Systems and methods for drip purging

Abstract

The present invention discloses a device for treating a tissue site, the device comprising a negative pressure source configured to be fluidically coupled to the tissue site; a drip source configured to be fluidically coupled to the tissue site; and a controller operably coupled to the negative pressure source and the drip source. The controller can be configured to operate the negative pressure source and the drip source to intermittently deliver negative pressure to the tissue site for a negative pressure interval, and deliver the drip fluid to the tissue site for a drip interval. A certain purge volume of the drip fluid can be delivered to the tissue site at a purge frequency. In some examples, the purge volume can be delivered through a second fluid conductor and removed through a first fluid conductor during the negative pressure interval.

Description

[0001] Related patent applications

[0002] The present invention claims the benefit of U.S. Provisional Patent Application No. 62 / 797,035, filed on January 25, 2019, which is incorporated herein by reference for all purposes. Technical Field

[0003] The present invention as set forth in the appended claims relates generally to tissue treatment systems and more particularly, but not by way of limitation, to methods of treating tissue using negative pressure and instillation therapy. Background Art

[0004] Clinical studies and practice have shown that reducing the pressure near the tissue site can enhance and accelerate the growth of new tissue at the tissue site. The application of this phenomenon is numerous, but it has been proven to be particularly advantageous for treating wounds. Regardless of the cause of the wound, whether it is trauma, surgery or other reasons, the correct care of the wound is important for the result. Treating wounds or other tissues by decompression can generally be referred to as "negative pressure therapy", but is also referred to as other names, including, for example, "negative pressure wound therapy", "decompression therapy", "vacuum therapy", "vacuum assisted closure" and "local negative pressure". Negative pressure therapy can provide many benefits, including migration of epithelial tissue and subcutaneous tissue, improved blood flow and micro-deformation of tissue at the wound site. These benefits can increase the development of granulation tissue and reduce healing time together.

[0005] It is also widely recognized that cleaning tissue sites can be very beneficial for new tissue growth. For example, for therapeutic purposes, a wound or cavity can be cleaned with a liquid solution. These practices are commonly referred to as "rinsing" and "lavage". "Instillation" is another practice, which generally refers to the process of slowly introducing a fluid into a tissue site and leaving the fluid for a specified period of time before removing the fluid. For example, instilling a topical treatment solution on a wound surface can be combined with negative pressure therapy to further promote wound healing by releasing soluble contaminants in the wound surface and removing infectious substances. Therefore, soluble bacterial loads can be reduced, contaminants can be removed, and the wound can be cleaned.

[0006] While the clinical benefits of negative pressure therapy and / or infusion therapy are well known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients. Summary of the invention

[0007] New and useful systems, devices and methods for treating tissue with negative pressure, instillation of therapeutic solutions, or both are set forth in the appended claims. Exemplary embodiments are also provided to enable one skilled in the art to make and use the claimed subject matter.

[0008] For example, in some embodiments, the treatment device is capable of intermittently delivering various instillation solutions to the wound surface. Solution instillation may occur during a negative pressure pause, allowing the solution to soak and dissolve wound debris for a set period of time. The solution and dissolved debris may be removed during subsequent cycles of negative pressure. The treatment device may additionally have a controller configured to provide an intermittent purge cycle of the vacuum tube during the negative pressure stage to minimize wound fluid accumulation and potential blockage. In addition or alternatively, the controller may be configured to provide an intermittent purge cycle of the drip tube using a relatively small volume of instillation solution to minimize material deposition at the interface between the dressing and the tube. The software control may provide a user interface for setting various instillation purge levels. For example, the level may depend on the type of instillation solution and other factors related to the cause of the wound, which may affect viscosity and other exudate properties.

[0009] More generally, an apparatus for treating a tissue site may include a negative pressure source configured to be fluidly coupled to the tissue site; a drip source configured to be fluidly coupled to the tissue site; and a controller operably coupled to the negative pressure source and the drip source. In some examples, the negative pressure source may be coupled to a first fluid conductor configured to be coupled to a dressing, and the drip source may be coupled to a second fluid conductor configured to be coupled to a dressing. The controller may be configured to operate the negative pressure source and the drip source to intermittently deliver negative pressure to the tissue site for a negative pressure interval, and deliver drip fluid to the tissue site for a drip interval. A purge volume of the drip fluid may be delivered to the tissue site at a purge frequency. In some examples, the purge volume may be delivered through the second fluid conductor and removed through the first fluid conductor during the negative pressure interval.

[0010] The method of treating a tissue site with negative pressure and a therapeutic solution may include delivering negative pressure to the tissue site for a first interval; delivering the therapeutic solution to the tissue site for a second interval; and delivering a purge volume of the therapeutic solution to the tissue site during the first interval. Alternatively, the purge volume may be delivered prior to the first interval. The purge volume may be removed by the negative pressure during the first interval.

[0011] The objects, advantages and preferred modes of making and using the claimed subject matter may be best understood by referring to the accompanying drawings in conjunction with the following detailed description of illustrative embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a functional block diagram of an exemplary embodiment of a therapy system that can provide negative pressure therapy and infusion therapy according to the present specification;

[0013] Figure 2 It shows that Figure 1A graph of additional details of exemplary pressure control modes associated with some embodiments of the therapeutic system;

[0014] Figure 3 It shows that Figure 1 A graph of additional details associated with another exemplary pressure control mode in some embodiments of the treatment system;

[0015] Figure 4 It is shown that the operation Figure 1 diagrams of details associated with exemplary methods of treating the system; and

[0016] Figure 5 It shows that Figure 1 A graph of additional details of another exemplary control mode associated with some embodiments of the therapeutic system. Specific implementation plan

[0017] The following description of the exemplary embodiments provides information enabling those skilled in the art to make and use the subject matter set forth in the appended claims, but certain details well known in the art may be omitted. Therefore, the following detailed description should be regarded as illustrative rather than limiting.

[0018] Exemplary embodiments may also be described herein with reference to the spatial relationships between various elements or the spatial orientations of various elements depicted in the accompanying drawings. Generally, such relationships or orientations assume a frame of reference consistent with or relative to the patient in the position to be treated. However, as will be appreciated by those skilled in the art, this frame of reference is merely a descriptive convenience and not a strict rule.

[0019] Treatment system

[0020] Figure 1 is a simplified functional block diagram of an exemplary embodiment of a treatment system 100 that can provide negative pressure therapy in conjunction with instillation of a localized therapeutic solution to a tissue site in accordance with the present specification.

[0021] In this context, the term "tissue site" refers broadly to a wound, defect or other treatment target located on or in a tissue, including but not limited to bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendon or ligament. Wounds may include, for example, chronic wounds, acute wounds, traumatic wounds, subacute wounds and dehiscence wounds, partial thickness burns, ulcers (such as diabetic ulcers, pressure ulcers or venous insufficiency ulcers), flaps and grafts. The term "tissue site" may also refer to an area of ​​any tissue that is not necessarily injured or defective, but an area in which it may be desired to add or promote additional tissue growth. For example, negative pressure may be applied to a tissue site to allow additional tissue to grow, and then the additional tissue may be harvested and transplanted.

[0022] The treatment system 100 may include a negative pressure source or negative pressure supply device such as negative pressure source 105, and one or more dispensing components. The dispensing components are preferably detachable and may be disposable, reusable, or recyclable. Dressings (such as dressing 110) and fluid containers (such as container 115) are examples of dispensing components that may be associated with some examples of the treatment system 100. Figure 1 As shown in the example of , in some embodiments, the dressing 110 may include or consist essentially of a tissue interface 120, a cover 125, or both.

[0023] A fluid conductor is another illustrative example of a distribution component. In this context, a "fluid conductor" broadly includes a tube, pipe, hose, conduit, or other structure having one or more lumens or open paths suitable for conveying fluid between two ends. Typically, the tube is an elongated cylindrical structure with a certain flexibility, but the geometry and stiffness can vary. In addition, some fluid conductors can be molded into other components or otherwise integrally combined with other components. The distribution component can also include or contain an interface or fluid port to facilitate coupling and disconnection of other components. In some embodiments, for example, a dressing interface can facilitate coupling the fluid conductor to the dressing 110. For example, such a dressing interface can be a SENSAT.RAC available from Kinetic Concepts, Inc., San Antonio, Texas. TM pad.

[0024] The treatment system 100 may also include a regulator or controller, such as controller 130. In addition, the treatment system 100 may include sensors to measure operating parameters and provide feedback signals indicative of the operating parameters to the controller 130. Figure 1 As shown, for example, treatment system 100 may include a first sensor 135 and a second sensor 140 coupled to controller 130 .

[0025] The treatment system 100 may also include an instillation solution source. In some examples, the instillation source may include a solution source operably coupled to a positive pressure source. For example, the solution source 145 may be fluidly coupled to the dressing 110, such as Figure 1 As shown in the exemplary embodiment of . In some embodiments, the solution source 145 can be fluidly connected to a pump or other positive pressure source such as positive pressure source 150, a negative pressure source such as negative pressure source 105, or both. A regulator such as a drip regulator 155 can also be fluidly connected to the solution source 145 and the dressing 110 to ensure that the infusion solution (such as saline) is appropriately dosed to the tissue site. For example, the drip regulator 155 may include a piston that can be pneumatically actuated by the negative pressure source 105 to draw the infusion solution from the solution source during the negative pressure interval and drip the solution into the dressing during the discharge interval. In addition or alternatively, the controller 130 can be connected to the negative pressure source 105, the positive pressure source 150, or both to control the dose of the infusion solution to the tissue site. In some embodiments, the drip regulator 155 can also be fluidly connected to the negative pressure source 105 through the dressing 110, such as Figure 1 as shown in the example.

[0026] Some components of the treatment system 100 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 treatment. For example, in some embodiments, the negative pressure source 105 may be combined with the controller 130, the solution source 145, and other components into a treatment unit.

[0027] In general, the components of the treatment system 100 may be coupled directly or indirectly. For example, the negative pressure source 105 may be directly coupled to the container 115, and may be indirectly coupled to the dressing 110 through the container 115. The coupling may include a fluid coupling, a mechanical coupling, a thermal coupling, an electrical coupling, or a chemical coupling (such as a chemical bond), or in some cases some combination of couplings. For example, the negative pressure source 105 may be electrically coupled to the controller 130, and may be fluidly coupled to one or more distribution components to provide a fluid path to the tissue site. In some embodiments, the components may also be coupled by means of physical proximity, being integral to a single structure, or being formed from the same piece of material.

[0028] For example, a negative pressure supply device (such as a negative pressure source 105) may be a reservoir of air at negative pressure, or may be a manual or electric device, such as a vacuum pump, a suction pump, a wall suction port or a micro pump available at many healthcare institutions. "Negative pressure" generally refers to a pressure less than the local ambient pressure, such as the ambient pressure in the local environment outside the sealed treatment environment. In many cases, the local ambient pressure may also be the atmospheric pressure at the tissue site. Alternatively, the pressure may be less than the hydrostatic pressure associated with the tissue at the tissue site. Unless otherwise specified, the pressure values ​​described herein are gauge pressures. Reference to an increase in negative pressure generally refers to a decrease in absolute pressure, while a decrease in negative pressure generally refers to an increase in absolute pressure. Although the amount and nature of the negative pressure provided by the negative pressure source 105 may vary according to treatment requirements, the pressure is generally a low vacuum (also commonly referred to as a rough vacuum) between -5mmHg (-667Pa) and -500mmHg (-66.7kPa). Common treatment ranges are between -50 mm Hg (-6.7 kPa) and -300 mm Hg (-39.9 kPa).

[0029] Container 115 represents a container, canister, pouch, or other storage component that can be used to manage exudate and other fluids drawn from a tissue site. In many environments, a rigid container may be preferred or required for collecting, storing, and disposing of fluids. In other environments, fluids may be properly disposed of without a rigid container storage device, and a reusable container may reduce waste and costs associated with negative pressure therapy.

[0030] A controller, such as controller 130, may be a microprocessor or computer programmed to operate one or more components of treatment system 100, such as negative pressure source 105. In some embodiments, for example, controller 130 may be a microcontroller that typically includes an integrated circuit that includes a processor core and a memory programmed to directly or indirectly control one or more operating parameters of treatment system 100. The operating parameters may include, for example, the power applied to negative pressure source 105, the pressure generated by negative pressure source 105, or the pressure distributed to tissue interface 120. Controller 130 is also preferably configured to receive one or more input signals, such as feedback signals, and is programmed to modify one or more operating parameters based on the input signals.

[0031] Sensors such as the first sensor 135 and the second sensor 140 are generally known in the art as any device that can be operated to detect or measure a physical phenomenon or characteristic, and generally provide a signal indicating the phenomenon or characteristic being detected or measured. For example, the first sensor 135 and the second sensor 140 may be configured to measure one or more operating parameters of the treatment system 100. In some embodiments, the first sensor 135 may be a transducer configured to measure the pressure in the pneumatic passage and convert the measured value into a signal indicating the measured pressure. In some embodiments, for example, the first sensor 135 may be a piezoresistive strain gauge. In some embodiments, the second sensor 140 may optionally measure an operating parameter of the negative pressure source 105, such as voltage or current. Preferably, the signals from the first sensor 135 and the second sensor 140 are suitable as input signals to the controller 130, but in some embodiments, certain signal conditioning may be appropriate. For example, before the signal can be processed by the controller 130, it may be necessary to filter or amplify the signal. Typically, the signal is an electrical signal, but may be represented in other forms, such as an optical signal.

[0032] The tissue interface 120 may generally be adapted to partially or completely contact a tissue site. The tissue interface 120 may take a variety of forms and may have a variety of sizes, shapes, or thicknesses, depending on various factors, such as the type of treatment being administered or the nature and size of the tissue site. For example, the size and shape of the tissue interface 120 may be adapted to the contours of a deeper and irregularly shaped tissue site. Any or all surfaces of the tissue interface 120 may have an uneven, rough, or jagged profile.

[0033] In some embodiments, the tissue interface 120 may include or consist essentially of a manifold. In this context, the manifold may include or consist essentially of a device for collecting or distributing fluids under pressure on the tissue interface 120. For example, the manifold may be adapted to receive negative pressure from a source and distribute the negative pressure on the tissue interface 120 through a plurality of openings, which may have the effect of collecting fluids on the tissue site and drawing the fluids toward the source. In some embodiments, the fluid path may be reversed or an auxiliary fluid path may be provided to facilitate delivery of fluids, such as fluids from an instillation solution source, on the tissue site.

[0034] In some exemplary embodiments, the manifold may include a plurality of passages that may be interconnected to improve the distribution or collection of fluids. In some exemplary embodiments, the manifold may include or be substantially composed of a porous material having interconnected fluid passages. Examples of suitable porous materials that may be suitable for forming interconnected fluid passages (e.g., channels) may include cellular foams, including open-cell foams such as reticulated foams; porous tissue collections; and other porous materials that typically include pores, edges, and / or walls, such as gauze or felt pads. Liquids, gels, and other foams may also include or be cured to include open pores and fluid passages. In some embodiments, the manifold may additionally or alternatively include protrusions that form interconnected fluid passages. For example, the manifold may be molded to provide surface protrusions that define interconnected fluid passages.

[0035] In some embodiments, the tissue interface 120 may include or consist essentially of a reticulated foam having a pore size and free volume that can vary according to the needs of the prescribed treatment. For example, a reticulated foam having a free volume of at least 90% may be suitable for many therapeutic applications, and a foam having an average pore size in the range of 400 microns to 600 microns (40 pores / inch to 50 pores / inch) may be particularly suitable for some types of treatment. The tensile strength of the tissue interface 120 may also vary according to the needs of the prescribed treatment. For example, the tensile strength of the foam may be increased for instillation of a local therapeutic solution. The 25% compressive load deflection of the tissue interface 120 may be at least 0.35 pounds per square inch, and the 65% compressive load deflection may be at least 0.43 pounds per square inch. In some embodiments, the tensile strength of the tissue interface 120 may be at least 10 pounds per square inch. The tissue interface 120 may have a tear strength of at least 2.5 pounds per inch. In some embodiments, the tissue interface can be a foam composed of a polyol (such as a polyester or a polyether), an isocyanate (such as toluene diisocyanate), and a polymerization modifier (such as an amine and a tin compound). In some examples, the tissue interface 120 can be a reticulated polyurethane foam, such as that found in GRANUFOAM. TM Dressing or VACVERAFLO TM The reticulated polyurethane foam in the dressing is available from Kinetic Concepts, San Antonio, Texas.

[0036] The thickness of the tissue interface 120 may also vary depending on the needs of the prescribed treatment. For example, the thickness of the tissue interface may be reduced to reduce tension on the surrounding tissue. The thickness of the tissue interface 120 may also affect the conformability of the tissue interface 120. In some embodiments, a thickness in the range of about 5 mm to about 10 mm may be suitable.

[0037] The tissue interface 120 may be hydrophobic or hydrophilic. In examples where the tissue interface 120 may be hydrophilic, the tissue interface 120 may also wick fluid away from the tissue site while continuing to distribute negative pressure to the tissue site. The wicking properties of the tissue interface 120 may draw fluid away from the tissue site by capillary flow or other wicking mechanisms. An example of a potentially suitable hydrophilic material is a polyvinyl alcohol open-cell foam, such as WHITEFOAM available from Kinetic Concepts, Inc. of San Antonio, Texas. TM Dressings. Other hydrophilic foams may include those made from polyethers. Other foams that may exhibit hydrophilic properties include hydrophobic foams that have been treated or coated to render them hydrophilic.

[0038] In some embodiments, the tissue interface 120 can be constructed of a bioabsorbable material. Suitable bioabsorbable materials may include, but are not limited to, polymer blends of polylactic acid (PLA) and polyglycolic acid (PGA). The polymer blends may also include, but are not limited to, polycarbonate, polyfumarate, and caprolactone. The tissue interface 120 may also be used as a scaffold for new cell growth, or a scaffold material may be used in conjunction with the tissue interface 120 to promote cell growth. A scaffold is typically a substance or structure for enhancing or promoting the growth of cells or the 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 hydroxyapatite, carbonate, or processed allograft material.

[0039] In some embodiments, the cover 125 can provide a bacterial barrier and protection from physical trauma. The cover 125 can also be constructed of a material that can reduce evaporative losses and provide a fluid seal between two components or two environments (such as between a treatment environment and a local external environment). The cover 125 may include or be composed of an elastomeric film or film that can provide a seal sufficient to maintain a negative pressure at the tissue site for a given negative pressure source. In some applications, the cover 125 can have a high moisture vapor transmission rate (MVTR). For example, in some embodiments, the MVTR can be at least 250 grams per square meter per 24 hours (g / m 2 / 24 hours), measured using the upright cup technique at 38°C and 10% relative humidity (RH) according to ASTM E96 / E96M positive cup method. In some embodiments, up to 5000 g / m 2 / 24-hour MVTR provides effective breathability and mechanical properties.

[0040] In some exemplary embodiments, the cover 125 may be a polymeric disinfection drape that is permeable to water vapor but impermeable to liquids, such as a polyurethane film. Such disinfection drapes typically have a thickness in the range of 25 microns to 50 microns. For permeable materials, the permeability should generally be low enough so that the desired negative pressure can be maintained. The cover 125 may include, for example, one or more of the following materials: polyurethane (PU), such as hydrophilic polyurethane; cellulose; hydrophilic polyamide; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylic resin; silicone, such as hydrophilic silicone elastomer; natural rubber; polyisoprene; styrene-butadiene rubber; chloroprene rubber; polybutadiene; nitrile rubber; butyl rubber; ethylene propylene rubber; ethylene propylene diene monomer; chlorosulfonated polyethylene; polysulfide rubber; ethylene-vinyl acetate (EVA); copolyesters; and polyether block polyamide copolymers. Such materials are commercially available, for example, from 3M Company, Minneapolis Minnesota. Drapes; polyurethane (PU) drapes commercially available from Avery Dennison Corporation, Pasadena, California; polyether block polyamide copolymer (PEBAX), available, for example, from Arkema SA, Colombes, France; and Inspire 2301 and Inpsire 2327 polyurethane films commercially available from Expopack Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the cover 125 may include a 2600 g / m 2 / 24 hours MVTR (positive cup technology) and a thickness of about 30 microns for INSPIRE 2301.

[0041] Attachment devices can be used to attach cover 125 to an attachment surface, such as an undamaged epidermis, a pad, or another cover. Attachment devices can take a variety of forms. For example, the attachment device can be a medically acceptable pressure-sensitive adhesive configured to bond cover 125 to the epidermis around the tissue site. In some embodiments, for example, some or all of cover 125 may be coated with an adhesive having a coating weight between 25 grams per square meter and 65 grams per square meter (gsm), such as an acrylic adhesive. In some embodiments, a thicker adhesive or a combination of adhesives can be applied to improve sealing and reduce leakage. Other exemplary embodiments of the attachment device may include double-sided tape, paste, aqueous colloid, hydrogel, silicone gel, or organic gel.

[0042] Solution source 145 may also represent a container, canister, pouch, bag, or other storage component that may provide a solution for the infusion therapy. The composition of the solution may vary depending on the prescribed therapy, but examples of solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions.

[0043] Treatment Mode

[0044] In operation, the tissue interface 120 can be placed in the tissue site, above the tissue site, on the tissue site, or otherwise placed close to the tissue site. For example, if the tissue site is a wound, the tissue interface 120 can partially or completely fill the wound, or it can be placed above the wound. The cover 125 can be placed above the tissue interface 120 and sealed to the attachment surface near the tissue site. For example, the cover 125 can be sealed to the undamaged epidermis around the tissue site. Therefore, the dressing 110 can provide a sealed treatment environment that is basically isolated from the external environment close to the tissue site. The negative pressure source 105 and the solution source 145 can be fluidly connected to the tissue interface through one or more fluid conductors. The negative pressure source 105 can reduce the pressure in the sealed treatment environment, and the fluid from the solution source 145 can be dripped into the sealed treatment environment.

[0045] The fluid mechanics of using a negative pressure source to reduce the pressure in another component or location (such as within a sealed treatment environment) can be mathematically complex. However, the basic principles of fluid mechanics applicable to negative pressure therapy and instillation are generally well known to those skilled in the art, and the process of reducing pressure can be described herein illustratively as, for example, "delivering," "dispensing," or "generating" negative pressure.

[0046] Generally speaking, exudate and other fluids flow toward lower pressure along the fluid path. Therefore, the term "downstream" generally means something in the fluid path that is relatively closer to the negative pressure source or farther away from the positive pressure source. On the contrary, the term "upstream" means something that is relatively farther away from the negative pressure source or closer to the positive pressure source. Similarly, certain features can be conveniently described according to the fluid "inlet" or "outlet" in this reference system. This orientation is usually assumed for the purpose of describing the various features and components of this article. However, in some applications, the fluid path may also be reversed, such as by replacing the negative pressure source with a positive pressure source, and this description convention should not be understood as a restrictive convention.

[0047] The negative pressure applied to the tissue site through the tissue interface 120 in the sealed treatment environment can induce macro-strain and micro-strain in the tissue site. The negative pressure can also remove exudate and other fluids from the tissue site, which can be collected in the container 115.

[0048] In some embodiments, the controller 130 may receive and process data from one or more sensors, such as the first sensor 135. The controller 130 may also control the operation of one or more components of the treatment system 100 to manage the pressure delivered to the tissue interface 120. In some embodiments, the controller 130 may include an input for receiving a desired target pressure, and may be programmed to process data related to the setting and input of the target pressure to be applied to the tissue interface 120. In some exemplary embodiments, the target pressure may be a fixed pressure value, which is set by the operator as the target negative pressure desired for treatment at the tissue site and then provided as an input to the controller 130. The target pressure may vary from one tissue site to another based on the type of tissue forming the tissue site, the type of injury or wound (if any), the patient's medical condition, and the preferences of the attending physician. After selecting the desired target pressure, the controller 130 may operate the negative pressure source 105 in one or more control modes based on the target pressure, and may receive feedback from one or more sensors to maintain the target pressure at the tissue interface 120.

[0049] Figure 2 205 and 210. In some embodiments, the controller 130 may have a continuous pressure mode, in which the negative pressure source 105 is operated to provide a constant target negative pressure for the duration of the treatment or until manually deactivated, as indicated by lines 205 and 210. Additionally or alternatively, the controller may have an intermittent pressure mode, such as Figure 2 . Figure 2 In FIG. 1 , the x-axis represents time, and the y-axis represents the negative pressure generated by the negative pressure source 105 over time. Figure 2In the example of FIG. 2 , the controller 130 may operate the negative pressure source 105 to cycle between the target pressure and the atmospheric pressure. For example, the target pressure may be set at a value of −125 mmHg, as indicated by line 205, for a specified period of time (e.g., 5 minutes), followed by a specified period of time of deactivation (e.g., 2 minutes), as indicated by the gap between solid lines 215 and 220. The cycle may be repeated by activating the negative pressure source 105, as indicated by line 220, which may form a square wave pattern between the target pressure and the atmospheric pressure.

[0050] In some exemplary embodiments, the increase in negative pressure from ambient pressure to target pressure may not be instantaneous. For example, the negative pressure source 105 and the dressing 110 may have an initial rise time, as indicated by the dashed line 225. The initial rise time may vary depending on the type of dressing and treatment device used. For example, the initial rise time of one treatment system may be in the range of about 20 mmHg / s to 30 mmHg / s, and the initial rise time of another treatment system may be in the range of about 5 mmHg / s to 10 mmHg / s. If the treatment system 100 is operated in intermittent mode, the repetitive rise time as indicated by the solid line 220 may be a value substantially equal to the initial rise time as indicated by the dashed line 225.

[0051] Figure 3 is a graph showing additional details that may be associated with another exemplary pressure control mode in some embodiments of treatment system 100. Figure 3 In FIG. 1 , the x-axis represents time, and the y-axis represents the negative pressure generated by the negative pressure source 105 . Figure 3 The target pressure in the example of the treatment system 100 can vary over time in the dynamic pressure mode. For example, the target pressure can vary in the form of a triangular waveform, varying between negative pressures of 50 mmHg and 135 mmHg, with the rise time 305 set at a rate of +25 mmHg / min and the fall time 310 set at -25 mmHg / min. In other embodiments of the treatment system 100, the triangular waveform can vary between negative pressures of 25 mmHg and 135 mmHg, with the rise time 305 set at a rate of +30 mmHg / min and the fall time 310 set at -30 mmHg / min.

[0052] In some embodiments, the controller 130 can control or determine a variable target pressure in a dynamic pressure mode, and the variable target pressure can vary between a maximum pressure value and a minimum pressure value, which can be set as an input specified by the operator as a desired negative pressure range. The variable target pressure can also be processed and controlled by the controller 130, and the controller can change the target pressure according to a predetermined waveform such as a triangular waveform, a sine waveform, or a sawtooth waveform. In some embodiments, the waveform can be set by the operator to a predetermined or time-varying negative pressure required for treatment.

[0053] Figure 4 405 is a diagram illustrating details associated with an exemplary method 400 for operating the treatment system 100 to provide negative pressure therapy and instillation therapy to the tissue interface 120. In some embodiments, the controller 130 may receive and process data, such as data related to the instillation solution provided to the tissue interface 120. Such data may include the type of instillation solution specified by the clinician, the volume of the fluid or solution to be instilled into the tissue site ("fill volume"), and the amount of time specified for the solution to remain at the tissue site before negative pressure is applied to the tissue site ("residence time"). The fill volume may be, for example, between 10 mL and 500 mL, and the residence time may be between 1 second and 30 minutes. The controller 130 may also control the operation of one or more components of the treatment system 100 to instill the solution, as shown at 405. For example, the controller 130 may manage the fluid distributed from the solution source 145 to the tissue interface 120. In some embodiments, fluid may be instilled into a tissue site by applying negative pressure from negative pressure source 105 to reduce pressure at the tissue site, thereby drawing solution into tissue interface 120, as shown at 410. In some embodiments, solution may be instilled into a tissue site by applying positive pressure from positive pressure source 150 to move solution from solution source 145 to tissue interface 120, as shown at 415. Additionally or alternatively, solution source 145 may be elevated to a height sufficient to allow gravity to move solution into tissue interface 120, as shown at 420.

[0054] At 425, the controller 130 may also control the fluid dynamics of the instillation by providing a continuous flow of solution at 430 or an intermittent flow of solution at 435. At 440, negative pressure may be applied to provide a continuous flow or an intermittent flow of solution. The application of negative pressure may be implemented to provide a continuous pressure operating mode at 445, thereby achieving a continuous flow of the instillation solution flowing through the tissue interface 120, or it may be implemented to provide a dynamic pressure operating mode at 450, thereby changing the flow of the instillation solution flowing through the tissue interface 120. Alternatively, the application of negative pressure may be implemented to provide an intermittent operating mode at 455, thereby allowing the instillation solution to reside at the tissue interface 120. In the intermittent mode, a specific fill volume and residence time may be provided depending on, for example, the type of tissue site being treated and the type of dressing being utilized. Negative pressure therapy may be applied at 460 after or during the instillation of the solution. The controller 130 may be used to select an operating mode and duration of negative pressure therapy before initiating another infusion cycle at 465 by instilling more solution at 405 .

[0055] Figure 5is a graph illustrating additional details of another exemplary control mode that may be associated with some embodiments of the controller 130 to provide negative pressure therapy and instillation therapy to the tissue interface 120. Figure 5 In an example of , the controller 130 is configured to provide discrete intervals of negative pressure and instillation. The controller 130 may operate the negative pressure source 105 in an intermittent pressure mode to maintain a target negative pressure 205 during the negative pressure intervals. During the instillation interval 505, the controller 130 may deactivate the negative pressure source 105 and operate the positive pressure source 150 to instill a specified volume of fluid from the solution source 145 into the tissue site. In some examples, the target negative pressure, the specified volume, or both may be preset by the controller 130, or may be set by an operator at runtime. The controller 130 may also provide a pressure holding interval 510, during which neither the negative pressure source 105 nor the positive pressure source 150 is active. In some examples, the cycle may be repeated. Figure 5 In the example of FIG. 5 , the controller 130 reactivates the negative pressure source 105 after the dwelling interval 510 .

[0056] Figure 5 Also shown is an example of a controller 130 configured to provide an intermittent purge cycle. Figure 5 In the embodiment, the controller 130 periodically activates a first purge cycle 515 and a second purge cycle 520. For example, the negative pressure source 105 can be connected to the dressing 110 via a first fluid conductor, and the controller 130 can activate the first purge cycle 515 by opening a valve to expose the first fluid conductor to ambient pressure or positive pressure. The increase in pressure can force exudate to leave the first fluid conductor, thereby reducing the accumulation of exudate that can block the first fluid conductor. Similarly, the solution source 145 can be connected to the dressing 110 via a second fluid conductor, and the second purge cycle 520 can include dripping a relatively small volume of fluid from the solution source 145 through the second fluid conductor. For example, a suitable purge volume can be in the range of about 0.1 milliliters to about 1 milliliter. The purge frequency can also vary. In some embodiments, the frequency can be in the range of about 5 minutes to 20 minutes. In some embodiments, a purge volume of about 0.2 milliliters and a frequency of about 10 minutes can be suitable for reducing material deposition in the second fluid conductor near the dressing 110. The second purge cycle 520 can be activated during negative pressure intervals, such as Figure 5 As shown in the example of, or activated between negative pressure intervals. In some configurations, the purge volume of solution can be removed by negative pressure through the first fluid conductor. In some examples, the first purge cycle 515 and the second purge cycle 520 can be activated at the same time.

[0057] The systems, devices, and methods described herein can provide significant advantages. For example, the interaction between the instillation solution and the proteins and lipids from the exudate can produce sticky deposits that can collect at the dressing interface. The instillation purge cycle can substantially reduce or eliminate these deposits that can clog the fluid conductors and other dispensing components.

[0058] Although shown in several exemplary embodiments, it will be appreciated by those skilled in the art that the systems, devices and methods herein are susceptible to various changes and modifications, and that such changes and modifications fall within the scope of the appended claims. In addition, unless the context clearly requires otherwise, descriptions of various alternatives using terms such as "or" do not need to be mutually exclusive, and unless the context clearly requires otherwise, the indefinite article "a" or "an" does not limit the subject matter to a single instance. For the purposes of sale, manufacture, assembly or use, it is also possible to combine or eliminate components in various configurations. For example, in some configurations, the dressing 110, the container 115, or both may be eliminated or separated from the manufacture or sale of the other components. In other exemplary configurations, the controller 130 may also be manufactured, configured, assembled or sold independently of the other components.

[0059] The appended claims set forth novel and inventive aspects of the subject matter described above, but the claims may also cover additional subject matter not specifically cited. For example, certain features, elements, or aspects may be omitted from the claims if it is not necessary to distinguish novel and inventive features from features known to those of ordinary skill in the art. Features, elements, and aspects described herein in the context of some embodiments may also be omitted, combined, or replaced by alternative features serving the same, equivalent, or similar purposes without departing from the scope of the invention as defined by the appended claims.

Claims

1. A device for treating a tissue site, the device comprising: a negative pressure source configured to be fluidly coupled to the tissue site; an instillation source configured to be fluidly coupled to the tissue site; and a controller operatively coupled to the negative pressure source and the instillation source, the controller being configured to: The negative pressure source and the infusion source are operated to: intermittently delivering negative pressure to the tissue site for a negative pressure interval; delivering a fill volume of instillation fluid to the tissue site for an instillation interval; and A purge volume of instillation fluid is delivered to the tissue site at a purge frequency, the controller being configured to deliver the purge volume during the negative pressure interval.

2. The device of claim 1, wherein the fill volume is at least 10 times the purge volume.

3. The device of claim 1, wherein a ratio of the fill volume to the purge volume is in a range of 10:1 to 5000:

1.

4. The device of claim 1, wherein the fill volume is in the range of 10 ml to 500 ml, and the purge volume is in the range of 0.1 ml to 1 ml.

5. The device according to claim 1, wherein the purge frequency is in the range of 5 minutes to 20 minutes.

6. The device according to claim 1, wherein: The filling volume is in the range of 10 ml to 500 ml; The purge volume is in the range of 0.1 ml to 1 ml; and The purge frequency is in the range of 5 minutes to 20 minutes.

7. The apparatus of claim 1, further comprising a fluid conductor fluidly coupled to the instillation source, and wherein the controller is configured to deliver the purge volume of instillation fluid through the fluid conductor.

8. The apparatus of claim 1 , further comprising a first fluid conductor fluidly coupled to the negative pressure source, a second fluid conductor fluidly coupled to the drip source, and wherein the controller is configured to deliver the purge volume of drip fluid through the second fluid conductor and to remove the purge volume of drip fluid through the first fluid conductor.

9. The apparatus of claim 1, further comprising a user interface coupled to the controller and operable to receive input to configure at least one of the purge volume and the purge frequency.

10. A device for treating a tissue site, the device comprising: dressing; a first fluid conductor coupled to the dressing; a second fluid conductor coupled to the dressing; a negative pressure source coupled to the first fluid conductor; a drip source coupled to the second fluid conductor; and a controller operatively coupled to the negative pressure source and the instillation source, the controller being configured to: delivering negative pressure to the dressing via the first fluid conductor for a negative pressure interval, delivering a fill volume of instillation fluid to the dressing via the second fluid conductor for a sustained instillation interval, and delivering a purge volume of instillation fluid to the dressing at a purge frequency via the second fluid conductor; wherein the purge volume is delivered during the negative pressure interval.

11. The device of claim 10, wherein the fill volume is at least 10 times the purge volume.

12. The apparatus of claim 10, wherein a ratio of the fill volume to the purge volume is in the range of 10:1 to 5000:

1.

13. The device of claim 10, wherein the purge volume is in the range of 0.1 ml to 1 ml.

14. The device of claim 10, wherein the sweep volume is delivered at a frequency of no greater than 20 minutes.

15. The device of claim 10, wherein the sweep volume is delivered at a frequency of no less than 5 minutes.

16. The device of claim 10, wherein the sweep volume is delivered at a frequency of between 5 minutes and 20 minutes.

Images