Patent Description:
Treatment of wounds or other tissue with reduced pressure may be commonly referred to as "negative-pressure therapy," but is also known by other names, including "negative-pressure wound therapy," "reduced-pressure therapy," "vacuum therapy," and "vacuum-assisted closure," for example.

In addition, the delivery of therapeutic fluids (e.g. saline or antibiotic fluids) to the tissue site can also provide benefits to healing of a tissue site. Treatment of tissue sites with the delivery of therapeutic fluids may also be referred to as "instillation therapy. " Instillation therapy may assist in cleaning the tissue site by aiding in the removal of infectious agents or necrotic tissue. The therapeutic fluids used in instillation therapy may also provide medicinal fluids, such as antibiotics, anti-fungals, antiseptics, analgesics, or other similar substances, to aid in the treatment of a tissue site.

<CIT> concerns an apparatus for delivering medical fluids, such as drugs, wherein negative pressure is used to force fluid from a container.

While the clinical benefits of negative-pressure therapy and instillation therapy are widely known, the cost and complexity of negative-pressure therapy and instillation therapy can be a limiting factor in its application, and the development and operation of delivery systems, components, and processes continues to present significant challenges to manufacturers, healthcare providers, and patients.

New and useful systems and apparatuses for providing instillation and negative-pressure therapy to a tissue site are set forth in the appended claims. Illustrative embodiments are also provided to enable a person skilled in the art to make and use the claimed subject matter.

<FIG> is a simplified functional block diagram of an example embodiment of a therapy system <NUM> that can provide instillation therapy in accordance with this specification. The therapy system <NUM> may include a dressing and a negative-pressure source. For example, a dressing <NUM> may be fluidly coupled to a negative-pressure source <NUM>, as illustrated in <FIG>. A dressing generally includes a cover and a tissue interface. The dressing <NUM>, for example, includes a cover <NUM> and a tissue interface <NUM>. The therapy system <NUM> may also include a fluid management device, such as a cartridge <NUM>, fluidly coupled to the dressing <NUM> and to the negative-pressure source <NUM>.

For example, the negative-pressure source <NUM> may be directly coupled to the cartridge <NUM> and indirectly coupled to the dressing <NUM> through the cartridge <NUM>. Components may be fluidly coupled to each other to provide a path for transferring fluids (i.e., liquid and/or gas) between the components.

In some embodiments, for example, components may be fluidly coupled through a tube. A "tube," as used herein, broadly refers to a tube, pipe, hose, conduit, or other structure with one or more lumina adapted to convey a fluid between two ends. In some embodiments, components may additionally or alternatively be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material. Coupling may also include mechanical, thermal, electrical, or chemical coupling (such as a chemical bond) in some contexts.

The cover <NUM> may be placed over the tissue interface <NUM> and sealed to tissue near the tissue site. Thus, the dressing <NUM> can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source <NUM> can reduce the pressure in the sealed therapeutic environment. Negative pressure applied across the tissue site through the tissue interface <NUM> in the sealed therapeutic environment can induce macrostrain and microstrain in the tissue site, as well as remove exudates and other fluids from the tissue site, which can be collected and disposed of properly. The dressing <NUM> may also provide a sealed therapeutic environment proximate to a tissue site that may allow fluid to be instilled to the tissue site for instillation therapy.

The fluid mechanics of using a negative-pressure source to reduce pressure in another component or location, such as within the cartridge <NUM>, can be mathematically complex. However, the basic principles of fluid mechanics applicable to negative-pressure therapy are generally well-known to those skilled in the art, and the process of reducing pressure may be described illustratively herein as "delivering," "distributing," or "generating" negative pressure, for example.

In general, exudates and other fluids flow toward lower pressure along a fluid path. Thus, the term "downstream" typically refers to a position in a fluid path relatively closer to a negative-pressure source, and conversely, the term "upstream" refers to a position relatively further away from a negative-pressure source. Similarly, it may be convenient to describe certain features in terms of fluid "inlet" or "outlet" in such a frame of reference. This orientation is generally presumed for purposes of describing various features and components of therapy systems herein. However, the fluid path may also be reversed in some applications (such as by substituting a positive-pressure source for a negative-pressure source) and this descriptive convention should not be construed as a limiting convention.

The term "tissue site" in this context broadly refers to a wound or defect located on or within tissue, including but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. A wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial-thickness burns, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term "tissue site" may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be used in certain tissue areas to grow additional tissue that may be harvested and transplanted to another tissue location.

"Negative pressure" generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to the cartridge <NUM>. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. Unless otherwise indicated, values of pressure stated herein are gauge pressures. Similarly, references to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure.

A negative-pressure source, such as the negative-pressure source <NUM>, may be a reservoir of air at a negative pressure, or may be a manual or electrically-powered device that can reduce the pressure in a sealed volume, such as a pump, a suction pump, a wall suction port available at many healthcare facilities, or a micro-pump, for example. A negative-pressure source may be housed within or used in conjunction with other components, such as sensors, processing units, alarm indicators, memory, databases, software, display devices, or user interfaces that further facilitate negative-pressure therapy.

A negative-pressure source may include a user interface. A user interface may be a device configured to allow communication between a controller and an environment external to a negative-pressure source. In some embodiments, an external environment may include an operator or a computer system configured to interface with a negative-pressure source, for example. In some embodiments, a user interface may receive a signal from a controller and present the signal in a manner that may be understood by an external environment. In some embodiments, a user interface may receive signals from an external environment and, in response, send signals to a controller.

In some embodiments, a user interface may be a graphical user interface, a touchscreen, or one or more motion tracking devices. A user interface may also include one or more display screens, such as a liquid crystal display ("LCD"), lighting devices, such as light emitting diodes ("LED") of various colors, and audible indicators, such as a whistle, configured to emit a sound that may be heard by an operator. A user interface may further include one or more devices, such as knobs, buttons, keyboards, remotes, touchscreens, ports that may be configured to receive a discrete or continuous signal from another device, or other similar devices; these devices may be configured to permit the external environment to interact with the user interface. A user interface may permit an external environment to select a therapy to be performed with a negative-pressure source. In some embodiments, a user interface may display information for an external environment such as a duration of therapy, a type of therapy, an amount of negative pressure being supplied, an amount of instillation solution being provided, a fluid level of a container, or a fluid level of a cartridge, for example.

A negative-pressure source may also include one or more pressure sensors. A pressure sensor, may be a piezoresistive strain gauge, a capacitive sensor, an electromagnetic sensor, a piezoelectric sensor, an optical sensor, or a potentiometric sensor, for example. In some embodiments, a pressure sensor can measure a strain caused by an applied pressure. A pressure sensor may be calibrated by relating a known amount of strain to a known pressure applied. The known relationship may be used to determine an unknown applied pressure based on a measured amount of strain. In some embodiments, a pressure sensor may include a receptacle configured to receive an applied pressure.

A negative-pressure source may include one or more controllers communicatively coupled to components of the negative-pressure source, such as a valve, a flow meter, a sensor, a user interface, or a pump, for example, to control operation of the same. As used herein, communicative coupling may refer to a coupling between components that permits the transmission of signals between the components. In some embodiments, the signals may be discrete or continuous signals. A discrete signal may be a signal representing a value at a particular instance in a time period. A plurality of discrete signals may be used to represent a changing value over a time period. A continuous signal may be a signal that provides a value for each instance in a time period. The signals may also be analog signals or digital signals. An analog signal may be a continuous signal that includes a time varying feature that represents another time varying quantity. A digital signal may be a signal composed of a sequence of discrete values.

In some embodiments, communicative coupling between a controller and other devices may be one-way communication. In one-way communication, signals may only be sent in one direction. For example, a sensor may generate a signal that may be communicated to a controller, but the controller may not be capable of sending a signal to the sensor. In some embodiments, communicative coupling between a controller and another device may be two-way communication. In two-way communication, signals may be sent in both directions. For example, a controller and a user interface may be communicatively coupled so that the controller may send and receive signals from the user interface. Similarly, a user interface may send and receive signals from a controller. In some embodiments, signal transmission between a controller and another device may be referred to as the controller operating the device. For example, interaction between a controller and a valve may be referred to as the controller: operating the valve; placing the valve in an open position, a closed position, or a metering position; and opening the valve, closing the valve, or metering the valve.

A controller may be a computing device or system, such as a programmable logic controller, or a data processing system, for example. In some embodiments, a controller may be configured to receive input from one or more devices, such as a user interface, a sensor, or a flow meter, for example. In some embodiments, a controller may receive input, such as an electrical signal, from an alternative source, such as through an electrical port, for example.

In some embodiments, a controller may be a data processing system. A data processing system suitable for storing and/or executing program code may include at least one processor coupled directly or indirectly to memory elements through a system bus. The memory elements can include local memory employed during actual execution of the program code, bulk storage, and cache memories which provide temporary storage of at least some program code in order to reduce the number of times code is retrieved from bulk storage during execution.

In some embodiments, a controller may be a programmable logic controller (PLC). A PLC may be a digital computer configured to receive one or more inputs and send one or more outputs in response to the one or more inputs. A PLC may include a non-volatile memory configured to store programs or operational instructions. In some embodiments, the non-volatile memory may be operationally coupled to a battery-back up so that the non-volatile memory retains the programs or operational instructions if the PLC otherwise loses power. In some embodiments, a PLC may be configured to receive discrete signals and continuous signals and produce discrete and continuous signals in response.

A negative-pressure source may also include a power source. A power source may be a device that supplies electric power to an electric load. A power source may include a battery, a direct current (DC) power supply, an alternating current (AC) power supply, a linear regulated power supply, or a switched-mode power supply, for example. A power supply may supply electric power to a controller, a sensor, a flow meter, a valve, a user interface, or a pump, for example.

The tissue interface <NUM> can be generally adapted to contact a tissue site. The tissue interface <NUM> may be partially or fully in contact with the tissue site. If the tissue site is a wound, for example, the tissue interface <NUM> may partially or completely fill the wound, or may be placed over the wound. The tissue interface <NUM> may take many forms, and may have many sizes, shapes, or thicknesses depending on a variety of factors, such as the type of treatment being implemented or the nature and size of a tissue site.

In some embodiments, the tissue interface <NUM> may be a manifold. A "manifold" in this context generally includes any substance or structure providing a plurality of pathways adapted to collect or distribute fluid across a tissue site under a pressure gradient. For example, a manifold may be adapted to receive negative pressure from a source and distribute the negative pressure through multiple apertures across a tissue site, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid across a tissue site.

In some illustrative embodiments, the pathways of a manifold may be channels interconnected to improve distribution or collection of fluids across a tissue site. For example, cellular foam, open-cell foam, reticulated foam, porous tissue collections, and other porous material such as gauze or felted mat generally include pores, edges, and/or walls adapted to form interconnected fluid pathways. Liquids, gels, and other foams may also include or be cured to include apertures and flow channels. In some illustrative embodiments, a manifold may be a porous foam material having interconnected cells or pores adapted to distribute fluid to a tissue site. The foam material may be either hydrophobic or hydrophilic. In one non-limiting example, a manifold may be an open-cell, reticulated polyurethane foam such as GranuFoam® dressing available from Kinetic Concepts, Inc.

In an example in which the tissue interface <NUM> may be made from a hydrophilic material, the tissue interface <NUM> may also wick fluid away from a tissue site, while continuing to distribute negative pressure to the tissue site. The wicking properties of the tissue interface <NUM> may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic foam is a polyvinyl alcohol, open-cell foam such as V. WhiteFoam® dressing available from Kinetic Concepts, Inc. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

The tissue interface <NUM> may further promote granulation at a tissue site when pressure within the sealed therapeutic environment is reduced. For example, any or all of the surfaces of the tissue interface <NUM> may have an uneven, coarse, or jagged profile that can induce microstrains and stresses at a tissue site if negative pressure is applied through the tissue interface <NUM>.

In some embodiments, the tissue interface <NUM> may be constructed from bioresorbable materials. Suitable bioresorbable materials may include, without limitation, a polymeric blend of polylactic acid (PLA) and polyglycolic acid (PGA). The polymeric blend may also include without limitation polycarbonates, polyfumarates, and capralactones. The tissue interface <NUM> may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface <NUM> to promote cell-growth. A scaffold is generally a substance or structure used to enhance or promote the growth of cells or formation of tissue, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, or processed allograft materials.

In some embodiments, the cover <NUM> may provide a bacterial barrier and protection from physical trauma. The cover <NUM> may also be constructed from a material that can reduce evaporative losses and provide a fluid seal between two components or two environments, such as between a therapeutic environment and a local external environment. The cover <NUM> may be, for example, an elastomeric film or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. In some example embodiments, the cover <NUM> may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of <NUM>-<NUM> microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained.

An attachment device may be used to attach the cover <NUM> to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many forms. For example, an attachment device may be a medically-acceptable, pressure-sensitive adhesive that extends about a periphery, a portion, or an entire sealing member. In some embodiments, for example, some or all of the cover <NUM> may be coated with an acrylic adhesive having a coating weight between <NUM>-<NUM> grams per square meter (gsm). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Other example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.

The dressing <NUM> may also be used to provide a sealed therapeutic environment for instillation therapy. Instillation therapy may include the slow introduction of a solution to a tissue site. The solution may be used to provide moisture to the tissue site, to provide warmth or cold to the tissue site, to provide a drug to the tissue site, soak the tissue site in a fluid, or to provide another substance to the tissue site. Often, different types of instillation therapy may require a different type of instillation fluid to achieve a desired effect. For example, a first type of fluid may provide moisture to the tissue site. A different type of fluid may supply a drug to the tissue site. Many times, the need for different types of fluid to treat the tissue site may make instillation therapy time consuming to administer.

Some patients may experience improved outcomes with a combined treatment that includes using both negative-pressure therapy and instillation therapy. Existing therapy systems that provide instillation or irrigation of a tissue site as well as negative-pressure therapy can be complicated to use and setup. Multiple tubes, clamps, and interfaces may often be needed to properly apply both negative pressure and fluid to the tissue site. For example, to set up a therapy system having both negative-pressure therapy and instillation therapy, components for both systems may be placed proximate to a patient. Unfortunately, the cost of a combined treatment system can be prohibitive in many clinical environments, reducing the likelihood that a patient may receive the benefits of both systems.

In many clinical environments, negative-pressure therapy relies on a dedicated therapy system to provide negative-pressure therapy to a tissue site. The dedicated therapy system may be positioned proximate to a patient receiving negative-pressure therapy and the dedicated therapy system may be fluidly coupled to a tissue site to provide negative-pressure therapy. Similarly, instillation therapy often relies on a dedicated instillation therapy system to provide instillation therapy to a tissue site. The dedicated instillation therapy system may also be positioned proximate to a patient receiving instillation therapy, and the dedicated instillation therapy device may be fluidly coupled to a tissue site to provide instillation therapy. Having both therapy system components and instillation therapy system components proximate to a patient may make the area around the patient cluttered, which can lead to negative outcomes for the patient.

Both dedicated negative-pressure therapy systems and dedicated instillation therapy systems may be expensive. Generally, given the costs associated with negative-pressure therapy and instillation therapy, medical facilities may not be willing to purchase both a dedicated negative-pressure therapy system and a dedicated instillation therapy system. As a result, some clinical facilities may choose to forgo some types of clinical treatment. For example, some clinical facilities may maintain a dedicated negative-pressure therapy system to provide negative-pressure therapy. If a patient requires instillation therapy, a clinician may be required to physically administer instillation therapy, such as with a syringe. Application of instillation therapy in this manner may also require the clinician to remove the dressing, which can cause pain to the patient and potentially increase infection risks. Physical administration of instillation therapy can require a significant investment of clinician time, increase the likelihood of misapplication of therapy, and potentially increase the risk of infection of a tissue site.

Some clinical facilities employ multi-channel dedicated negative-pressure therapy systems. A multi-channel negative-pressure therapy system may be capable of providing negative-pressure therapy to more than one tissue site at a time. A multi-channel negative-pressure therapy system may be large and inhibit placement of other devices near a patient. If instillation therapy is also needed, it may be difficult to place a dedicated instillation therapy system proximate to a patient. Consequently, a clinician may be required to physically administer instillation therapy, which can cause some or all of the complications previously described.

The therapy system <NUM> described herein can solve these problems and others by managing negative-pressure to deliver instillation fluids. In some embodiments, the therapy system <NUM> can provide negative-pressure therapy to the tissue site. For example, the therapy system <NUM> can be fluidly coupled to the dressing <NUM> to provide negative-pressure therapy to a tissue site. In some embodiments, the therapy system <NUM> can provide instillation therapy to the tissue site. For example, the cartridge <NUM> can be fluidly coupled to the dressing <NUM> and the negative-pressure source <NUM> to use the therapy system <NUM> to provide instillation therapy.

<FIG> is a schematic sectional diagram, illustrating additional details that may be associated with some example embodiments of the cartridge <NUM>. Generally, the cartridge <NUM> may have many different shapes and sizes. In some embodiments, the cartridge <NUM> may be manufactured to physically couple to existing negative-pressure therapy products. For example, the cartridge <NUM> and the components described below may be manufactured to resemble a canister, such as a Bemis canister, that can be coupled to the negative-pressure source <NUM>. In other embodiments, the cartridge <NUM> may be manufactured to resemble a canister for a V. ULTA ™ negative-pressure wound therapy system manufactured by Kinetic Concepts, Inc. In still other embodiments, the cartridge <NUM> may be manufactured to resemble a canister for an InfoV. ® negative-pressure therapy system manufactured by Kinetic Concepts, Inc.

The cartridge <NUM> may have a housing <NUM>. The housing <NUM> forms an outer portion of the cartridge <NUM>. In other embodiments, the housing <NUM> may be disposed inside another container so that the housing <NUM> may be enclosed in the cartridge <NUM>. In some embodiments, the housing <NUM> may generally define a chamber and have a structural arrangement to fluidly isolate the chamber from the ambient environment. In some embodiments, the housing <NUM> may be cubic in shape and form a cubic chamber having a square cross-section. In other embodiments, the housing <NUM> may have other suitable shapes, such as spherical, ovoid, or amorphous shaped, which may form similarly shaped chambers having similarly shaped cross-sections. In some embodiments, the shape of the chamber may not correspond with the shape of the housing <NUM>. In some embodiments, the housing <NUM> may be formed of EASTAR ™ DN004 produced by Eastman Chemical Company. In other embodiments, the housing <NUM> may be formed of Terlux ® 2802HD or Terlux ® 2822HD produced by Styrolution Group GmbH.

A fluid source <NUM> is disposed in the housing <NUM>. The fluid source <NUM> is a reservoir of fluid placed in the chamber of the housing <NUM>. In some embodiments, the fluid may be fluidly isolated from the chamber of the housing <NUM> so that fluid may not flow from the fluid source <NUM> into the chamber of the housing <NUM>. In some embodiments, the fluid source <NUM> may be sealed to the housing <NUM>. In some embodiments, the fluid source <NUM> may be a bag of fluid, such as a <NUM> milliliter bag of instillation fluid, placed inside the chamber of the housing <NUM>. In some embodiments, the fluid source <NUM> may be formed of a flexible plastic, such as polyvinyl chloride. In some embodiments, the fluid source <NUM> may be collapsible or (as claimed) compressible. The housing <NUM> may be sized to hold varying volumes of fluid. For example, in some embodiments, the fluid source <NUM> may hold <NUM> milliliters of fluid, and the housing <NUM> may be sized to hold the <NUM> milliliter fluid source. In other embodiments, the fluid source <NUM> may hold more or less fluid, and the housing <NUM> may be sized correspondingly. In some embodiments, the housing <NUM> may include an opening or a hinged wall that permits the fluid source <NUM> to be removed and replaced. In other embodiments, the fluid source <NUM> may not be removed from the housing <NUM>.

A barrier is disposed within the chamber of the housing <NUM>. A barrier may be a solid object positioned within the chamber of the housing <NUM> to divide the chamber of the housing <NUM> into two separate fluid chambers. A portion or an entirety of a barrier is movable, such as a piston or a diaphragm <NUM>, to adjust respective volumes of the chambers created by the barrier. In some embodiments, the diaphragm <NUM> may be a membrane or a sheet of semi-flexible material having a periphery. The periphery of the diaphragm <NUM> may be coupled to the housing <NUM> to form a negative-pressure chamber <NUM> and an ambient chamber <NUM>. Generally, the periphery of the diaphragm <NUM> may be coupled to the housing <NUM> so that the negative-pressure chamber <NUM> is fluidly isolated from the ambient chamber <NUM>. For example, the diaphragm <NUM> may be sealed to the housing <NUM>, may be welded to the housing <NUM>, may be adhered to the housing <NUM>, or may be otherwise coupled to the housing <NUM> to prevent fluid movement across the diaphragm <NUM>. In some embodiments, the diaphragm <NUM> may be formed of an elastic or a semi-elastic material. In some embodiments, the diaphragm <NUM> may be formed of rubber, thermoplastic, or polytetrafluoroethlyene. In some embodiments, the diaphragm <NUM> may be formed of a polyurethane film, a polymer of butyl, epichlorohydrin, vinyl acrylic (also known as Vamac®), polychloroprenen, chlorosulphonated polyethylene (hypalon®), PEBAX®, thermoplastic elastomers (such as Medalist®, Kraton®, or Kraiburg®), and thermoplastic vulcanizates (such as Santoprene®).

In some embodiments, the periphery of the diaphragm <NUM> may be coupled to the housing <NUM> so that the diaphragm <NUM> may flex between a discharge position and a charge position. The discharge position of the diaphragm <NUM> is the position of the diaphragm <NUM> that maximizes the volume of the ambient chamber <NUM> and minimizes the volume of the negative-pressure chamber <NUM>. The charge position of the diaphragm <NUM> is the position of the diaphragm <NUM> that maximizes the volume of the negative-pressure chamber <NUM> and minimizes the volume of the ambient chamber <NUM>. In some embodiments, the periphery of the diaphragm <NUM> may be coupled proximate to a center of a cross-section of the housing <NUM>. For example, the housing <NUM> may form a cube. In some embodiments, the periphery of the diaphragm <NUM> may be coupled to the housing <NUM> so that the diaphragm <NUM> coincides with a line bisecting opposing walls of the housing <NUM> if the volumes of the negative-pressure chamber <NUM> and the ambient chamber <NUM> are equal. In other embodiments, the diaphragm <NUM> may be coupled to the housing <NUM> in other locations of the housing <NUM>. For example, as shown in <FIG>, the housing <NUM> has at least two pairs of opposing walls. The diaphragm <NUM> may be coupled to a first pair of opposing walls of the housing <NUM> and may be parallel to a second pair of opposing walls of the housing <NUM>. In some embodiments, the diaphragm <NUM> may be coupled to the housing <NUM> so that the diaphragm <NUM> is closer to one of the second pair of opposing walls than the other.

In some embodiments, the dimensions of the diaphragm <NUM>, the negative-pressure chamber <NUM>, and the ambient chamber <NUM> may be determined by a size of the housing <NUM>. In some embodiments, the housing <NUM> may be sized to hold a <NUM> milliliter fluid source <NUM>. The diaphragm <NUM>, the negative-pressure chamber <NUM>, and the ambient chamber <NUM> may be sized to accommodate the volume of the fluid source <NUM> while operating as described herein.

The housing <NUM> has a negative-pressure port <NUM>. The negative-pressure port <NUM> may be a fluid passage formed in the housing <NUM> to provide fluid communication with the negative-pressure chamber <NUM>. In some embodiments, the negative-pressure port <NUM> may be a tube having at least one lumen. The tube may be coupled to the housing <NUM> so that the lumen of the tube is in fluid communication with the negative-pressure chamber <NUM>. The negative-pressure port <NUM> is further fluidly coupled to the negative-pressure source <NUM>. In some embodiments, a filter may be disposed in the negative-pressure port <NUM>. For example, a hydrophobic filter may be disposed in the negative-pressure port <NUM>.

In some embodiments, the cartridge <NUM> may include a sensing port <NUM>. The sensing port <NUM> may be a fluid passage coupled to the housing <NUM>. In some embodiments, the sensing port <NUM> may be a tube having at least one lumen. The tube may be coupled to the housing <NUM> so that a lumen of the tube is in fluid communication with the negative-pressure chamber <NUM>. In some embodiments, the sensing port <NUM> may be further fluidly coupled to the negative-pressure source <NUM>.

The cartridge <NUM> also has a fluid outlet <NUM>. The fluid outlet <NUM> may be a fluid passage coupled to the fluid source <NUM> to provide a fluid path out of the housing <NUM>. In some embodiments, the fluid outlet <NUM> may be a tube having at least one lumen. The tube may be coupled to the housing <NUM> so that a lumen of the tube is in fluid communication with the fluid source <NUM>. In some embodiments, the fluid outlet <NUM> may be further fluidly coupled to a dressing, such as the dressing <NUM>. If the fluid outlet <NUM> is fluidly coupled to the dressing <NUM>, the dressing <NUM> may be in fluid communication with the fluid source <NUM> through the fluid outlet <NUM>.

In some embodiments, the cartridge <NUM> may include a calibrated orifice <NUM>. A calibrated orifice may be a nozzle, aperture, opening, porthole, spout, or vent, having a predetermined internal diameter. The calibrated orifice <NUM> may be fluidly coupled to the fluid outlet <NUM>. In some embodiments, the calibrated orifice <NUM> may be coupled to the fluid outlet <NUM> so that fluid flowing from the fluid source <NUM> flows through the calibrated orifice <NUM>.

In some embodiments, the cartridge <NUM> may include an occluder <NUM>. In some embodiments, the occluder <NUM> may be fluidly coupled to the fluid outlet <NUM>. In some embodiments, the occluder <NUM> may be coupled to the housing <NUM> and the fluid outlet <NUM> may be coupled to the occluder <NUM> so that the occluder <NUM> is fluidly coupled in the fluid path provided by the fluid outlet <NUM>. In some embodiments, the occluder <NUM> may be fluidly coupled to the calibrated orifice <NUM> so that the calibrated orifice <NUM> is upstream from the occluder <NUM>. In other embodiments, the occluder <NUM> may be coupled in other locations. In some embodiments, the occluder <NUM> may have a first port, a second port, and a membrane disposed between the first port and the second port. If positive pressure is supplied to the first port, the first port may be in fluid communication with the second port. If negative-pressure is supplied to the second port, the first port and the second port may not be in fluid communication. Generally, if negative pressure is supplied downstream of the occluder <NUM>, the occluder <NUM> may prevent fluid communication of the negative-pressure through the occluder <NUM>. An occluder may be described in more detail with respect to <CIT>. For example, if the fluid outlet <NUM> is fluidly coupled to a dressing and negative-pressure is supplied to the dressing, the occluder <NUM> may prevent fluid communication of the negative pressure to the fluid source <NUM> through the fluid outlet <NUM>.

The housing <NUM> has a vent <NUM>. The vent <NUM> is an opening formed in the housing <NUM>. The vent <NUM> is in fluid communication with the ambient chamber <NUM>. In some embodiments, the vent <NUM> may fluidly couple the ambient chamber <NUM> to the ambient environment so that the ambient chamber <NUM> may be maintained at ambient pressure.

<FIG> is a schematic sectional diagram illustrating additional details that may be associated with some example embodiments of the cartridge <NUM>. As shown in <FIG>, the diaphragm <NUM> may be in the discharge position. In operation, the negative-pressure source <NUM> may generate a negative-pressure in the negative-pressure chamber <NUM> by drawing fluid from the negative-pressure chamber <NUM> through the negative-pressure port <NUM>. As a negative pressure is generated in the negative-pressure chamber <NUM>, the pressure differential between the negative pressure in the negative-pressure chamber <NUM> and the ambient pressure in the ambient chamber <NUM> may generate a force that acts on the diaphragm <NUM>. The force caused by the differential pressure may cause the diaphragm <NUM> to move toward the negative-pressure port <NUM>. In response, the movement of the diaphragm <NUM> toward the negative-pressure port <NUM> compresses the fluid source <NUM>, forcing fluid from the fluid source <NUM>, through the calibrated orifice <NUM>, through the occluder <NUM>, and to the dressing <NUM>.

In some embodiments, negative pressure may be generated in the negative-pressure chamber <NUM> by the negative-pressure source <NUM>. The negative pressure in the negative-pressure chamber <NUM> may be communicated to a controller of the negative-pressure source <NUM> through the sensing port <NUM> that may be fluidly coupled to the negative-pressure source <NUM>. In response, the controller of the negative-pressure source <NUM> may determine a level of negative pressure in the negative-pressure chamber <NUM>. In some embodiments, the inner diameter of the calibrated orifice <NUM> may be predetermined and provided to the controller of the negative-pressure source <NUM>. The controller may then determine a rate of fluid flow through the calibrated orifice <NUM> based on the inner diameter of the calibrated orifice <NUM> and the level of negative pressure in the negative-pressure chamber <NUM>. The controller of the negative-pressure source <NUM> may then maintain a level of negative pressure in the negative-pressure chamber <NUM> for a period of time until a therapeutic dose of instillation fluid has been supplied through the fluid outlet <NUM>. A therapeutic dose of instillation fluid may be a volume of fluid required to be delivered to a tissue site to provide suitable therapeutic benefits to the tissue site. In some embodiments, the therapeutic dose may be an entire volume of the fluid source <NUM>. In other embodiments, a therapeutic dose may be less than an entire volume of the fluid source <NUM>. If a therapeutic dose of fluid has passed through the fluid outlet <NUM>, the controller may stop drawing fluid from the negative-pressure chamber <NUM> and allow the negative-pressure chamber <NUM> to vent to the ambient pressure, stopping flow through the fluid outlet <NUM>.

In other embodiments, the chamber of the housing <NUM> may include a diaphragm <NUM> coupled to each wall of the housing <NUM>. For example, the negative-pressure chamber <NUM> may have a diaphragm <NUM> on each side of the negative-pressure chamber <NUM>. In some embodiments, the ambient chamber <NUM> may be multiple chambers, each having a separate vent <NUM> coupling the ambient chamber <NUM> to the ambient environment. In other embodiments, the negative-pressure chamber <NUM> may be a flexible bag having the fluid source <NUM> disposed therein. Operation of the negative-pressure source <NUM> may generate a negative pressure in the negative-pressure chamber <NUM>, and the diaphragms <NUM> may compress the fluid source <NUM> as described.

<FIG> is a flow chart <NUM> illustrating exemplary logical operations that can be implemented in some embodiments of the therapy system <NUM>. For example, the operations may be implemented by a controller operably associated with a negative-pressure source, such as the negative-pressure source <NUM>, configured to execute the operations. In some embodiments, the negative-pressure source <NUM> may have a mechanical apparatus adapted to be operated by a clinician for the selection of instillation or negative-pressure therapy. For example, the negative-pressure source <NUM> may include a switch, sensor, or other user interface that allows a user to select between instillation therapy and negative-pressure therapy. In some embodiments, the negative-pressure source <NUM> may include software or other control devices to distinguish between a fluid instillation cartridge, such as the cartridge <NUM>, and other types of fluid management devices coupled to the negative-pressure source <NUM>. For example, a collection canister may be distinguished from an instillation cartridge. In these embodiments, the negative-pressure source <NUM> may then provide negative-pressure therapy or instillation therapy based on the determination of the type of fluid management devices fluidly coupled to the negative-pressure source <NUM>.

At block <NUM>, a negative-pressure source may be operated to provide negative pressure to the cartridge. For example, a controller of the negative-pressure source <NUM> may operate the negative-pressure source <NUM>. At block <NUM>, a rate of change of negative-pressure may be calculated. For example, a controller of the negative-pressure source <NUM> may calculate the rate of change of negative pressure based on one or more pressure readings from a pressure sensor located in the negative-pressure source <NUM>. In some embodiments, the rate of change of negative pressure may indicate how quickly or slowly the negative pressure in the negative-pressure chamber <NUM> is increasing within a time period. In some embodiments, the time period may be predetermined. For example, the time period may correspond to a known amount of time that may be required to evacuate a collection canister. At block <NUM>, it can be determined if the rate of change of the negative pressure is greater than a threshold rate of change of the negative pressure. In some embodiments, if a collection canister for negative-pressure therapy is fluidly coupled to the negative-pressure source <NUM>, the rate of change of negative pressure may be within a predetermined range. Similarly, if the cartridge <NUM> is fluidly coupled to the negative-pressure source <NUM>, the rate of change of negative pressure may fall within a different predetermined range. For example, a collection canister for negative-pressure therapy may have a larger volume than the negative-pressure chamber <NUM> of the cartridge <NUM>. Because the canister has a larger volume, the threshold rate of change of negative pressure may be lower than the threshold rate of change of negative pressure for the cartridge <NUM>. For example, a controller of the negative-pressure source <NUM> may determine if the rate of change of negative pressure is within the predetermined rate of change for the cartridge <NUM>, that is, high. In other embodiments, a controller of the negative-pressure source <NUM> may be programmed to compare the rate of change of negative pressure to a threshold rate of change of negative pressure for the cartridge <NUM>. If a controller is programmed to compare the rate of change of negative-pressure to the threshold rate of change of negative pressure for the cartridge <NUM>, a controller may determine if the rate of change of negative pressure is less than the threshold rate of change of negative pressure, that is, low.

If rate of change of the negative pressure exceeds the threshold, it may be inferred at block <NUM> that a cartridge for providing instillation therapy is fluidly coupled to the negative-pressure source. For example, a controller of the negative-pressure source <NUM> may determine that the cartridge <NUM> is fluidly coupled to the negative-pressure source <NUM>. At block <NUM>, a negative-pressure source may be operated in an instill mode or an instill sequence to provide instillation therapy to a tissue site. For example, a controller of the negative-pressure source <NUM> may operate the negative-pressure source <NUM> and the cartridge <NUM> as described above with respect to <FIG> to provide instillation therapy to a tissue site.

At block <NUM>, if the rate of change of negative pressure is less than the threshold, it may be inferred at block <NUM> that a collection canister or other fluid management device for negative-pressure therapy is fluidly coupled to the negative-pressure source. For example, a controller of the negative-pressure source <NUM> may determine that a canister for negative-pressure therapy is fluidly coupled to the negative-pressure source <NUM>. At block <NUM>, dead space can be calculated. For example, a controller of the negative-pressure source <NUM> may perform dead space calculations for the canister. In some embodiments, the amount of dead space in a canister may be calculated by supplying a negative-pressure to the canister and monitoring the rate of change to determine the empty volume of the canister. At block <NUM>, the calculations of the dead space can be used to determine if a fluidly coupled canister is full. For example, a controller of the negative-pressure source <NUM> can determine if a fluidly coupled canister is full.

At block <NUM>, if the canister is not full, a negative-pressure source can provide negative-pressure therapy at block <NUM>. For example, a controller of the negative-pressure source <NUM> can operate the negative-pressure source <NUM> to provide negative-pressure therapy to a tissue site. While the amount and nature of negative pressure applied to a tissue site may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -<NUM> Hg (-<NUM> Pa) and -<NUM> Hg (-<NUM> kPa). Common therapeutic ranges are between -<NUM> Hg (-<NUM> kPa) and -<NUM> Hg (-<NUM> kPa). At block <NUM>, if the canister is full, a full canister indication may be provided at block <NUM>. For example, a controller may provide a full canister indication on a user interface of the negative-pressure source <NUM>.

<FIG> is a flow chart <NUM> illustrating exemplary logical operations for an instill sequence that can be implemented in some embodiments of the therapy system <NUM> of <FIG>. For example, the operations may be implemented by a controller in a negative-pressure source, such as the negative-pressure source <NUM>, configured to execute the operations. At block <NUM>, a negative-pressure source may be turned on and a timer started. For example, a controller of the negative-pressure source <NUM> may turn on a pump in the negative-pressure source <NUM> to generate a negative pressure at a predetermined pressure setting in the cartridge <NUM> and may start a timer in the negative-pressure source <NUM>.

At block <NUM>, a rate of change of negative pressure can be determined. For example, a controller of the negative-pressure source <NUM> can determine the rate of change of negative pressure in the negative-pressure chamber <NUM> through the sensing port <NUM> during a predetermined period of time. In some embodiments, the predetermined period of time may be an expected time period during which the negative-pressure chamber <NUM> may be evacuated. In some embodiments, the expected time period may vary based on the size of the fluid source <NUM>, and the level of fluid in the fluid source <NUM>.

At block <NUM>, it can be determined if the fluid outlet is blocked. For example, a controller of the negative-pressure source <NUM> can determine if the fluid outlet <NUM> is blocked. For example, if the rate of change of negative pressure previously determined is within a predetermined tolerance of zero, the pressure in the negative-pressure chamber <NUM> may not be increasing, indicating that no fluid may be flowing through the fluid outlet <NUM>. At block <NUM>, if the fluid outlet is blocked, an instill blockage error may be provided. For example, a controller of the negative-pressure source <NUM> may provide an instill blockage error on a user interface of the negative-pressure source <NUM>.

At block <NUM>, if the fluid outlet is not blocked, a level of negative pressure may be maintained at block <NUM>. For example, a level of negative pressure, such as -<NUM> Hg, may be maintained in the negative-pressure chamber <NUM>. In some embodiments, a controller may monitor the negative pressure in the negative-pressure chamber <NUM> and operate the negative-pressure source <NUM> to maintain a level of negative pressure in the negative-pressure chamber <NUM> within a predetermined range. At block <NUM>, a negative-pressure source can determine if a therapeutic dose has been dispensed. For example, a controller of the negative-pressure source <NUM> can determine a flow rate through the fluid outlet <NUM> based on the level of negative pressure in the negative-pressure chamber <NUM> and the inner diameter of the calibrated orifice <NUM>. The controller can monitor the timer to determine how much fluid has passed through the fluid outlet <NUM> based on the length of time measured by the timer. At block <NUM>, if a therapeutic dose of fluid has not been delivered, the level of negative pressure may be maintained at block <NUM>.

At block <NUM>, if a therapeutic dose of fluid has been provided, a status of the fluid source may be determined at block <NUM>. For example, a controller of the negative-pressure source <NUM> may perform dead space calculations on the negative-pressure chamber <NUM> to determine if the fluid source <NUM> is empty. In some embodiments, a negative-pressure may be supplied to negative-pressure chamber <NUM> and the rate of change of negative pressure may be monitored. The rate of change of negative pressure may be related to an empty volume of the negative-pressure chamber <NUM> to determine the volume of empty space in the negative-pressure chamber <NUM>. The remaining volume of the fluid in the fluid source <NUM> may be inferred from the volume of empty space in the negative-pressure chamber <NUM>. At block <NUM>, if the fluid source is empty, an alert may be provided at block <NUM>. For example, a controller of the negative-pressure source <NUM> can provide an empty bag alert through a user interface of the negative-pressure source <NUM>.

At block <NUM>, if the fluid source is not empty, a negative-pressure source may be turned off and the negative pressure in a cartridge may be vented at block <NUM>. For example, a controller of the negative-pressure source <NUM> may turn off a pump of the negative-pressure source <NUM> and vent the negative pressure in the negative-pressure chamber <NUM> to the ambient environment. At block <NUM>, the negative-pressure source can determine if the total volume of instillation fluid has been provided. For example, a controller of the negative-pressure source <NUM> can include a counter that increments upwards each time the pump of the negative-pressure source <NUM> is operated during the instillation therapy cycle. If the therapeutic dose of instillation fluid provided during each operation of the negative-pressure source <NUM> is known, a controller can determine the total volume of fluid provided through the fluid outlet <NUM>. A controller can then compare the total volume of fluid provided to a predetermined volume of instillation fluid to be provided to determine if the predetermined volume of instillation fluid has been provided. The predetermined volume of instillation fluid required may be based on a total volume prescribed by a clinician. At block <NUM>, if the predetermined volume of instillation fluid has not been provided, the negative-pressure source may be turned on at block <NUM>. At block <NUM>, if the predetermined volume of instillation fluid has been provided, a signal can be provided at block <NUM> to indicate that the instill sequence is complete. For example, a controller may provide an indication on the user interface of the negative-pressure source <NUM>.

The systems, apparatuses, and methods described herein may provide significant advantages. Example embodiments of the cartridge <NUM> have been described herein that can be combined with an existing negative-pressure wound treatment therapy system to provide controlled instillation therapy. The cartridge <NUM> can also be calibrated to provide a dosage of fluid at a pressure suitable for use with a tissue site, for example, approximately <NUM> mmHg. The cartridge <NUM> can also be calibrated to provide an accurate dosing of a prescribed amount of fluids. Furthermore, the cartridge can be used with a multi-channel negative-pressure system so that the multi-channel negative-pressure system can provide both instillation and negative-pressure therapy. Alternatively, multiple cartridges can be used with a multi-channel negative-pressure system to provide instillation of multiple different types of fluids. The cartridge <NUM> may also be combined with a tissue site drain to allow for continuous washing of the tissue site with instillation fluids. Some embodiments may be combined with software suitable for controlling negative-pressure therapy and instillation therapy so that the negative-pressure therapy system may be combined with another negative-pressure therapy system to provide alternating negative-pressure therapy and instillation therapy. Example embodiments may also include a negative-pressure therapy system having the capability to determine if a canister or an instillation cartridge is fluidly coupled to the negative-pressure source and provide an appropriate therapy in response to the determination.

Claim 1:
A system (<NUM>) for providing instillation and negative-pressure therapy to a tissue site with a negative-pressure source (<NUM>), the system comprising:
a housing (<NUM>) forming an outer portion of a cartridge (<NUM>), the housing (<NUM>) defining a chamber;
a movable barrier disposed within the chamber of the housing (<NUM>), the movable barrier dividing the chamber of the housing (<NUM>) into a first fluid chamber (<NUM>) and a second fluid chamber (<NUM>), said chambers being fluidly isolated from each other, said second fluid chamber (<NUM>) being for fluid placed under negative-pressure, and said first fluid chamber (<NUM>) being an ambient chamber for the atmospheric pressure at which the tissue site is located, the moveable barrier being operable to move between a charge position and a discharge position in response to negative pressure, said charge position maximizing the volume of the second fluid chamber (<NUM>) and minimizing the volume of the first fluid chamber (<NUM>), and said discharge position maximizing the volume of the first fluid chamber (<NUM>) and minimizing the volume of the second fluid chamber (<NUM>);
a reservoir of fluid (<NUM>) disposed in the second fluid chamber (<NUM>), the reservoir being compressible in response to movement of the movable barrier to the discharge position; and
a fluid outlet (<NUM>) in fluid communication with the reservoir of fluid (<NUM>);
a negative-pressure port (<NUM>) in fluid communication with the second fluid chamber (<NUM>);
a negative-pressure source (<NUM>) coupled to the negative-pressure port (<NUM>) and configured to provide the application of negative pressure; and
a vent opening (<NUM>) formed in the housing (<NUM>), the opening (<NUM>) in fluid communication with the first fluid chamber (<NUM>).