Patent Application
20060100578
The present invention relates to apparatus and methodology for the delivery, e.g., intravenous infusion, of medication and/or other fluids in accordance with a predetermined medical therapy. More particularly, the present invention relates to medication delivery apparatus and methodology with improved ease of administration of a variety of therapeutic agents by intravenous infusion.
Intravenous medications including antibiotics and the like may be administered intermittently over an extended period of time. Each administration of an intravenous therapy generally follows a predefined procedure that often includes a series of manual steps. Such manual steps may include saline flushes and generally terminate with the application of anti-clotting medication. The manual steps in the therapy procedures are a principle source of error, infection, and other complications that may arise during intermittent infusion therapy.
Examples of medication delivery containers and medication delivery pumps have been described in U.S. Pat. No. 6,146,360; U.S. Pat. No. 6,074,366; U.S. patent application Ser. No. 09/434,972, filed on Nov. 5, 1999; and U.S. patent application Ser. No. 09/434,974, filed on Nov. 5, 1999; each of which is hereby incorporated by reference in its entirety, including all tables, figures, and claims.
Accordingly, there is still a need in the art for apparatus and methodology which improve the administration of intermittent medication infusion therapy. The present invention satisfies these and other needs in the art.
The present invention overcomes many of the problems in the art by providing medication delivery containers designed to deliver fluids in a predetermined sequence, and methods for their construction and use. The containers described herein comprise a plurality of non-fluidly connected chambers that are integral to the container. The phrase “integral container” is defined hereinafter. The integral containers of the present invention may be configured to deliver a volume of each fluid in a selected infusion regimen in a predetermined sequence, duration, volume, and/or interval from these chambers. Alternatively, a container may be part of a larger device that provides additional hardware to perform the desired sequential delivery. The container provides improved infusion therapy administration by reducing opportunities for error, infection, adverse drug interactions, or other complications.
In various embodiments, fluids may be delivered from the integral containers of the present invention by application of positive pressure to one or more non-fluidly connected chambers, by application of negative pressure to one or more non-fluidly connected chambers, by gravity feed from one or more non-fluidly connected chambers, or by some combination of these delivery modes.
In certain preferred embodiments, positive pressure is created by compression of a chamber within the integral containers of the present invention, thus expressing fluid from that chamber through a port in the chamber wall. In these embodiments, the chamber is preferably flexible, and positive pressure may be generated in a plurality of chambers in a predetermined sequence, for example, by a roller pump compressing each chamber at the proper time, thereby delivering the fluids from the integral container in the desired sequence. Other means of generating positive pressure, such as injection of a gas or other fluid into a chamber to express some or all of the contents of that chamber, are also contemplated by the present invention.
In other preferred embodiments, negative pressure is created by application of a pump to an output port or conduit fluidly connected to a chamber within the integral containers of the present invention, thereby extracting fluid from that chamber through a port in the chamber wall.
Controlled fluid flow from the integral containers of the present invention may be obtained using a variety of methodologies. For example, force (either positive, negative, or gravity) may be used to deliver fluid from one or more chambers within the integral container in sequence. This may be achieved, e.g., by allowing a single pump to access a plurality of chambers in sequence; or by having multiple pumps, each of which may be connected to a corresponding chamber, and actuating the pumps in sequence. Alternatively, valves that control flow from each chamber may be actuated (manually, electronically, pneumatically, etc.) in sequence, thereby permitting flow to occur from a given chamber. The skilled artisan will understand that such control means need not be selected individually, and that a given device might include control at both the pump and valve level for example.
In certain preferred embodiments, fluid flows from a plurality of chambers to a manifold that receives flow from several input conduits, and that generates flow through a single exit conduit. The functionality of a manifold may also be served by other flow structures, such as a set of multi-path (e.g., three-way) valves or connections placed in series. In such embodiments, each multi-path connection might receive flow from a previous chamber or valve, as well as from a new chamber, with a resulting flow to a single exit conduit or port.
In certain preferred embodiments, the integral containers of the present invention may be constructed as a flexible bag having a plurality of non-fluidly connected chambers. Such containers may also include structures for minimizing pressure drop which may be associated with a chamber upon the application of pressure to the respective chamber, thereby allowing relatively unimpeded fluid flow from the respective chamber to an associated conduit during the application of pressure to the chamber.
While the present invention relates in part to containers that may be provided to a medical provider (e.g., physician or pharmacist) or other user in an unfilled state for subsequent filling in a manner deemed appropriate by that user, in various aspects the invention also relates to containers in which one or more, and preferably all, chambers within the container are provided to a user pre-filled with fluids to be delivered in a predetermined sequence.
In accordance with additional embodiments of the present invention, there are provided medication delivery systems comprising a bag having at least one chamber containing a medication fluid and a manifold, and a pump having an activating mechanism configured to activate the chamber(s) to dispense the fluid from the bag.
In accordance with further embodiments of the present invention, there are provided medication delivery containers comprising a bag having a plurality of chambers, and a manifold assembly coupled to the plurality of chambers for delivering medications out of the chambers.
In accordance with still further embodiments of the present invention, there are provided fluid delivery containers comprising a bag having at least one fluid chamber and structure for minimizing pressure drop between the chamber and an associated conduit upon the application of pressure to the chamber.
In accordance with additional embodiments of the present invention, there are provided fluid delivery containers for the automated infusion of a plurality of pharmacological agents, wherein the container comprises a plurality of chambers each configured with a respective geometry for controlling the administration of the plurality of pharmacological agents. The container additionally comprises a manifold assembly having a plurality of valves for controlling the administration of the plurality of pharmacological agents to an infusion site. Each chamber of the fluid delivery container has a configuration that controls the volume of each pharmacological agent administered and the regimen with which said pharmacological agent is administered.
In accordance with further embodiments of the present invention, there are provided fluid delivery pumps comprising a structure for sequentially applying constant force to compress a flexible fluid container from a first end towards a second end of said container; and an energy absorption device coupled to the structure for sequentially applying constant force for limiting the maximum rate at which said structure compresses the fluid container.
In accordance with still further embodiments of the present invention, there are provided charging disks comprising first and second spring-loaded pawls, the first pawl having a shaft that engages a slot in the second pawl, the shaft and slot being configured such that the second pawl is depressed when the first pawl is depressed, but the first pawl is not depressed when the second pawl is depressed.
In accordance with additional embodiments of the present invention, there are provided methods for filling an invention fluid delivery bag having a plurality of chambers. In the invention methods, a first predetermined fluid volume is measured; at least one chamber of the bag is constrained to a second predetermined volume; and the plurality of chambers are filled through a bulk fill port with the first predetermined volume of fluid such that a constrained chamber is filled with the second predetermined volume of fluid. A remaining chamber is then filled with the first predetermined volume of fluid minus the fluid of the constrained chamber.
In accordance with further embodiments of the present invention, there are provided methods for delivering medication fluids. Invention fluid delivery methods comprise compressing a bag having at least one chamber containing a medication fluid using a constant force spring to generate a predetermined pressure in the chamber based on the chamber's configuration and delivering the medication fluid from the bag at the predetermined pressure to an infusion site using a micro-bore tubing having a length and an inner diameter that establishes a predetermined flow rate.
In accordance with still further embodiments of the present invention, there are provided methods for charging an infusion pump having a constant force spring coupled to first and second cover doors by a charging assembly. The invention charging method comprises opening the first cover door to partially charge the constant force spring; and opening the second cover door to fully charge the constant force spring.
The foregoing summary of the invention is non-limiting, and other features of the invention will be apparent to those of skill in the art from the following figures, detailed description of the invention, and the claims.
In accordance with the present invention, there are provided medication delivery containers designed to deliver fluids in a predetermined sequence, and methods for the construction and use thereof. The containers described herein comprise a plurality of non-fluidly connected chambers that are integral to the container. The containers may be configured to deliver a volume of each fluid of an infusion therapy regimen in a predetermined sequence, duration, volume and/or interval from these chambers; alternatively, a container may be part of a larger device that provides the necessary hardware to perform such sequential delivery.
Fluids may be delivered from the non-fluidly connected chambers by gravity, by the generation of positive pressure within a chamber, by the generation of negative pressure within a chamber, or by a combination of the above. Control of this fluid flow may be obtained by careful configuration of the geometry of the chambers and conduits within the container, by controlled pump actuation, by controlled valve actuation, or by a combination of such control means.
The phrase “integral container” as used herein refers to a container comprising a plurality of non-fluidly connected chambers, in which removal of a chamber would result in a loss of integrity of the entire container. For example, a preferred embodiment of the integral containers of the present invention is a flexible bag in which the chamber walls are formed from the container walls. Thus, in these embodiments, removal of a chamber would also entail removal of a portion of the container itself. By way of contrast, U.S. Pat. No. 5,658,271 discloses a device in which individual containers are placed in a housing. In this non-integral container, each bag may be replaced without disrupting the integrity of the larger housing.
The phrase “non-fluidly connected” as used herein in reference to chambers within an integral container refers to an absence of fluid connections between the chambers themselves that would allow fluids to intermingle before flowing from one of the chambers to a patient. Such chambers may intermingle fluids at a point downstream from the chambers, such as at a manifold, but the chambers from which the fluids originate would still be non-fluidly connected. Additionally, such chambers may be connected, such as via a conduit, but so long as no fluids to be delivered from each chamber to a patient intermingle before their delivery out of the chambers, the chambers would still be said to be non-fluidly connected.
The phrase “substantially non-fluidly connected” as used herein in reference to chambers within an integral container refers to chambers in which fluid connections between the chambers allow less than 10% of fluids from one chamber to intermingle with the fluids in another chamber before flowing from one of the chambers to a patient. More preferably, chambers that are substantially non-fluidly connected allow less than 5%, and most preferably less than 1%, of fluids from one chamber to intermingle with the fluids in another chamber before flowing from one of the chambers to a patient.
The phrase “fluidly connected” as used herein in reference to chambers within an integral container refers to chambers in which fluid connections between the chambers allow 10% or more of the fluids from one chamber to intermingle with the fluids in another chamber before flowing from one of the chambers to a patient. Such fluidly connected chambers may originate as non-fluidly connected or substantially non-fluidly connected chambers, but be rendered fluidly connected prior to delivery of fluids from one of the chambers. For example, a frangible seal between chambers may be breached, allowing the fluids in the chambers to intermingle. Preferably, fluidly connected chambers allow 50% or more, and most preferably 90% or more, of the fluids from one chamber to intermingle with the fluids in another chamber before flowing from one of the chambers to a patient.
The phrase “predetermined sequence” refers to delivery of a plurality of fluids from an integral container to a patient according to a treatment regimen desired by a clinician. Such a predetermined sequence may involve delivery of fluids discretely, i.e., a first fluid is completely delivered before a second fluid is delivered, or in an overlapping manner, i.e., all or a portion of a second fluid is delivered at the same time that a first fluid is delivered. The predetermined sequence may include both controlled timing of delivery, volume of delivery, and/or order of delivery.
The phrase “positive pressure” as used herein refers to the application of force to a fluid or chamber resulting in fluid pressure within a chamber that is greater than the force of gravity; that is, a pressure greater than that created by the hydrostatic head pressure within the chamber. Such positive pressures may be generated by a pump or other means of pushing on a fluid or chamber. Suitable positive pressures are any pressure that the chamber may withstand without breaching the integrity of the chamber (e.g., bursting). Preferred pressures are between 100 psi and 0.1 psi, more preferably between 40 psi and 0.5 psi, and most preferably between 10 psi and 1 psi.
Similarly, the phrase “negative pressure” refers to the application of force to a chamber resulting in fluid pressure within a chamber or conduit that is less than the force of gravity. Such pressures are often referred to as “suction pressures” or “vacuum pressures.” Negative pressures may be generated by a pump or other means of pulling fluid from chamber. Suitable negative pressures are any pressure that the chamber, or any conduit between the chamber and the source of the negative pressure, may withstand without collapsing. Preferred pressures are between 5 psi and 0.1 psi, more preferably between 3 psi and 0.25 psi, and most preferably between 1 psi and 0.5 psi.
The phrase “gravity feed” refers to the use of only gravitational forces to deliver a fluid. The skilled artisan will understand that gravity feed methods may be used to differentially deliver fluids from two or more chambers, e.g., by varying the head height of each chamber.
The term “manifold” as used herein refers to a discrete structure that receives fluid flow from a plurality of input ports, and allows a resulting flow through a reduced number of output ports. In preferred embodiments, a manifold receives flow from at least three input ports, and allows a resulting flow through a single output port. In particularly preferred embodiments, a manifold receives flow from each non-fluidly connected chamber through a corresponding number of input ports, and allows a resulting flow through a single output port. Flow from one or more input ports to an output port in a manifold may be passive, or may be controlled by one or more valves.
The term “upstream” as used herein refers to any point in a flow path that is closer to the source of the flow path than to the destination of the flow path. An upstream point may also be referred to as a “proximal” location. Similarly, “downstream” refers to any point in a flow path that is closer to the destination of the flow path than to the source of the flow path. A downstream point may also be referred to as a “distal” location.
The phrase “control device” as used herein refers to any device that can reversibly modulate flow down a particular flow path. Control devices of the present invention may be active or passive, as described below, or may serve both an active or passive control function.
The term “valve” as used herein refers to any device within a flow path that starts, stops, or modulates flow through the flow path. Suitable valve configurations are well known to those of skill in the art, including umbrella valves, disc valves, poppet valves, duckbill valves, ball valves, and flapper valves, shuttle valves, gate valves, slit membrane, check valves, and the like.
The phrase “active control device” as used herein refers to any device that can reversibly modulate flow down a particular flow path, and which is not actuated by only the flow or pressure within the flow path itself. An active control device can be one intended to be operated manually, such as a manual valve, stopcock or a pinch clamp, or can be a valve or stopcock that is operated pneumatically, hydraulically, mechanically, by vacuum, or electrically for example. Active control devices may be located within the integral container itself, or along a flow path (e.g., within or along a conduit) between a chamber and the patient. In preferred embodiments, an active control device can reversibly halt all flow down a particular flow path.
The phrase “passive control device” as used herein refers to any device that can reversibly modulate flow down a particular flow path, and which is actuated by only the flow or pressure within the flow path itself. A passive control device can be a valve or stopcock that is opened or closed by altering the flow rate or pressure at the passive control device location. Passive control devices may also be located within the integral container itself, or along a flow path (e.g., within or along a conduit) between a chamber and the patient. In preferred embodiments, a passive control device can reversibly halt all flow down a particular flow path.
As discussed herein, an integral container can be formed from any material from which a container comprising a plurality of integral, non-fluidly connected chambers may be fabricated. As will be appreciated by those of skill in the art, any suitable biocompatible material may be employed in the construction of the integral container, however, it is presently preferred that at least one side of the integral container be transparent to facilitate viewing of the contents. It is also presently preferred that the container be formed of two sheets of flexible material (athough three, four, or more sheets may also be used). For example, the flexible sheets may be ethyl vinyl acetate (EVA), polyvinyl chloride (PVC), polyolefin, or other suitable material. In one embodiment, the first sheet of flexible material has a relatively smooth inner surface and the second sheet of plastic has a texture, such as a taffeta texture (e.g., a diamond taffeta), ribs, or the like, embossed on its inner surface. Alternatively, both sheets may have a patterned inner surface, e.g., a raised diamond taffeta. The sheets are joined together around the perimeter of the container by any means suitable for forming an air and fluid-tight seal that can withstand the pressure generated by the pump apparatus. Fluid-tight seals are also formed between the individual chambers, and should have the same minimum pressure tolerances as the perimeter seals. Thus, the sheets are bonded together to create the patterns for the chambers, conduits, and ports. The materials may be bonded in a variety of ways, e.g., by a radio frequency (rf) seal, a sonication seal, a heat seal, adhesive, or the like, to form an air and fluid-tight seal as described herein.
Each chamber of the integral container preferably has one or more associated conduits. The conduits provide a pathway for fluid to enter and/or exit each chamber. The conduits can be integrally formed during construction of the container, for example, by leaving channels unbonded when the two sheets are fused together to form the container. Optionally, additional internal structure (e.g., rigid or semi-rigid tubing, or the like) may be provided to facilitate fluid flow to and from each chamber.
In an integral container in which fluid is to be delivered by compression of one or more chambers, it is preferred that the conduit through which fluid exits such a chamber lies outside of the compression region (i.e., the region to which pressure is directly applied by contact with a pressure applying structure in the pump apparatus). In this manner, mixing of residual medications in the conduits with subsequently administered medications from other chambers can be minimized. Alternatively, the conduits may lie within the compression region, particularly if mixing is not a concern.
If the conduits are constructed by leaving unbonded channels in the integral container, the conduit will have a generally flat shape but enlarges to have a more tubular shape upon the application of pressure to the corresponding chamber. The shape of the conduit depends on the strength of the materials used to construct the integral container and the pressure of the fluid therein. Specifically, less flexible material (e.g., more rigid or thicker materials) may be more difficult to flex and thus require greater pressure for enlarging the conduit. Advantageously, the textured inner surface of at least one side of the integral container provides flow channels that allow liquid pressure to act along the length of the conduit to assist in opening the conduit upon the application of pressure to the respective chamber. Otherwise, if both inner sides of the container are smooth, surface tension may hold them together and a greater amount of pressure may be required to open the conduits and initiate flow.
The skilled artisan will also understand that a variety of methods may be provided to provide sequential flow control from the various non-fluidly connected chambers within an integral container. One method of providing such control is to configure the integral container itself to provide such sequential flow. Methods and compositions for providing such integral containers are described in U.S. Pat. No. 6,146,360; U.S. Pat. No. 6,074,366; U.S. Pat. No. 6,669,668; U.S. Pat. No. 6,726,555; U.S. patent application Ser. No. 09/713,521, each of which is incorporated by reference herein in its entirety, including all tables, figures, and claims.
In one embodiment of the present invention, the chambers and corresponding conduits from each chamber are arranged in the integral container so that when pressure is applied sequentially from one end of the integral container to the opposite end, individual chambers are sequentially activated. It is presently preferred that the pressure be applied evenly. Even, sequential application of pressure can be accomplished by employing a constant force spring, a roller attached to a constant force spring, a motor-driven roller, or the like.
Additionally, sequential flow control from the various non-fluidly connected chambers within an integral container can be provided by inclusion of one or more pumps, or other means for generating positive or negative pressures, along one or more flow paths between the integral container and the patient. For example, in embodiments where positive pressure is generated, each chamber may be connected to an independently controllable source of pressurization, such as a compressed gas source or a pressurization pump. Similarly, an independently controllable source of negative pressure (e.g., individual pumps or one or more multichannel pumps) can be placed along the flow path from the non-fluidly connected chambers. Suitable pumps are well known in the art. See, e.g., U.S. Pat. Nos. 6,669,668; 6,270,478; 6,213,738; 5,743,878; 5,665,070; 5,522,798; and 5,171,301, each of which is hereby incorporated by reference in its entirety, including all tables, figures, and claims. Pumps useful in the present invention can be simple pumps which are either “on” or “off,” or may comprise a programmable controller (referred to herein as a “smart pump”) that may be integral to the pump or exist as a separate controller unit interfaced in a wired (e.g., via hard wiring, a serial port (such as a standard RS-232 port), a USB port, a “fire wire” port, etc.) or wireless fashion (e.g., connected via an infrared connection, a radio frequency connection, a “bluetooth” connection, etc.).
Suitable programmable pumps are available that permit the operator to generate a pre-defined or user-defined pumping profile. Such pumps may be used to define a volume and rate for fluid flow from each chamber in the integral container. For example, in an integral container having 4 chambers of 10 mL, 100 mL, 10 mL, and 5 mL, the pump could be programmed to run at 1000 ml/hr for the volume of chamber 1, then 200 ml/hr for the volume of chamber 2, then 1000 ml/hr for the volume of Chamber 3, and finally 1000 ml/hr for the volume of chamber 4. Alternatively, four separate pumps (or the individual pumping heads of a 4-channel pump) could be individually or collectively programmed to perform this profile.
Similarly, a pump could be configured to determine a suitable rate, limited by a maximum rate threshold and maximum pressure threshold. In this embodiment, the pump would ramp up the pumping rate until some pre-set maximum rate or pressure was reached. Alternatively, a pump could deliver a “pulsatile” rate, alternating between a preset minimum and a preset or pump-determined maximum rate. These examples are not limiting, and additional pumping profiles could be readily determined by the skilled artisan.
As an alternative to, or in conjunction with one or more pumps for providing sequential flow, one or more active control devices can also be located along one or more flow paths between the integral container and the patient. In these embodiments, controlled actuation of the active control device(s) can provide the required flow control of fluids from the integral container. An active control device can be as simple as a manual pinch valve, which the operator will open as required by the sequential delivery method, or can be a more complicated electrically or pneumatically operated valve. In the latter case, the active control device can be integrally controlled, or can be connected to a controller unit in a wired fashion (e.g., via hard wiring, a serial port (such as a standard RS-232 port), a USB port, a “fire wire” port, etc.) or in a wireless fashion (e.g., connected via an infrared connection, a radio frequency connection, a “bluetooth” connection, etc.).
The various flow paths (ports, conduits, etc.) from each non-fluidly connected chamber to the patient will preferably merge at some point into a single conduit through which fluids are infused to the patient. Numerous methods are well known to the skilled artisan to merge such flow paths. These can include simple connections, such as 3-way (or 4-way, or 5-way, etc.) connectors in which two (or three, or four, etc.) input paths flow out through a single output path. In more complex arrangements, the placement of valves (arranged in parallel or series, or a combination of the two) on each flow path, and/or one or more manifold units can provide the required merger of flow paths. Exemplary manifolds are described hereinafter. Other manifolds are disclosed in, e.g., U.S. Pat. Nos. 5,374,248; 5,217,432; and 5,431,185, each of which is hereby incorporated by reference in its entirety, including all tables, figures, and claims. Manifolds may additionally contain one or more control devices, either active, passive, or a combination thereof, to control the flow of fluid through the manifold.
In embodiments where negative pressure is used to withdraw fluid from the chambers of an integral container, the skilled artisan will understand that the overall configuration of the device may depend on the position of the pump relative to the merger of the various flow paths. For example, a plurality of pumps (or a multichannel pump) corresponding to a plurality of flow paths flowing into a manifold may be placed upstream from the manifold, thereby providing a means to provide negative pressure along each flow path. Alternatively, a single pump placed downstream of a manifold may be used to provide negative pressure along each flow path that flows into the manifold.
It may be desirable to include an accumulator chamber, either in the integral container itself or on one or more flow paths leading from the container. Some positive displacement pumps have a relatively high flow rate when the displacement chamber in the pump is being refilled. If the refill flow rate is faster than the gravity flow rate from the multi-chambered container, fluid could potentially be pulled out of more than one chamber. To avoid this, an accumulator chamber that is preferably flexible, is placed in series with the pump. Fluid may be permitted to flow (e.g., by gravity) into the accumulator until it is full, and when the downstream pump pulls fluid, it will pull only from the accumulator. Flow out of the appropriate chamber will then re-fill the accumulator for the next fill stroke of the down stream pump.
It may also be desirable to mix the contents of two or more chambers immediately prior to administration to form a single chamber that is not fluidly connected to other chambers within the integral container. Accordingly, in another embodiment of the present invention, frangible seals between two or more adjacent chambers may be formed. In this manner, upon application of pressure sufficient to rupture the seal, the contents of selected adjacent chambers will be mixed. The chambers may be side by side, parallel or perpendicular relative to one axis of the integral container.
Chambers may also be configured to have a “blow down” period between activation of one chamber and activation of the next chamber during an infusion sequence to prevent mixing of medications during the infusion. As described in greater detail below, this can be accomplished, for example, by providing a space between adjacent chambers, or the like.
In those embodiments where the integral container is of a flexible configuration (e.g., a bag) it has been observed that there can be a pressure drop between a chamber and its corresponding conduit when pressure is applied to the contents of the integral container. This is largely due to the formation of kinks in the flexible material when pressure is applied to the contents of the integral container. The region of primary concern is the interface between the chamber and its corresponding conduit. Thus in one embodiment of the present invention, structure is provided to alleviate pressure drop between each chamber and its corresponding conduit. This can be achieved by one or more of several methods, including quilting of the chamber, incorporation into the chamber of internal structures (e.g., a stent, tubing, conduit bead(s), solid filament, or the like), employing external structures (e.g., a source of pressure on the container, such as a protruding member of the pump apparatus, or the like), and the like. Additionally, the width, angle and/or taper of the conduit, the thickness of the chamber or conduit, and/or the type of material forming the chamber or conduit may be selected to minimize flow resistance.
As used herein, “quilting” means forming a structure in the interior of the chamber wherein the bottom and top sides of the integral container are connected, preferably by fusing them together. It is presently preferred that quilting be employed to manage pressure drop, as the desired connection between first and second sides of the integral container can be accomplished by the same methods used to form the perimeter seal of the container. Quilting may be at any region of the chamber that provides a substantially reduced or eliminated pressure drop between the chamber and its corresponding conduit. It is presently preferred that the quilting be in the region of the chamber that is proximal to the conduit. In this region of the chamber, any one of a number of quilt shapes may be employed, including a T dot configuration, 55a and 56a, as shown in
Other features suitable for minimizing flow resistance (i.e., pressure drop) caused by kinks include thermoforming of the conduit, introduction of an internal conduit bead in the region where the conduit joins the chamber, coining, or the like. Thermoforming involves heating the integral container materials in the region of the exit and associated conduit until the materials are softened slightly. Air pressure is applied to the chamber to open (or inflate) the exit and the conduit. The material is allowed to cool such that the exit and conduit retain a slightly circular opening or cross-section after the pressure is removed. In certain embodiments, a mold may be used to constrain the shape of the blow-molded conduit. For employing internal conduit bead(s), a portion of the bag adjacent the exit to the conduit is stamped with an offset bonding pattern or shim to provide a three-dimensional structure in the region of the exit. (See, e.g., structure 59,
It is contemplated that each conduit will have an associated port where, at a minimum, fluids exit the integral container. These conduits may serve the dual purpose of providing a channel for both the introduction of fluids into the chamber(s) and exit of fluids from the chambers. The container may have one or more ports for introduction of fluids into one or more of the individual chambers of the container. In one embodiment, these ports have associated conduits, separate from the exit conduits. The ports are configured to allow regulated, sterile introduction of fluids. This can be accomplished by fitting the ports with injection ports, or the like.
Containers may be filled in a variety of ways by suitable personnel, e.g., by a pharmacist. Similarly, the container may be provided to a pharmacist in a variety of states. For example, the bag may be provided filled, or empty for subsequent sterilization and filling at the pharmacy. It is presently preferred that the multi-chambered bag is provided sterile and is then filled at the pharmacy. The bag may be appropriately filled using standard pharmaceutical admixture procedures and equipment. Each chamber may be manually filled using injection ports or the like. Alternatively each chamber can be filled by introduction of fluids into a common filling conduit that branches off to the respective fill or dual purpose fill/exit conduit associated with each chamber. Once the bag is prepared, it is labeled and sent from the pharmacy to the end user.
As discussed above, the fluid delivery devices of the present invention can comprise a manifold to regulate delivery of fluids from the ports on the integral container corresponding to each chamber to an administration tube set (“administration set”). Such a manifold may optionally provide a structure for filling one or more chambers. As used herein, “container port of the conduit” and “container port” refer to the terminal portion of each conduit leading to/from a chamber in the integral container. The container ports may have an adapter affixed thereto for mating the ports with the manifold, or the manifold may be attached directly to the container ports. The manifold can be any structure that is attachable to the bag ports (or adapters) in a fluid-tight manner while providing a common outlet for all bag ports to the administration set.
In describing the manifold, reference will be made to the “integral container side” of the manifold (where the manifold attaches to the integral container ports) and the “infusion side” (where the manifold attaches to the administration set). Further reference will be made to chamber ports of the manifold, where the manifold attaches to and is in fluid communication with the chamber ports. Additional reference will be made to an output port of the manifold, where the manifold attaches to and is in fluid communication with the administration set. Although optional, it is presently preferred that the manifold also have a bulk fill port, where the manifold can be attached to, and be in fluid communication with, a source of fluids for introduction into the integral container.
Manifolds contemplated for use in the practice of the present invention will have manifold conduits for directing fluid from chamber ports to the output port for exit to the administration set, and from the bulk fill port, when employed, to the chamber ports. These manifold conduits can be isolated from one another in a fluid-tight manner and can comprise internal chambers connecting the desired portions of the manifold, or they may comprise internally mounted tubing connecting the appropriate portions of the manifold, combinations thereof, or the like.
In order to regulate the flow of fluid through the manifold and to prevent backflow from the output port to the chamber ports, it is presently preferred that the manifold have check valves therein. Check valves can be configured in a variety of manners to regulate fluid flow as desired; all such configurations are contemplated as being within the scope of the present invention. In one embodiment of the present invention, fluid flow is regulated so that fluid exiting the container and entering the manifold through the chamber ports can only exit the manifold through the output port without returning to the bag by way of any other chamber port. This is accomplished by interposing a first check valve in a first conduit between each chamber port and the output port. The check valve only allows fluid to flow from the bag side of the manifold towards the infusion side where the output port is located.
It is important to note that some or all of the chambers may be individually filled by way of optional separate fill ports on the integral container and/or by way of the optional bulk fill port of the manifold. In an embodiment of the present invention, when a bulk fill port is to be used, fluid flow in the manifold is further regulated so that fluid introduced through the bulk fill port can access one or more of the chamber ports for filling of chambers in the integral container. Accordingly, chamber ports to be used for both filling and dispensing fluids will have two manifold conduits associated therewith: a first manifold conduit, as described above, for directing fluids from the chamber port(s) to the output port; and a second manifold conduit branching off of the first at a point between each chamber port and the first check valve. In this embodiment, a second check valve is located on each second manifold conduit between the chamber port and the bulk fill port. The second check valve only allows fluid to flow from the bulk fill port towards the chamber port. A schematic of one example of this embodiment is provided in
Any type of check valve can be employed in the practice of the present invention, including ball check valves, umbrella check valves, and the like. In a presently preferred embodiment of the present invention, an umbrella check valve is employed. Umbrella valves are inexpensive, simple in their operation and easy to install. Because umbrella valves are held in place by friction, it is presently preferred that the interior of the manifold be configured so that, upon assembly of the manifold, the umbrella valves are held securely in place by the internal structure of the manifold. This can be accomplished simply by having a structure that contacts the center of the umbrella portion (i.e., the dome of the umbrella) to bias the valve towards its associated passageway. In this manner, the force of liquid flowing past the valve will open but not unseat the valve.
The ports, valves and conduits of the manifold may be configured in any manner that permits the desired flow of fluid through the manifold. It is presently preferred that the conduits and output port be configured so that fluid exiting each sequentially activated bag chamber flows through its associated first check valve and then past all conduits leading from previously emptied bag chambers, before the output port is encountered. In this manner, residual fluid output from each bag chamber is pushed through the manifold and out through the output port by fluid from subsequently emptied bag chambers.
In order for the fluid flow to be further regulated (e.g., to prevent unintentional fluid flow from the bag through to the output port), it is desirable that the check valves be controllable as to when flow is permitted therethrough. This can be accomplished in a number of ways, depending on the type of check valve employed. For example, a valve can be employed having a threshold operating pressure (i.e., a cracking pressure) that opens the valve. The cracking pressure of the valve may be any pressure suitable for the intended application. Suitable cracking pressures should be no higher than the pressure generated by the pump apparatus, yet high enough to prevent unintentional flow through the manifold. Preferred cracking pressures can be in the range of about 0.25 lbs per square inch up to about 2 lbs per square inch. It is more preferred that the cracking pressures be in the range of about 0.50 lbs per square inch up to about 1 lbs per square inch. In a most preferred embodiment, the cracking pressure is about 0.75 lbs per square inch. The cracking pressures should be consistent in a given direction of fluid flow. Thus, the check valves associated with the chamber ports and the output port can have one cracking pressure while the check valve(s) associated with the bulk fill port has a different cracking pressure. Due to economies of scale, it is presently preferred that the valve types and cracking pressures be consistent throughout the manifold.
An administration set is optionally provided in one embodiment of the present invention. The administration set comprises a length of medical grade tubing, such as a micro-bore tube, or the like, with structures at each end: at one end (proximal end) for connecting the tubing to the output port of the manifold and at the opposite (distal) end for connection to a standard intravenous-type needle. Standard luer connectors, needleless connectors, or the like may be used in the practice of the present invention.
The administration set may be further configured to regulate the rate of fluid administration to the patient. It is necessary to know the pressure generated by the pump/manifold combination in order to calibrate the delivery rate of the administration set. The devices of the present invention may be configured so that gravity or the pump apparatus generates predictable fluid pressures based on the volume of solution in each chamber. Using the predictable fluid pressures, the flow rate from the integral container may be selectable using administration sets having predetermined tubing lengths and inner diameters. The flow rate through the administration set is selected by varying the microbore tubing's inner diameter and length. The relationship is approximated by Poiseulle's equation:
Error! Objects cannot be created from editing field codes. Equation 1
where Q is the flow rate, Δp is the pressure drop across a flow controlling orifice, D is the inside diameter of the orifice, μ is the dynamic viscosity of the fluid and L is the length of the orifice. Thus, any structures included in the administration set will effect the flow rate in a predictable and calculable manner. Structures contemplated for optional incorporation into the administration set include particulate filters, air elimination filters, fluid flow restrictors, flow indicators, drop counters, drip chambers, pressure indicators, and the like. The administration set may further comprise a clamp, or the like, for stopping fluid flow, as desired.
In another embodiment of the present invention there is provided a restrictor set for attachment to the distal end of the administration set. In this manner, the rate of fluid flow can be altered with the simple addition of a restrictor set, rather than by re-engineering the administration set. Of course, the maximum fluid flow rate will be determined by the configuration of the administration set, with fine-tuning to slower rates provided by the restrictor set. Restrictor sets may be located at a variety of positions in a flow path, such as in a chamber, in a conduit, in a manifold, etc.
The integral containers of the present invention may be provided to a user (e.g., a physician or pharmacist) in an unfilled state for subsequent filling with fluids deemed appropriate by the user; that is, the bags may be configured by a clinician or pharmacist to deliver a regimen of fluids deemed advantageous to a particular patient. Alternatively, one or more, and preferably all, chambers within the integral container may be provided to the user pre-filled with fluids to be delivered in a predetermined sequence.
The integral containers and methods described herein can provide a methodology by which a course of therapy involving multiple fluids can be preconfigured and stored, e.g., in a hospital or pharmacy, for “off the shelf” delivery to the clinician or patient. Additionally, the integral containers and methods described herein allow for the careful preselection of fluids, to ensure that none of the fluids to be delivered to a patient from the integral container will interact adversely with other fluids to be delivered from the same integral container. The present invention contemplates that any compounds or groups of compounds that may be delivered in a fluid format may be delivered to a patient in accordance with the foregoing description. An exemplary list of suitable compounds is provided below.
This list is not intended to be limiting. Additional agents contemplated for delivery employing the devices and methods described herein include agents useful for the treatment of diabetes (e.g., activin, glucagon, insulin, somatostatin, proinsulin, amylin, and the like), carcinomas (e.g., taxol, interleukin-1, interleukin-2 (especially useful for treatment of renal carcinoma), and the like, as well as leuprolide acetate, LHRH analogs (such as nafarelin acetate), and the like, which are especially useful for the treatment of prostatic carcinoma), endometriosis (e.g., LHRH analogs), uterine contraction (e.g., oxytocin), diuresis (e.g., vasopressin), cystic fibrosis (e.g., Dnase (i.e., deoxyribonuclease), SLPI, and the like), neutropenia (e.g., GCSF), lung cancer (e.g., beta 1-interferon), respiratory disorders (e.g., superoxide dismutase), RDS (e.g., surfactants, optionally including apoproteins), and the like.
Presently preferred indications which can be treated employing the device and methods described herein include diabetes, carcinomas (e.g., prostatic carcinomas), bone disease (via calcium regulation), cystic fibrosis and breathing disorders (employing bronchodilators), and the like.
In accordance with the present invention, there are also provided medication delivery containers that are configured to administer an infusion therapy upon activation by a pump mechanism. The container is preferably further configured to interface with a pump apparatus in a manner that securely maintains the container in position during pumping.
The invention container comprises a multi-chamber bag wherein the chambers, each configured to deliver predetermined amounts of liquid medication at a predetermined rate and pressure, and each placed in relation to the others in a manner that determines the order in which the fluids contained therein, are administered.
Each chamber has an associated exit conduit whereby fluid can exit each chamber for administration to a patient. Thus, for example, a container might have four separate chambers, each sized to hold a different amount of fluid. The container can be filled so that each chamber has a different medication therein. If the four chambers are arranged sequentially in the bag from one end of the bag to the other, and each chamber is activated sequentially from one end of the bag to the other, then fluid will be driven out of the first chamber, and then the second, and so on until each chamber has been emptied.
Each chamber has one or more associated conduits. The conduits provide a pathway for fluid to enter and/or exit each chamber. The conduits can be integrally formed during construction of the container, for example, by leaving channels unbonded when two flexible sheets are fused together to form the container. Optionally, additional internal structure (e.g., rigid or semi-rigid tubing, or the like) may be provided to facilitate fluid flow to and from each chamber. It is presently preferred that the conduits through which medication exits the chambers lie outside of the compression region (i.e., the region to which pressure is directly applied by contact with a pressure applying structure in the pump apparatus). In this manner, mixing of residual medications in the conduits with subsequently administered medications from other chambers is minimized. Alternatively, the conduits may lie within the compression region, particularly if mixing is not a concern.
Because the container is to be subject to the sequential application of pressure, it is desirable for the container to be anchored inside the pump apparatus in a manner that prevents the pressure application device from merely moving the container ahead of it as the pressure is applied from one end of the bag to the other. Accordingly, it is presently preferred that the container be anchorable to the pump apparatus. This can be accomplished in a variety of ways, including the use of fasteners secured to the bag that will mate with counterpart fasteners in the pump apparatus. Such fasteners include hook and loop fasteners, snaps, buttons, zippers, and the like. In a presently preferred embodiment, the container is anchored by forming holes in a non-fluid containing portion of the bag, and mating these holes with corresponding protrusions such as pins, or the like, in the pump housing. These anchoring structures can serve the dual purpose of securing the bag and positioning it properly in the pump apparatus. This latter purpose can be accomplished by orienting the attachment structures so that there is only one orientation with which the bag can be positioned in the pump apparatus.
With reference to
The multi-chamber bag, as shown in
The multi-chamber bag 12 is preferably formed of two flexible sheets 50 and 52, of material and has a generally rectangular flat shape. The flexible sheets may be ethyl vinyl acetate (EVA), polyvinyl chloride (PVC), polyolefin or other suitable material. One sheet may have a relatively smooth inner surface and the other sheet may have a taffeta texture (or similar pattern that is not smooth, such as ribs) embossed on its inner surface. Alternatively, both sheets may have an inner surface that is not smooth. The sheets are bonded together to create the patterns for the chambers, conduits, and ports. The materials may be bonded by suitable means, e.g., by a radio frequency (rf seal, sonication, by heat seal, adhesive, or the like, to form an air and fluid tight seal between the chambers and the conduits. When filled with medication fluids, the chambers bulge creating a “pillow-like” shape (
The first chamber 18 is furthest from the port side 48 of the bag and may contain a first medication fluid of an infusion therapy sequence. The first chamber is coupled to a first bag port 26 by a first conduit 36. The first chamber is filled with fluid through the first bag port.
The spacings 60, 62 and 64 between the chambers advantageously provides a “blow-down” period during an infusion sequence to prevent mixing of medications during the infusion. The spacing 62 between the second chamber 20 and the third chamber 22 is sized based on the time needed for the chamber and conduit to “blow down”, or flow until the residual pressure is below the cracking pressure of the associated check valves in the manifold. The area of the spacing 62 may be sealed only around the perimeter with no bond between completion of the sheets in the central spacing area to provide additional kink and flex absorbing characteristics to the bag. This spacing 62 is configured to allow a sufficient time period between completion of the infusion of the medication in the second chamber and the beginning of the infusion of medication in the third chamber so as to minimize or prevent mixing of the medication in the second chamber with the medication in the third chamber. This time period is sufficient to allow the material spring strength of the flexible sheets, 50 and 52, that form the conduits to pull the respective conduit 38 flat to expel residual fluid from the conduit. The time required will, of course, vary with the size of the chamber, the rate of infusion, and the like. Note that the spacing 60 between the first chamber 18 and the second chamber is effectively as large as the spacing 62 because a significant portion of the second chamber must be compressed before the pressure is sufficient to expel residual fluid from the second chamber. Thus, the spacing between chambers provides a delay between chambers to allow expulsion of residual conduit fluid before the start of the infusion of medication from the next chamber. This is especially advantageous for preventing mixing of agents from non-adjacent chambers.
The second chamber 20 typically has the largest fluid volume of the four chambers. As discussed in more detail below, the second chamber is coupled to the second port 28 and the sixth port 35 by respective conduits. When filled with medication, the second chamber has a pillow-like shape. As a result of the relatively large pillow-like shape of the second chamber (and the flexible nature of the materials used to construct the bag), when pressure is applied to the second chamber, there may be a resistance to flow because the chamber has a tendency to kink near the chamber exit 54 to the conduit, often cutting off fluid flow to the conduit. To prevent a pressure drop due to kinks from forming at the exit port, a “quilt” pattern of bonds may be placed near the exit. The quilt pattern may consist of two spot bonds, 55a and 56a, having a “T dot” configuration. The quilt pattern moves the chamber's kinking tendencies to other areas of the bag where kinking is not of concern, away from the exit 54. The first bond 55a has a “T” shape providing first and second openings, 57 and 58. From observation, it appears that the cross bar of the T causes the chamber to kink laterally and preferentially above the outlet 54. The leg of the T further causes a longitudinal kink away from the outlet 54. After the chamber has been compressed to the first opening 57, the “pillow” of the compressed chamber is of a size that is less susceptible to exit kinks. The second “dot” bond further discourages kinking of the second opening 58. The quilt pattern may be provided to other ports of the chamber to prevent kinking while removing air, etc. Empirical tests have determined that the quilt pattern configuration discourages kinks at the exit and allows reliable delivery of the medication from the second chamber into the respective conduit 38.
In an alternative embodiment of the invention, the quilt pattern may consist of the two spot bonds, 55b and 56b, shown in
In another embodiment of the invention, the quilt pattern may consist of the bond blocks, 55c and 56c, shown in
Referring to
The six ports are used to fill and/or empty the fluid in the chambers. Two of the ports, the fifth and sixth ports, 34 and 35 (see
The bag may be constructed of an EVA (ethylene vinyl acetate) or like film material which is often used in the construction of intravenous solution containers. This material is generally rugged, durable and biocompatible. The bag is configured to withstand pressures greater than those achieved during an infusion. The interior of the pump housing where the bag resides is configured such that a filled bag will be positioned correctly and securely. In the depicted embodiment, this is accomplished by the use of registration pins 151 (or similar features) in the pump receptacle (
The tubes may be formed of co-extruded plastic for providing a compatible bonding surface. For example, if the bag 12 is formed of EVA and the manifold is formed of acrylonitrile butadiene styrene (ABS), the co-extruded tube 66 would have an exterior of EVA and an interior of PVC. The outside of the tube (FVA) would be heat sealed to the bag (EVA) and the inside of the tube (PVC) would be solvent bonded to the outside of a corresponding port of the manifold (ABS).
In one application of the invention, the first, second and third chambers, 18, 20 and 22, may be filled with a diluent such as a saline solution, a dextrose solution or sterile water, and the fourth chamber 24 is filled with heparinized saline (e.g., through the fifth port 34). A medication, such as an antibiotic, may be injected into the second chamber through the sixth port 35 before commencing delivery of the infusion therapy to a patient.
The multi-chamber bag 12 also may include a plurality of alignment holes, e.g., 68 and 70. The alignment holes may be offset and aligned with corresponding features such as pins in a pump. The alignment holes ensure that the bag is installed into the pump in the correct position, and maintained in that position during pumping.
With reference to
In a particular embodiment, as shown in
The medication delivery container 10 may have a wide variety of configurations and dimensions based on the prescribed infusion therapy. For example, when infusion therapies permit (e.g., when small volumes of concentrated solution are to be infused), bags may be sufficiently small to incorporate into an easily portable pump apparatus. Chambers may be configured for the simultaneous infusion of medicaments from separate chambers. Empirical evaluation of the container and manifold configuration shown in
In accordance with another embodiment of the present invention, there is provided a pump that is configured to administer an infusion therapy using an invention medication delivery container by expelling medications in the flexible bag of the invention container from the bag and delivering the medications to an infusion site. The pump provides improved administration of infusion therapy which is particularly advantageous for reducing errors, infections and other complications associated with manual infusion techniques.
The pump can be configured to administer an infusion therapy using an invention medication delivery container. The pump can be further configured to specifically interface with an invention medication delivery container (hereinafter, “bag”) that is compartmentalized to contain multiple, separate medication solutions, and to deliver the solutions in a sequential, rate-controlled manner. Accordingly, invention pumps comprise a structure for applying constant force to a bag in a manner that sequentially activates chambers within the bag so that fluid contained therein is driven out through one or more conduits associated with each chamber, and into an intravenous (i.v.) drug delivery system (e.g., an administration set comprising microbore tubing that is attachable to a standard i.v. needle).
In accordance with yet another embodiment of the present invention, there is provided a housing for receiving and retaining an invention medication delivery container (bag), as described herein, during the pumping operation. The housing further contains the structure for applying constant force to the bag.
The housing (e.g., a pump housing as described herein) can be configured to specifically receive a particular type of bag. This configuration can comprise any structure(s) that will serve to hold a specific bag in operative relationship with the mechanism for constant force. As used herein, “operative relationship with the mechanism for applying force” means that the bag is retained in a manner that allows the mechanism for applying force to activate bag chambers in the intended sequence, without displacing the bag so as to prevent correct operation. For example, the housing can include positioning pins that match holes in a medication container bag, fasteners (e.g., hook and loop, snaps, buttons, zippers, or the like) that mate with counterparts on the bag, or the like. In a particular embodiment, the housing is further configured to receive a manifold attached to the bag. By employing sufficient structure to retain the manifold, the bag is further secured.
In a preferred embodiment, the mechanism for applying force to expel liquid from the container contemplated for use in the practice of the present invention is a pump with a constant force spring. However it should be understood that other structures for applying force may be substituted therefor, including a roller attached to a constant force spring, a motor-driven roller, or the like. Each such mechanism will require a different housing configuration to retain the structure and to maintain it in operative relationship with the bag during the pumping or activation process. All such housing configurations are contemplated as within the scope of the present invention.
Because it is often desirable to further control the rate at which force is applied by the constant force spring, in one embodiment, invention pumps comprise an energy absorption device. Any suitable energy absorption device may be employed. Energy absorption devices contemplated for use in the practice of the present invention include both mechanical and electrically operated devices. Mechanical devices include watch-type gear assemblies (as further described herein), watch escapements, an air resistance device, a resistance rack, an eddy current gear, a viscous damper, and the like. As used herein “watch-type gear assembly” means an assembly comprising a plurality of interconnected toothed cogs or gears that operate, in a manner known to those of skill in the art, to absorb energy by rotating and also to modulate the rate of rotation in a predictable manner. The energy absorption device can be secured to the constant force spring at its hub. Thus, the constant force spring has a maximum rate it can travel as determined by the strength of the spring, the configuration of the bag, and the amount and nature of the fluid contained in the bag. The energy absorbing device then further limits the rate at which the constant force spring can travel (i.e., work).
The invention pump can further comprise an activating mechanism for charging or cocking the mechanism for applying force to the container. This can be accomplished in a variety of ways depending on the exact type of activating mechanism employed. In an embodiment where a constant force spring is used, the charging mechanism will act to translate energy input by the user into stored energy in the constant force spring. This can be accomplished in a variety of ways, depending on the exact type of constant force spring employed. In one embodiment, wherein the constant force spring comprises a coiled leaf of metal or other suitable material attached to a hub at the center of the coil, the charging mechanism is attached to the hub. The other end of the spring is fixed to the pump housing proximal to one end of the housing. In this manner, force can be applied to the center of the hub and directed away from the fixed end of the spring, thereby causing the spring to unroll. It is presently preferred that the hub of the spring protrude from either side of the spring so that the hub can be captured in a track or like structure for retaining and guiding the travel of the constant force spring. In this manner, the travel of the spring can be controlled during charging and in performing its work. It is even more preferred that the hub have additional structure for facilitating even retraction of the spring (i.e., so that one side is not unrolled faster than the other). This can be accomplished in a variety of ways, including employing a toothed gear and track assembly, as further described herein, or the like. The hub, gear and track assembly serves an additional function of providing an attachment point for the energy absorption device described herein, as well as a means to control the forward (i.e., work producing) travel of the spring.
Charging mechanisms contemplated for use in the practice of the present invention can include a force transmission structure suitable for pushing or pulling the hub of the spring in the intended direction (i.e., away form the fixed end of the spring). Suitable force transmission structures include chains, belts, rods or the like, if the hub is to be pulled; and rods, or the like if the hub is to be pushed. More specifically, charging can be accomplished by employing a crank, a pneumatically operated mechanism, a plunger, a slide, or the like. It is presently preferred that the force transmission structure be connected to a mechanism for providing a mechanical advantage to the user, as the energy required to charge the constant force spring can be substantial. A mechanical advantage can be provided in the form of a lever mechanism, a multi-stage cocking mechanism, or the like. A multi-stage cocking mechanism allows partial cocking or charging of the constant force spring during each stage of the cocking. In this manner, the often substantial force required to charge the constant force spring can be parceled out over several operation stages, thereby making cocking easier than if a single stage mechanism where employed.
Advantageously, the pump will also comprise an indicator such as a wheel, or the like to indicate the progress of infusion of the medication to the patient. The indicator can interface with the activating mechanism and any associated gearing to provide a true indication of the progress made by the activating mechanism. In a preferred embodiment, the indicator is geared in a manner to amplify the progress of infusion.
In one embodiment, described with reference to
With reference to
As shown in
It can be advantageous to access the components of the pump for purposes such as maintenance or adjustment; accordingly, in one embodiment of the present invention, the housing can have one or more removable portions to provide the needed access. For example, a bottom cover 132 can be removably secured to the bottom of the frame. The housing is sized to accommodate the pump spring in any state of charging. In one embodiment, the bottom (or bottom cover, when employed) has an inclined plate 164 (
The constant force pump spring assembly can be retained in the housing in a variety of ways. Referring to the embodiment shown in
A mechanism for charging the constant force spring can be attached to the spring hub for pulling or pushing the hub away from the fixed end of the spring. In one embodiment, the charging mechanism is coupled to the spring hub by a belt assembly. In this embodiment, the hub will have sufficient structure, either as part of the hub, or attached to the hub, to facilitate secure attachment of the charging mechanism to the hub. For example, at each end of the shaft, adjacent to the respective gear (if employed), can be a belt hub 184 (
A constant force spring 136 has a tendency to roll up the bag 188 (
In the embodiment depicted in the
The charging assembly 134 includes the belts 186, two belt drums 144 (
The gear box assembly 202, shown in
The energy absorption device/assembly 116, shown in
A charging disk 194, shown in
The pump spring charging operation will now be described with reference to
As shown in
The pump may include a number of features for ensuring the correct administration of the desired infusion therapy. The receptacle may have two spring guards 246, shown in
Interlocks can also be included so that the pump can only operate as intended. For example, a door interlock can be employed to prevent the inner door from being opened until the outer door is fully opened. The pump may also have a start button interlock 250 (
The fit and form of the pump with the doors closed is shown in the embodiment exemplified by cross-sectional diagram of
The medication delivery pump automates a number of labor steps typically used to administer multiple intravenous solutions in the proper volumes and in the proper sequence with minimal user interaction. Further, in a preferred embodiment, the pump is a mechanical device which does not require electrical energy nor software to correctly implement an infusion therapy.
An administration set, as described hereinabove, is optionally provided in one embodiment of the present invention and can optionally be included in the invention medication delivery system. The embodiment of the administration set shown in
In another embodiment of the present invention there is provided a restrictor set for attachment to the distal end of the administration set. In this manner, the rate of fluid flow can be altered with the simple addition of a restrictor set, rather than by re-engineering the administration set. Of course, the maximum fluid flow rate will be determined by the configuration of the administration set, with fine-tuning to slower rates provided by the restrictor set.
The invention methods will now be described in greater detail by reference to specific, non-limiting embodiments as illustrated in
In accordance with a specific embodiment of the invention methods, the user attaches the administration set (
The medication delivery system is designed to be simple, safe, intuitive, and cost effective. Further, the system is designed to (1) reduce the need for supplies, (2) diminish manual manipulations and labor complexity, (3) decrease entries into the patient's TV catheter, and (4) ensure fluids will be administered in the proper volumes and in the proper sequence.
The invention medication delivery pump provides the advantage that it is a mechanical device which does not require electrical energy nor software to infuse the solutions in the correct volume, order, and flow rate. An activating mechanism such as a constant force stainless steel spring provides the mechanical energy to express the fluids as it compresses each solution chamber of the bag.
The solution pressures and infusion rates are determined by the system's configuration. A governing mechanism in the pump works to limit the maximum allowable speed of advance of the spring. When the rate of travel of the constant force spring exceeds the maximum rate allowed by the governor, the governor absorbs some of the spring energy to limit the speed of the spring's travel. The governor allows the spring to move over the entire distance of the pump at a minimum, predetermined amount of time. Thus, the pump generates predictable fluid pressures based on the volume of solution in each chamber. Using the predictable fluid pressures, the flow rate from the bag may be selectable using administration sets having predetermined tubing lengths and inner diameters. The continuous force by the spring on the bag, in combination with check valves in a manifold of the container, prevents the reverse flow of fluids from the administration set to the container.
In the embodiment where the pump comprises a two stage charging mechanism comprising inner and outer doors, the pump's outer door and inner door must be opened in order to place a filled bag inside the pump. The opening motion of the outer door and inner door is the mechanism by which the mechanical pump spring is pulled back to the start position. After the inner and outer doors are closed, the pump is ready to be started upon pushing of the “start” button. The cut out windows in the inner and outer door allow the user to observe the position of the spring as it moves in relation to the bag. Accordingly, the user is able to visually monitor the progress of the infusion.
The pump may be designed to separate the bag compartment or receptacle from most of the pump's moving parts. Corrosion resistant materials may be used for any parts that may come in contact with liquids. This attention to the physical design facilitates cleaning of the pump.
The flow of solution from each chamber is initiated due to a pressure build up caused by the pump spring compressing the filled chamber. As the pressure increases, a check valve in the manifold opens, allowing the fluid to flow from the chamber, down a fluid conduit, past the valve, and out through a single outlet tubing into the patient. When the solution is expelled from the chamber, a drop of pressure occurs which allows the valve to close. It is the opening and closing of the valves that governs the starting and stopping of solution flow from each respective chamber. The controlled rate at which the spring compresses the bag maintains the solution pressure below the typical maximum safe pressure for i.v. devices (i.e., catheters, luers, needles, and the like).
Features for filling and using the invention medication delivery system are described with reference to
The bag includes a shipping clamp 368 for preventing leakage of any solutions subsequent to filling. When the bag is inserted in the filling fixture, the clamp is released to allow filling. Conversely, when filling is completed, the shipping clamp is closed to prevent leakage of solution from the filled bag prior to use.
A filling fixture is a pharmacy tool used only in filling the chambers of the bag. By restraining chambers 1 and 3 with the interior walls of the filling fixture, the operator assures that the filling fixture provides a physical constraint to the bag 314 to assure that each of chambers 1, 2 and 3 is filled to the correct nominal fill volume. Thus, in use, the operator places the bag 314 into the filling fixture prior to initiating the fill. Once the bag is in the filling fixture, the shipping clamp on the bag, if provided, is opened and the operator bulk fills chambers 1, 2 and 3 of the bag through the bulk fill port 360 in one step, using standard pharmacy filling equipment and procedures.
For example, the operator may fill the bag with 10 mls in chambers 1 and 3, and 100 mls in chamber 2, by setting the standard pharmacy filling equipment to dispense 120 ml. The fluid will flow into the bag, filling chambers 1 and 3 to 10 mls. The filling fixture will constrain chambers 1 and 3 to this volume and the remainder of the fluid (100 mls) will flow into chamber 2. When the bag chambers 1, 2 and 3 are filled, each to the desired volume, the operator removes the bag from the filling fixture. The bag is now ready to have solution added to chambers 2 and 4 via the injection sites, 362 and 364, respectively, as required by the operator. The chamber 2 and chamber 4 injection sites are accessed via standard pharmacy filling equipment and procedures. Upon completion of filling, the bag is ready for insertion into the pump 310 for delivery of the solutions.
The invention will now be described in greater detail by reference to the following non-limiting example.
The following example illustrates flow from the invention medication delivery system using a four-chambered bag having the following chamber fill volumes:
A typical flow profile of fluid flow from the four bag chambers over time is shown in
While the invention has been described in detail with reference to certain preferred embodiments thereof, it will be understood that modifications and variations are within the spirit and scope of that which is described and claimed.
This application is a continuation-in-part of U.S. patent application Ser. No. 10/111,587, filed Apr. 24, 2002 (pending), which is a 371 of PCT/US00/41860, filed Nov. 2, 2000, which claims priority to U.S. patent application Ser. No. 09/434,975, filed Nov. 5, 1999 (and has issued as U.S. Pat. No. 6,428,518). The present application also claims priority to U.S. patent application Ser. No. 10/251,491, filed Sep. 19, 2002, which, in turn, claims priority to U.S. Provisional Patent Application No. 60/337,407, filed Dec. 3, 2001 (abandoned); to U.S. patent application Ser. No. 09/713,521, filed Nov. 14, 2000 (pending), which is a divisional of U.S. patent application Ser. No. 09/231,535, filed Jan. 14, 1999, which issued as U.S. Pat. No. 6,146,360, which is a continuation of U.S. patent Ser. No. 09/008,111, filed Jan. 16, 1998, which issued as U.S. Pat. No. 6,074,366; to U.S. patent application Ser. No. 09/434,974, filed Nov. 5, 1999, which issued as U.S. Pat. No. 6,669,668; and to U.S. patent application Ser. No. 09/434,972, filed Nov. 5, 1999, which issued as U.S. Pat. No. 6,726,555; each of which is hereby incorporated by reference in their entirety, including all tables, figures, and claims.
