 64 is an illustration of an another exemplary embodiment of an infusion pump that allows a user to modify the configuration and showing the infusion pump attached to a user in various stages of assembly;
FIG. 65 is an illustration of an another exemplary embodiment of an infusion pump that allows a user to modify the configuration and showing the infusion pump attached to a user in various stages of assembly; and
FIG. 66 is an illustration of an another exemplary embodiment of an infusion pump that allows a user to modify the configuration and showing the infusion pump attached to a user in various stages of assembly.
DETAILED DESCRIPTION OF THE INVENTION
Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.
Various exemplary methods and devices are provided for electrokinetic pumping, which provides a driving force for displacing infusion liquid. Electrokinetic pumping (also known as electroosmotic flow) works by applying an electric potential across an electrokinetic porous media that is filled with electrokinetic solution. Ions in the electrokinetic solution form double layers in the pores of the electrokinetic porous media, countering charges on the surface of the electrokinetic porous media. Ions migrate in response to the electric potential, dragging the bulk electrokinetic solution with them. Electrokinetic pumping can be direct or indirect, depending upon the design. In direct pumping, infusion liquid is in direct contact with the electrokinetic porous media, and is in direct electrical contact with the electrical potential. In indirect pumping, infusion liquid is separated from the electrokinetic porous media and the electrokinetic solution by way of a moveable partition. Further details regarding electrokinetic pumps, including materials, designs, and methods of manufacturing, suitable for use in devices according to the present invention are included in U.S. patent application Ser. No. 10/322,083 filed on Dec. 17, 2002, which is hereby incorporated by reference.
A variety of infusion liquids can be used in the electrokinetic infusion pumps illustrated in FIGS. 1-66, including insulin for diabetes; morphine and/or other analgesics for pain; barbiturates and ketamine for anesthesia; anti-infective and antiviral therapies for AIDS; antibiotic therapies for preventing infection; bone marrow for immunodeficiency disorders, blood-borne malignancies, and solid tumors; chemotherapy for cancer; and dobutamine for congestive heart failure. The electrokinetic infusion pumps illustrated in FIGS. 1-66 can also be used to deliver biopharmaceuticals. Biopharmaceuticals are difficult to administer orally due to poor stability in the gastrointestinal system and poor absorption. Biopharmaceuticals that can be delivered using the electrokinetic infusion pumps illustrated in FIGS. 1-62 include monoclonal antibodies and vaccines for cancer, BNP-32 (Natrecor) for congestive heart failure, and VEGF-121 for preeclampsia. A person skilled in the art will appreciate that any infusion liquid can be used with the infusion pumps described herein. The electrokinetic infusion pumps illustrated in FIGS. 1-62 can deliver infusion liquids to the patient in a number of ways, including subcutaneously, intravenously, or intraspinally. For example, the electrokinetic infusion pumps illustrated in FIGS. 1-66 can deliver insulin subcutaneously as a treatment for diabetes, or can deliver stem cells and/or sirolimus to the adventitial layer in the heart via a catheter as a treatment for cardiovascular disease.
FIGS. 1A and 1B are schematic illustrations of an electrokinetic infusion pump with closed loop control 100 according to an embodiment of the present invention. The electrokinetic infusion pump with closed loop control 100 illustrated in FIGS. 1A and 1B includes an electrokinetic infusion pump 103, and a closed loop controller 105. The electrokinetic infusion pump with closed loop control 100 illustrated in FIG. 1A is in a first dispense position, while the electrokinetic infusion pump with closed loop control 100 illustrated in FIG. 1B is in a second dispense position. Electrokinetic infusion pump 103 includes an electrokinetic engine 102 and an infusion module 104. Electrokinetic engine 102 includes an electrokinetic supply reservoir 106, an electrokinetic porous media 108, an electrokinetic solution receiving chamber 118, a first electrode 110, a second electrode 112, and an electrokinetic solution 114. Closed loop controller 105 includes a voltage source 115, and controls the electrokinetic engine 102. Infusion module 104 includes an infusion housing 116, an electrokinetic solution receiving chamber 118, a movable partition 120, an infusion reservoir 122, an infusion reservoir outlet 123, and an infusion liquid 124. In operation, the electrokinetic engine 102 provides the driving force for displacing the infusion liquid 124 from the infusion module 104.
In one aspect, the electrokinetic supply reservoir 106, the electrokinetic porous media 108, and the electrokinetic solution receiving chamber 118 can be filled during fabrication with an electrokinetic solution 114. Before use, the majority of the electrokinetic solution 114 is typically in the electrokinetic supply reservoir 106, with a small amount in the electrokinetic porous media 108 and the electrokinetic solution receiving chamber 118. To displace the infusion liquid 124, a voltage is established across the electrokinetic porous media 108 by applying potential across the first electrode 110 and the second electrode 112. This causes electrokinetic pumping of the electrokinetic solution 114 from the electrokinetic supply reservoir 106, through the electrokinetic porous media 108, and into the electrokinetic solution receiving chamber 118. As the electrokinetic solution receiving chamber 118 receives the electrokinetic solution 114, pressure in the electrokinetic solution receiving chamber 118 increases, forcing the moveable partition 120 in the direction of arrows 127. As the moveable partition 120 moves in the direction of arrows 127, it forces the infusion liquid 124 out of the infusion reservoir outlet 123. The electrokinetic engine 102 continues to pump the electrokinetic solution 114 until the moveable partition 120 reaches the end nearest the infusion reservoir outlet 123, displacing nearly all the infusion liquid 124 from the infusion reservoir 122.
Once again referring to the electrokinetic infusion pump with closed loop control 100 illustrated in FIGS. 1A and lB, the rate of displacement of the infusion liquid 124 from the infusion reservoir 122 is directly proportional to the rate at which the electrokinetic solution 114 is pumped from the electrokinetic supply reservoir 106 to the electrokinetic solution receiving chamber 118. The rate at which the electrokinetic solution 114 is pumped from the electrokinetic supply reservoir 106 to the electrokinetic solution receiving chamber 118 is a function of the voltage and current applied across the first electrode 110 and the second electrode 112. It is also a function of the physical properties of the electrokinetic porous media 108 and the physical properties of the electrokinetic solution 114. As mentioned previously, further details regarding electrokinetic pumps, including materials, designs, and methods of manufacturing, suitable for use in devices according to the present invention are included in U.S. patent application Ser. No. 10/322,083 filed on Dec. 17, 2002, which has been incorporated by reference.
In FIG. 1A, the movable partition 120 is in a first position 119, while in FIG. 1B, the movable partition 120 is in a second position 121. The position of the movable partition 120 can be determined, and used by the closed loop controller 105 to control the voltage and current applied across the first electrode 110 and the second electrode 112. By controlling the voltage and current applied across the first electrode 110 and the second electrode 112, the rate at which the electrokinetic solution 114 is pumped from the electrokinetic supply reservoir 106 to the electrokinetic solution receiving chamber 118 and the rate at which the infusion liquid 124 is pumped through the infusion reservoir outlet 123 can be controlled. The use of the position of the movable partition 120 to control the voltage and current applied to the first electrode 110 and the second electrode 112 is referred to as closed loop control, and is a feature of an electrokinetic infusion pump according to one embodiment of the invention.
The position of the movable partition 120 can be determined using a variety of techniques. In one exemplary embodiment, the movable partition 120 can include a magnet, and a magnetic sensor can be used to determine its position. In another exemplary embodiment, optical components can be used to determine the position of the movable partition 120. Light emitters and photodetectors can be placed adjacent to the infusion housing 116, and the position of the movable partition 120 can be determined by measuring variations in detected light. In still other embodiments, a linear variable differential transformer (LVDT) can be used. In embodiments where an LVDT is used, the moveable partition 120 can include an armature made of magnetic material. An LVDT that is suitable for use in this invention can be purchased from RDP Electrosense Inc., of Pottstown, Pa.
Depending upon the desired end use, electrokinetic infusion pumps can be completely integrated in a single assembly, or can be separated into a multitude of subassemblies that are connected by way of tubing. The electrokinetic infusion pumps 100 illustrated in FIGS. 2 through 29 are integrated, while the electrokinetic infusion pump illustrated in FIG. 30 and 39 are not integrated. Regardless of whether the electrokinetic engine 102 and the infusion module 104 are integrated, the position of the movable partition 120 can be measured, and used to control the voltage and current applied across the electrokinetic porous media 108. In this way, the electrokinetic solution 114 and the infusion liquid 124 can be delivered consistently in either an integrated or separate configuration.
Electrokinetic supply reservoirs 106 as used in the electrokinetic infusion pumps 100 illustrated in FIGS. 2-29, 33, and 35-38, and in low profile electrokinetic infusion pumps 101 illustrated in FIGS. 44A-49, are collapsible, at least in part. This allows the size of the electrokinetic supply reservoir 106 to decrease as the electrokinetic solution 114 is removed, helping to minimize the power required in moving the electrokinetic solution 114 from the electrokinetic supply reservoir 106 to the electrokinetic solution receiving chamber 118, and helping to prevent bubble formation that could cover the first electrode 110, the second electrode 112, or the electrokinetic porous media 108. The electrokinetic supply reservoir 106 can be constructed using a collapsible sack, or can include a moveable piston with seals. Also, the infusion housing 116, as used in the electrokinetic infusion pumps 100 illustrated in FIGS. 2 through 30, can be often rigid, at least in part. This feature favors displacement of the moveable partition 120 as opposed to expansion of the infusion housing 116 as the electrokinetic solution receiving chamber 118 receives the electrokinetic solution 114 pumped from the electrokinetic supply reservoir 106, and can provide more precise delivery of infusion liquid 124. Moveable partition 120 is designed to prevent migration of the electrokinetic solution 114 into the infusion liquid 124, while minimizing resistance to displacement as the electrokinetic solution receiving chamber 118 receives the electrokinetic solution 114 pumped from the electrokinetic supply reservoir 106. In some embodiments, the moveable partition 120 includes elastomeric seals that provide intimate yet movable contact between moveable partition 120 and infusion housing 116. In some embodiments, the moveable partition 120 is piston-like, while in other embodiments the moveable partition 120 is fabricated using membranes and/or bellows. As mentioned previously, closed loop control helps in maintaining consistent delivery of the electrokinetic solution 114 and the infusion liquid 124, in spite of variations in resistance caused by variations in the volume of the electrokinetic supply reservoir 106, by variations in the diameter of the infusion housing 116, and by variations in back pressure at the user's infusion site.
FIG. 2 is an illustration of an electrokinetic infusion pump 100 coupled to a vial 134 containing the infusion liquid 124. The electrokinetic infusion pump 100 illustrated in FIG. 2 has been partially filled with infusion liquid 124 and is connected to a needle 136. When filling electrokinetic infusion pump 100 with infusion liquid 124, the electrokinetic infusion pump 100 and the vial 134 are connected by way of the needle 136, and can be oriented as shown in FIG. 2. This assures introduction of the infusion liquid 124 into the electrokinetic infusion pump 100, as opposed to gas 125. Vial 134 is typically sealed with a rubber septum 135. Rubber septum 135 can be punctured by the needle 136, providing a conduit for the infusion liquid 124 to travel into the infusion module 104. When filling electrokinetic infusion pump 100 using the needle 136 and the vial 134, the electrokinetic engine 102 can be pulled out of the infusion module 104, drawing the infusion liquid 124 into the infusion module 104 in the same way one withdraws the plunger of a hypodermic syringe to draw liquid into the syringe. In another embodiment of this invention, a plunger can be sealingly adapted to said inner surface of the infusion housing 116. The plunger may include a handle capable of being manually withdrawn to prime the infusion housing 116 with the infusion liquid 124. The plunger may further include a displacement piston 146, a fixed receiving chamber 154, and the electrokinetic engine 102. Displacement piston 146 may be fixedly attached to a forward piston 166, sometimes referred to as a forward portion. In turn, the forward piston 166 may be fixedly attached to the fixed receiving chamber 154. Fixed receiving chamber 154 may be fixedly attached to the electrokinetic engine 102.
FIG. 3 is an illustration of a low profile electrokinetic infusion pump 101 according to an additional embodiment of the present invention. Low profile electrokinetic infusion pump 101 includes controller 105 and combined electrokinetic engine/infusion module 103. In the embodiments of low profile electrokinetic infusion pump 101 illustrated in FIGS. 1, 2, 3A, 3B, 3C, 4A, 4B, 4C, 5A, 5B, 6, 7, and 8, combined electrokinetic engine/infusion module 103 and controller 105 can be handheld, or mounted to a user by way of clips, adhesives, or non-adhesive removable fasteners. The controller 105 can be directly or wirelessly connected to remote controllers that provide additional data processing and/or analyte monitoring capabilities. The controller 105 includes display 140, input keys 142, and insertion port 156. After filling combined electrokinetic engine/infusion module 103 with infusion liquid, combined electrokinetic engine/infusion module 103 is inserted into insertion port 156. Upon insertion into insertion port 156, electrical contact is established between controller 105 and combined electrokinetic engine/infusion module 103. An infusion set is connected to the infusion reservoir outlet 123 after combined electrokinetic engine/infusion module 103 is inserted into insertion port 156, or before it is inserted into insertion port 156. Various means can be provided for priming of the infusion set, such as manual displacement of moveable partition 120 towards infusion reservoir outlet 123. After insertion, voltage and current are applied to the combined electrokinetic engine/infusion module 103, and infusion liquid is dispensed. In one embodiment, the low profile electrokinetic infusion pump 101 can be worn on a user's belt providing an ambulatory infusion system. Display 140 can be used to display a variety of information, including infusion rates, error messages, and logbook information. The controller 105 can be designed to communicate with other equipment, such as analyte measuring equipment and computers, either wirelessly or by direct connection.
FIG. 4 is an illustration of the electrokinetic infusion pump 100 and the pump controller 115 of FIG. 3 after the electrokinetic infusion pump 100 has been filled with the infusion liquid 124, connected to the infusion tube 138, and inserted into the pump controller 115. While the electrokinetic infusion pump 100 is in the pump controller 115, an electrical contact is established between the electrokinetic infusion pump 100 and the pump controller 115. This allows the pump controller 115 to apply potential to the electrokinetic infusion pump 100, causing it to displace the infusion liquid 124. The infusion tube 138 can be connected to a user subcutaneously to facilitate delivery of infusion liquid. Electrokinetic infusion pump 100, the pump controller 115, and the infusion tube 138 can be worn on a user's belt, providing an ambulatory infusion system. The pump controller 115 can include the display 140 and the input keys 142, allowing the user to communicate with the pump controller 115. The display 140 can be used to display a variety of information, including infusion rates, error messages, and logbook information. The pump controller 115 can be designed to communicate with other equipment, such as analyte measuring equipment and computers, either wirelessly or by direct connection. The infusion tube 138 can be made using a wide variety of materials, but is typically made from flexible tubing, as commonly found in intravenous and subcutaneous infusion lines. Such lines are typically terminated with luer or other interlocking fittings.
FIG. 5 is an illustration of an electrokinetic infusion pump 100 according to an embodiment of the present invention. The electrokinetic infusion pump 100, as shown in FIG. 5, includes an infusion housing 116, infusion reservoir outlet 123, a positioning knob 170, and an alignment tab 176. The infusion housing 116 is typically made from injection molded plastic, or machined plastic or metal. In one example, infusion housing 116 is injection molded polypropylene, and is about 0.5 inches in diameter and about 2 inches long with a wall thickness of about 0.040 inches. The infusion reservoir outlet 123 provides a conduit for infusion liquid to leave electrokinetic infusion pump 100, and is designed in a way that allows rapid and removable connection to infusion tube 138, illustrated in FIG. 4. The infusion reservoir outlet 123 can include an appropriate connector mechanism, such as male or female luer fittings to facilitate ease of connection to infusion tube 138. The positioning knob 170 and the alignment tab 176 allow precise positioning of electrokinetic infusion pump 100 components, as discussed below. The positioning knob 170 can be made out of any rigid material, but is typically injection molded from materials such as acrylic, polypropylene, and polycarbonate. The alignment tab 176 can be a separate component, but is typically an integral part of infusion housing 116. The alignment tab 176 can be formed by injection molding or by machining, and it is generally finger-shaped such that it can provide deflection while in contact with positioning grooves, as discussed below. The infusion housing 116 can be opaque, or it can be clear, thus allowing the amount of infusion liquid in electrokinetic infusion pump 100 to be determined visually.
FIG. 6 is a cross-sectional illustration of the electrokinetic infusion pump 100 of FIG. 5. As illustrated in FIG. 6, the electrokinetic infusion pump 100 is an integrated design, and includes the electrokinetic engine 102 and the infusion module 104. For purposes of clarity, the electrokinetic infusion pumps 100 that are illustrated in FIGS. 6 through 29 are drawn without infusion liquid and electrokinetic solution, even though infusion liquid and electrokinetic solution is present in operation. It is envisioned that electrokinetic infusion pump 100 could be provided to the user with the infusion liquid 124 preloaded. Alternatively, the electrokinetic infusion pump 100 can be provided without the infusion liquid 124, and the user can fill electrokinetic infusion pump 100 with the infusion liquid 124, such as by the technique illustrated in FIG. 2. Filling electrokinetic infusion pump 100 is discussed in greater detail in reference to FIGS. 16 through 29. Whether electrokinetic infusion pump 100 is provided to the user with or without infusion liquid, it will be pre-filled with electrokinetic solution.
Referring again to FIG. 6, the electrokinetic engine 102 includes the engine housing 163, the positioning knob 170, fixed supply reservoir 162, collapsible supply reservoir 160, fixed receiving chamber 154, connecting channel 156, electrokinetic seal 168, first electrode 110, electrokinetic porous media 108, second electrode 112, and connector 172. The engine housing 163 has both a forward portion 166 and rear portion 164. The axial groove 174 is located on the outside of rear portion 164 of engine housing 163. The engine housing 163 can be made using rigid materials, such as metals or plastics. The engine housing 163 is typically formed from injection molded plastics, such as polycarbonate, acrylic, acrylonitrile butadiene styrene, polypropylene, and polyethylene. Although engine housing 163 is illustrated as a single piece, it can be molded in sections, then assembled using a variety of methods, including ultrasonic welding, adhesives, or mechanical press fit. The fixed supply reservoir 162 and the fixed receiving chamber 154 are disposed inside engine housing 163, and their inner surfaces may include portions of first electrode 110 and second electrode 112. Fixed supply reservoir 162 and fixed receiving chamber 154 are typically not flexible, and retain their shape during use. Collapsible supply reservoir 160, on the other hand, is typically flexible, and collapses during use. Collapsible supply reservoir 160 is typically molded using thermoplastic rubbers or reaction injection molding compounds. It can also be thermoformed using thin sheets of plastic. The connecting channel 156 is typically tubular in shape, and provides a conduit for electrokinetic solution to flow from fixed receiving chamber 154 to adjustable receiving chamber 158. The connecting channel 156 is typically about 0.039 inches in diameter by about 0.8 inches in length, and is formed by a variety of methods including injection molding and machining.
The first electrode 110 and the second electrode 112 can be made using a variety of techniques, as is described in previously mentioned U.S. patent application Ser. No. 10/322,083 filed on Dec. 17, 2002, which is incorporated by reference herein. In some embodiments of the present invention, the first electrode 110 and the second electrode 112 can be made from materials that do not produce gas bubbles when conducting electrical current, such as silver/silver chloride, oxides such as iridium oxide and zinc oxide, or combinations of metals and oxides. In other embodiments, a combination of electrode material and electrokinetic solution can be selected as to minimize gas bubble formation when conducting electrical current. For example, platinum electrodes can be used with an electrokinetic solution that contains quinone ions. When current is passed through platinum electrodes and electrokinetic solution that contains quinone ions, quinone is converted to hydroquinone without generating gas. It is desirable that the electrodes are conductive on at least the inside and outside surfaces to allow connection with the connector 172.
Again referring to FIG. 6, the infusion module 104 includes the infusion housing 116, the alignment tab 176, the movable partition 120, the infusion reservoir 122, and the infusion reservoir outlet 123. The alignment tab 176 is movably disposed in the axial groove 174 of the electrokinetic engine 102 so as to guide movement of the electrokinetic engine 102 when it travels in an axial direction. In one embodiment, the movable partition 120 forms a distal portion of the displacement piston 146, which can also include a first infusion seal 148 and a second infusion seal 150 on an outer surface thereof, and an adjustable receiving chamber 158 extending axially therein. A first latch pocket 152 can also be formed on an outer surface of the displacement piston 146. Together with the latch 151, the first latch pocket 152 provides a means for removably latching electrokinetic engine 102 to displacement piston 146.
During operation, latch 151 is unlatched from the electrokinetic engine 102, enabling the displacement piston 146 to be free to move towards infusion reservoir outlet 123, and during such movement, the first infusion seal 148 and second infusion seal 150 maintain a seal between the infusion housing 116 and the displacement piston 146. Although two infusion seals are illustrated in FIGS. 6, 7, 9, and 14 through 30, a single infusion seal can alternatively be used.
The first infusion seal 148 and the second infusion seal 150 can be made from a variety of materials, including buna, viton, and neoprene elastomers. The first infusion seal 148 and second infusion seal 150 are typically ring shaped, and they can have a variety of cross-sectional shapes, including square, rectangular, and circular. The first infusion seal 148 and the second infusion seal 150 typically have an inside diameter of about 0.350 inches, and a cross sectional diameter of about 0.080 inches.
One skilled in the art will appreciate that the infusion reservoir 122 can vary in size, depending upon a variety of factors, including the particular pump application and the position of the displacement piston 146. When the displacement piston 146 is in the completely forward position nearest the infusion reservoir outlet 123, the volume of the infusion reservoir 122 is nearly zero.
As further illustrated in FIG. 6, the engine housing 163 has both a forward portion 166 and rear portion 164. The forward portion 166 mates within a channel formed inside of the displacement piston 146 forming the adjustable receiving chamber 158. The electrokinetic seal 168 forms a seal between the inner surface of the adjustable receiving chamber 158 and the forward portion 166 of the engine housing 163.
The electrokinetic seal 168 can be made from a variety of materials, as discussed previously with respect to the first infusion seal 148 and the second infusion seal 150. The electrokinetic seal 168 typically has an inside diameter of about 0.110 inches, and a cross sectional diameter of about 0.085 inches. When the displacement piston 146 is in the completely retracted position, farthest from the infusion reservoir outlet 123, the adjustable receiving chamber 158 is at its minimum volume. When the displacement piston 146 is in the completely forward position, closest to the infusion reservoir outlet 123, the adjustable receiving chamber 158 is at its maximum volume.
FIG. 7 is an exploded view of the electrokinetic infusion pump 100 of FIG. 5, illustrating the infusion housing 116, the displacement piston 146, the engine housing 163, and internal engine components 165. The displacement piston 146 can include the first infusion seal 148, the second infusion seal 150, and the first latch pocket 152. The engine housing 163 can include a rear portion 164, a forward portion 166, a second latch pocket 178, a first connector opening 180, a second connector opening 182, and an electrokinetic seal 168. Internal engine components 165 can include the first electrode 110, the second electrode 112, the electrokinetic porous media 108, the collapsible supply reservoir 160, the connector 172 and the positioning knob 170. Latch 151 is also illustrated in FIG. 7.
The positioning knob 170 can perform several functions. First, it provides a handle that allows a user to grip and move the electrokinetic engine 102 and the displacement piston 146, as further described below. The positioning knob 170 can also provide a means to compress internal engine components 165. For example, during assembly, the first electrode 110, the second electrode 112, the electrokinetic porous media 108, the collapsible supply reservoir 160, and the connector 172 can be press fit into the engine housing 163 using the positioning knob 170. Once assembled, the positioning knob 170 remains in place as a result of being press fit.
The connector 172 provides means for making electrical contact between the first electrode 110, the second electrode 112, and the electrokinetic pump controller 115, which is illustrated in FIGS. 3 and 4. The connector 172 can be fabricated using a variety of materials and processes. In one embodiment, the connector 172 is die cut polyester, about 0.003 inches thick, with screen printed conductive carbon traces. In another embodiment, the connector 172 is die cut polyimide, about 0.003 inches thick, with gold traces that are formed using lithography. In either embodiment, the connector 172 is sandwiched between the first electrode 110 and the second electrode 112, and the engine housing 163 during assembly, establishing electrical contact with the first electrode 110 and the second electrode 112. As illustrated in FIG. 4, when the electrokinetic infusion pump 100 is inserted into the electrokinetic pump controller 115, electrical contact is established with the connector 172 by way of first connector opening 180 and second connector opening 182. The first connector opening 180 and the second connector opening 182 are typically holes in the engine housing 163, allowing contact with the connector 172, and can have diameters of approximately 0.060 inches.
FIG. 8 is an illustration of an electrokinetic engine subassembly 184, as used in the electrokinetic infusion pump 100 of FIG. 5. FIG. 8 illustrates the assembly of internal engine components, including the first electrode 110, the second electrode 112, the electrokinetic porous media 108, the collapsible supply reservoir 160, the connector 172, and the positioning knob 170. The engine subassembly 184 can be fitted into the engine housing 163, as illustrated in FIG. 6, by a variety of techniques that are effective to form a leak proof seal between these components. Effective sealing is important to ensure that that the only path for flow of electrokinetic solution is through the electrokinetic porous media 108. For this reason a tight, and leak-proof assembly is required. Suitable joinder techniques includes press fitting, the use of adhesives, or heat sealing.
FIG. 9 is an illustration of a piston/engine subassembly 186, as used in the electrokinetic infusion pump 100 of FIG. 5. In FIG. 9, the displacement piston 146 is attached to the engine housing 163, and fastened using the latch 151. Also visible in this view are the first infusion seal 148, the second infusion seal 150, the first connector opening 180, and the second connector opening 182. As will be discussed in respect to FIGS. 16 through 29, the displacement piston 146 is initially attached to the engine housing 163 using the latch 151. This allows the displacement piston 146 and the engine housing 163 to be moved back and forth as a unit, such as to load the infusion liquid 124. During operation, the latch 151 is disengaged, allowing the displacement piston 146 and the engine housing 163 to move independently, such as to dispense infusion liquid 124.
FIG. 10 is a perspective view of the infusion housing 116, as used in the electrokinetic infusion pump 100 of FIG. 5. As illustrated in FIG. 10, the infusion reservoir outlet 123 and the alignment tab 176 form part of the infusion housing 116.
FIG. 11 is another perspective view of the infusion housing 116, as used in the electrokinetic infusion pump 100 of FIG. 5. In FIG. 11, the alignment tab 176 can be seen to include an alignment pin 188. The alignment pin 188 rides in the axial groove 174 and the perimeter groove 192, as described below with reference to FIG. 13. The alignment pin 188 can have a variety of shapes, such as cylindrical or spherical, and it can be about 0.030 inches in diameter by about 0.040 inches high, and is either cylindrical or spherical in shape.
FIG. 12 is a perspective view of the engine housing 163, as used in the electrokinetic infusion pump 100 of FIG. 5. In FIG. 12, the first connector opening 180 and the second connector opening 182 can be seen, as well as the second latch pocket 178 and electrokinetic seal groove 190. The latch 151, as seen in FIG. 9, is attached to the engine housing 163 using the second latch pocket 178, and can be attached permanently, for example, using adhesives, or it can be removable. The electrokinetic seal groove 190 can provide a pocket for placement of the electrokinetic seal 168, as seen in FIG. 7. The electrokinetic seal groove 190 can have a variety of shapes and configurations that are appropriate to seat the electrokinetic seal 168, but is typically rectangular in cross section and about 0.085 inches wide by about 0.049 inches deep.
FIG. 13 is another perspective view of engine housing 163, as used in the electrokinetic infusion pump 100 of FIG. 5. The engine housing 163 can include an axial groove start 175, an axial groove 174, an axial groove stop 177, a perimeter groove 192, and a perimeter groove stop 194 formed on the outside surface of the rear portion 164 of the engine housing 163. As shown in FIG. 13, the electrokinetic seal 168 is disposed at the end of the forward portion 166 of the engine housing 163. Referring to FIGS. 6, 7, 11, and 13, the axial groove start 175, the axial groove 174, the axial groove stop 177, the perimeter groove 192, and the perimeter groove stop 194 can provide a guide when positioning electrokinetic engine 102. The alignment pin 188 is movably disposed in the axial groove start 175, the axial groove 174, the axial groove stop 177, the perimeter groove 192, and the perimeter groove stop 194, and can provide precise positioning of the electrokinetic engine 102 relative to the infusion housing 116. The axial groove start 175 can limit movement of the alignment pin 188 in the forward direction, towards the infusion reservoir outlet 123, and the axial groove stop 177 can limit movement of the alignment pin 188 in the backward direction, away from the infusion reservoir outlet 123. The axial groove 174 can also limit rotational motion about the axis of the infusion housing 116 while positioning the electrokinetic engine 102 in either the forward or backward direction, towards or away from the infusion reservoir outlet 123. The perimeter groove 192 and the perimeter groove stop 194 can be used to provide a consistent displacement of the infusion liquid 124 while priming the electrokinetic infusion pump 100, which is discussed in more detail below relative to FIGS. 20 through 23. The axial groove start 175, the axial groove 174, the axial groove stop 177, the perimeter groove 192, and the perimeter groove stop 194 can have a variety of sizes, but in one embodiment, are typically about 0.031 inches wide and about 0.040 inches deep and can be formed from a variety of techniques, including by machining or injection molding.
FIG. 14 is a perspective view of the displacement piston 146, as used in the electrokinetic infusion pump 100 of FIG. 5. The displacement piston 146 can include a first latch pocket 152, an adjustable receiving chamber 158, a first infusion seal groove 196, and a second infusion seal groove 198. As mentioned above, although two infusion seals are illustrated in FIGS. 6, 7, 9, and 14 through 30, a single infusion seal can be used in some embodiments. The displacement piston 146 can be made from a variety of materials, although it is preferably made of a plastic such as polyethylene, polypropylene, polycarbonate, acrylic, and acrylonitrile butadiene styrene. The displacement piston 146 can be machined, although it is typically injection molded. The displacement piston 146 typically is about 0.450 inches in diameter and about 0.819 inches long.
The adjustable receiving chamber 158 is typically formed on an inner surface of the displacement piston 146, and it is typically about 0.230 inches in diameter by about 0.731 inches long, and can be machined or injection molded. The surface of the adjustable receiving chamber 158 can be smooth to allow a seal to be formed between the adjustable receiving chamber 158 and the forward portion 166 of the engine housing 163 using the electrokinetic seal 168, as illustrated in FIG. 6. The latch 151, as shown in FIG. 9, can be attached to the displacement piston 146 using the first latch pocket 152. The latch 151 is typically pressed into the first latch pocket 152 without the use of adhesive, since it can be removed in subsequent steps, as discussed below relative to FIG. 24. Below the first latch pocket 152 is an enlarged pocket 153. The enlarged pocket 153 is adapted to allow the circular end of the latch 151 to clear the first latch pocket 152 by pressing the latch 151 inwards, towards the enlarged pocket 153, which allows the displacement piston 146 to disengage from the latch 151.
Referring to FIGS. 1, 6, and 14, when the electrokinetic infusion pump 100 is filled with the infusion liquid 124 and the electrokinetic solution 114, a potential can be applied across the first electrode 110 and the second electrode 112 to cause the electrokinetic solution 114 to be pumped from the collapsible supply reservoir 160 and the fixed supply reservoir 162, across the electrokinetic porous media 108, and into the fixed receiving chamber 154, the connecting channel 156, and the adjustable receiving chamber 158. The pressure generated inside the fixed receiving chamber 154, the connecting channel 156, and the adjustable receiving chamber 158 causes the displacement piston 146 to move in the direction of the infusion reservoir outlet 123, displacing a portion of the infusion liquid 124. In one exemplary embodiment, the diameter (D1) of the adjustable receiving chamber 158 is less than the diameter (D2) of the collapsible supply reservoir 160 and the fixed supply reservoir 162, causing the volume of infusion liquid 124 that is displaced to be greater than the volume of electrokinetic solution 114 that is pumped by a factor (D2/D1)2, referred to as the hydraulic amplification factor. Using a hydraulic amplification factor less electrokinetic solution 114 is required to displace infusion liquid 124, thus reducing the overall size of the electrokinetic infusion pump 100, and the size of the first electrode 110 and the second electrode 112. Similarly, since less electrokinetic solution 114 is pumped, total energy consumption is reduced. A side effect of the hydraulic amplification factor is that force on the displacement piston 146 is reduced by the same factor, (D2/D1)2but generating higher pressures with the electrokinetic engine 102 can compensate for this side effect. While the hydraulic amplification factor can vary, it is generally greater than 1 or 2, and in one embodiment, the hydraulic amplification factor (D2/D1)2 is approximately 4. There are two additional advantages of designing electrokinetic infusion pumps 100 with hydraulic amplification factors of greater than 1, as illustrated in FIGS. 5 through 29. First, a non pressurized region 167, illustrated in FIG. 6, is created between the electrokinetic seal 168 and the second infusion seal 150, which reduces pressure buildup in the electrokinetic solution should it leak beyond the electrokinetic seal 168, and thus minimizes the chance of electrokinetic solution migrating into the infusion liquid. A second advantage of designing electrokinetic infusion pumps 100 with hydraulic amplification factors of greater than 1 is that the wall thickness of the displacement piston 146 can be increased, providing a stiffer adjustable receiving chamber 158 which results in more consistent delivery of the infusion liquid 124. Although the electrokinetic infusion pumps 100 illustrated in FIGS. 5 through 29 were designed with a hydraulic amplification factor of 4, both higher and lower hydraulic amplification factors can be used. In some designs a factor of 1 is used, while in other designs factors of less than 1 or greater than 1 are used.
FIG. 15 is another perspective view of the displacement piston 146, as used in the electrokinetic infusion pump 100 of FIG. 5. As shown in FIG. 15, the displacement piston 146 can include the first infusion seal 148 and the second infusion seal 150.
FIGS. 16 through 29 illustrate the operation of the electrokinetic infusion pump 100 shown in FIG. 5. In FIG. 16, the electrokinetic engine 102 and the displacement piston 146 are in a completely forward position within the infusion housing 116. The alignment tab 176 and the alignment pin 188 (not shown) are positioned at the axial groove start 175.
In FIG. 17, the positioning knob 170 is pulled in the direction indicated by arrow 200. The alignment tab 176 and the alignment pin 188 (not shown) move slidably along the axial groove 174 in the direction indicated by arrow 202. The displacement piston 146 and the electrokinetic engine 102 travel in the direction indicated by arrow 200, which increases the volume of the adjustable infusion reservoir 122. Although infusion liquid 124 is not shown in FIG. 17, the motion of the displacement piston 146 and the electrokinetic engine 102 can be used to fill the infusion reservoir 122 with the infusion liquid 124 by way of the infusion reservoir outlet 123 when the infusion reservoir outlet is coupled to the vial 134, as illustrated in FIG. 2. As mentioned previously, the infusion liquid 124 is not shown in FIGS. 16 through 29 to make the illustrations more clear.
In FIGS. 18 and 19, the positioning knob 170 is pulled further in the direction indicated by arrow 200, causing the alignment tab 176 and the alignment pin 188 (not shown) to continue to move slidably along the axial groove 174 in the direction indicated by arrow 202. The displacement piston 146 and the electrokinetic engine 102 travel in the direction indicated by arrow 200, which further increases the volume of the adjustable infusion reservoir 122, which further fills the infusion reservoir 122 with the infusion liquid 124.
In FIG. 20, the positioning knob 170 is pulled in the direction indicated by arrow 200 until the alignment tab 176 and the alignment pin 188 (not shown) reach the axial groove stop 177. At this point, the displacement piston 146 and the electrokinetic engine 102 have reached their maximum travel in the direction indicated by arrow 200, and the adjustable infusion reservoir 122 is expanded to its maximum size, enabling it to accommodate a maximum volume of the infusion liquid 124. The infusion tube 138, as illustrated in FIG. 4, can then be attached to the electrokinetic infusion pump 100 and primed, as described below relative to FIGS. 21 through 23.
In FIG. 21, the positioning knob 170 is turned in the direction indicated by arrow 204, causing the alignment tab 176 and the alignment pin 188 (not shown) to move slidably along the perimeter groove 192. Referring to FIG. 20, the perimeter groove 192 is not perpendicular to the axial groove 174, but is angled back slightly towards the positioning knob 170. While the perimeter groove 174 can be positioned at a variety of angles with respect to the axial groove 174, the perimeter groove 192 is typically angled about 80 degrees relative to the axial groove 174, as indicated by an angle callout 193, illustrated in FIG. 20. The angle of the perimeter groove 192 relative to the axial groove 174 allows the displacement piston 146 and the electrokinetic engine 102 to travel in the direction indicated by arrow 202 while the positioning knob 170 is turned in the direction of arrow 204. Because the displacement piston 146 and the electrokinetic engine 102 travel in the direction indicated by arrow 202 as a result of movement along perimeter groove 192, the infusion liquid 124 is dispensed through the infusion reservoir outlet 123, thus priming the infusion tube 138, as illustrated in FIG. 4, by displacing air, and the filling the infusion tube 138 with the infusion liquid 124. The perimeter groove 192 therefore provides precise, reproducible displacement while priming the infusion tube 138.
In FIG. 22, the positioning knob 170 is turned further in the direction indicated by the arrow 204. The alignment tab 176 and the alignment pin 188 (not shown) move slidably along the perimeter groove 192, causing movement of the displacement piston 146 and the electrokinetic engine 102 in the direction indicated by the arrow 202, which further displaces the infusion liquid 124 through the infusion reservoir outlet 123 and into the infusion tube 138.
In FIG. 23, the positioning knob 170 is turned further in the direction indicated by arrow 204 until the alignment tab 176 and the alignment pin 188 (not shown) reach the perimeter groove stop 194. At this point, the positioning knob 170 is no longer turned, priming of the infusion tube 138 is complete, and the electrokinetic infusion pump 100 is inserted into the pump controller 115, as illustrated in FIG. 4. The infusion tube 138 can be connected to a users tissue, subcutaneously, as mentioned previously. The electrokinetic infusion pump 100 is then ready to dispense the infusion liquid 124, as illustrated in FIGS. 24 through 29.
FIG. 24 illustrates the latch 151 as being disengaged from the first latch pocket 152 by pressing it inward. As discussed above in the description of FIG. 14, the first latch pocket 152 can include an enlarged pocket 153 below its surface that allows the circular end of the latch 151 to clear the first latch pocket 152 when the latch 151 is pressed inward towards the center of the displacement piston 146, allowing the displacement piston 146 to disengage from the latch 151. Once the displacement piston 146 is disengaged from the latch 151, the displacement piston 146 can move in the direction of arrow 202 while the electrokinetic engine 102 remains stationary. The latch 151 can be disengaged either before or after insertion of the electrokinetic infusion pump 100 into the pump controller 115. The latch 151 can be pressed towards the center of the displacement piston 146 (i.e., disengaged) by deflecting the infusion housing 116 in the vicinity of the latch 151, or an opening can be provided in the infusion housing 116 allowing direct contact with the latch 151. In designs where the latch 151 is pressed after the electrokinetic infusion pump 100 is inserted into the pump controller 115, means can be provided in the pump controller 115 that can press the latch 151.
FIG. 25 is a cross sectional view of the electrokinetic infusion pump 100 of FIG. 24 in which the displacement piston 146 is shown in the fully back position, with the infusion reservoir 122 at its maximum volume. The forward portion 166 of the engine housing 163 is positioned inside of the displacement piston 146, sealed with the electrokinetic seal 168. The infusion reservoir 122 is sealed with the first infusion seal 148 and the second infusion seal 150 to prevent the infusion liquid from flowing beyond the displacement piston 146.
In FIG. 26, an electrical potential is applied to the electrokinetic engine 102 by way of the first connector opening 180 and the second connector opening 182, causing the displacement piston 146 to move in the direction indicated by arrow 202, while the electrokinetic engine 102 remains stationary. The motion of the displacement piston 146 in the direction of arrow 202 causes the infusion liquid 124 to be displaced from the infusion reservoir 122, through the infusion reservoir outlet 123, through an infusion tube, and into the user. In FIG. 27, the displacement piston 146 has moved further in the direction indicated by arrow 202, thus displacing additional infusion liquid.
FIG. 28 is a cross sectional view of the electrokinetic infusion pump 100 illustrated in FIG. 27. As a result of the applied electrical potential, electrokinetic solution is pumped across the electrokinetic porous media 108 from the collapsible supply reservoir 160 and the fixed supply reservoir 162 to the electrokinetic solution receiving chamber 118, the connecting channel 156, and the adjustable receiving chamber 158. Pumping is caused by the electrical potential applied across the first electrode 110 and the second electrode 112 by the pump controller 115 (illustrated in FIG. 4).
In FIG. 29, the displacement piston 146 has moved in the direction of arrow 202 and is in the fully forward position. Infusion liquid has been completely dispensed through the infusion reservoir outlet 123 and the operation of the electrokinetic infusion pump 100 is stopped. At this point the electrokinetic infusion pump 100 can be removed from pump controller 115 (illustrated in FIG. 4) and discarded.
EXAMPLE
As discussed previously with respect to FIG. 1, when designing electrokinetic infusion pumps 100, the infusion module 104 and the electrokinetic engine 102 can be integrated, as illustrated in FIGS. 2 through 29, or they can be separate components connected with tubing, as illustrated in FIG. 30. As illustrated in FIG. 30, the electrokinetic infusion pump 100 includes the infusion module 104 and the electrokinetic engine 102, connected by connection a tubing 300. Further details regarding electrokinetic engine 102, including materials, designs, and methods of manufacturing, suitable for use in the electrokinetic infusion pump 100 illustrated in FIG. 30 are included in U.S. patent application Ser. No. 10/322,083, previously incorporated by reference. Using the electrokinetic infusion pump 100 that is illustrated in FIG. 30, basal and bolus infusion liquid delivery rates were determined. Basal infusion liquid delivery rates typically dispense smaller volumes at a higher frequency, whereas bolus infusion liquid delivery rates typically dispense larger volumes at a lower frequency. Basal and bolus infusion liquid delivery rates were determined by applying an electric field across electrokinetic engine 102 for a period of time (referred to as the pump on time), then switching the electric field off for a period of time (referred to as the pump off time). The sum of pump on time and pump off time is referred to as cycle time. The mass of infusion liquid pumped during each cycle time (referred to as the shot size) was determined with a Mettler Toledo AX205 electronic balance. The shot size was determined repeatedly, using the same the same pump on time and the same cycle time, giving an indication of shot size repeatability. Using the density of water (1 gram per cubic centimeter), the shot size volume was derived from the mass of infusion liquid pumped during each cycle time. Electrokinetic engine 102 was connected to infusion module 104 using connection tubing 300. Connection tubing 300 was rigid PEEK tubing with an inside diameter of 0.040 inches, an outside diameter of 0.063 inches, and a length of approximately 3 inches. A similar piece of PEEK tubing, approximately 24 inches long, was connected to infusion reservoir outlet 123 on one end, and to glass capillary tubing on the other end. The glass capillary tubing had an inside diameter of 0.021 inches, an outside diameter of 0.026 inches, and a length of about 6 inches. The end of the glass capillary tubing not connected to infusion reservoir outlet 123 was inserted into a small vial being weighed by the Mettler Toledo AX205 electronic balance. A small amount of water was placed in the bottom of the small vial, covering the end of the glass capillary tubing, and a drop of oil was placed on top of the water in the bottom of the small vial to reduce evaporation of the water. Electrokinetic engine 102 was also connected to a vented electrokinetic solution reservoir (not shown in FIG. 30) that provided electrokinetic solution to electrokinetic engine 102. Electrokinetic engine 102, vented electrokinetic solution reservoir, infusion module 104, connection tubing 300, the glass capillary tubing, and the Mettler Toledo AX205 electronic balance, were placed inside a temperature-controlled box, held to +/−1 degree C., to eliminate measurement errors associated with temperature variations. The temperature-controlled box was placed on top of a marble table to reduce errors from vibration. A personal computer running LabView software controlled electrokinetic infusion pump 100 and collected data from the Mettler Toledo AX205 electronic balance.
To determine basal delivery of infusion liquid, electrokinetic engine 102 was connected to infusion module 104 with connection tubing 300 and driven with a potential of 75V. At 75V, electrokinetic engine 102 delivered electrokinetic solution to infusion module 104 at a rate of approximately 3.6 microliters/minute. Infusion module 104 included displacement piston 146 that was designed with the hydraulic amplification factor (D2/D1)2 equal to 4, as described previously relative to FIG. 14. Electrokinetic infusion pump 100 was run with an on time of 12 seconds and a cycle time of 60 seconds, over a 12-hour period. During 12 hours, 720 shots were delivered. FIG. 31 is a graph showing measured shot size as a function of time for basal delivery of infusion liquid. As can be seen in FIG. 31, the shot size asymptotically approached a shot size of approximately 0.55 microliters. The average shot size was 0.65 microliters with a standard deviation of 0.1 microliters. In this experiment, no attempt was made to control shot size by varying the potential applied to electrokinetic engine 102.
To determine bolus delivery of infusion liquid, electrokinetic engine 102 was connected to infusion module 104 with connection tubing 300 and driven with a potential of 75V. At 75V, electrokinetic engine 102 delivered electrokinetic solution to infusion module 104 at a rate of approximately 3.6 microliters/minute. Infusion module 104 included displacement piston 146 that was designed with the hydraulic amplification factor (D2/D1)2 equal to 4, as described previously relative to FIG. 14. The electrokinetic infusion pump 100 was run with an on time of 80 seconds and a cycle time of 10 minutes, over a period of 3 hours and 50 minutes. During 3 hours and 50 minutes, 23 shots were delivered. FIG. 32 is a graph showing measured shot size as a function of time. As can be seen in FIG. 32, the average shot size was 9.8 microliters with a standard deviation of 0.6 microliters. In this experiment, no attempt was made to control shot size by varying the potential applied to electrokinetic engine 102.
Closed Loop Control
As discussed above, in one exemplary embodiment, the electrokinetic infusion pump can use closed loop control.
FIG. 33 is an illustration of an electrokinetic infusion pump with closed loop control 1100 according to an additional embodiment of the present invention. The electrokinetic infusion pump with closed loop control 1100 includes a closed loop controller 1105 and an electrokinetic infusion pump 1103. In the embodiments of electrokinetic infusion pump with closed loop control 1100 illustrated in FIGS. 33, 35, 36, 37 and 38, the electrokinetic infusion pump 1103 and closed loop controller 1105 can be handheld, or mounted to a user by way of clips, adhesives, or non-adhesive removable fasteners. The closed loop controller 1105 can be directly or wirelessly connected to remote controllers that provide additional data processing and/or analyte monitoring capabilities. As outlined earlier, and referring to FIGS. 1 and 33, closed loop controller 1105 and electrokinetic infusion pump 103 can include elements that enable the position of movable partition 1120 to be determined. The closed loop controller 1105 includes display 1140, input keys 1142, and insertion port 1156. After filling electrokinetic infusion pump 1103 with infusion liquid 1124, electrokinetic infusion pump 1103 is inserted into insertion port 1156. Upon insertion into insertion port 1156, electrical contact is established between the closed loop controller 1105 and the electrokinetic infusion pump 1103. An infusion set is connected to the infusion reservoir outlet 1123 after electrokinetic infusion pump 1103 is inserted into insertion port 1156, or before it is inserted into insertion port 1156. Various means can be provided for priming of the infusion set, such as manual displacement of moveable partition 1120 towards infusion reservoir outlet 1123. After determining the position of moveable partition 1120, voltage and current are applied across electrokinetic porous media 1108, and infusion liquid 1124 is dispensed. The electrokinetic infusion pump with the closed loop control 1100 can be worn on a user's belt providing an ambulatory infusion system. The display 1140 can be used to display a variety of information, including infusion rates, error messages, and logbook information. The closed loop controller 1105 can be designed to communicate with other equipment, such as analyte measuring equipment and computers, either wirelessly or by direct connection.
As discussed above, the position of the movable partition 1120 can be determined using a magnetic position sensor. FIG. 34 illustrates the principals of magnetic position sensor 1176. A magnetic position sensor 1176, suitable for use in this invention, can be purchased from MTS Systems Corporation, Sensors Division, of Cary, N.C. In the magnetic position sensor 1176, a sonic strain pulse is induced in a magnetostrictive waveguide 1177 by the momentary interaction of two magnetic fields. A first magnetic field 178 is generated by a movable permanent magnet 1149 as it passes along the outside of the magnetostrictive waveguide 1177. A second magnetic field 1180 is generated by a current pulse 1179 as it travels down the magnetostrictive waveguide 1177. The interaction of the first magnetic field 1178 and the second magnetic field 1180 creates a strain pulse. The strain pulse travels, at sonic speed, along the magnetostrictive waveguide 1177 until the strain pulse is detected by a strain pulse detector 1182. The position of a movable permanent magnet 1149 is determined by measuring the elapsed time between application of the current pulse 1179 and detection of the strain pulse at the strain pulse detector 1182. The elapsed time between application of the current pulse 1179 and arrival of the resulting strain pulse at the strain pulse detector 1182 can be correlated to the position of the movable permanent magnet 1149. Alternative magnetic sensors are disclosed in the co-pending application entitled “Infusion Pumps with a Position Sensor” (Attorney Docket No. 106731-18), filed concurrently herewith.
FIGS. 35-36 illustrate portions of an electrokinetic infusion pump with closed loop control according to an embodiment of the present invention. FIGS. 35-36 include the electrokinetic infusion pump 1103, the closed loop controller 1105, the magnetic position sensor 1176, and the position sensor control circuit 1160. The position sensor control circuit 1160 is connected to the closed loop controller 105 by way of a feedback 138. The electrokinetic infusion pump 1103 can include an infusion housing 1116, an electrokinetic supply reservoir 1106, an electrokinetic porous media 1108, an electrokinetic solution receiving chamber 1118, an infusion reservoir 1122, and a moveable partition 1120. The moveable partition 1120 includes a first infusion seal 1148, a second infusion seal 1150, and a moveable permanent magnet 1149. The infusion reservoir 1122 can be formed between the moveable partition 1120 and a tapered end of the infusion housing 1116. The electrokinetic supply reservoir 1106, the electrokinetic porous media 1108, and the electrokinetic solution receiving chamber 1118 can contain electrokinetic solution 1114, while the infusion reservoir 1122 can contain an infusion liquid 1124. An electrical potential, such as voltage, is controlled by the closed loop controller 105, and is applied across the first electrode 1110 and the second electrode 1112. The magnetic position sensor 1176 includes the magnetostrictive waveguide 1177, the position sensor control circuit 160, and the strain pulse detector 182. The magnetostrictive waveguide 1177 and the strain pulse detector 1182 are typically mounted on the position sensor control circuit 1160.
In FIG. 35, the moveable partition 120 is in a first position 1168. The position sensor control circuit 1160 sends a current pulse down the magnetostrictive waveguide 1177, and by interaction of the magnetic field created by the current pulse with the magnetic field created by the moveable permanent magnet 1149, a strain pulse is generated and detected by the strain pulse detector 1182. The first position 1168 can be derived from the time between initiating the current pulse and detecting the strain pulse. In FIG. 36, the electrokinetic solution 1114 has been pumped from the electrokinetic supply reservoir 1106 to the electrokinetic solution receiving chamber 1118, which pushes the moveable partition 1120 toward a second position 1172. The position sensor control circuit 1160 sends a current pulse down the magnetostrictive waveguide 1177, and by interaction of the magnetic field created by the current pulse with the magnetic field created by the moveable permanent magnet 1149, a strain pulse is generated and detected by the strain pulse detector 1182. The second position 1172 can be derived from the time between initiating the current pulse and detecting the strain pulse. A change in position 1170 can be determined using the difference between the first position 1168 and the second position 1172. As discussed above, the position of the moveable partition 1120 can be used in controlling flow in the electrokinetic infusion pump 1103.
Although the electrokinetic infusion pumps with closed loop control described in this invention are described in respect to electrokinetic engines, embodiments using other engines are envisioned. These include the use of engines based on gas generation and expanding gels and polymers, used alone or in combination with electrokinetic engines. Closed loop control, as envisioned in this invention, is useful in many types of infusion pumps. While closed loop control and occlusion detection are described herein with respect to an electrokinetic infusion pump, the principals of closed loop control and occlusion detection are applicable to any actuator that generates pressure in a hydraulic medium which causes movement of a moveable partition.
FIG. 37 is a block diagram of a circuit that can be used in an electrokinetic infusion pump with closed loop control according to another exemplary embodiment of the present invention. The electrokinetic infusion pump 1103 includes the electrokinetic engine 1102, and the moveable partition 1120. The moveable partition 1120 includes the moveable permanent magnet 1149. The position of moveable permanent magnet 149 in electrokinetic infusion pump 1103 is detected by magnetostrictive waveguide 1177. Alternative magnetic position sensors are disclosed in co-pending application entitled “Infusion Pumps with a Position Sensor” (Attorney Docket No. 106731-18), filed concurrently herewith. Electrokinetic infusion pump with closed loop control 1100 includes master control unit 1190 and master control software 1191. Master control unit 1190 and master control software 1191 control various elements in electrokinetic infusion pump with closed loop control 1100, including display 1140, input keys 1142, non-volatile memory 1200, system clock 1204, user alarm 1212, radio frequency communication circuit 1216, position sensor control circuit 160, electrokinetic engine control circuit 1222, and system monitor circuit 1220. A battery 1208 powers master control unit 1190, and is controlled by a power supply and management circuit 1210. The user alarm 1212 can be audible, vibrational, or optical.
Referring again to FIG. 37, electrokinetic infusion pump 1103 includes electrokinetic engine 1102 and moveable partition 1120. Electrokinetic engine 1102 displaces moveable partition 1120 by pumping electrokinetic solution 114 (not shown) against moveable partition 1120. Moveable partition 1120 includes moveable permanent magnet 1149, and the position of moveable permanent magnet 1149 in electrokinetic infusion pump 1103 is detected by magnetostrictive waveguide 1177. Although in this illustration magnetic techniques are used to determine the position of moveable partition 1120, other techniques can be used, as mentioned previously. Other techniques include the use of light emitters and photodetectors. Electrokinetic infusion pump with closed loop control 1100 includes master control unit 1190 and master control software 1191. Master control unit 1190 is typically mounted to a printed circuit board and includes a microprocessor. Master control software 1191 controls the master control unit 1190. Display 1140 provides visual feedback to users, and is typically a liquid crystal display, or its equivalent. Display driver 1141 controls display 1140, and is an element of master control unit 1190. Input keys 1142 allow the user to enter commands into closed loop controller 1105 and master control unit 1190, and are connected to master control unit 1190 by way of digital input and outputs 1143. Non-volatile memory 1200 provides memory for closed loop controller 1105, and is connected to master control unit 1190 by way of serial input and output 1202. The system clock 1204 provides a microprocessor time base and real time clock for master control unit 1190. The user alarm 1212 provides feedback to the user, and can be used to generate alarms, warnings, and prompts. Radio frequency communication circuit 1216 is connected to the master control unit 1190 by way of serial input and output 1218, and can be used to communicate with other equipment such as self monitoring blood glucose meters, electronic log books, personal digital assistants, cell phones, and other electronic equipment. Information that can be transmitted via radio frequency, or with other wireless methods, include pump status, alarm conditions, command verification, position sensor status, and remaining power supply. The position sensor control circuit 1160 is connected to the master control unit 1190 by way of digital and analog input and output 1161, and is connected to magnetostrictive waveguide 1177 by way of connector 1175. As discussed previously, position sensor control circuit 1160 uses magnetostrictive waveguide 1177 and moveable permanent magnet 1149 to determine the position of moveable partition 1120. Electrokinetic engine control circuit 1222 is connected to master control unit 190 by way of digital and analog input and output 1224, and to electrokinetic engine 1102 by way of connector 1223. The electrokinetic engine control circuit 1222 controls pumping of the electrokinetic solution 1114 and the infusion liquid 1124, as mentioned previously. The electrokinetic engine control circuit 1222 relies upon input from the position sensor control circuit 1160, and commands issued by the master control unit 1190 and the master control software 1191, via digital and analog input and output 1224. Fault detection in the electrokinetic engine control circuit 1222 is reported to the master control unit 1190 and the master control software 1191 by way of the digital input and output 1226. The system monitor circuit 1220 routinely checks for system faults, and reports status to the master control unit 190 and the master control software 1191 by way of the digital input and output 1221. The battery 1208 provides power to the master control unit 1190 and is controlled by the power supply and management circuit 1210.
FIG. 38 is a block diagram of a position sensor signal processing circuit that can be used in an electrokinetic infusion pump with closed loop control according to an additional embodiment of the present invention. The block diagram illustrated in FIG. 38 includes the electrokinetic infusion pump 1103, the magnetorestrictive waveguide 1177, the position sensor control circuit 1160, the voltage nulling device 1228, the voltage amplifier 1238, digital to analog converter 1232, the analog to digital converter 1236, and the microprocessor 1234. The electrokinetic infusion pump 1103 includes moveable partition 1120 and infusion liquid 1124. The moveable partition 1120 includes the moveable permanent magnet 1149, which interacts with the magnetostrictive waveguide 1177 in determining the position of the moveable partition 1120 in the electrokinetic infusion pump 1103. When the position sensor signal processing circuit illustrated in FIG. 38 is used, the resolution of magnetostrictive waveguide 1177 is increased. In operation, the magnetostrictive waveguide 1177 yields a voltage that varies as a function of the position of moveable permanent magnet 1149. When the position sensor signal processing circuit illustrated in FIG. 38 is not used, the voltage from the magnetostrictive waveguide 1177 ranges from 0 to a maximum value that is determined by analog to digital converter 1236. The resolution of magnetostrictive waveguide 1177 is determined by the maximum voltage analog to digital converter 236 can process divided by the length of the magnetostrictive waveguide 1177. When the position sensor signal processing circuit illustrated in FIG. 6 is used, voltage nulling device 1228 offsets the voltage from the magnetostricitive waveguide 1177 to either zero, or a value near zero. After the voltage from the magnetostrictive waveguide 1177 is offset by voltage nulling device 1228, nulled voltage 1229 can be multiplied using voltage amplifier 1238 to a value less than the maximum voltage that can be processed by analog to digital converter 1236. The combined effect of nulling device 1228 and voltage amplifier 1238 is to divide the maximum voltage that can be processed by analog to digital converter 1236 by a smaller length, and in that way increase the voltage change per unit length of movement by moveable permanent magnet 1149. To avoid exceeding the capacity of analog to digital converter 1236, the nulling step is repeated by voltage nulling device 1228 multiple times as moveable partition 1120 moves along the length of electrokinetic infusion pump 1103. Larger voltage change per unit length of movement by moveable permanent magnet 1149 allows smaller detectable volumes, and more sensitive determination of the position of moveable permanent magnet 1149. Upon insertion of electrokinetic infusion pump 1103 into closed loop controller 1105, an amplification factor of approximately 1 can be used by voltage amplifier 1238, with a nulling voltage of 0 volts. Once moveable permanent magnet 1149 moves from its original position, voltage nulling device 1228 can apply nulling voltage that results in a nulled voltage of approximately zero, and voltage amplifier 1238 can amplify the voltage, while keeping the voltage in the range of analog to digital converter 1236. If power to closed loop controller 1105 is inadvertently lost, the nulling voltage and amplification factor can be recovered from non-volatile memory 1200, if it has been previously stored. In alternative embodiments, a fixed amplification factor can be used, and the nulling voltage varied to keep the voltage within the range of analog to digital converter 1236.
EXAMPLE
As mentioned previously, when designing an electrokinetic infusion pump with closed loop control 1100, the infusion module 1104 and the electrokinetic engine 1102 can be integrated, as illustrated in FIGS. 33, 35, 36, 37, and 38, or they can be separate components connected with tubing, as illustrated in FIG. 39. In FIG. 39, electrokinetic infusion pump with closed loop control 1100 includes infusion module 1104 and electrokinetic engine 1102, connected by connection tubing 1244. Infusion module 1104 includes moveable partition 1120 and infusion reservoir outlet 1123. The moveable partition 1120 includes moveable permanent magnet 1149. Further details regarding electrokinetic engine 1102, including materials, designs, and methods of manufacturing, suitable for use in electrokinetic infusion pump with closed loop control 1100 are included in U.S. patent application Ser. No. 10/322,083, previously incorporated by reference. Using electrokinetic infusion pump with closed loop control 1100 illustrated in FIG. 39, basal and bolus infusion liquid delivery rates were determined, using a method similar to the one described above.
To determine basal delivery of infusion liquid, electrokinetic engine 1102 was connected to the infusion module 1104 with the connection tubing 244 and driven with a potential of 75V. At 75V, electrokinetic engine 1102 delivered electrokinetic solution to infusion module 1104 at a rate of approximately 15 microliters/minute. The electrokinetic engine 1102 was run with an on time of approximately 2 seconds and an off time of approximately 58 seconds, resulting in a cycle time of 60 seconds and a shot size of approximately 0.5 microliters. The on time of electrokinetic engine 1102 was adjusted, based upon input from the magnetostrictive waveguide 1177 and position sensor control circuit 160. For each cycle of basal delivery, the position of the moveable permanent magnet 1149 was determined. If the moveable permanent magnet 1149 did not move enough, the on time for the next cycle of basal delivery was increased. If the moveable permanent magnet 1149 moved too much, the on time for the next cycle of basal delivery was decreased. The determination of position of the moveable permanent magnet 1149, and any necessary adjustments to on time, was repeated for every cycle of basal delivery.
To determine bolus delivery of infusion liquid, the electrokinetic engine 102 was connected to the infusion module 1104 with the connection tubing 1244 and driven with a potential of 75V. Once again, at 75V electrokinetic engine 1102 delivered electrokinetic solution to infusion module 104 at a rate of approximately 15 microliters/minute. The electrokinetic engine 1102 was run with an on time of approximately 1120 seconds and an off time of approximately 120 seconds, resulting in a cycle time of 4 minutes and a shot size of approximately 30 microliters. For each cycle of bolus delivery, the position of moveable permanent magnet 1149 was determined while the electrokinetic engine 1102 was on. Once the moveable permanent magnet 1149 moved the desired amount, electrokinetic engine 1102 was turned off. The position of the moveable permanent magnet 1149 was used to control on time of the electrokinetic engine 1102 for every cycle of bolus delivery.
Basal and bolus delivery of infusion liquid were alternated, as follows. Thirty cycles of basal delivery was followed by one cycle of bolus delivery. Then, thirty-seven cycles of basal delivery, was followed by one cycle of bolus delivery. Finally, thirty-eight cycles of basal delivery was followed by a one cycle of bolus delivery and forty-nine additional cycles of basal delivery. FIG. 40 is a graph showing measured shot size as a function of time, for alternating basal delivery 1243 and bolus delivery 1245, as outlined above. In basal mode, the average shot size was about 0.5 microliters with a standard deviation of less than 2%.
FIG. 41 is a flow diagram illustrating a method of detecting occlusions in an electrokinetic infusion pump with closed loop control 1100 according to an embodiment of the present invention. With reference to FIG. 41, and FIGS. 33 through 40, closed loop controller 1105 starts with a normal status 1246. In the next step, closed loop controller 1105 determines position 1250 of the moveable partition 1120. After determining the position 1250 of the moveable partition 1120, the closed loop controller 1105 waits before dose 1252. During this time, the pressure in electrokinetic infusion pump 1103 decreases. After waiting before dose 1252, a fixed volume is dosed 1254. This is accomplished by activating the electrokinetic engine 1102. As a result of dosing a fixed volume 1254 (electrokinetic engine on time), the pressure in the electrokinetic infusion pump 1103 increases as a function of time, as illustrated in FIG. 10. Multiple graphs are illustrated in FIG. 42, showing the effect of time between shots (electrokinetic engine off time) on pressure in the electrokinetic infusion pump 1103. Waiting 1 minute between shots results in a rapid build up of pressure. Waiting 5 minutes between shots results in a longer time to build pressure. The rate at which pressure builds is the same in each graph, but the starting pressure decreases as a function of time between shots, and therefore results in longer times to build pressure. Each graph eventually reaches the same approximate pressure, in this case about 3.2 psi. This is the pressure needed to displace moveable partition 1120. Returning to FIG. 41, after dosing a fixed amount 1254, and waiting after dose 1256 (during which time the pressure in electrokinetic infusion pump 1103 increases), the change in position 1258 of moveable partition 1120 is determined. The position of moveable partition 1120 can be determined using a variety of techniques, as mentioned previously. After determining the change in position 1258 of moveable partition 1120, closed loop controller 1105 determines if moveable partition 1120 has moved as expected 1260, or if it has not moved as expected 1264. If the moveable partition 1120 has moved as expected 1260, then no occlusion 1262 has occurred, and the closed loop controller 1105 returns to normal status 1246. If the moveable partition 1120 has not moved as expected 1264, then an occlusion 1266 has occurred, and the closed loop controller 1105 enters an alarm status 248. FIG. 43 is a graph illustrating the position of moveable partition 1120 as a function of time when an occlusion occurs in an electrokinetic infusion pump with closed loop control 1100, according to the embodiment described in the previous example. As can be seen in FIG. 43, after about 70 minutes the rate at which the moveable partition 1120 moves as a function of time suddenly decreases in region 1251, even though constant voltage is applied to electrokinetic engine 1102. This indicates that an occlusion has occurred, blocking the movement of the moveable partition 1120.
Electrokinetic Infusion Pump with a Detachable Controller
FIGS. 44A-44C illustrate a low profile electrokinetic infusion pump according to an additional embodiment of the present invention. In FIG. 44A, combined electrokinetic engine/infusion module 2103 is in an initial state, ready to draw infusion liquid 2124 from vial 2107. The combined electrokinetic engine/infusion module 2103 includes an infusion housing 2116, an electrokinetic solution receiving chamber 2118, an electrokinetic supply reservoir 2106, an electrokinetic porous media 2108, and an infusion reservoir 2122. The electrokinetic supply reservoir 2106 and the electrokinetic solution receiving chamber 2118 include electrokinetic solution 2114. The infusion reservoir 2122 is empty initially. In FIG. 44B, the electrokinetic engine 2102 has been moved by the user in the direction of arrow 2328, drawing the infusion liquid 2124 from a vial 2107 and into the infusion reservoir 2122. At the top of the infusion reservoir 2122, a moveable partition 2120 forms an interface between the infusion reservoir 2122 and the electrokinetic solution receiving chamber 2118. In FIG. 44C, electrical potential has been applied across the electrokinetic porous media 2108, and the electrokinetic solution 2114 has moved from the electrokinetic supply reservoir 2106 to the electrokinetic solution receiving chamber 2118, displacing the infusion liquid 2124 from the infusion reservoir 2122 and through an infusion reservoir outlet 2123. As electrokinetic solution 2114 is pumped through the electrokinetic porous media 2108 into the electrokinetic solution receiving chamber 2118, the electrokinetic solution receiving chamber 118 expands and the moveable partition 2120 pushes against the infusion liquid 2124 in infusion reservoir 2122. The infusion reservoir 2122, electrokinetic solution receiving chamber 2118, and the electrokinetic supply reservoir 2106 can be fabricated using a variety of techniques, although a preferred embodiment includes flexible plastic films in compliant pouch-like configurations. Compliant pouch-like configurations allow infusion reservoir 2122, electrokinetic solution receiving chamber 2118, and electrokinetic supply reservoir 2106 to readily expand and contract, and create minimal resistance to flow in electrokinetic solution 2114. By using compliant pouch-like configurations with the infusion reservoir 2122, the electrokinetic solution receiving chamber 2118, and the electrokinetic supply reservoir 2106, various cross sectional configurations can be used for combined electrokinetic engine/infusion module 2103, including circular, oval, and rectangular. Non-circular cross sections can allow for a more compact configuration, and are desirable in some embodiments. Although not shown in this figure, electrodes (as illustrated in FIG. 1) allow electrical contact with electrokinetic solution 2114, on both sides of the electrokinetic porous media 2108. The electrodes can be disk shaped, cylindrically shaped, or shaped like wires, and allow electrical contact with the electrokinetic solution 2114 from the outside of the electrokinetic supply reservoir 2106 and the electrokinetic solution receiving chamber 2118.
FIGS. 44A
45C are illustrations of a low profile electrokinetic infusion pump 2101 according to an additional embodiment of the present invention. The low profile electrokinetic infusion pump 2101 illustrated in FIGS. 44A-44C include a combined electrokinetic engine/infusion module 2103, and a controller 2105. In FIG. 45A, combined electrokinetic engine/infusion module 2103 and controller 2105 are detached. Electrokinetic engine/infusion module 2103 includes a retaining clip 2317 and pump contacts 2331. The controller 2105 includes input keys 2142, a display 2140, and controller contacts 2333 (shown in FIG. 47). The retaining clip 2317 secures the controller 2105 to combined electrokinetic engine/infusion module 2103 when they are attached. The retaining clip 2317 can be a molded feature, as shown, or a separate mechanical piece, as long as it secures the controller 2105 to combined electrokinetic engine/infusion module 2103 and is easily fastened and unfastened. The pump contacts 2331 interface with the controller contacts 2333 (shown in FIG. 47), and enable electrical connection between the controller 2105 and combined electrokinetic engine/infusion module 2103. Among other things, this allows the controller 2105 to control pumping action in combined electrokinetic engine/infusion module 2103, and can allow controller 2105 to determine the status of combined electrokinetic engine/infusion module 2103 in respect to errors and remaining infusion liquid. In some embodiments, the display 2140 includes at least one light emitting diode, and in other embodiments the display 2140 includes a liquid crystal display. In embodiments where the display 2140 includes at least one light emitting diode, different colors can be used to indicate the status of low profile electrokinetic infusion pump 2101. In embodiments where the display 2140 includes a liquid crystal display, text messages can be used to communicate the status of low profile electrokinetic infusion pump 2101. The input keys 2142 can be used to navigate messages provided by display 2140, and in issuing commands to low profile electrokinetic infusion pump 2101. Although two input keys 2142 are illustrated, a single input key 2142 can be used, or more than two input keys 2142 can be used, depending upon their function. In FIG. 45B, combined electrokinetic engine/infusion module 2103 and controller 2105 are attached. The retaining clip 2317 keeps controller 2105 in place, but it can be displaced to allow detachment of controller 2105 from combined electrokinetic engine/infusion module 2103. The overall size of low profile electrokinetic infusion pump 2101 can vary, but is typically the size of a small mobile phone, allowing for discrete placement by its user. In FIG. 4C, the perspective has been rotated, allowing infusion reservoir outlet 2123 and contact surface 2325 to be seen. In FIG. 45C, infusion reservoir outlet 2123 is a fixed cannula that allows injection of infusion liquid 2124 into the body of a user. When infusion reservoir outlet 2123 is in the form of a fixed cannula, it penetrates the skin when low profile electrokinetic infusion pump 2101 is attached to the user, eliminating the need for an additional infusion line. The fixed cannula can be permanently or removably attached to combined electrokinetic engine/infusion module 2103. A removably attached fixed cannula allows periodic replacement. The combined electrokinetic engine/infusion module 2103 includes contact surface 325, providing a support for controller 2105 and a surface for contact with a user. The contact surface 2325 can optionally include an adhesive 2326 (as illustrated in FIGS. 46A and 46B) or a mounting clip 2335 (as illustrated in FIG. 47).
FIGS. 46A and 46B are cross sectional illustrations of low profile electrokinetic infusion pump 2101 illustrated in FIGS. 44A-45C. In FIG. 46A, combined electrokinetic engine/infusion module 2103 is filled with infusion liquid 2124. The electrokinetic supply reservoir 2106 is filled with electrokinetic solution 2114, while the electrokinetic porous media 2108 and the electrokinetic solution receiving chamber 2118 also contain small amounts of electrokinetic solution 2114. In this embodiment, the infusion reservoir outlet 2123 is a fixed cannula, and the contact surface 2325 is covered with adhesive 2326. The controller 2105 is attached to combined electrokinetic engine/infusion module 2103, and is fixed in place by retaining clip 2317. The controller contacts 2333 are connected to the pump contacts 2331, establishing electrical contact between the controller 2105 and the combined electrokinetic engine/infusion module 2103. In the embodiment of low profile electrokinetic infusion pump 2101 illustrated in FIGS. 46A and 46B, the controller 2105 includes a battery 2313 that can be reused when the combined electrokinetic engine/infusion module 2103 is spent. In the embodiment of low profile electrokinetic infusion pump 2101 illustrated in FIG. 47, the combined electrokinetic engine/infusion module 2103 includes a battery 2313 that can be disposed of when the combined electrokinetic engine/infusion module 2103 is spent. In FIG. 46B, the low profile electrokinetic infusion pump 2101 has dispensed a portion of infusion liquid 2124. The electrokinetic solution 2114 has been pumped from the electrokinetic supply reservoir 2106, across the electrokinetic porous media 2108, and into the electrokinetic solution receiving chamber 2118. As the electrokinetic solution 2114 flows into the electrokinetic solution receiving chamber 2118, the electrokinetic solution receiving chamber 2118 expands, forcing infusion liquid 2124 out of the infusion reservoir 2122, and through the infusion reservoir outlet 2123, as indicated by arrow 2329. The controller 2105 applies potential across the electrokinetic porous media 2108, causing the electrokinetic solution 2114 to flow from the electrokinetic supply reservoir 2106 into the electrokinetic solution receiving chamber 2118. As previously mentioned, electrodes (as illustrated in FIG. 1) allow electrical contact with the electrokinetic solution 2114, on both sides of the electrokinetic porous media 2108. The electrodes can be of a variety of appropriate shapes, including disk shaped, cylindrical, or shaped like wires, and they are effective to allow electrical contact with the electrokinetic solution 2114 from the outside of the electrokinetic supply reservoir 2106 and the electrokinetic solution receiving chamber 2118. In some embodiments, the display 2140 includes indication that electrokinetic solution 2114 is being pumped from the electrokinetic supply reservoir 2106 into the electrokinetic solution receiving chamber 2118, causing infusion liquid 2124 to flow from the infusion reservoir 2122 through the infusion reservoir outlet 2123. The battery 2313 provides power for the controller 2105, allowing voltage to be applied across the electrokinetic porous media 2108. To prime the infusion reservoir outlet 2123, pumping of the electrokinetic solution 2114 from the electrokinetic supply reservoir 2106 into the electrokinetic solution receiving chamber 2118 can occur before attaching low profile electrokinetic infusion pump 2101 to the user. As mentioned previously, the electrokinetic supply reservoir 2106, the electrokinetic solution receiving chamber 2118, and the infusion reservoir 2122 can be fabricated using compliant pouch-like configurations, allowing for compact design.
FIG. 47 is an illustration of the low profile electrokinetic infusion pump illustrated in FIGS. 45A, 45B, 45C, 46A, and 46B with an alternative infusion reservoir outlet 2123 and mounting clip 2335. In FIG. 47, combined electrokinetic engine/infusion module 2103 and controller 2105 are detached, and combined electrokinetic engine/infusion module 2103 is partially filled with infusion liquid. In contrast to the design illustrated in FIGS. 46A and 46B, the design illustrated in FIG. 47 includes battery 2313 as part of electrokinetic engine/infusion module 2103. This can result in smaller battery size, since battery 2313 provides power for a single use of electrokinetic engine/infusion module 103. A smaller battery can result in smaller overall size for low profile electrokinetic infusion pump 2101. Electrokinetic engine/infusion module 2103 also includes mounting clip 2335, as opposed to adhesive 326 illustrated in FIGS. 46A and 46B. Mounting clip 2335 can be connected to a user's belt or clothing, and can be repositioned, as needed. In the embodiment of low profile electrokinetic infusion pump 2101 illustrated in FIG. 47, infusion reservoir outlet 2123 includes an infusion line with infusion tip 2337. When controller 2105 applies electrical potential across electrokinetic porous media 2108, electrokinetic solution 2114 flows from electrokinetic supply reservoir 2106, through electrokinetic porous media 2108, and into electrokinetic solution receiving chamber 2118, displacing infusion liquid 2124 from infusion reservoir 2122, through infusion reservoir outlet 2123 and infusion tip 2337. After priming the infusion line, infusion tip 2337 can be placed under the skin of the user, and infusion liquid 2124 can be pumped into the user by low profile electrokinetic infusion pump 2101. The infusion line used as infusion reservoir outlet 2123 can be any of those currently used with mechanical infusion pumps. The controller 2105 includes controller contacts 2333, input keys 2142, and display 2140, as described previously. When the controller 2105 is connected to electrokinetic engine/infusion module 2103, and fastened in place with retaining clip 2317, electrical connection is made between controller contacts 2333 and pump contacts 2331, allowing controller 2105 to control pumping in electrokinetic engine/infusion module 2103. As previously mentioned, electrodes (as illustrated in FIG. 1) allow electrical contact with electrokinetic solution 2114, on both sides of electrokinetic porous media 2108. The electrodes can be disk shaped, cylindrically shaped, or shaped like wires, and allow electrical contact with electrokinetic solution 2114 from the outside of electrokinetic supply reservoir 106 and electrokinetic solution receiving chamber 2118.
FIG. 48 is an illustration of the low profile electrokinetic infusion pump 2101 illustrated in FIGS. 46A and 46B attached to a user by way of adhesive 2326. In FIG. 48, the low profile electrokinetic infusion pump 2101 is in wireless communication with remote controller 2343. The remote controller 2343 can include various features, such as electronic log book entry, blood glucose or other analyte monitoring, additional pump control electronics and algorithms, alarms, and communication capabilities. Although the remote controller 2343 and the low profile electrokinetic infusion pump 2101 are illustrated in wireless communication, they can also be hard-wired. In FIG. 48, the low profile electrokinetic infusion pump 2101 is fastened directly to a users skin by way of the adhesive 2326 (shown in FIGS. 46A and 46B). This embodiment is particularly useful when the infusion reservoir outlet 2123 is a fixed cannula, and the low profile electrokinetic infusion pump 2101 remains in one location while dispensing infusion liquid 2124. The low profile electrokinetic infusion pump 2101 can be attached to a users skin, and covered with clothing, as desired. Once infusion liquid 2124 is completely dispensed, the low profile electrokinetic infusion pump 2101 can be removed from the skin, the controller 2105 can be detached from the electrokinetic engine/infusion module 2103, and the electrokinetic engine/infusion module 2103 can be disposed of. In this way, the low profile electrokinetic infusion pump 2101 provides a compact, discrete, and convenient infusion system.
FIG. 49 is an illustration of the low profile electrokinetic infusion pump 2101 illustrated in FIGS. 47, attached to a user by way of mounting clip a 2335. In FIG. 49, the low profile electrokinetic infusion pump 2101 is in wireless communication with the remote controller 2343, as described previously. The low profile electrokinetic infusion pump 2101 is fastened directly to a belt 2345 by way of the mounting clip 2335 (shown in FIG. 47). This embodiment is particularly useful when the infusion reservoir outlet 2123 is an infusion line, and the low profile electrokinetic infusion pump 2101 can be moved from one location to another while dispensing infusion liquid 2124. The low profile electrokinetic infusion pump 2101 can be attached to the belt 2345, and covered with clothing, as desired. Once infusion liquid 2124 is completely dispensed, the low profile electrokinetic infusion pump 2101 can be removed from the belt 2345, the controller 2105 can be detached from the electrokinetic engine/infusion module 2103, and the electrokinetic engine/infusion module 2103 can be disposed of.
In the low profile electrokinetic infusion pump embodiments described above, a variety of infusion reservoir outlets have been described. In some embodiments, an infusion reservoir outlet can include an insertion device and a cannula for delivering infusion liquid hypodermically. In other embodiments, infusion reservoir outlets include hollow needles for delivering infusion liquid hypodermically. In embodiments that include cannulas, insertion devices can be removed after the cannula is positioned under the epidermis, making the device more comfortable for the user. A variety of cannulas, hollow needles, and insertion devices can be used with low profile electrokinetic infusion pumps of the present invention. Insertion devices can include automatic or manual actuators. For some users, using infusion reservoir outlets as illustrated in FIGS. 45A-46B may limit their selection of cannulas and needles, preventing them from selecting a favorite design. In addition, the designs illustrated in FIGS. 45A-46B may pose difficulties in respect to insertion because of the inability to see the infusion reservoir outlet while it is being inserted into the tissue. To address these limitations, additional embodiments of the present invention are anticipated, and are illustrated in FIGS. 50-54.
In the embodiments illustrated in FIGS. 50-54, a mounting plate 2347 is fixed to the user's skin. The mounting plate can include an infusion tip, such as a hollow needle or a cannula, or can include a hole that allows an infusion tip to pass through. The mounting plate includes features that allow it to be attached and detached from a low profile electrokinetic infusion pump. The mounting plate can be made out of clear plastic, and can include a clear pressure sensitive adhesive for mounting to the user's skin. In embodiments where the mounting plate includes a through hole, an insertion device can be used to introduce a cannula and can be removed, leaving the cannula in place. The mounting plate can then be mounted to the skin over the cannula, with the cannula centered in the mounting plate hole. An electrokinetic infusion pump can then be fastened to the mounting plate, while establishing a seal between the pump components and the cannula. In embodiments where a hollow needle is used to deliver infusion liquid, the needle can be rigidly fixed to the mounting plate, penetrating the tissue while the mounting plate is fixed to the user. An electrokinetic infusion pump can then be fastened to the mounting plate, while establishing a seal between the pump components and the needle. The mounting plate can be made out of a variety of materials, including transparent plastic that enables visualization of the infusion site by the user.
In FIG. 50, low profile electrokinetic infusion pump 2101 is attached to mounting plate 2347, as it would be when delivering infusion liquid. Although electrokinetic infusion pump 2101 is illustrated as a single piece, in other embodiments it includes a separate controller 2105 and combined electrokinetic engine/infusion module 2103, as illustrated in FIGS. 45A-47. In FIG. 51, low profile electrokinetic infusion pump 2101 is detached from mounting plate 2347. Mounting plate 2347 includes retaining clips 2317, which interlock with features in low profile electrokinetic infusion pump 2101 when mounting plate 2347 and low profile electrokinetic infusion pump 2101 are attached. Mounting plate 2347 also includes infusion tip 337 and connector 349. Infusion tip 337 can include a hollow needle, an insertion device, and/or a cannula, as described previously. In FIG. 51, infusion tip 2337 and connector 349 are fixed to mounting plate 2347, and are inserted into the user's tissue while mounting plate 2347 is being fastened to the user. In the embodiment illustrated in FIG. 52, mounting plate 2347 includes hole 2355, and is not connected to infusion tip 2337 or connector 2349. This allows infusion tip 2337 and connector 2349 to be inserted into the tissue independently from mounting plate 2347. Some users may prefer the embodiment illustrated in FIG. 52, as it allows better visualization of insertion of infusion tip 2337 into the tissue, and more readily allows the use of a cannula (as infusion tip 2337) and insertion device 2359. After inserting a cannula (as infusion tip 2337) into the user's tissue, insertion device 2359 can be removed, and mounting plate 2347 can be fixed to the user while centering infusion tip 2337 in hole 2355. This may help in forming a seal between connector 349 and low profile electrokinetic infusion pump 101 when low profile electrokinetic infusion pump 2101 is fixed to mounting plate 2347. In FIG. 53, mounting plate 2347 and low profile electrokinetic infusion pump 101 are viewed from the bottom. Mounting plate 2347 includes adhesive 2326, while low profile electrokinetic infusion pump 2101 includes retaining pocket 2318, pump components 2353, and connection port 2351. Adhesive 2326 can be made using a wide variety of adhesives, including pressure sensitive acrylic based adhesives. The adhesive 2326 can completely cover the surface of mounting plate 2347, or can partially cover the surface of mounting plate 2347. As illustrated in FIG. 53, a portion of the surface of mounting plate 2347 in the area of infusion tip 2337 may be free of adhesive, improving visibility through mounting plate 2347. This can be particularly advantageous when inserting infusion tip 337 into the skin, or when inspecting the infusion site. Retaining pocket 2318 mates with retaining clip 2317, securing low profile electrokinetic infusion pump 2101 in place over mounting plate 2347. When low profile electrokinetic infusion pump 2101 is attached to mounting plate 2347, connector 2349 mates with connection port 2351, forming a leak-proof seal. Although the embodiment illustrated in FIG. 53 does not include hole 2355, as seen in FIG. 52, it optionally can include hole 2355.
In conventional infusion pumps, an infusion pump and infusion reservoir are connected to a user's infusion site by way of tubing, and either a needle or a cannula. An adhesive patch is often used to fasten the needle or cannula to the user's infusion site. The tubing, needle or cannula, and adhesive patch are often referred to as an infusion set, and is replaced every three days or so to prevent infection and scar tissue formation at the infusion site. Many different infusion sets are commercially available, allowing patients to choose an infusion set according to their personal preference. Features that vary from one infusion set to another include means for a connection between the tubing and the pump, means for disconnection between the tubing and the needle or cannula (particularly near the infusion site), the length of tubing, the insertion angle of the needle or cannula, means for inserting cannulas, means for manually or automatically inserting the needle or cannula, and variations in the shape and kind of adhesive for fastening the needle or cannula to the infusion site. In some embodiments of the present invention, a needle or cannula is connected directly to the infusion pump, eliminating the need for tubing. Eliminating tubing can be desirable in that many of the problems encountered by users of infusion pumps are related to the use of tubing. Tubing can become tangled with clothing or other objects, and can dislodge a needle or cannula when cleared. In addition, tubing can become kinked, causing an interruption in the flow of infusion liquid. While embodiments of the present invention that do not include tubing avoid tubing related problems, they may require removal of the needle or cannula when inspecting the infusion site or when inspecting the pump. To address this issue, the embodiment of the present invention illustrated in FIG. 54 is envisioned.
In the embodiment of the present invention illustrated in FIG. 54, the low profile electrokinetic infusion pump is connected to an infusion tip by way of tubing. The tubing is retractable, and can be stored within the low profile electrokinetic infusion pump. A spring-loaded mechanism can be used to retract and coil the tubing around a tubing spool. The tubing spool releases tubing the low profile electrokinetic infusion pump is detached from the mounting plate, as is the case when the user wishes inspect the pump or the infusion site. When the low profile electrokinetic infusion pump is re-attached, the tubing recoils on the tubing spool. The embodiment illustrated in FIG. 54 prevents entanglement, disconnection, and kinking of the infusion set. As illustrated in FIG. 54, low profile electrokinetic infusion pump 2101 includes retaining pocket 2318, pump components 2353, and tubing spool 2357. Mounting plate 2347 includes retaining clip 2317, infusion tip 2337, and connector 2349. Although the embodiment illustrated in FIG. 54 shows infusion tip 337 and connector 2349 fixed to mounting plate 2347, they can be separate from mounting plate 347 as illustrated in FIG. 52 and described previously. Tubing 2356 is wound around tubing spool 2357, and is connected to pump components 2353 on one end and connector 2349 on the other end. As low profile electrokinetic infusion pump 2101 is detached and moved away from mounting plate 2347, tubing 2356 unwinds from tubing spool 2357, allowing low profile electrokinetic infusion pump 2101 to be inspected, as needed. When desired, low profile electrokinetic infusion pump 2101 can be moved back towards mounting plate 2347, while tubing 2356 winds around tubing spool 2357, re-attaching to mounting plate 2347. While low profile electrokinetic infusion pump 2101 is detached from mounting plate 2347, infusion tip 2337 and the user's infusion site can be inspected, and adjusted, as needed. Although tubing spool 2357 is illustrated as part of low profile electrokinetic infusion pump 2101, it can also be attached to mounting plate 2347 in alternative embodiments. As mentioned in reference to FIGS. 50-53, low profile electrokinetic infusion pump 2101 can be a single unit, or can include a separate controller and combined electrokinetic engine/infusion module. Since low profile electrokinetic infusion pump 2101 is detachable in the embodiment illustrated in FIG. 54, it can be attached to mounting plate 2347, or placed remotely, in a pocket, purse, or on a belt clip, for example. Although the system illustrated in FIG. 54 has been described in respect to a low profile electrokinetic infusion pump, elements can be used with conventional infusion systems. For instance, infusion tip 2337, connector 2349, tubing 2356, and tubing spool 2357 can be used as infusion sets for commercially available electromechanical based infusion pumps, such as those sold by Medtronic Diabetes, of Northridge, Calif.
While this particular embodiment describes a bag-to-bag pump design, the electrokinetic pump described above is also applicable to a variety of other designs, including a removable pump with a movable seal.
In another exemplary embodiment, the pump is adapted to allow a user to adjust the depth of the needle which is inserted into the skin of the user, as shown in FIGS. 55-62. One feature of this embodiment is that it allows the temporary removal of the pump from the skin of the user. In general, as shown in FIG. 55, an adjustment assembly 3000 can include cannula channel mold 3080, which includes a cannula channel 3070 and cavities for top and bottom septum caps 3050, 3090. A needle inserter assembly 3130 is provided which is adapted to insert a cannula 3020 housing a needle 3010 at a user selected depth. To adjust the depth of the cannula 3020, an adjustment key 3030 is provided, having multiple positions, such as a first, second, and third position corresponding to three depths for the needle inserter 3130.
FIG. 56 shows the adjustment key 3030 at a first position in which the needle inserter and the cannula 3020 are at a first position, for example, at a depth of 9 mm. In order to position the depth of the needle inserter 3130, a first shoulder 3110 is adapted to engage with a top surface of the adjustment key 3030. This stops the needle inserter 3130 at the first position. FIG. 57 shows the adjustment key 3030 shifted from the first position 3110 to a second position in which the needle inserter and cannula are at a second position, for example, at a depth of 12 mm. A second shoulder 3120 is adapted to engage the adjustment key 3030 is stop the adjustment key 3030 at the second position 3120. FIG. 58 shows the adjustment key 3030 shifted from the second position to a third position in which the needle inserter 3130 and the cannula 3020 are at a third position, for example, at a depth of 15 mm. The first shoulder 3110 engages with a top surface of the cannula channel mold 3080 to stop the needle inserter 3130 at the third position.
FIG. 59 shows the needle inserter assembly 3130 holding the cannula 3020 which houses the needle 3010. The cannula 3020 can be press-fit within the cannula channel 3070 as the needle inserter 3130 moves through the channel 3070. The needle inserter 3130 can be removed after the needle insertion is completed, leaving the cannula 3020 and the needle 3010 held within the cannula channel 3070. The cannula 3020 can have a variety of configurations, as shown in FIGS. 60A-60B, which illustrate cannulas including a feature on a proximal end configured for allowing the cannula 3020 to press-fit within the cannula channel 3070. FIG. 60A illustrates a cannula 3020a having a flange 3022 disposed on the proximal end, FIG. 60B illustrates a cannula 3020b having a flared proximal end 3024, FIG. 60C illustrates a cannula 3020c having an extended flange 3026 disposed on the proximal end, and FIG. 60D illustrates a cannula 3020d having a squared flange 3028 disposed on the proximal end. A person skilled in the art will appreciate that any feature disposed on the proximal end of the cannula 3020, or any shape or configuration of the proximal end of the cannula, can be used to provide a press-fit of the cannula within the cannula channel.
The top and bottom septums 3040, 3090 and septum caps 3050, 3100 can be used to provide a seal to prevent leaking of the infusion liquid. The top septum 3040 and septum cap 3050, shown in FIG. 61, provide a seal and a conduit for the infusion liquid from the reservoir 3150 to the cannula channel 3070. The top septum 3040 maintains a water-tight seal for the reservoir needle, and can also self-seal after the reservoir 3150 and/or a controller is temporarily removed, which allows a user to remove the pump for a short period of time, for example, for activities such as sports or bathing, or permanently removed. The top septum 3040 also provides a water-tight seal after the removal of the needle inserter 3130. The top septum cap 3050 can latch into the top cavity of the cannula channel mold 3080 and maintains a water-tight seal between the bottom of the top septum 3040 and the top surface of the cannula channel mold 3080. The bottom septum 3090 and bottom septum cap 3100, shown in FIG. 62, provides a seal for leaks between the cannula 3020 and the cannula channel 3070, and horizontally stabilizes the cannula 3020. The bottom septum cap 3100 latches into the bottom cavity of the cannula channel mold 3080 and maintains a water-tight seal between the top of the bottom septum 3090 and the bottom surface of the cannula channel mold 3080.
The electrokinetic infusion pumps described above can also be adapted to allow a user to modify the configuration of the infusion pump to achieve a variety of options for wearing the infusion pump. The infusion pump can include a dock having a cannula with a needle housed therein. The needle extends into the skin of the user to allow infusion liquid to pass from the infusion pump to the user. A variety of components can be removably coupled to the dock and the cannula and needle to allow for flexibility in wearing the infusion pump.
As shown in FIG. 63, in one exemplary embodiment, a patch 4002, disposed on the user's skin, is directly coupled to an infusion dock 4004. The infusion pump 4006 is coupled to the infusion dock 4004, and the infusion pump 4006 is controlled using a remote control 4008. In another exemplary embodiment, shown in FIG. 64, the infusion pump 4006 is coupled to the infusion dock 4004 using a tubing 4010, and the infusion pump 4006 is controlled using a remote control 4008. In yet another exemplary embodiment, shown in FIG. 65, the infusion pump 4006 is coupled to the infusion dock 4004 using a tubing 4010, and the infusion pump 4006 is controlled manually with controls disposed on the infusion pump 4006. FIG. 66 shows another exemplary embodiment, the infusion pump 4006 is coupled to the infusion dock 4004, and the remote control 4008 for controlling the infusion pump 4006 is removably coupled to the infusion pump 4006 for storage. A person skilled in the art will appreciate that any combination of the infusion dock, infusion pump, tubing, remote control, and any other component used with an infusion pump, can be used to attach the infusion pump to the user and to control the pump for deliver of infusion liquid to the user.
One of ordinary skill in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the invention is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.
Patent Application
20070066939
