WO2023203399A1

WO2023203399A1 - Systems, methods, and apparatuses for indicating fill level of a canister

Info

Publication number: WO2023203399A1
Application number: PCT/IB2023/052647
Authority: WO
Inventors: Benjamin A. Pratt; Christopher BREACH; James K. SEDDON
Original assignee: 3M Innovative Properties Company
Priority date: 2022-04-19
Filing date: 2023-03-17
Publication date: 2023-10-26

Abstract

Apparatuses, systems, and methods for displaying a fill level of a canister of a negative pressure system are described. The apparatus includes an optical switching layer and an indicator layer. The optical switching layer is configured to be coupled to an inside of the canister. The optical switching layer is further configured to switch from a substantially opaque state to a substantially transparent state in response to fluid in the canister. The indicator layer includes a display side with at least one graphic on the display side. The indicator layer is coupled to the optical switching layer with the display side disposed adjacent to the optical switching layer. The at least one graphic is visible through the canister when the optical switching layer is in the substantially transparent state and the at least one graphic is not visible when the optical switching layer is in the substantially opaque state.

Description

SYSTEMS, METHODS, AND APPARATUSES FOR INDICATING FILL LEVEL OF A CANISTER

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 63/332,561, filed on April 19, 2022, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The invention set forth in the appended claims relates generally to tissue treatment systems and more particularly, but without limitation, to systems, methods, and apparatuses for indicating fill level of a canister in a negative pressure wound therapy system.

BACKGROUND

[0003] Clinical studies and practice have shown that reducing pressure in proximity to a tissue site can augment and accelerate growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but it has proven particularly advantageous for treating wounds. Regardless of the etiology of a wound, whether trauma, surgery, or another cause, proper care of the wound is important to the outcome. 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 "negativepressure wound therapy," "reduced-pressure therapy," "vacuum therapy," "vacuum-assisted closure," and "topical negative-pressure," for example. Negative-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and microdeformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times.

[0004] While the clinical benefits of negative-pressure therapy are widely known, improvements to therapy systems, components, and processes may benefit healthcare providers and patients.

BRIEF SUMMARY

[0005] New and useful systems, apparatuses, and methods for indicating fill level of a canister in a negative-pressure therapy environment 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.

[0006] For example, in some embodiments, an apparatus for use in a negative pressure system including a negative pressure pump and a canister fluidly coupled to the negative pressure pump for collecting fluid is described. The apparatus can include an optical switching layer and an indicator layer. The optical switching layer can be configured to be coupled to an inside of the canister. The optical switching layer can further be configured to switch from a substantially opaque state to a substantially transparent state in response to fluid in the canister. The indicator layer can include a display side. The display side can include at least one graphic. The indicator layer can be coupled to the optical switching layer with the display side disposed adjacent to the optical switching layer. The at least one graphic can be visible through the canister when the optical switching layer is in a substantially transparent state and not visible when the optical switching layer is in the substantially opaque state.

[0007] In some example embodiments, the optical switching layer can be configured to wick fluid in contact with the optical switching layer. In other example embodiments, the apparatus can further include a chamber between the optical switching layer and the canister. The chamber can be configured to receive a portion of the fluid in the canister. In any of the above example embodiments, the optical switching layer can be a microporous hydrophilic polymer that can be configured to absorb and desorb fluid.

[0008] In some example embodiments, the indicator layer can include a plurality of perforations between a periphery of the indicator layer and a central portion of the indicator layer. The plurality of perforations can be configured to enable fluid in the canister to pass through the indicator layer to reach the optical switching layer. In some embodiments, the optical switching layer can be coupled to the central portion of the indicator layer. The apparatus can further include an adhesive in some example embodiments. The adhesive can be coupled to the periphery of the indicator layer and can be configured to couple the apparatus to the inside of the canister.

[0009] In some example embodiments, the apparatus can further include a plurality of fluid breaks coupled to the optical switching layer. The plurality of fluid breaks can be configured to prevent fluid from wicking through the optical switching layer past the fill level of the canister. In other example embodiments, the optical switching layer can include a plurality of optical switching portions. Each optical switching portion of the plurality of optical switching portions can be separated from another optical switching portion of the plurality of optical switching portions.

[0010] In other example embodiments, a canister for storing fluid in a negative pressure wound therapy system is described. The canister can include a canister body configured to be opaque and a lid configured to couple to the canister body to form a sealed interior. The canister body can include a viewing window configured to be transparent and a fill level indicator. The fill level indicator can be configured to couple to an interior of the canister and can be configured to be visible through the viewing window. The fill level indicator can include an optical switching layer and an indicator layer. The optical switching layer can be configured to be coupled to an inside of the canister. The optical switching layer can further be configured to switch from a substantially opaque state to a substantially transparent state in response to fluid in the canister. The indicator layer can include a display side. The display side can include at least one graphic. The indicator layer can be coupled to the optical switching layer with the display side disposed adjacent to the optical switching layer. In some embodiments, the at least one graphic can be visible through the viewing window of the canister when the optical switching layer is in a substantially transparent state and not visible when the optical switching layer is in the substantially opaque state.

[0011] In some example embodiments, the optical switching layer can be configured to wick fluid in contact with the optical switching layer. In other example embodiments, a chamber can be disposed between the optical switching layer and the canister. The chamber can be configured to receive a portion of the fluid in the canister. In any of the above example embodiments, the optical switching layer can be a microporous hydrophilic polymer that can be configured to absorb and desorb fluid.

[0012] In some example embodiments, the indicator layer can include a plurality of perforations between a periphery of the indicator layer and a central portion of the indicator layer. The plurality of perforations can be configured to enable fluid in the canister to pass through the indicator layer to reach the optical switching layer. In some embodiments, the optical switching layer can be coupled to the central portion of the indicator layer. The fill level indicator can further include an adhesive in some example embodiments. The adhesive can be coupled to the periphery of the indicator layer and can be configured to couple the apparatus to the inside of the canister.

[0013] In some example embodiments, a plurality of fluid breaks can be coupled to the optical switching layer. The plurality of fluid breaks can be configured to prevent fluid from wicking through the optical switching layer past the fill level of the canister. In other example embodiments, the optical switching layer can include a plurality of optical switching portions. Each optical switching portion of the plurality of optical switching portions can be separated from another optical switching portion of the plurality of optical switching portions.

[0014] In other example embodiments, a method of displaying a fill level of a canister can be described. The method can include providing the canister including a fill level indicator, collecting fluid in the canister, and displaying, with the fill level indicator, the fill level of the canister. The fill level indicator can be coupled to an interior of the canister and can include the optical switching layer. The optical switching layer can be configured to switch from an opaque state to a transparent state in response to fluid in the canister. The fill level indicator can further include the indicator layer. The indicator layer can include a display side with at least one graphic on the display side. The indicator layer can be coupled to the optical switching layer with the display wide disposed adjacent to the optical switching layer.

[0015] In some example embodiments, displaying, with the fill level indicator, a level of the fluid in the canister can include wicking fluid through at least one edge of the optical switching layer exposed to the fluid in the canister. The fluid can transition the optical switching layer from the opaque state to the transparent state. The method can further include exposing the indicator layer through a transparent portion of the optical switching layer to reveal the fill level of the canister.

[0016] In other example embodiments, displaying, with the fill level indicator, a level of the fluid in the canister can include collecting fluid from the canister in a chamber between the fill level indicator and the interior of the canister through a plurality of perforations of the indicator layer. The method can further include wicking the fluid in the chamber through the optical switching layer. The fluid can transition the optical switching layer from the opaque state to the transparent state. The method can further include exposing the indicator layer through a transparent portion of the optical switching layer to reveal the fdl level of the canister.

[0017] Objectives, advantages, and a preferred mode of making and using the claimed subject matter may be understood best by reference to the accompanying drawings in conjunction with the following detailed description of illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a block diagram of an example embodiment of a therapy system that can provide negative-pressure treatment in accordance with this specification;

[0019] Figure 2A is a perspective view of an illustrative example embodiment of a canister of the therapy system of Figure 1 ;

[0020] Figure 2B is a perspective view of the canister of Figure 2A;

[0021] Figure 2C is an exploded view of the canister of Figure 2A;

[0022] Figure 3A is a perspective view of an illustrative example embodiment of a fill level indicator that may be associated with the canister of Figure 2A;

[0023] Figure 3B is an exploded view of the fill level indicator of Figure 3A;

[0024] Figure 4A is a perspective view of another illustrative example embodiment of the fill level indicator that may be associated with the canister of Figure 2A;

[0025] Figure 4B is an exploded view of the fill level indicator of Figure 4A;

[0026] Figure 5A is a side view of another illustrative example embodiment of the canister of the therapy system of Figure 1 ;

[0027] Figure 5B is a perspective view of the canister of Figure 5 A;

[0028] Figure 5 C is an exploded view of the canister of Figure 5 A;

[0029] Figure 6A is a perspective view of another illustrative example embodiment of the canister of the therapy system of Figure 1;

[0030] Figure 6B is a side view of the canister of Figure 6A;

[0031] Figure 7 is a front view of an illustrative example embodiment of a unit that may include a therapy unit and the canister of the therapy system of Figure 1 ;

[0032] Figure 8 is a graph illustrating a relationship between the distance traveled by saline through a PVDF material and a LIBELTEX material with respect to time;

[0033] Figure 9 is a graph illustrating a relationship between the distance traveled by 14cP SWF through a PVDF material and a LIBELTEX material with respect to time; and

[0034] Figure 10 is a graph illustrating a relationship between the distance traveled by 30cP SWF through a PVDF material and a LIBELTEX material with respect to time. DESCRIPTION OF EXAMPLE EMBODIMENTS

[0035] The following description of example embodiments provides information that enables a person skilled in the art to make and use the subject matter set forth in the appended claims, but it may omit certain details already well-known in the art. The following detailed description is, therefore, to be taken as illustrative and not limiting.

[0036] The example embodiments may also be described herein with reference to spatial relationships between various elements or to the spatial orientation of various elements depicted in the attached drawings. In general, such relationships or orientation assume a frame of reference consistent with or relative to a patient in a position to receive treatment. However, as should be recognized by those skilled in the art, this frame of reference is merely a descriptive expedient rather than a strict prescription.

[0037] Figure 1 is a block diagram of an example embodiment of a therapy system 100 that can provide negative-pressure therapy to a tissue site in accordance with this specification.

[0038] The term “tissue site” in this context broadly refers to a wound, defect, or other treatment target 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, partialthickness bums, 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 applied to a tissue site to grow additional tissue that may be harvested and transplanted.

[0039] The therapy system 100 may include a source or supply of negative pressure, such as a negative pressure pump or a negative-pressure source 105, and one or more distribution components. A distribution component is preferably detachable and may be disposable, reusable, or recyclable. A dressing, such as a dressing 110, and a fluid container, such as a canister 115, are examples of distribution components that may be associated with some examples of the therapy system 100. The dressing 110 may comprise or consist essentially of a tissue interface 120, a cover 125, or both in some embodiments.

[0040] A fluid conductor is another illustrative example of a distribution component. A “fluid conductor,” in this context, broadly includes a tube, pipe, hose, conduit, or other structure with one or more lumina or open pathways adapted to convey a fluid between two ends. Typically, a tube is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary. Moreover, some fluid conductors may be molded into or otherwise integrally combined with other components. Distribution components may also include or comprise interfaces or fluid ports to facilitate coupling and de-coupling other components. In some embodiments, for example, a dressing interface may facilitate coupling a fluid conductor to the dressing 110. For example, such a dressing interface may be a SENSAT.R.A.C.™ Pad available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0041] The therapy system 100 may also include a regulator or controller, such as a controller 130. Additionally, the therapy system 100 may include sensors to measure operating parameters and provide feedback signals to the controller 130 indicative of the operating parameters. As illustrated in Figure 1, for example, the therapy system 100 may include a first sensor 135 and a second sensor 140 coupled to the controller 130.

[0042] Some components of the therapy 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 therapy. For example, in some embodiments, the negative-pressure source 105 may be combined with the controller 130 and other components into a therapy unit 145.

[0043] In general, components of the therapy system 100 may be coupled directly or indirectly. For example, the negative-pressure source 105 may be directly coupled to the canister 115 and may be indirectly coupled to the dressing 110 through the canister 115. Coupling may include fluid, mechanical, thermal, electrical, or chemical coupling (such as a chemical bond), or some combination of coupling in some contexts. 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 a tissue site. In some embodiments, components may also be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material.

[0044] A negative-pressure supply, such as the negative-pressure source 105, may be a reservoir of air at a negative pressure or may be a manual or electrically-powered device, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micropump, for example. “Negative pressure” generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to a sealed therapeutic environment. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. Alternatively, the pressure may be less than a hydrostatic pressure associated with tissue at the tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures. 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. While the amount and nature of negative pressure provided by the negative-pressure source 105 may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -5 mm Hg (-667 Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are between -50 mm Hg (-6.7 kPa) and -300 mm Hg (-39.9 kPa).

[0045] The canister 115 is representative of a container, canister, pouch, or other storage component, which can be used to manage exudates and other fluids withdrawn 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 rigid container storage, and a re-usable container could reduce waste and costs associated with negative-pressure therapy.

[0046] A controller, such as the controller 130, may be a microprocessor or computer programmed to operate one or more components of the therapy system 100, such as the negativepressure source 105. In some embodiments, for example, the controller 130 may be a microcontroller, which generally comprises an integrated circuit containing a processor core and a memory programmed to directly or indirectly control one or more operating parameters of the therapy system 100. Operating parameters may include the power applied to the negative-pressure source 105, the pressure generated by the negative-pressure source 105, or the pressure distributed to the tissue interface 120, for example. The controller 130 is also preferably configured to receive one or more input signals, such as a feedback signal, and programmed to modify one or more operating parameters in response to the input signals.

[0047] Sensors, such as the first sensor 135 and the second sensor 140, are generally known in the art as apparatuses operable to detect or measure a physical phenomenon or property, and generally provide a signal indicative of the phenomenon or property that is 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 therapy system 100. In some embodiments, the first sensor 135 may be a transducer configured to measure pressure in a pneumatic pathway and convert the measurement to a signal indicative of the pressure measured. In some embodiments, for example, the first sensor 135 may be a piezo-resistive strain gauge. The second sensor 140 may optionally measure operating parameters of the negative-pressure source 105, such as a voltage or current, in some embodiments. The signals from the first sensor 135 and the second sensor 140 are operable as an input signal to the controller 130, but some signal conditioning may be appropriate in some embodiments. For example, the signal may need to be filtered or amplified before it can be processed by the controller 130. Typically, the signal is an electrical signal, but may be represented in other forms, such as an optical signal.

[0048] The tissue interface 120 can be generally adapted to partially or fully contact a tissue site. The tissue interface 120 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. For example, the size and shape of the tissue interface 120 may be adapted to the contours of deep and irregular shaped tissue sites. Any or all of the surfaces of the tissue interface 120 may have an uneven, coarse, or jagged profile.

[0049] In some embodiments, the tissue interface 120 may comprise or consist essentially of a manifold. A manifold in this context may comprise or consist essentially of a means for collecting or distributing fluid across the tissue interface 120 under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across the tissue interface 120, 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.

[0050] In some illustrative embodiments, a manifold may comprise a plurality of pathways, which can be interconnected to improve distribution or collection of fluids. In some illustrative embodiments, a manifold may comprise or consist essentially of a porous material having interconnected fluid pathways. Examples of suitable porous material that can be adapted to form interconnected fluid pathways (e.g., channels) may include cellular foam, including open-cell foam such as reticulated foam; porous tissue collections; and other porous material such as gauze or felted mat that generally include pores, edges, and/or walls. Liquids, gels, and other foams may also include or be cured to include apertures and fluid pathways. In some embodiments, a manifold may additionally or alternatively comprise projections that form interconnected fluid pathways. For example, a manifold may be molded to provide surface projections that define interconnected fluid pathways.

[0051] In some embodiments, the tissue interface 120 may comprise or consist essentially of reticulated foam having pore sizes and free volume that may vary according to needs of a prescribed therapy. For example, reticulated foam having a free volume of at least 90% may be suitable for many therapy applications, and foam having an average pore size in a range of 400-600 microns (40-50 pores per inch) may be particularly suitable for some types of therapy. The tensile strength of the tissue interface 120 may also vary according to needs of a prescribed therapy. For example, the tensile strength of foam may be increased for instillation of topical treatment solutions. The 25% compression load deflection of the tissue interface 120 may be at least 0.35 pounds per square inch, and the 65% compression 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 may be foam comprised of polyols such as polyester or polyether, isocyanate such as toluene diisocyanate, and polymerization modifiers such as amines and tin compounds. In some examples, the tissue interface 120 may be reticulated polyurethane foam such as found in GRANUFOAM™ dressing or V.A.C. VERAFLO™ dressing, both available from Kinetic Concepts, Inc. of San Antonio, Texas.

[0052] The thickness of the tissue interface 120 may also vary according to needs of a prescribed therapy. For example, the thickness of the tissue interface may be decreased to reduce tension on peripheral tissue. The thickness of the tissue interface 120 can also affect the conformability of the tissue interface 120. In some embodiments, a thickness in a range of about 5 millimeters to 10 millimeters may be suitable.

[0053] The tissue interface 120 may be either hydrophobic or hydrophilic. In an example in which the tissue interface 120 may be hydrophilic, the tissue interface 120 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 120 may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic material that may be suitable is a polyvinyl alcohol, open-cell foam such as V.A.C. WHITEFOAM™ dressing available from Kinetic Concepts, Inc. of San Antonio, Texas. 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.

[0054] In some embodiments, the tissue interface 120 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 120 may further serve 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 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.

[0055] In some embodiments, the cover 125 may provide a bacterial barrier and protection from physical trauma. The cover 125 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 125 may comprise or consist of, for example, an elastomeric fdm or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. The cover 125 may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least 250 grams per square meter per twenty-four hours in some embodiments, measured using an upright cup technique according to ASTM E96/E96M Upright Cup Method at 38°C and 10% relative humidity (RH). In some embodiments, an MVTR up to 5,000 grams per square meter per twenty-four hours may provide effective breathability and mechanical properties.

[0056] In some example embodiments, the cover 125 may be a polymer drape, such as a polyurethane fdm, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. The cover 125 may comprise, for example, one or more of the following materials: polyurethane (PU), such as hydrophilic polyurethane; cellulosics; hydrophilic polyamides; polyvinyl alcohol; polyvinyl pyrrolidone; hydrophilic acrylics; silicones, such as hydrophilic silicone elastomers; natural rubbers; 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); co-polyester; and polyether block polymide copolymers. Such materials are commercially available as, for example, Tegaderm® drape, commercially available from 3M Company, Minneapolis Minnesota; polyurethane (PU) drape, commercially available from Avery Dennison Corporation, Pasadena, California; polyether block polyamide copolymer (PEBAX), for example, from Arkema S.A., Colombes, France; and Inspire 2301 and Inpsire 2327 polyurethane fdms, commercially available from Expopack Advanced Coatings, Wrexham, United Kingdom. In some embodiments, the cover 125 may comprise INSPIRE 2301 having an MVTR (upright cup technique) of 2600 g/m²/24 hours and a thickness of about 30 microns.

[0057] An attachment device may be used to attach the cover 125 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 configured to bond the cover 125 to epidermis around a tissue site. In some embodiments, for example, some or all of the cover 125 may be coated with an adhesive, such as an acrylic adhesive, which may have a coating weight of about 25-65 grams per square meter (g.s.m.). 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.

[0058] In operation, the tissue interface 120 may be placed within, over, on, or otherwise proximate to a tissue site. If the tissue site is a wound, for example, the tissue interface 120 may partially or completely fill the wound, or it may be placed over the wound. The cover 125 may be placed over the tissue interface 120 and sealed to an attachment surface near a tissue site. For example, the cover 125 may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing 110 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source 105 can reduce pressure in the sealed therapeutic environment.

[0059] The fluid mechanics of using a negative-pressure source to reduce pressure in another component or location, such as within a sealed therapeutic environment, 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.

[0060] In general, exudate and other fluid flow toward lower pressure along a fluid path. Thus, the term “downstream” typically implies a location in a fluid path relatively closer to a source of negative pressure or further away from a source of positive pressure. Conversely, the term “upstream” implies a location relatively further away from a source of negative pressure or closer to a source of positive pressure. 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 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.

[0061] Negative pressure applied across the tissue site through the tissue interface 120 in the sealed therapeutic environment can induce macro-strain and micro-strain in the tissue site. Negative pressure can also remove exudate and other fluid from a tissue site, which can be collected in the canister 115.

[0062] 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 therapy 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 for processing data relating to the setting and inputting of the target pressure to be applied to the tissue interface 120. In some example embodiments, the target pressure may be a fixed pressure value set by an operator as the target negative pressure desired for therapy at a tissue site and then provided as input to the controller 130. The target pressure may vary from tissue site to tissue site based on the type of tissue forming a tissue site, the type of injury or wound (if any), the medical condition of the patient, and the preference of the attending physician. After selecting a desired target pressure, the controller 130 can 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.

[0063] Negative-pressure therapy has been repeatedly shown to be effective in the treatment of difficult to heal wounds. Manufacturers are designing current negative-pressure therapy systems to include opaque canisters to provide increased privacy to patients. Opaque canisters provide increased privacy but also make it difficult for health care providers to determine an accurate fill level of the canister. Without being able to determine an accurate fill level of an opaque canister, health care providers may replace the canister before it is full which may increase costs and reduce patient satisfaction with the negative-pressure therapy system. A negative-pressure therapy system capable of obscuring wound fluid while also providing a way for the fill level of the canister to be monitored is a long sought but unsolved solution in the art.

[0064] Figures 2A-2C depict an example embodiment of the canister 115 of Figure 1. The canister 115 may include a canister body 202 and a lid 204. The lid 204 may be releasably coupled to the canister body 202 to form a sealed interior 206 of the canister 115 between the canister body 202 and the lid 204. The lid 204 may be coupled to the canister body 202 at one or more attachment points, by one or more adhesives, or other suitable methods of creating the sealed interior 206. In some embodiments, the canister body 202 may be substantially opaque to hide any contents in the sealed interior 206 from being seen. In some embodiments, the lid 204 may also be opaque. In other embodiments, the lid 204 may be transparent. In embodiments where the lid 204 is transparent, the lid 204 may be obscured from view by another part of the therapy system 100 such that any fluids in the sealed interior 206 of the canister 115 are unable to be seen by observers. If the lid 204 is transparent, it may allow health care providers to easily view the contents of the canister 115 when the canister 115 is separated from the therapy system 100. [0065] The canister 115 may have a first end 208 and a second end 210 opposite the first end 208. The canister 115 may have an optimal orientation such that fluid 212 flows into the sealed interior 206 of the canister 115 and fills the canister 115 beginning at the first end 208 and filling towards the second end 210.

[0066] The canister 115 may have a first wall 214 that may have an exterior surface 216 and an interior surface opposite the exterior surface 216. In some embodiments, the first wall 214 may include a viewing window 218. The viewing window 218 may be transparent and may provide a window to the sealed interior 206 of the canister 115 from outside the canister 115. The first wall 214 may have a first edge 220, a second edge 222 opposite the first edge 220, a third edge 224 extending from the first edge 220 to the second edge 222, and a fourth edge 226 opposite the third edge 224. The canister 115 may further include a second wall 228, a third wall 230 opposite the second wall 228, a fourth wall 232 connecting the second wall 228 and the third wall 230, and a fifth wall 234 opposite the fourth wall 232. In some embodiments, the first edge 220 may be curved or beveled and may connect the first wall 214 to the second wall 228. Similarly, the second edge 222 may be curved or beveled and may connect the first wall 214 to the third wall 230, the third edge 224 may be curved or beveled and may connect the first wall 214 to the fourth wall 232, and the fourth edge 226 may be curved or beveled and may connect the first wall 214 to the fifth wall 234. In other embodiments, the first edge 220, the second edge 222, the third edge 224, and the fourth edge 226 may be planar or flat such that the canister body 202 is similar to a rectangular prism.

[0067] The lid 204 may have a first surface 236 and a second surface 238 opposite the first surface 236. The lid 204 may further include a first edge 240, a second edge 242 opposite the first edge 240, a third edge 244 configured to connect the first edge 240 to the second edge 242, and a fourth edge 246 opposite the third edge 244. The first edge 240 may be received by the second wall 228 when the lid 204 is coupled to the canister body 202. Similarly, when the lid 204 is coupled to the canister body 202, the second edge 242 may be received by the third wall 230, the third edge 244 may be received by the fourth wall 232, and the fourth edge 246 may be received by the fifth wall 234. In some embodiments, the third edge 244 and the fourth edge 246 of the lid 204 may be curved and the first edge 240 and the second edge 242 may be straight. In other embodiments, the lid 204 may be a different size or shape but may still be received by the canister body 202 to create the sealed interior 206.

[0068] The canister 115 may comprise a type of material having sufficient rigidity and structural integrity to withstand the negative pressure required for negative-pressure treatment and to contain fluid therein. Some exemplary materials of the canister 115 are plastics, polymers, thermoplastics, metals, metal alloys, composition material, fiber-type materials, and other similar materials. The plastics described herein may be a substance or structure capable of being shaped or molded with or without the application of heat, a high polymer, usually synthetic, combined with other ingredients such as curatives, fillers, reinforcing agents, plasticizers, etc. Plastics can be formed or molded under heat and pressure in its raw state and machined to high dimensional accuracy, trimmed and finished in its hardened state. The thermoplastic type can be resoftened to its original condition by heat. In addition, the plastics may mean engineered plastics such as those that are capable of sustaining high levels of stress and are machinable and dimensionally stable. Some exemplary plastics are nylon, acetyls, polycarbonates, ABS resins, PPO/styrene, ISOPLAST 2530, TURLUX HS 2822, and polybutylene terephthalate. The thermoplastics described herein may be high polymers that soften when exposed to heat and return to their original condition when cooled to room temperature.

[0069] In some embodiments, the canister 115 may further include a fill level indicator 250. The fill level indicator 250 may be configured to couple to the inside of the canister 115. In some embodiments, the fill level indicator 250 may couple to the interior surface of the first wall 214 of the canister 115. The fill level indicator 250 may be substantially aligned with the viewing window 218 of the first wall 214. The fill level indicator 250 may be configured to prevent the fluid 212 from being observed through the viewing window 218 and may be configured to display a fill level of the canister 115 without the need to see the fluid 212 in the canister 115.

[0070] Figures 3A and 3B depict the fill level indicator 250 of Figures 2A-2C. In some embodiments, the fill level indicator 250 may include an indicator layer 302, an optical switching layer 304, and an adhesive 306. The indicator layer 302 may have a display side or a first surface 310 and a second surface 312 opposite the first surface 310. The indicator layer 302 may be in the shape of a stadium and may have a first edge 314, a second edge 316 opposite the first edge 314, a third edge 318 connecting the first edge 314 and the second edge 316, and a fourth edge 320 opposite the third edge 318. The third edge 318 and the fourth edge 320 may be curved and may form an outline of a semicircle. The indicator layer 302 may further include a peripheral portion 322 and a central portion 324. The peripheral portion 322 may surround the central portion 324 of the indicator layer 302. In some embodiments, the indicator layer 302 may further include a border 326 separating the peripheral portion 322 from the central portion 324. The indicator layer 302 may further include a plurality of perforations 328. The plurality of perforations 328 may be disposed along the border 326 between the peripheral portion 322 and the central portion 324 of the indicator layer 302. The plurality of perforations 328 may extend from the first surface 310 to the second surface 312 and may permit fluid communication through the indicator layer 302.

[0071] The indicator layer 302 may further include at least one graphic such as a first fill level graphic 330, a second fill level graphic 332, a third fill level graphic 334, a fourth fill level graphic 336, and a fifth fill level graphic 338 disposed on the display side or the first surface 310 of the indicator layer 302. The first fill level graphic 330, the second fill level graphic 332, the third fill level graphic 334, the fourth fill level graphic 336, and the fifth fill level graphic 338 may represent the fill level of the canister 115. In some embodiments, the first fill level graphic 330, the second fill level graphic 332, the third fill level graphic 334, the fourth fill level graphic 336, and the fifth fill level graphic 338 may include indexed volume markings. In other embodiments, the first fill level graphic 330, the second fill level graphic 332, the third fill level graphic 334, the fourth fill level graphic 336, and the fifth fill level graphic 338 may include fill percentage markings, fill level warning indicators, a time indicator of when to change the canister, or another graphic that may be useful to a user or a health care professional for the purpose of assessing the fill level of the canister 115.

[0072] In some embodiments, the indicator layer 302 may be a medical grade embossed polyurethane carrier film. The indicator layer 302 may be between about 250pm thick to about 1000pm thick in some embodiments. The first fill level graphic 330, the second fill level graphic 332, the third fill level graphic 334, the fourth fill level graphic 336, and the fifth fill level graphic 338 may be comprised of a medical grade water insoluble ink graphic. In some embodiments, the first fill level graphic 330, the second fill level graphic 332, the third fill level graphic 334, the fourth fill level graphic 336, and the fifth fill level graphic 338 may comprise Colorcon No-Tox ® MD-1001-NRNT16 Black. In other embodiments another medical grade water insoluble ink graphic may be used.

[0073] The fill level indicator 250 may further include the optical switching layer 304. The optical switching layer 304 may include a first surface 340 and a second surface 342 opposite the first surface 340. The optical switching layer 304 may be in the shape of a stadium and may have a first edge 344, a second edge 346 opposite the first edge 344, a third edge 348 connecting the first edge 344 and the second edge 346, and a fourth edge 350 opposite the third edge 348. The third edge 348 and the fourth edge 350 may be curved and may form an outline of a semi-circle. In some embodiments, the optical switching layer 304 may further include a first opening 352, a second opening 354, a third opening 356, a fourth opening 358, and a fifth opening 360.

[0074] The optical switching layer 304 may be configured to rapidly absorb and desorb moisture. When the optical switching layer 304 comes into contact with fluid, it may switch from a substantially opaque state to a substantially transparent state. For example, the optical switching layer 304 may transition from an opaque state to a transparent state in about 5 seconds when it is immersed in water. Similar to water, fluid from a tissue site may transition the optical switching layer 304 from the opaque state to the transparent state.

[0075] The optical switching layer 304 may be a microporous hydrophilic polymer. In some embodiments, the optical switching layer 304 may be a polyvinylidene fluoride (PVFD) membrane. The optical switching layer 304 may be the GVWP00010 Millipore Durapore ® Membrane Filter, 0.22pm in some embodiments. The optical switching layer 304 may be about 0.125mm thick. In some embodiments, it may be advantageous to use a Durapore ® product because it can be sterilized with Autoclave sterilization, ethylene oxide (EtO) sterilization, or gamma sterilization.

[0076] The fill level indicator 250 may further include the adhesive 306. The adhesive 306 may have a first surface 362 and a second surface 364 opposite the first surface 362. The adhesive 306 may be substantially the same size and shape as the peripheral portion 322 of the indicator layer 302. In some embodiments, the adhesive 306 may be a pressure sensitive medical grade adhesive. For example, in some embodiments, the adhesive 306 may be 3M 1522 acrylic adhesive. In other embodiments, the adhesive 306 may be another medical grade adhesive. [0077] The indicator layer 302, the optical switching layer 304, and the adhesive 306 may be assembled to create the fill level indicator 250. The second surface 342 of the optical switching layer 304 may couple to the first surface 310 of the indicator layer 302. In some embodiments, the optical switching layer 304 may be applied in a continuous layer over the indicator layer 302. In other embodiments, the optical switching layer 304 may be coupled to the indicator layer 302 by an adhesive, a weld, or another method of coupling. Similarly, the second surface 364 of the adhesive 306 may couple to the first surface 310 of the indicator layer 302.

[0078] When assembled, the optical switching layer 304 may be coupled to the central portion 324 of the indicator layer 302. In some embodiments, the first edge 344, the second edge 346, the third edge 348, and the fourth edge 350 of the optical switching layer 304 may be substantially aligned with the border 326 of the indicator layer 302. Further, the first opening 352, the second opening 354, the third opening 356, the fourth opening 358, and the fifth opening 360 may align with the first fill level graphic 330, the second fill level graphic 332, the third fill level graphic 334, the fourth fill level graphic 336, and the fifth fill level graphic 338, respectively. Thus, when the fill level indicator 250 is placed in the canister 115, the first fill level graphic 330, the second fill level graphic 332, the third fill level graphic 334, the fourth fill level graphic 336, and the fifth fill level graphic 338 may be visible through the viewing window 218. In other embodiments, the optical switching layer 304 may not include the first opening 352, the second opening 354, the third opening 356, the fourth opening 358, and the fifth opening 360 and the optical switching layer 304 may be a continuous layer coupled to the first surface 310 of the indicator layer 302. In these embodiments, the first fill level graphic 330, the second fill level graphic 332, the third fill level graphic 334, the fourth fill level graphic 336, and the fifth fill level graphic 338 may not be visible when the optical switching layer 304 is in the opaque state and may be visible when the optical switching layer 304 is in the transparent state.

[0079] The adhesive 306 may be coupled to the peripheral portion 322 of the indicator layer 302. More specifically, the second surface 364 of the adhesive 306 may be coupled to the peripheral portion 322 of the first surface 310 of the indicator layer 302. The indicator layer 302 may be exposed between the optical switching layer 304 and the adhesive 306 such that the plurality of perforations 328 can provide fluid communication through the fill level indicator 250.

[0080] In some embodiments, there may be a chamber created by the fill level indicator 250 and the canister 115 when the fill level indicator 250 is coupled to the interior surface of the first wall 214 of the canister 115. The chamber may allow the fluid 212 from the sealed interior 206 of the canister 115 to pass through the fill level indicator 250 through the plurality of perforations 328 of the indicator layer 302. The fluid 212 may then contact the optical switching layer 304 and may wick through the optical switching layer 304. As the fluid 212 wicks through the optical switching layer 304, the fluid 212 may remain in the chamber and may initiate the transition of the optical switching layer 304 from an opaque state to a transparent state where the fluid 212 is in contact with the optical switching layer 304. For example, if the fluid 212 is contacting the optical switching layer 304 below the third opening 356, a portion of the optical switching layer 304 below the third opening 356 may be transparent and a portion of the optical switching layer 304 above the third opening 356 may be opaque. The portion of the optical switching layer 304 that is transparent may expose a portion of the indicator layer 302 such that the portion of the indicator layer 302 adjacent to the transparent portion of the optical switching layer 304 may be seen through the viewing window 218. The exposed portion of the indicator layer 302 may allow a user or a health care provider to determine the fill level of the canister 115.

[0081] Figures 4A and 4B depict another embodiment of the fill level indicator 250 that can be used with some embodiments of the canister 115. The fill level indicator 250 may include an indicator layer 402, an optical switching layer 404, and an adhesive 406.

[0082] The indicator layer 402 may have a first surface 410 and a second surface 412 opposite the first surface 410. The indicator layer 402 may be in the shape of a stadium and may have a first edge 414, a second edge 416 opposite the first edge 414, a third edge 418 connecting the first edge 414 and the second edge 416, and a fourth edge 420 opposite the third edge 418. The third edge 418 and the fourth edge 420 may be curved and may form an outline of a semi-circle. The indicator layer 402 may further include a first fill level graphic 430, a second fill level graphic 432, a third fill level graphic 434, a fourth fill level graphic 436, and a fifth fill level graphic 438. The first fill level graphic 430, the second fill level graphic 432, the third fill level graphic 434, the fourth fill level graphic 436, and the fifth fill level graphic 438 may represent the fill level of the canister 115. In some embodiments, the first fill level graphic 430, the second fill level graphic 432, the third fill level graphic 434, the fourth fill level graphic 436, and the fifth fill level graphic 438 may include indexed volume markings. In other embodiments, the first fill level graphic 430, the second fill level graphic 432, the third fill level graphic 334, the fourth fill level graphic 436, and the fifth fill level graphic 438 may include fill percentage markings, fill level warning indicators, a time indicator of when to change the canister, or another graphic that may be useful to a user or a health care professional for the purpose of assessing the fill level of the canister 115. The indicator layer 402 may be comprised of any of the materials described above for the indicator layer 302 of Figures 3A and 3B.

[0083] The fill level indicator 250 may further include the optical switching layer 404. The optical switching layer 404 may include a first surface 440 and a second surface 442 opposite the first surface 440. In some embodiments, the optical switching layer 404 may include a plurality of membrane sections. For example, the optical switching layer 404 may include a first section 446, a second section 448, a third section 450, a fourth section 452, a fifth section 454, and a sixth section 456. Each section of the first section 446, the second section 448, the third section 450, the fourth section 452, the fifth section 454, and the sixth section 456 may be separated from every other section such that each section is distinct from every other section.

[0084] Each of the first section 446, the second section 448, the third section 450, the fourth section 452, the fifth section 454, and the sixth section 456 of the optical switching layer 304 may be configured to rapidly absorb and desorb moisture as described above. Further, each of the first section 446, the second section 448, the third section 450, the fourth section 452, the fifth section 454, and the sixth section 456 of the optical switching layer 304 may be comprised of any of the materials described above for the optical switching layer 304 of Figures 3A and 3B.

[0085] The fill level indicator 250 may further include the adhesive 406. The adhesive 406 may have a first surface 462 and a second surface 464 opposite the first surface 462. The adhesive 406 may be substantially the same size and shape as the adhesive 306 described above with reference to Figures 3A and 3B. The adhesive 406 may be comprised of any of the materials as described above with reference to Figures 3 A and 3B.

[0086] The indicator layer 402, the optical switching layer 404, and the adhesive 406 may be assembled to create the fill level indicator 250. The second surface 442 of the optical switching layer 404 may couple to the first surface 410 of the indicator layer 402. In some embodiments, each of the first section 446, the second section 448, the third section 450, the fourth section 452, the fifth section 454, and the sixth section 456 of the optical switching layer 404 may be applied in a continuous layer over the indicator layer 402. In other embodiments, each of the first section 446, the second section 448, the third section 450, the fourth section 452, the fifth section 454, and the sixth section 456 of the optical switching layer 404 may be coupled to the indicator layer 402 by an adhesive, a weld, or another method of coupling. Similarly, the second surface 464 of the adhesive 406 may couple to the first surface 410 of the indicator layer 402.

[0087] When the fill level indicator 250 is assembled, each of the first section 446, the second section 448, the third section 450, the fourth section 452, the fifth section 454, and the sixth section 456 may couple to the indicator layer 402 and may extend from the first edge 414 to the second edge 416 of the indicator layer 402. Thus, when the fill level indicator 250 is placed in the canister 115, the first fill level graphic 330, the second fill level graphic 332, the third fill level graphic 334, the fourth fill level graphic 336, and the fifth fill level graphic 338 may be visible through the viewing window 218.

[0088] More specifically, when the fill level indicator 250 is assembled, the first section 446 of the optical switching layer 404 may couple to the indicator layer 402 between the first fill level graphic 430 and the fourth edge 420. An outer edge 470 of the first section 446 may be proximate to the fourth edge 420 of the indicator layer 402. The second section 448 of the optical switching layer 404 may couple to the indicator layer 402 between the first fill level graphic 430 and the second fill level graphic 432. A first outer edge 472 of the second section 448 may be proximate to the first edge 414 of the indicator layer 402 and a second outer edge 474 of the second section 448 may be proximate to the second edge 416 of the indicator layer 402. The third section 450 of the optical switching layer 404 may couple to the indicator layer 402 between the second fill level graphic 432 and the third fill level graphic 434. A first outer edge 476 of the third section 450 may be proximate to the first edge 414 of the indicator layer 402 and a second outer edge 478 of the third section 450 may be proximate to the second edge 416 of the indicator layer 402. The fourth section 452 of the optical switching layer 404 may couple to the indicator layer 402 between the third fill level graphic 434 and the fourth fill level graphic 436. A first outer edge 480 of the fourth section 452 may be proximate to the first edge 414 of the indicator layer 402 and a second outer edge 482 of the fourth section 452 may be proximate to the second edge 416 of the indicator layer 402. The fifth section 454 of the optical switching layer 404 may couple to the indicator layer 402 between the fourth fill level graphic 436 and the fifth fill level graphic 438. A first outer edge 484 of the fifth section 454 may be proximate to the first edge 414 of the indicator layer 402 and a second outer edge 486 of the fifth section 454 may be proximate to the second edge 416 of the indicator layer 402. The sixth section 456 of the optical switching layer 404 may couple to the indicator layer 402 between the fifth fill level graphic 438 and the third edge 418. An outer edge 488 of the sixth section 456 may be proximate to the third edge 418 of the indicator layer 402.

[0089] The adhesive 406 may be coupled to the optical switching layer 404 and the indicator layer 402 along a peripheral portion of both the optical switching layer 404 and the indicator layer 402. For example, the adhesive may extend through the gaps between the sections of the optical switching layer 404 to reach the indicator layer 402 of the fill level indicator. The adhesive 406 may couple the layers of the fill level indicator 250 together and to the canister 115 so that the fill level indicator 250 is secured to the canister 115.

[0090] When assembled and placed in the canister 115, the outer edge 470 of the first section 446, the first outer edge 472 and the second outer edge 474 of the second section 448, the first outer edge 476 and the second outer edge 478 of the third section 450, the first outer edge 480 and the second outer edge 482 of the fourth section 452, the first outer edge 484 and the second outer edge 486 of the fifth section 454, and the outer edge 488 of the sixth section 456 of the optical switching layer 404 may be exposed to fluid in the sealed interior 206 of the canister 115. The fluid 212 from the sealed interior 206 of the canister 115 may pass through the fill level indicator 250 by wicking along edges of the first section 446, the second section 448, the third section 450, the fourth section 452, the fifth section 454, and the sixth section 456 of the optical switching layer 404 that are exposed to the fluid 212 in the canister 115. The fluid 212 may wick through the optical switching layer 404 to initiate the transition of the optical switching layer 404 from an opaque state to a transparent state where the fluid 212 is in contact with the optical switching layer 404. For example, if the fluid 212 is contacting the first section 446, the second section 448, and the third section 450 of the optical switching layer 404, the first section 446, the second section 448, and the third section 450 may be transparent and the fourth section 452, the fifth section 454, and the sixth section 456 may be opaque. The indicator layer 402 adjacent to the first section 446, the second section 448, and the third section 450 of the optical switching layer 404 may be exposed such that it may be seen through the viewing window 218 of the canister 115 and the portion of the indicator layer 402 adjacent to the fourth section 452, the fifth section 454, and the sixth section 456 of the optical switching layer 404 may be blocked from view by the optical switching layer 404. The exposed portion of the indicator layer 302 may allow a user or a health care provider to determine the fill level of the canister 115. [0091] Figures 5A-5C depict another example embodiment of the canister 115 that can be used with the therapy system 100 of Figure 1. The canister 115 may include a first canister section 502, a second canister section 504, and the fill level indicator 250 of Figures 3 A and 3B. In other embodiments, the fill level indicator 250 of Figures 4A and 4B may be used in the canister 115. The first canister section 502 may couple to the second canister section 504 to create a sealed interior 506 that may be configured to store fluid 508 and exudate from a tissue site. The canister 115 may have a first end 510 and a second end 512 opposite the first end 510. In some embodiments, the canister 115 may have an optimal orientation such that the fluid 508 flows into the sealed interior 506 of the canister 115 and fills the canister 115 from the first end 510 towards the second end 512.

[0092] The first canister section 502 may include a first wall 516 with an exterior surface 518 and an interior surface opposite the exterior surface 518. The first wall 516 may have a first edge 520, a second edge 522 opposite the first edge 520, a third edge 524 extending from the first edge 520 to the second edge 522, and a fourth edge 526 opposite the third edge 524. The canister 115 may further include a second wall 528, a third wall 530 opposite the second wall 528, a fourth wall 532 connecting the second wall 528 and the third wall 530, and a fifth wall 534 opposite the fourth wall 532. In some embodiments, the first edge 520 may be curved or beveled and may connect the first wall 516 to the second wall 528. Similarly, the second edge 522 may be curved or beveled and may connect the first wall 516 to the third wall 530, the third edge 524 may be curved or beveled and may connect the first wall 516 to the fourth wall 532, and the fourth edge 526 may be curved or beveled and may connect the first wall 516 to the fifth wall 534. In other embodiments, the first edge 520, the second edge 522, the third edge 524, and the fourth edge 526 may be planar or flat such that the first canister section 502 is similar to a rectangular prism.

[0093] In some embodiments, the first canister section 502 may further include an extension 536. The extension 536 may couple to the second wall 528, the third wall 530, the fourth wall 532, and the fifth wall 534 opposite the first wall 516 and may extend away from the first wall 516. The extension 536 may be configured to couple the first canister section 502 to the second canister section 504.

[0094] The second canister section 504 may include a first wall 540 with an exterior surface 542 and an interior surface 544 opposite the exterior surface 542. In some embodiments, the first wall 540 may be in the shape of a stadium. The first wall 540 may have a first edge 546, a second edge 548 opposite the first edge 546, a third edge 550 connecting the first edge 546 and the second edge 548, and a fourth edge 552 opposite the third edge 550. The second canister section 504 may further include a second wall 554, athird wall 556 opposite the second wall 554, a fourth wall 558 connecting the second wall 554 to the third wall 556, and a fifth wall 560 opposite the fourth wall 558. The second wall 554 may extend from the first edge 546 away from the first wall 540, the third wall 556 may extend from the second edge 548 away from the first wall 540, the fourth wall 558 may extend from the third edge 550 away from the first wall 540, and the fifth wall 560 may extend away from the fourth edge 552 away from the first wall 540. In other embodiments, the first wall 540 of the second canister section 504 may have a different size or shape that may be configured to couple to the first canister section 502 to create the sealed interior 506.

[0095] In some embodiments, the second canister section 504 may further include an extension 562. The extension 562 may couple to the second wall 554, the third wall 556, the fourth wall 558, and the fifth wall 560 opposite the first wall 540 and may extend away from the first wall 540. The extension 562 may be configured to couple the second canister section 504 to the first canister section 502. In some embodiments, the extension 562 of the second canister section 504 may be configured to couple to the extension 536 of the first canister section 502. The canister 115 may be comprised of any of the materials discussed above with reference to Figures 2A-2C.

[0096] In some embodiments, the first canister section 502 may be opaque. The first wall 540 of the second canister section 504 may be transparent and the second wall 554, the third wall 556, the fourth wall 558, and the fifth wall 560 of the second canister section 504 may be opaque. The second wall 554 of the second canister section 504 may further include a viewing window 566. In some embodiments, a first end 570 of the viewing window 566 may extend onto an internal surface of the fifth wall 560 of the second canister section 504 and a second end 572 of the viewing window 566 may extend onto an internal surface of the fourth wall 558 of the second canister section 504. The viewing window 566 may be transparent to allow the sealed interior 506 of the canister 115 to be viewed from outside the canister 115. In some embodiments, the first wall 540 of the second canister section 504 may be shielded from view such that the only way to see into the sealed interior 506 of the canister 115 is through the viewing window 566 of the second wall 554 of the second canister section 504. In other embodiments, the canister 115 may have different sections that are opaque and transparent or the viewing window 566 may be located through a different wall of the canister 115.

[0097] The fill level indicator 250 may be configured to couple to an internal surface of the second wall 554 of the second canister section 504. When coupled to the canister 115, the fill level indicator 250 may be substantially aligned with the viewing window 566 of the second wall 554 of the second canister section 504. The fill level indicator 250 may be configured to prevent the fluid 508 from being observed through the viewing window 566 and may be configured to display a fill level of the canister 115 without the need to see the fluid 508 in the canister 115.

[0098] As shown in Figures 5 A and 5B, the canister 115 may be housing the fluid 508 in the sealed interior 506 of the canister 115. The fluid 508 maybe filling the canister 115 such that the canister 115 is about three quarters of the way full. The fluid 508 may flow through the perforations 328 of the indicator layer 302 and may reach the optical switching layer 304. The fluid 508 contacting the optical switching layer 304 may transition the optical switching layer 304 from opaque to transparent. The optical switching layer 304 may be transparent from the first end 510 of the canister 115 to the fill level of the canister 115. The indicator layer 302 may be visible through the optical switching layer 304 from the first end 510 of the canister 115 to the fill level of the canister 115. In this embodiment, the fill level is between the third fill level graphic 334 and the fourth fill level graphic 336 of the indicator layer 302. If additional fluid is added to the canister 115, more of the optical switching layer 304 may transition from an opaque state to a transparent state to reflect the new volume of the fluid 508 in the sealed interior 506 of the canister 115. If any of the fluid 508 is removed from the canister 115, the portion of the optical switching layer 304 that is no longer in contact with the fluid 508 may transition back to an opaque state from the transparent state to reflect the new volume of the fluid 508 in the sealed interior 506 of the canister 115.

[0099] Figure 6A and 6B show another embodiment of the canister 115 of Figure 1. The canister 115 of Figures 6A and 6B may be similar to the canister 115 of Figures 5A-5C. The canister 115 may include a first canister section 602, a second canister section 604, and the fill level indicator 250 of Figures 4A and 4B. In other embodiments, the fill level indicator 250 of Figures 3A and 3B may be used in the canister 115. The first canister section 602 may couple to the second canister section 604 to create a sealed interior 606 that may be configured to store fluid 608 and exudate from a tissue site. The canister 115 may have a first end 610 and a second end 612 opposite the first end 610. In some embodiments, the canister 115 may have an optimal orientation such that the fluid 608 flows into the sealed interior 606 of the canister 115 and fills the canister 115 from the first end 610 towards the second end 612.

[00100] The first canister section 602 may include a first wall 616 with an exterior surface and an interior surface 618 opposite the exterior surface. The first wall 616 may have a first edge 620, a second edge 622 opposite the first edge 620, a third edge 624 extending from the first edge 620 to the second edge 622, and a fourth edge 626 opposite the third edge 624. The canister 115 may further include a second wall 628, a third wall 630 opposite the second wall 628, a fourth wall 632 connecting the second wall 628 and the third wall 630, and a fifth wall 634 opposite the fourth wall 632. In some embodiments, the first edge 620 may be curved or beveled and may connect the first wall 616 to the second wall 628. Similarly, the second edge 622 may be curved or beveled and may connect the first wall 616 to the third wall 630, the third edge 624 may be curved or beveled and may connect the first wall 616 to the fourth wall 632, and the fourth edge 626 may be curved or beveled and may connect the first wall 616 to the fifth wall 634. In other embodiments, the first edge 620, the second edge 622, the third edge 624, and the fourth edge 626 may be planar or flat such that the first canister section 602 is similar to a rectangular prism.

[00101] In some embodiments, the first canister section 602 may further include an extension 636. The extension 636 may couple to the second wall 628, the third wall 630, the fourth wall 632, and the fifth wall 634 opposite the first wall 616 and may extend away from the first wall 616. The extension 636 may be configured to couple the first canister section 602 to the second canister section 604.

[00102] The second canister section 604 may include a first wall 640 with an exterior surface 642 and an interior surface opposite the exterior surface 642. In some embodiments, the first wall 640 may be in the shape of a stadium. The first wall 640 may have a first edge 646, a second edge 648 opposite the first edge 646, a third edge 650 connecting the first edge 646 and the second edge 648, and a fourth edge 652 opposite the third edge 650. The second canister section 604 may further include a second wall 654, athird wall 656 opposite the second wall 654, a fourth wall 658 connecting the second wall 654 to the third wall 656, and a fifth wall 660 opposite the fourth wall 658. The second wall 654 may extend from the first edge 646 away from the first wall 640, the third wall 656 may extend from the second edge 648 away from the first wall 640, the fourth wall 658 may extend from the third edge 650 away from the first wall 640, and the fifth wall 660 may extend away from the fourth edge 652 away from the first wall 640. In other embodiments, the first wall 640 of the second canister section 604 may have a different size or shape that may be configured to couple to the first canister section 602 to create the sealed interior 606.

[00103] In some embodiments, the second canister section 604 may further include an extension 662. The extension 662 may couple to the second wall 654, the third wall 656, the fourth wall 658, and the fifth wall 660 opposite the first wall 640 and may extend away from the first wall 640. The extension 662 may be configured to couple the second canister section 604 to the first canister section 602. In some embodiments, the extension 662 of the second canister section 604 may be configured to couple to the extension 636 of the first canister section 602. The canister 115 may be comprised of any of the materials discussed above with reference to Figures 2A-2C.

[00104] In some embodiments, the first canister section 602 may be opaque and the second canister section 604 may be transparent. The fill level indicator 250 may be configured to couple to an internal surface of the second wall 654 of the second canister section 604. In some embodiments, a first end 670 of the fill level indicator 250 may extend onto an internal surface of the fifth wall 660 of the second canister section 604 and a second end 672 of the fill level indicator 250 may extend onto an internal surface of the fourth wall 658 of the second canister section 604. The fill level indicator 250 may be configured to display a fill level of the canister 115. The fluid 608 may be visible through the second canister section 604 but the fill level indicator 250 may provide an easy way for a user or a health care provider to quickly determine what the fill level of the canister 115 is based on how much of the optical switching layer 404 is in a transparent state rather than an opaque state.

[00105] As shown in Figures 6A and 6B, the canister 115 may be housing the fluid 608 in the sealed interior 606 of the canister 115. The fluid 608 may be filling the canister 115 such that the canister 115 is about three quarters of the way full. The fluid 608 may by in contact with edges of the first section 446, the second section 448, the third section 450, the fourth section 452, the fifth section 454, and the sixth section 456 of the optical switching layer 404 and may wick through the sections of the optical switching layer 404 that are in contact with the fluid 608. The fluid 508 contacting the optical switching layer 404 may transition the optical switching layer 404 from opaque to transparent. The optical switching layer 404 may be transparent from the first end 610 of the canister 115 to the fill level of the canister 115. Thus, the indicator layer 402 may be visible through the optical switching layer 404 from the first end 610 of the canister 115 to the fill level of the canister 115. In this embodiment, the fill level is between the third fill level graphic 434 and the fourth fill level graphic 436 of the indicator layer 402. If additional fluid is added to the canister 115, more of the optical switching layer 404 may transition from an opaque state to a transparent state to reflect the new volume of the fluid 608 in the sealed interior 606 of the canister 115. If any of the fluid 608 is removed from the canister 115, the portion of the optical switching layer 404 that is no longer in contact with the fluid 608 may transition back to an opaque state from the transparent state to reflect the new volume of the fluid 608 in the sealed interior 606 of the canister 115.

[00106] Figure 7 depicts a unit 700 that may be configured to receive the canister 115 of Figures 6A and 6B. In some embodiments, the unit 700 may further include the therapy unit 145 of Figure 1. The unit 700 may include an insert or a cut out that may be configured to receive the canister 115. The second canister section 604 may be configured to be inserted into the unit 700 such that the second canister section 604 is hidden from view by the unit 700. The first canister section 602 may be visible from outside the unit 700. The fluid 608 stored in the sealed interior 606 of the canister 115 may be hidden from view because the first canister section 602 may be opaque. The fluid 608 may be visible through the second canister section 604 when the canister 115 is removed from the unit 700. It may be desirable for the second canister section 604 to be transparent so that a health care provider can easily observe the fluid 608 in the sealed interior of the canister 115 when the canister 115 is removed from the unit 700.

[00107] In some embodiments, the unit 700 may include a first wall 702 with a user interface 704. In some embodiments, the user interface 704 may be configured to output information about the therapy system 100 to a user or a healthcare provider. In other embodiments, the user interface 704 may allow the user or the healthcare provider to adjust therapy settings for the therapy system 100 or may allow the user or the healthcare provider to interact with the therapy system 100 in another way. The first wall 702 may further include an opening 706. The opening 706 may be a cut-out through the first wall 702 of the unit 700. In other embodiments, the opening 706 may be a window or another transparent element that enables a user to view through the first wall 702 of the unit 700. When the canister 115 is inserted into the unit 700, the fill level indicator 250 may be aligned with the opening 706 of the unit 700. The opening 706 may enable the fill level indicator 250 to be seen from outside the unit 700 such that the fluid 608 within the sealed interior 606 of the canister 115 is completely shielded from view.

[00108] In some embodiments, the unit 700 may be substantially rectangular. The unit may have a second wall opposite the first wall 702. There may be a third wall 710 that connects the first wall 702 to the second wall. In some embodiments, the third wall 710 may be proximate to the second end 612 of the canister 115 when the canister 115 is inserted into the unit 700. The unit 700 may further have a fourth wall 712 opposite the third wall 710. The fourth wall 712 may be proximate to the first end 610 of the canister 115 when the canister 115 is inserted into the unit 700. The unit may further include a fifth wall 714 that may connect the third wall 710 and the fourth wall 712. The fifth wall 714 may further connect the first wall 702 to the second wall of the unit. In some embodiments, the third wall 710, the fourth wall 712, and the fifth wall 714 may be curved such that they have beveled edges. In other embodiments, the unit 700 may have walls that are planar and have square edges. In still other embodiments, the unit 700 may be a different size or shape but may be configured to receive the canister 115 such that any transparent walls of the canister 115 are hidden from view to provide privacy to the user.

[00109] Figure 8 is a graphical representation illustrating the relationship between the distance traveled by saline in a PVDF material and a LIBELTEX material with respect to time. In the graph of Figure 8, the distance traveled in millimeters (mm) is represented on the Y-axis. The X-axis represents the elapsed time in minutes. The distance traveled by the saline in the PVDF material and in the LIBELTEX material was first measured at 10 minutes. At the ten-minute mark, the saline in the PVDF material had traveled approximately 21mm and the saline in the LIBELTEX material had traveled approximately 1mm. As time elapsed, the saline in the PVDF material continued to wick through the PVDF material and traveled about 15mm more for a total of about 36mm after an elapsed time of about 50 minutes. Line 802 represents a best fit regression line for the distance traveled by the saline through the PVDF material. A regression function for the regression line is d=l 1.8t⁰²⁸, where d represents distance and t represents time. The saline in the LIBELTEX material did not wick through the LIBELTEX material and had still traveled only about 1mm after about 50 minutes.

[00110] Figure 9 is a graphical representation illustrating the relationship between the distance traveled by a simulated wound fluid with a viscosity of 14cP (14cP SWF) in a PVDF material and a LIBELTEX material with respect to time. In the graph of Figure 9, the distance traveled in millimeters (mm) is represented on the Y-axis. The X-axis represents the elapsed time in minutes. The distance traveled by the 14cP SWF in the PVDF material and in the LIBELTEX material was first measured at 10 minutes. At the ten-minute mark, the saline in the PVDF material had traveled approximately 20mm and the 14cP SWF in the LIBELTEX material had traveled approximately 5mm. As time elapsed, the 14cP SWF in the PVDF material continued to wick through the PVDF material and traveled about 17mm more for a total of about 37mm after an elapsed time of about 50 minutes. Line 902 represents a best fit regression line for the distance traveled by the 14cP SWF through the PVDF material. A regression function for the regression line is d=9.3t⁰³⁴, where d represents distance and t represents time. As time elapsed, the 14cP SWF in the LIBELTEX material traveled about 2mm for atotal distance of about 7mm after about 50 minutes.

[00111] Figure 10 is a graphical representation illustrating the relationship between the distance traveled by a simulated wound fluid with a viscosity of 30cP (30cP SWF) in a PVDF material and a LIBELTEX material with respect to time. In the graph of Figure 10, the distance traveled in millimeters (mm) is represented on the Y-axis. The X-axis represents the elapsed time in minutes. The distance traveled by the 30cP SWF in the PVDF material and in the LIBELTEX material was first measured at 10 minutes. At the ten-minute mark, the 30cP SWF in the PVDF material had traveled approximately 15mm and the 30cP SWF in the LIBELTEX material had traveled approximately 4mm. As time elapsed, the 30cP SWF in the PVDF material continued to wick through the PVDF material and traveled about 15mm more for a total of about 30mm after an elapsed time of about 50 minutes. Line 1002 represents a best fit regression line for the distance traveled by the 30cP SWF through the PVDF material. A regression function for the regression line is d=7.6t⁰³⁵, where d represents distance and t represents time. As time elapsed, the 30cP SWF in the LIBELTEX material traveled about 2mm for a total distance of about 6mm after about 50 minutes.

[00112] Referring to Figures 3A, 3B, 4A, 4B, and 8-10, the optical switching layer 304 and the optical switching layer 404 of the fill level indicator 250 may be made of a PVDF material in some embodiments. The PVDF material may be preferable to a LIBELTEX material or another material because the PVDF material may allow fluid from the sealed interior to wick through the optical switching layer 304 and the optical switching layer 404 quickly so that an accurate fill level of the canister 115 can be determined. If the optical switching layer 304 and the optical switching layer 404 were comprised of LIBELTEX, the fluid may not wick across the entirety of the optical switching layer 304 and the optical switching layer 404 at the fill level and thus an accurate fill level may not be able to be determined. In some embodiments, there may be a plurality of fluid breaks added to the optical switching layer 304 and the optical switching layer 404. The plurality of fluid breaks may be perpendicular to the filling direction of the canister 115 to prevent fluid from wicking higher on the optical switching layer 304 or the optical switching layer 404 than the actual fill level of the canister 115. In some embodiments, the plurality of fluid lines may be weld lines. The plurality of fluid lines may be dispersed along the optical switching layer 304 and the optical switching layer 404 at regularly spaced intervals or randomly and may collapse the structure of the PVDF membrane of the optical switching layer 304 and the optical switching layer 404 such that fluid is prevented from wicking higher than the fill level of the canister 115. In embodiments of the fill level indicator 250 where the optical switching layer 404 is split into discrete sections, such as is Figures 4A and 4B, the weld lines may not be necessary because fluid may be prevented from wicking to an adjacent section because of the space between the sections of the optical switching layer 404. In other embodiments, there may be additional structures that can be added to prevent fluid from wicking along the optical switching layer 304 and the optical switching layer 404 higher than the fill level of the canister 115. For example, in some embodiments, the optical switching layer 404 may include more sections than the embodiment of Figures 4A and 4B.

[00113] A method of displaying a fill level of the canister 115 is also described herein. The method may include providing the canister 115, including the fill level indicator 250, collecting fluid in the canister 115, and displaying, with the fill level indicator, the fill level of the canister 115. The fill level indicator 250 may be coupled to an interior of the canister 115 and may include the optical switching layer 304. The optical switching layer 304 may be configured to switch from an opaque state to a transparent state in response to fluid in the canister 115. The fill level indicator 250 may further include the indicator layer 302. The indicator layer 302 may include the display side or the first surface 310 with at least one graphic on the display side. The indicator layer 302 may be coupled to the optical switching layer 304 with the display wide disposed adjacent to the optical switching layer 304. In some embodiments, the method may include the optical switching layer 404 and the indicator layer 402 in place of the optical switching layer 304 and the indicator layer 302.

[00114] In some embodiments, displaying, with the fdl level indicator 250, a level of the fluid in the canister 115 may include wicking fluid through at least one edge of the optical switching layer 404 exposed to the fluid in the canister 115. The fluid may transition the optical switching layer 404 from the opaque state to the transparent state. The method may further include exposing the indicator layer 402 through a transparent portion of the optical switching layer 404 to reveal the fdl level of the canister 115.

[00115] In other embodiments, displaying, with the fdl level indicator 250, a level of the fluid in the canister 115 may include collecting fluid from the canister 115 in a chamber between the fdl level indicator 250 and the interior of the canister 115 through the plurality of perforations 328 of the indicator layer 302. The method may further include wicking the fluid in the chamber through the optical switching layer 304. The fluid may transition the optical switching layer 304 from the opaque state to the transparent state. The method may further include exposing the indicator layer 302 through a transparent portion of the optical switching layer 304 to reveal the fdl level of the canister 115.

[00116] The systems, apparatuses, and methods described herein may provide significant advantages. For example, incorporating the fdl level indicator 250 into the canister 115 may allow the canister 115 to be completely opaque to provide a user with increased privacy. The fdl level indicator 250 may allow the fdl level of the canister 115 to be monitored in real time without needing to see the sealed interior of the canister 115. Some embodiments may include the unit 700 that may allow the canister 115 to be partially opaque and partially transparent to provide the user with privacy while allowing for easy monitoring of any wound exudate or fluid stored in the canister 115 by a healthcare provider. In any of the embodiments described herein, the user is afforded privacy to move about and live a normal life without bystanders being able to see fluid stored in the canister 115.

[00117] While shown in a few illustrative embodiments, a person having ordinary skill in the art will recognize that the systems, apparatuses, and methods described herein are susceptible to various changes and modifications that fall within the scope of the appended claims. Moreover, descriptions of various alternatives using terms such as “or” do not require mutual exclusivity unless clearly required by the context, and the indefinite articles "a" or "an" do not limit the subject to a single instance unless clearly required by the context. Components may also be combined or eliminated in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations the dressing 110, the canister 115, or both may be eliminated or separated from other components for manufacture or sale. In other example configurations, the controller 130 may also be manufactured, configured, assembled, or sold independently of other components. [00118] The appended claims set forth novel and inventive aspects of the subject matter described above, but the claims may also encompass additional subject matter not specifically recited in detail. For example, certain features, elements, or aspects may be omitted from the claims if not necessary to distinguish the novel and inventive features from what is already known to a person having ordinary skill in the art. Features, elements, and aspects described in the context of some embodiments may also be omitted, combined, or replaced by alternative features serving the same, equivalent, or similar purpose without departing from the scope of the invention defined by the appended claims.

Claims

CLAIMS What is claimed is:

1. An apparatus for use in a negative pressure system including a negative pressure pump and a canister fluidly coupled to the negative pressure pump for collecting fluid, comprising: an optical switching layer configured to be coupled to an inside of the canister and configured to switch from a substantially opaque state to a substantially transparent state in response to fluid in the canister; and an indicator layer having a display side including at least one graphic on the display side and coupled to the optical switching layer with the display side disposed adjacent the optical switching layer; wherein the at least one graphic is visible through the canister when the optical switching layer is in the substantially transparent state and not visible when the optical switching layer is in the substantially opaque state.

2. The apparatus of claim 1, wherein the optical switching layer wicks fluid in contact with the optical switching layer.

3. The apparatus of claim 1 , further comprising a chamber between the optical switching layer and the canister for receiving a portion of the fluid in the canister.

4. The apparatus of claim 1, wherein the optical switching layer is a microporous hydrophilic polymer that absorbs and desorbs the fluid.

5. The apparatus of claim 1, wherein the indicator layer comprises a plurality of perforations between a periphery of the indicator layer and a central portion of the indicator layer, the plurality of perforations being configured to enable fluid in the canister to pass through the indicator layer to reach the optical switching layer.

6. The apparatus of claim 5, wherein the optical switching layer is coupled to the central portion of the indicator layer.

7. The apparatus of claim 5, further comprising an adhesive coupled to the periphery of the indicator layer, the adhesive configured to couple the apparatus to an inside of the canister.

8. The apparatus of claim 1, further comprising a plurality of fluid breaks coupled to the optical switching layer, the plurality of fluid breaks configured to prevent fluid from wicking through the optical switching layer past a fill level of fluid in the canister.

9. The apparatus of claim 1, wherein the optical switching layer comprises a plurality of optical switching portions.

10. The apparatus of claim 9, wherein each optical switching portion of the plurality of optical switching portions is separated from another optical switching portion of the plurality of optical switching portions.

11. A canister for storing fluid in a negative pressure wound therapy system comprising: a canister body configured to be opaque, the canister body comprising: a viewing window configured to be transparent; and a fill level indicator configured to couple to the interior of the canister and configured to be visible through the viewing window, the fill level indicator comprising: an optical switching layer configured to switch from an opaque state to a transparent state in response to fluid in the canister; and an indicator layer having a display side including at least one graphic on the display side and coupled to the optical switching layer with the display side disposed adjacent the optical switching layer; and a lid configured to couple to the canister body to form a sealed interior.

12. The canister of claim 11, wherein the optical switching layer wicks fluid in contact with the optical switching layer.

13. The canister of claim 11, further comprising a chamber between the optical switching layer and the canister for receiving a portion of the fluid in the canister.

14. The canister of claim 11, wherein the optical switching layer is a microporous hydrophilic polymer that absorbs and desorbs the fluid.

15. The canister of claim 11, wherein the at least one graphic of the indicator layer is visible through the viewing window of the canister when the optical switching layer is in the transparent state and is not visible when the optical switching layer is in the opaque state.

16. The canister of claim 11, wherein the indicator layer comprises a plurality of perforations between a periphery of the indicator layer and a central portion of the indicator layer, the plurality of perforations being configured to enable fluid in the canister to pass through the indicator layer to reach the optical switching layer.

17. The canister of claim 16, wherein the optical switching layer is coupled to the central portion of the indicator layer.

18. The canister of claim 16, wherein the fill level indicator further comprises an adhesive coupled to the periphery of the indicator layer, the adhesive configured to couple the fill level indicator to the interior of the canister.

19. The canister of claim 11, further comprising a plurality of fluid breaks coupled to the optical switching layer, the plurality of fluid breaks configured to prevent fluid from wicking through the optical switching layer past a fill level of the fluid in the sealed interior of the canister. 0. The canister of claim 11, wherein the optical switching layer comprises a plurality of optical switching portions. 1. The canister of claim 20, wherein each optical switching portion of the plurality of optical switching portions is separated from another optical switching portion of the plurality of optical switching portions. A method of determining a fill level of a canister comprising: providing the canister with a fill level indicator coupled to an interior of the canister, the fill level indicator comprising: an optical switching layer configured to switch from an opaque state to a transparent state in response to fluid in the canister; and an indicator layer having a display side including at least one graphic on the display side and coupled to the optical switching layer with the display side disposed adjacent the optical switching layer; collecting fluid in the canister; and displaying, with the fill level indicator, the fill level of the canister. The method of claim 22, wherein displaying, with the fill level indicator, a level of the fluid in the canister comprises: wicking fluid through at least one edge of the optical switching layer exposed to the fluid in the canister, the fluid configured to transition the optical switching layer from the opaque state to the transparent state; and exposing the indicator layer through a transparent portion of the optical switching layer to reveal the fill level of the canister. The method of claim 22, wherein displaying, with the fill level indicator, a level of the fluid in the canister comprises: collecting fluid from the canister in a chamber between the fill level indicator and the interior of the canister through a plurality of perforations of the indicator layer; wicking the fluid in the chamber through the optical switching layer, the fluid configured to transition the optical switching layer from the opaque state to the transparent state; and exposing the indicator layer through a transparent portion of the optical switching layer to reveal the fill level of the canister. The systems, apparatuses, and methods substantially as described herein.