Patent Publication Number: US-2022226559-A1

Title: Wireless system to enable auto-determination of application specific therapy device screens and setting options

Description:
RELATED APPLICATIONS 
     The present application claims priority to U.S. Provisional Patent Application No. 62/734,010, entitled “Wireless System To Enable Auto-Determination Of Application Specific Therapy Device Screens And Setting Options,” filed Sep. 20, 2018, which is incorporated herein by reference for all purposes 
    
    
     TECHNICAL FIELD 
     The invention set forth in the appended claims relates generally to tissue treatment systems and more particularly, but without limitation, to systems and methods for remotely controlling negative-pressure therapy systems. 
     BACKGROUND 
     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 “negative-pressure 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 micro-deformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times. 
     There is also widespread acceptance that cleansing a tissue site can be highly beneficial for new tissue growth. For example, a wound can be washed out with a stream of liquid solution, or a cavity can be washed out using a liquid solution for therapeutic purposes. These practices are commonly referred to as “irrigation” and “lavage” respectively. “Instillation” is another practice that generally refers to a process of slowly introducing fluid to a tissue site and leaving the fluid for a prescribed period of time before removing the fluid. For example, instillation of topical treatment solutions over a wound bed can be combined with negative-pressure therapy to further promote wound healing by loosening soluble contaminants in a wound bed and removing infectious material. As a result, soluble bacterial burden can be decreased, contaminants removed, and the wound cleansed. 
     However, the size, location, and etiology of wounds may vary widely. This leads to the use of diverse types of negative-pressure wound therapy (NPWT) systems and instillation therapy systems that are customized to one degree or another to the type of wound being treated. For example, a negative therapy wound dressing used to treat a “clean” surgical incision on a forearm is likely to be considerably smaller than a negative therapy wound dressing used to treat a large deep bruise and/or laceration on the chest caused by blunt force trauma. This customization extends to the controllers implemented in the negative therapy wound dressing, the operator interface(s), the physical connections to an external therapy control system, and the communication interfaces connecting the wound dressing, the operator interface, and the external therapy control systems. Such customization greatly increases equipment costs and may also increasing training costs for the operator. 
     There is a need to standardize negative-pressure wound therapy (NPWT) systems and instillation therapy systems to reduce equipment cost and training costs. In particular, there is a need to standardize the controllers embedded in therapeutic wound dressings, the operator interface(s), and the communication interfaces of the physical connections to an external therapy control system, and the communication interfaces of NPWT systems. 
     BRIEF SUMMARY 
     New and useful systems, apparatuses, and methods for instilling fluid to a tissue site 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. Some embodiments are illustrative of an apparatus or system for delivering negative-pressure and therapeutic solution of fluids to a tissue site, which can be used in conjunction with sensing properties of wound exudates extracted from a tissue site. For example, an apparatus may include a pH sensor, a humidity sensor, a temperature sensor and a pressure sensor embodied on a single pad proximate the tissue site to provide data indicative of acidity, humidity, temperature and pressure. Such apparatus may further comprise an algorithm for processing such data for detecting leakage and blockage as well as providing information relating to the progression of healing of wounds at the tissue site. 
     It is an object of the disclosure to provide a standardized, extendable “core” system that is configured to perform wireless data collection, communications, and control within therapy devices of different types. The core system is flexible and adaptable to different needs and therapy treatments, while providing certain common features most likely to be needed within NPWT related therapy systems. The flexible core architecture reduces costs, but may be quickly adapted to incorporate new features or upgrades across different therapy platforms. 
     It is an object to provide a system for wirelessly controlling a dressing interface that performs negative pressure wound therapy and fluid instillation therapy at a wound site. In one embodiment, the system comprises a core module comprising: i) a plurality of sensors configured to determine a plurality of physical parameter data associated with the wound site; ii) a processor coupled to the plurality of sensors and configured to read the physical parameter data from the plurality of sensors; iii) a wireless transceiver coupled to the processor and configured to communicate with an external therapy controller; and iv) at least a first internal peripheral device coupled to the processor. The system further comprises at least a first external peripheral interface coupled to the core module and configured to communicate with the processor, wherein the core module and the at least a first external peripheral interface are disposed within a housing of the dressing interface. 
     In another embodiment, the housing includes a therapy cavity including an opening configured to be disposed in fluid communication with the wound site and a negative-pressure port adapted to fluidly couple the therapy cavity to a source of negative-pressure. 
     In still another embodiment, the core module further comprises a first communication bus configured to couple the plurality of sensors and the at least a first internal peripheral device to the processor. 
     In yet another embodiment, the core module further comprises a second communication bus configured to couple a second internal peripheral device to the processor, wherein the first communication bus operates at a lower speed that the second communication bus. 
     In a further embodiment, the first communication bus comprises a first external bus portion configured to couple a second external peripheral interface to the processor and the second communication bus comprises a second external bus portion configured to couple a third external peripheral interface to the processor. 
     In a still further embodiment, the processor and the wireless transceiver are implemented in a system on a chip (SoC) device disposed in the core module. 
     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 
         FIG. 1  is a functional block diagram of an example embodiment of a therapy system that can provide negative-pressure and instillation in accordance with this specification; 
         FIG. 2A  is a graph illustrating an illustrative embodiment of pressure control modes for the negative-pressure and instillation therapy system of  FIG. 1  wherein the x-axis represents time in minutes (min) and/or seconds (sec) and the y-axis represents pressure generated by a pump in Torr (mmHg) that varies with time in a continuous pressure mode and an intermittent pressure mode that may be used for applying negative pressure in the therapy system; 
         FIG. 2B  is a graph illustrating an illustrative embodiment of another pressure control mode for the negative-pressure and instillation therapy system of  FIG. 1  wherein the x-axis represents time in minutes (min) and/or seconds (sec) and the y-axis represents pressure generated by a pump in Torr (mmHg) that varies with time in a dynamic pressure mode that may be used for applying negative pressure in the therapy system; 
         FIG. 3  is a schematic block diagram showing an illustrative embodiment of a therapy method for providing negative-pressure and instillation therapy for delivering treatment solutions to a dressing at a tissue site; 
         FIG. 4  is a sectional side view of a dressing interface comprising a housing and a wall disposed within the housing and forming a therapy cavity including sensors and a component cavity including electrical devices that may be associated with some example embodiments of the therapy system of  FIG. 1 ; 
         FIG. 5A  is a perspective top view of the dressing interface of  FIG. 4 ,  FIG. 5B  is a side view of the dressing interface of  FIG. 4  disposed on a tissue site, and  FIG. 5C  is an end view of the dressing interface of  FIG. 4  disposed on the tissue site; 
         FIG. 6A  is an assembly view of the dressing interface of  FIG. 4  comprising components of the housing and a first example embodiment of a sensor assembly including the wall, the sensors, and the electrical devices; 
         FIG. 6B  is a system block diagram of the sensors and electrical devices comprising the sensor assembly of  FIG. 6A ; 
         FIGS. 7A, 7B and 7C  are a top view, side view, and bottom view, respectively, of the sensor assembly of  FIG. 6 ; 
         FIG. 7D  is a perspective top view of the sensor assembly of the sensor assembly of  FIG. 6  including one example embodiment of a pH sensor; 
         FIG. 8A  is a perspective bottom view of the dressing interface of  FIG. 4 , and  FIG. 8B  is a bottom view of the dressing interface of  FIG. 4 ; 
         FIG. 9A  is a top view of a first embodiment of a pH sensor that may be used with the sensor assembly of  FIG. 8B , and  FIG. 9B  is a top view of a second embodiment of a pH sensor that may be used with the sensor assembly of  FIG. 8B ; 
         FIG. 10  is a flow chart illustrating a method for treating a tissue site utilizing the dressing interface of  FIG. 4  for applying negative-pressure therapy with fluid instillation and sensing properties of wound exudates extracted from the tissue site; 
         FIG. 11  is a schematic block diagram illustrating a negative pressure control algorithm utilized within the tissue treatment method of  FIG. 10  including the detection of dressing flow characteristics within the system and the assessment of sensor properties; 
         FIG. 12  is a block diagram of a user interface illustrating alerts and alarms associated with the dressing flow characteristics of  FIG. 11 ; 
         FIG. 13A  is a flow chart illustrating a wound pressure control method configured to operate in the negative pressure control algorithm of  FIG. 11 ; 
         FIG. 13B  is a flow chart illustrating a method for detecting blockages and fluid leaks as two of the dressing flow characteristics of  FIG. 11 ; 
         FIG. 13C  is a flow chart illustrating a method for detecting air leaks and desiccation as two of the dressing flow characteristics of  FIG. 11 , and for logging and assessing the sensing properties; 
         FIG. 14  is a graph illustrating data associated with the detection of blockages based on the assessment of humidity data and wound pressure over time generated by the negative pressure control algorithm of  FIG. 11 ; 
         FIG. 15  is a graph illustrating data associated with the detection of fluid leaks based on the assessment of humidity data and wound pressure data over time generated by the negative pressure control algorithm of  FIG. 11 ; 
         FIG. 16  is a graph illustrating data associated with the detection of air leaks based on the assessment of humidity data, wound pressure data, and pump pressure data over time generated by the negative pressure control algorithm of  FIG. 11 ; 
         FIG. 17  is a graph illustrating data associated with the detection of desiccation conditions based on the assessment of humidity data over time generated by the negative pressure control algorithm of  FIG. 11 ; 
         FIG. 18  is a schematic block diagram illustrating a fluid instillation control algorithm utilized within the tissue treatment method of  FIG. 10  including the detection of dressing flow characteristics within the system and the assessment of sensor properties and dispensed volume; 
         FIG. 19A  is a flow chart illustrating an automated fill assist control method configured to operate in the fluid instillation control algorithm of  FIG. 18 ; 
         FIG. 19B  is a flow chart illustrating a method for detecting blockages and fluid leaks as two of the dressing flow characteristics of  FIG. 18 ; and 
         FIG. 20  is a graph illustrating an instillation response curve including data associated with the relative humidity percentage of a dressing in response to the fluid instillation control algorithm of  FIG. 18 . 
         FIG. 21  is a block diagram of a wireless module architecture of the sensor assembly and therapy system according to an exemplary embodiment of the disclosure. 
         FIG. 22  is a first wireless network topology for controlling the therapy system according to an exemplary embodiment of the disclosure. 
         FIG. 23  is a second wireless network topology for controlling the therapy system according to an exemplary embodiment of the disclosure. 
         FIG. 24  is a third wireless network topology for controlling the therapy system according to an exemplary embodiment of the disclosure. 
         FIG. 25  is a method for wirelessly controlling the dressing interface and the therapy system according to an exemplary embodiment of the disclosure. 
         FIG. 26  is a method for wirelessly controlling the dressing interface and the therapy system according to an exemplary embodiment of the disclosure. 
         FIG. 27  is a block diagram of a wireless therapy controller according to an exemplary embodiment of the disclosure. 
         FIG. 28  is a method for wirelessly controlling the dressing interface and the therapy system according to an exemplary embodiment of the disclosure. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     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 may omit certain details already well-known in the art. The following detailed description is, therefore, to be taken as illustrative and not limiting. 
     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. 
     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, partial-thickness burns, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term “tissue site” may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be applied to a tissue site to grow additional tissue that may be harvested and transplanted. 
     The present technology also provides negative pressure therapy devices and systems, and methods of treatment using such systems with antimicrobial solutions.  FIG. 1  is a simplified functional block diagram of an example embodiment of a therapy system  100  that can provide negative-pressure therapy with instillation of treatment solutions in accordance with this specification. The therapy system  100  may include a negative-pressure supply, and may include or be configured to be coupled to a distribution component, such as a dressing. In general, a distribution component may refer to any complementary or ancillary component configured to be fluidly coupled to a negative-pressure supply between a negative-pressure supply and a tissue site. A distribution component is preferably detachable, and may be disposable, reusable, or recyclable. For example, a dressing  102  is illustrative of a distribution component that may be coupled to a negative-pressure source and other components. The therapy system  100  may be packaged as a single, integrated unit such as a therapy system including all of the components shown in  FIG. 1  that are fluidly coupled to the dressing  102 . The therapy system may be, for example, a V.A.C. Ulta™ System available from Kinetic Concepts, Inc. of San Antonio, Tex. 
     The dressing  102  may be fluidly coupled to a negative-pressure source  104 . A dressing may include a cover, a tissue interface, or both in some embodiments. The dressing  102 , for example, may include a cover  106 , a dressing interface  107 , and a tissue interface  108 . A computer or a controller device, such as a controller  110 , may also be coupled to the negative-pressure source  104 . In some embodiments, the cover  106  may be configured to cover the tissue interface  108  and the tissue site, and may be adapted to seal the tissue interface and create a therapeutic environment proximate to a tissue site for maintaining a negative pressure at the tissue site. In some embodiments, the dressing interface  107  may be configured to fluidly couple the negative-pressure source  104  to the therapeutic environment of the dressing. The therapy system  100  may optionally include a fluid container, such as a container  112 , fluidly coupled to the dressing  102  and to the negative-pressure source  104 . 
     The therapy system  100  may also include a source of instillation solution, such as a solution source  114 . A distribution component may be fluidly coupled to a fluid path between a solution source and a tissue site in some embodiments. For example, an instillation pump  116  may be coupled to the solution source  114 , as illustrated in the example embodiment of  FIG. 1 . The instillation pump  116  may also be fluidly coupled to the negative-pressure source  104  such as, for example, by a fluid conductor  119 . In some embodiments, the instillation pump  116  may be directly coupled to the negative-pressure source  104 , as illustrated in  FIG. 1 , but may be indirectly coupled to the negative-pressure source  104  through other distribution components in some embodiments. For example, in some embodiments, the instillation pump  116  may be fluidly coupled to the negative-pressure source  104  through the dressing  102 . In some embodiments, the instillation pump  116  and the negative-pressure source  104  may be fluidly coupled to two different locations on the tissue interface  108  by two different dressing interfaces. For example, the negative-pressure source  104  may be fluidly coupled to the dressing interface  107  while the instillation pump  116  may be fluidly to the coupled to dressing interface  107  or a second dressing interface  117 . In some other embodiments, the instillation pump  116  and the negative-pressure source  104  may be fluidly coupled to two different tissue interfaces by two different dressing interfaces, one dressing interface for each tissue interface (not shown). 
     The therapy system  100  also may include sensors to measure operating parameters and provide feedback signals to the controller  110  indicative of the operating parameters properties of fluids extracted from a tissue site. As illustrated in  FIG. 1 , for example, the therapy system  100  may include a pressure sensor  120 , an electric sensor  124 , or both, coupled to the controller  110 . The pressure sensor  120  may be fluidly coupled or configured to be fluidly coupled to a distribution component such as, for example, the negative-pressure source  104  either directly or indirectly through the container  112 . The pressure sensor  120  may be configured to measure pressure being generated by the negative-pressure source  104 , i.e., the pump pressure (PP). The electric sensor  124  also may be coupled to the negative-pressure source  104  to measure the pump pressure (PP). In some example embodiments, the electric sensor  124  may be fluidly coupled proximate the output of the negative-pressure source  104  to directly measure the pump pressure (PP). In other example embodiments, the electric sensor  124  may be electrically coupled to the negative-pressure source  104  to measure the changes in the current in order to determine the pump pressure (PP). 
     Distribution components may be fluidly coupled to each other to provide a distribution system for transferring fluids (i.e., liquid and/or gas). For example, a distribution system may include various combinations of fluid conductors and fittings to facilitate fluid coupling. A fluid conductor generally includes any structure with one or more lumina adapted to convey a fluid between two ends, such as a tube, pipe, hose, or conduit. Typically, a fluid conductor is an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary. Some fluid conductors may be molded into or otherwise integrally combined with other components. A fitting can be used to mechanically and fluidly couple components to each other. For example, a fitting may comprise a projection and an aperture. The projection may be configured to be inserted into a fluid conductor so that the aperture aligns with a lumen of the fluid conductor. A valve is a type of fitting that can be used to control fluid flow. For example, a check valve can be used to substantially prevent return flow. A port is another example of a fitting. A port may also have a projection, which may be threaded, flared, tapered, barbed, or otherwise configured to provide a fluid seal when coupled to a component. 
     In some embodiments, distribution 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. Coupling may also include mechanical, thermal, electrical, or chemical coupling (such as a chemical bond) in some contexts. For example, a tube may mechanically and fluidly couple the dressing  102  to the container  112  in some embodiments. In general, components of the therapy system  100  may be coupled directly or indirectly. For example, the negative-pressure source  104  may be directly coupled to the controller  110 , and may be indirectly coupled to the dressing interface  107  through the container  112  by conduit  126  and conduit  130 . The pressure sensor  120  may be fluidly coupled to the dressing  102  directly (not shown) or indirectly by conduit  121  and conduit  122 . Additionally, the instillation pump  116  may be coupled indirectly to the dressing interface  107  through the solution source  114  and the instillation regulator  115  by fluid conductors  132 ,  134  and  138 . Alternatively, the instillation pump  116  may be coupled indirectly to the second dressing interface  117  through the solution source  114  and the instillation regulator  115  by fluid conductors  132 ,  134  and  139 . 
     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 and instillation are generally well-known to those skilled in the art, and the process of reducing pressure may be described illustratively herein as “delivering,” “distributing,” or “generating” negative pressure, for example. 
     In general, exudates and other fluids flow toward lower pressure along a fluid path. Thus, the term “downstream” typically implies something 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 something 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. 
     “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 provided by the dressing  102 . 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. Similarly, references to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure. While the amount and nature of negative pressure applied to a tissue site may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between −5 mm Hg (−667 Pa) and −500 mm Hg (−66.7 kPa). Common therapeutic ranges are between −75 mm Hg (−9.9 kPa) and −300 mm Hg (−39.9 kPa). 
     A negative-pressure supply, such as the negative-pressure source  104 , may be a reservoir of air at a negative pressure, or may be a manual or electrically-powered device that can reduce the pressure in a sealed volume, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micro-pump, for example. A negative-pressure supply 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  104  may be combined with the controller  110  and other components into a therapy unit. A negative-pressure supply may also have one or more supply ports configured to facilitate coupling and de-coupling the negative-pressure supply to one or more distribution components. 
     The tissue interface  108  can be generally adapted to contact a tissue site. The tissue interface  108  may be partially or fully in contact with the tissue site. If the tissue site is a wound, for example, the tissue interface  108  may partially or completely fill the wound, or may be placed over the wound. The tissue interface  108  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  108  may be adapted to the contours of deep and irregular shaped tissue sites. Moreover, any or all of the surfaces of the tissue interface  108  may have projections or an uneven, course, or jagged profile that can induce strains and stresses on a tissue site, which can promote granulation at the tissue site. 
     In some embodiments, the tissue interface  108  may be a manifold such as manifold  408  shown in  FIG. 4 . A “manifold” in this context generally includes any substance or structure providing a plurality of pathways adapted to collect or distribute fluid across a tissue site under pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute negative pressure through multiple apertures across a tissue site, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid across a tissue site. 
     In some illustrative embodiments, the pathways of a manifold may be interconnected to improve distribution or collection of fluids across a tissue site. In some illustrative embodiments, a manifold may be a porous foam material having interconnected cells or pores. For example, cellular foam, open-cell foam, reticulated foam, porous tissue collections, and other porous material such as gauze or felted mat generally include pores, edges, and/or walls adapted to form interconnected fluid channels. 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. 
     The average pore size of a foam manifold may vary according to needs of a prescribed therapy. For example, in some embodiments, the tissue interface  108  may be a foam manifold having pore sizes in a range of 400-600 microns. The tensile strength of the tissue interface  108  may also vary according to needs of a prescribed therapy. For example, the tensile strength of a foam may be increased for instillation of topical treatment solutions. In one non-limiting example, the tissue interface  108  may be an open-cell, reticulated polyurethane foam such as GranuFoam® dressing or VeraFlo® foam, both available from Kinetic Concepts, Inc. of San Antonio, Tex. 
     The tissue interface  108  may be either hydrophobic or hydrophilic. In an example in which the tissue interface  108  may be hydrophilic, the tissue interface  108  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  108  may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic foam is a polyvinyl alcohol, open-cell foam such as V.A.C. WhiteFoam® dressing available from Kinetic Concepts, Inc. of San Antonio, Tex. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity. 
     The tissue interface  108  may further promote granulation at a tissue site when pressure within the sealed therapeutic environment is reduced. For example, any or all of the surfaces of the tissue interface  108  may have an uneven, coarse, or jagged profile that can induce microstrains and stresses at a tissue site if negative pressure is applied through the tissue interface  108 . 
     In some embodiments, the tissue interface  108  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  108  may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface  108  to promote cell-growth. A scaffold is generally a substance or structure used to enhance or promote the growth of cells or formation of tissue, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, or processed allograft materials. 
     In some embodiments, the cover  106  may provide a bacterial barrier and protection from physical trauma. The cover  106  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  106  may be, for example, an elastomeric film or membrane that can provide a seal adequate to maintain a negative pressure at a tissue site for a given negative-pressure source. The cover  106  may have a high moisture-vapor transmission rate (MVTR) in some applications. For example, the MVTR may be at least 300 g/m{circumflex over ( )}2 per twenty-four hours in some embodiments. In some example embodiments, the cover  106  may be a polymer drape, such as a polyurethane film, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained. In some embodiments, the cover may be a drape such as drape  406  shown in  FIG. 4 . 
     An attachment device may be used to attach the cover  106  to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many forms. For example, an attachment device may be a medically-acceptable, pressure-sensitive adhesive that extends about a periphery, a portion, or an entire sealing member. In some embodiments, for example, some or all of the cover  106  may be coated with an acrylic adhesive having a coating weight between 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. 
     In some embodiments, the dressing interface  107  may facilitate coupling the negative-pressure source  104  to the dressing  102 . The negative pressure provided by the negative-pressure source  104  may be delivered through the conduit  130  to a negative-pressure interface, which may include an elbow portion. In one illustrative embodiment, the negative-pressure interface may be a T.R.A.C.® Pad or Sensa T.R.A.C.® Pad available from KCI of San Antonio, Tex. The negative-pressure interface enables the negative pressure to be delivered through the cover  106  and to the tissue interface  108  and the tissue site. In this illustrative, non-limiting embodiment, the elbow portion may extend through the cover  106  to the tissue interface  108 , but numerous arrangements are possible. 
     A controller, such as the controller  110 , may be a microprocessor or computer programmed to operate one or more components of the therapy system  100 , such as the negative-pressure source  104 . In some embodiments, for example, the controller  110  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  104 , the pressure generated by the negative-pressure source  104 , or the pressure distributed to the tissue interface  108 , for example. The controller  110  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 based on the input signals. 
     Sensors, such as the pressure sensor  120  or the electric sensor  124 , are generally known in the art as any apparatus 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 pressure sensor  120  and the electric sensor  124  may be configured to measure one or more operating parameters of the therapy system  100 . In some embodiments, the pressure sensor  120  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 pressure sensor  120  may be a piezoresistive strain gauge. The electric sensor  124  may optionally measure operating parameters of the negative-pressure source  104 , such as the voltage or current, in some embodiments. Preferably, the signals from the pressure sensor  120  and the electric sensor  124  are suitable as an input signal to the controller  110 , 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  110 . Typically, the signal is an electrical signal that is transmitted and/or received on by wire or wireless means, but may be represented in other forms, such as an optical signal. 
     The solution source  114  is representative of a container, canister, pouch, bag, or other storage component, which can provide a solution for instillation therapy. Compositions of solutions may vary according to a prescribed therapy, but examples of solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions. Examples of such other therapeutic solutions that may be suitable for some prescriptions include hypochlorite-based solutions, silver nitrate (0.5%), sulfur-based solutions, biguanides, cationic solutions, and isotonic solutions. In one illustrative embodiment, the solution source  114  may include a storage component for the solution and a separate cassette for holding the storage component and delivering the solution to the tissue site  150 , such as a V.A.C. VeraLink™ Cassette available from Kinetic Concepts, Inc. of San Antonio, Tex. 
     The container  112  may also be representative of a container, canister, pouch, or other storage component, which can be used to collect and manage exudates and other fluids withdrawn from a tissue site. In many environments, a rigid container such as, for example, a container  162 , 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. In some embodiments, the container  112  may comprise a canister having a collection chamber, a first inlet fluidly coupled to the collection chamber and a first outlet fluidly coupled to the collection chamber and adapted to receive negative pressure from a source of negative pressure. In some embodiments, a first fluid conductor may comprise a first member such as, for example, the conduit  130  fluidly coupled between the first inlet and the tissue interface  108  by the negative-pressure interface described above, and a second member such as, for example, the conduit  126  fluidly coupled between the first outlet and a source of negative pressure whereby the first conductor is adapted to provide negative pressure within the collection chamber to the tissue site. 
     The therapy system  100  may also comprise a flow regulator such as, for example, a regulator  118  fluidly coupled to a source of ambient air to provide a controlled or managed flow of ambient air to the sealed therapeutic environment provided by the dressing  102  and ultimately the tissue site. In some embodiments, the regulator  118  may control the flow of ambient fluid to purge fluids and exudates from the sealed therapeutic environment. In some embodiments, the regulator  118  may be fluidly coupled by a fluid conductor or vent conduit  135  through the dressing interface  107  to the tissue interface  108 . The regulator  118  may be configured to fluidly couple the tissue interface  108  to a source of ambient air as indicated by a dashed arrow. In some embodiments, the regulator  118  may be disposed within the therapy system  100  rather than being proximate to the dressing  102  so that the air flowing through the regulator  118  is less susceptible to accidental blockage during use. In such embodiments, the regulator  118  may be positioned proximate the container  112  and/or proximate a source of ambient air where the regulator  118  is less likely to be blocked during usage. 
     In operation, the tissue interface  108  may be placed within, over, on, or otherwise proximate a tissue site, such as tissue site  150 . The cover  106  may be placed over the tissue interface  108  and sealed to an attachment surface near the tissue site  150 . For example, the cover  106  may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing  102  can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source  104  can reduce the pressure in the sealed therapeutic environment. Negative pressure applied across the tissue site through the tissue interface  108  in the sealed therapeutic environment can induce macrostrain and microstrain in the tissue site, as well as remove exudates and other fluids from the tissue site, which can be collected in container  112 . 
     In one embodiment, the controller  110  may receive and process data, such as data related to the pressure distributed to the tissue interface  108  from the pressure sensor  120 . The controller  110  may also control the operation of one or more components of therapy system  100  to manage the pressure distributed to the tissue interface  108  for application to the wound at the tissue site  150 , which may also be referred to as the wound pressure (WP). In one embodiment, controller  110  may include an input for receiving a desired target pressure (TP) set by a clinician or other user and may be programmed for processing data relating to the setting and inputting of the target pressure (TP) to be applied to the tissue site  150 . In one example embodiment, the target pressure (TP) may be a fixed pressure value determined by a user/caregiver as the reduced pressure target desired for therapy at the tissue site  150  and then provided as input to the controller  110 . The user may be a nurse or a doctor or other approved clinician who prescribes the desired negative pressure to which the tissue site  150  should be applied. The desired negative pressure may vary from tissue site to tissue site based on the type of tissue forming the tissue site  150 , the type of injury or wound (if any), the medical condition of the patient, and the preference of the attending physician. After selecting the desired target pressure (TP), the negative-pressure source  104  is controlled to achieve the target pressure (TP) desired for application to the tissue site  150 . 
     Referring more specifically to  FIG. 2A , a graph illustrating an illustrative embodiment of pressure control modes  200  that may be used for the negative-pressure and instillation therapy system of  FIG. 1  is shown wherein the x-axis represents time in minutes (min) and/or seconds (sec) and the y-axis represents pressure generated by a pump in Torr (mmHg) that varies with time in a continuous pressure mode and an intermittent pressure mode that may be used for applying negative pressure in the therapy system. The target pressure (TP) may be set by the user in a continuous pressure mode as indicated by solid line  201  and dotted line  202  wherein the wound pressure (WP) is applied to the tissue site  150  until the user deactivates the negative-pressure source  104 . The target pressure (TP) may also be set by the user in an intermittent pressure mode as indicated by solid lines  201 ,  203  and  205  wherein the wound pressure (WP) is cycled between the target pressure (TP) and atmospheric pressure. For example, the target pressure (TP) may be set by the user at a value of 125 mmHg for a specified period of time (e.g., 5 min) followed by the therapy being turned off for a specified period of time (e.g., 2 min) as indicated by the gap between the solid lines  203  and  205  by venting the tissue site  150  to the atmosphere, and then repeating the cycle by turning the therapy back on as indicated by solid line  205  which consequently forms a square wave pattern between the target pressure (TP) level and atmospheric pressure. In some embodiments, the ratio of the “on-time” to the “off-time” or the total “cycle time” may be referred to as a pump duty cycle (PD). 
     In some example embodiments, the decrease in the wound pressure (WP) at the tissue site  150  from ambient pressure to the target pressure (TP) is not instantaneous, but rather gradual depending on the type of therapy equipment and dressing being used for the particular therapy treatment. For example, the negative-pressure source  104  and the dressing  102  may have an initial rise time as indicated by the dashed line  207  that may vary depending on the type of dressing and therapy equipment being used. For example, the initial rise time for one therapy system may be in the range between about 20-30 mmHg/second or, more specifically, equal to about 25 mmHg/second, and in the range between about 5-10 mmHg/second for another therapy system. When the therapy system  100  is operating in the intermittent mode, the repeating rise time as indicated by the solid line  205  may be a value substantially equal to the initial rise time as indicated by the dashed line  207 . 
     The target pressure may also be a variable target pressure (VTP) controlled or determined by controller  110  that varies in a dynamic pressure mode. For example, the variable target pressure (VTP) may vary between a maximum and minimum pressure value that may be set as an input determined by a user as the range of negative pressures desired for therapy at the tissue site  150 . The variable target pressure (VTP) may also be processed and controlled by controller  110  that varies the target pressure (TP) according to a predetermined waveform such as, for example, a sine waveform or a saw-tooth waveform or a triangular waveform, that may be set as an input by a user as the predetermined or time-varying reduced pressures desired for therapy at the tissue site  150 . 
     Referring more specifically to  FIG. 2B , a graph illustrating an illustrative embodiment of another pressure control mode  210  for the negative-pressure and instillation therapy system of  FIG. 1  is shown wherein the x-axis represents time in minutes (min) and/or seconds (sec) and the y-axis represents pressure generated by a pump in Torr (mmHg) that varies with time in a dynamic pressure mode that may be used for applying negative pressure in the therapy system. For example, the variable target pressure (VTP) may be a reduced pressure that provides an effective treatment by applying reduced pressure to tissue site  150  in the form of a triangular waveform varying between a minimum and maximum pressure of 50-125 mmHg with a rise time  212  set at a rate of +25 mmHg/minute and a descent time  211  set at −25 mmHg/minute, respectively. In another embodiment of the therapy system  100 , the variable target pressure (VTP) may be a reduced pressure that applies reduced pressure to tissue site  150  in the form of a triangular waveform varying between 25-125 mmHg with a rise time  212  set at a rate of +30 mmHg/min and a descent time  211  set at −30 mmHg/min. Again, the type of system and tissue site determines the type of reduced pressure therapy to be used. 
       FIG. 3  is a flow chart illustrating an illustrative embodiment of a therapy method  300  that may be used for providing negative-pressure and instillation therapy for delivering an antimicrobial solution or other treatment solution to a dressing at a tissue site. In one embodiment, the controller  110  receives and processes data, such as data related to fluids provided to the tissue interface. Such data may include the type of instillation solution prescribed by a clinician, the volume of fluid or solution to be instilled to the tissue site (“fill volume”), and the amount of time needed to soak the tissue interface (“soak time”) before applying a negative pressure to the tissue site. The fill volume may be, for example, between 10 and 500 mL, and the soak time may be between one second to 30 minutes. The controller  110  may also control the operation of one or more components of the therapy system  100  to manage the fluids distributed from the solution source  114  for instillation to the tissue site  150  for application to the wound as described in more detail above. In one embodiment, fluid may be instilled to the tissue site  150  by applying a negative pressure from the negative-pressure source  104  to reduce the pressure at the tissue site  150  to draw the instillation fluid into the dressing  102  as indicated at  302 . In another embodiment, fluid may be instilled to the tissue site  150  by applying a positive pressure from the negative-pressure source  104  (not shown) or the instillation pump  116  to force the instillation fluid from the solution source  114  to the tissue interface  108  as indicated at  304 . In yet another embodiment, fluid may be instilled to the tissue site  150  by elevating the solution source  114  to height sufficient to force the instillation fluid into the tissue interface  108  by the force of gravity as indicated at  306 . Thus, the therapy method  300  includes instilling fluid into the tissue interface  108  by either drawing or forcing the fluid into the tissue interface  108  as indicated at  310 . 
     The therapy method  300  may control the fluid dynamics of applying the fluid solution to the tissue interface  108  at  312  by providing a continuous flow of fluid at  314  or an intermittent flow of fluid for soaking the tissue interface  108  at  316 . The therapy method  300  may include the application of negative pressure to the tissue interface  108  to provide either the continuous flow or intermittent soaking flow of fluid at  320 . The application of negative pressure may be implemented to provide a continuous pressure mode of operation at  322  as described above to achieve a continuous flow rate of instillation fluid through the tissue interface  108  or a dynamic pressure mode of operation at  324  as described above to vary the flow rate of instillation fluid through the tissue interface  108 . Alternatively, the application of negative pressure may be implemented to provide an intermittent mode of operation at  326  as described above to allow instillation fluid to soak into the tissue interface  108  as described above. In the intermittent mode, a specific fill volume and the soak time may be provided depending, for example, on the type of wound being treated and the type of dressing  102  being utilized to treat the wound. After or during instillation of fluid into the tissue interface  108  has been completed, the therapy method  300  may be utilized using any one of the three modes of operation at  330  as described above. The controller  110  may be utilized to select any one of these three modes of operation and the duration of the negative pressure therapy as described above before commencing another instillation cycle at  340  by instilling more fluid at  310 . 
     As discussed above, the tissue site  150  may include, without limitation, any irregularity with a tissue, such as an open wound, surgical incision, or diseased tissue. The therapy system  100  is presented in the context of a tissue site that includes a wound that may extend through the epidermis and the dermis, and may reach into the hypodermis or subcutaneous tissue. The therapy system  100  may be used to treat a wound of any depth, as well as many different types of wounds including open wounds, incisions, or other tissue sites. The tissue site  150  may be the bodily tissue of any human, animal, or other organism, including bone tissue, adipose tissue, muscle tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, ligaments, or any other tissue. Treatment of the tissue site  150  may include removal of fluids originating from the tissue site  150 , such as exudates or ascites, or fluids instilled into the dressing to cleanse or treat the tissue site  150 , such as antimicrobial solutions. 
     As indicated above, the therapy system  100  may be packaged as a single, integrated unit such as a therapy system including all of the components shown in  FIG. 1  that are fluidly coupled to the dressing  102 . In some embodiments, an integrated therapy unit may include the negative-pressure source  104 , the controller  110 , the pressure sensor  120 , and the container  112  which may be fluidly coupled to the dressing interface  107 . In this therapy unit, the negative-pressure source  104  is indirectly coupled to the dressing interface  107  through the container  112  by conduit  126  and conduit  130 , and the pressure sensor  120  is indirectly coupled to the dressing interface  107  by conduit  121  and conduit  122  as described above. In some embodiments, the negative pressure conduit  130  and the pressure sensing conduit  122  may be combined in a single fluid conductor that can be, for example, a multi-lumen tubing comprising a central primary lumen that functions as the negative pressure conduit  130  for delivering negative pressure to the dressing interface  107  and several peripheral auxiliary lumens that function as the pressure sensing conduit  122  for sensing the pressure that the dressing interface  107  delivers to the tissue interface  108 . In this type of therapy unit wherein the pressure sensor  120  is removed from and indirectly coupled to the dressing interface  107 , the negative pressure measured by the pressure sensor  120  may be different from the wound pressure (WP) actually being applied to the tissue site  150 . Such pressure differences must be approximated in order to adjust the negative-pressure source  104  to deliver the pump pressure (PP) necessary to provide the desired or target pressure (TP) to the tissue interface  108 . Moreover, such pressure differences and predictability may be exacerbated by viscous fluids such as exudates being produced by the tissue site or utilizing a single therapy device including a pressure sensor to deliver negative pressure to multiple tissue sites on a single patient. 
     What is needed is a pressure sensor that is integrated within the dressing interface  107  so that the pressure sensor is proximate the tissue interface  108  when disposed on the tissue site in order to provide a more accurate reading of the wound pressure (WP) being provided within the therapy environment of the dressing  102 . The integrated pressure sensor may be used with or without the remote pressure sensor  120  that is indirectly coupled to the dressing interface  107 . In some example embodiments, the dressing interface  107  may comprise a housing having a therapy cavity that opens to the tissue site when positioned thereon. The integrated pressure sensor may have a sensing portion disposed within the therapy cavity along with other sensors including, for example, a temperature sensor, a humidity sensor, and a pH sensor. The sensors may be electrically coupled to the controller  110  outside the therapy cavity to provide data indicative of the pressure, temperature, humidity, and acidity properties within the therapeutic space of the therapy cavity. The sensors may be electrically coupled to the controller  110 , for example, by wireless means. Systems, apparatuses, and methods described herein provide the advantage of more accurate measurements of these properties, as well as other significant advantages described below in more detail. 
     As indicated above, the dressing  102  may include the cover  106 , the dressing interface  107 , and the tissue interface  108 . Referring now to  FIGS. 4, 5A, 5B, 5C, 6A, 6B , and  7 , a first dressing is shown comprising a dressing interface  400 , a cover or drape  406 , and a tissue interface or manifold  408  disposed adjacent a tissue site  410 , all of which may be functionally similar in part to the dressing interface  107 , the cover  106 , and the tissue interface  108 , respectively, as described above. In one example embodiment, the dressing interface  400  may comprise a housing  401  and a wall  402  disposed within the housing  401  wherein the wall  402  forms a recessed space or a therapy cavity  403  that opens to the manifold  408  when disposed at the tissue site  410  and a component cavity  404  opening away from the tissue site  410  of the upper portion of the dressing interface  400 . In some embodiments, sensing portions of various sensors may be disposed within the therapy cavity  403 , and electrical devices associated with the sensors may be disposed within the component cavity  404  and electrically coupled to the sensing portions through the wall  402 . Electrical devices disposed within the component cavity  404  may include components associated with some example embodiments of the therapy system of  FIG. 1 . Although the dressing interface  400  and the therapy cavity  403  are functionally similar to the dressing interface  107  as described above, the dressing interface  400  further comprises the wall  402 , the sensors, and the associated electrical devices described below in more detail. In some embodiments, the housing  401  may further comprise a neck portion or neck  407  fluidly coupled to a conduit  405 . In some embodiments, the housing  401  may further comprise a flange portion or flange  409  having flow channels (see  FIG. 8 ) configured to be fluidly coupled to the therapy cavity  403  when disposed on the manifold  408 . 
     In an advantageous embodiment, the housing  401  may include a communication port  412  that may be used to couple one of more external devices to the sensor assembly  425  of the dressing interface  400 . By way of example and not limitation, communications port  412  may comprise a USB 3.0 port that couples to a USB 3.0 connector  412 A on the circuit board  432  that supports the wireless communications module  422  and that couples the sensor assembly  425  of the dressing interface  400  to one or more of a display and/or operator interface, one of more supplemental sensors, a Bluetooth module, or an external power supply. One example of a display or operator interface may be a mobile phone or a computer tablet that an operator uses to control and communicate with the sensor assembly  425  of the dressing interface  400 . 
     In an advantageous embodiment, the housing  401  may include a product identifier  499  that may be read by a therapy control device in order to accurately identify the dressing interface  400 . As will be explained below in greater detail, the therapy control device or therapy controller is capable of identifying the exact product and model of dressing interface  400  and can then select the correct therapy protocol(s) and operating parameters for dressing interface  400 . By way of example and not limitation, product identifier  499  may be a bar code, a Q code, an RFID tag (passive or active), a near-field communications (NFC) tag, or the like. The therapy controller is simply brought within close proximity of the product identifier  499  in order to automatically read the product and model information and thereby select, for example, the proper graphical user interface (GUI) to allow an operator to follow the correct therapy protocol(s) and operating parameters for dressing interface  400 . By way of example, a camera in the therapy controller may be used to read a product identifier  499  that is a bar code or Q code in order to identify the product and model information of dressing interface  499 . Alternatively, an NFC-enabled transceiver in the therapy controller may be used to read a product identifier  499  that is an NFC tag in order to identify the product and model information of dressing interface  400 . Alternatively, an RFID-enabled transceiver in the therapy controller may be used to read a product identifier  499  that is an RFID tag. 
     In some example embodiments, the neck  407  of the housing  401  may include portions of both the therapy cavity  403  and the component cavity  404 . That portion of the neck  407  extending into the therapy cavity  403  is fluidly coupled to the conduit  405 , while the portion extending into the component cavity  404  may contain some of the electrical devices. In some example embodiments, the conduit  405  may comprise a primary lumen  430  and auxiliary lumens  435  fluidly coupled by the neck  407  of the housing  401  to the therapy cavity  403 . The primary lumen  430  is similar to the negative pressure conduit  130  that may be coupled indirectly to the negative-pressure source  104 . The auxiliary lumens  435  are collectively similar to the vent conduit  135  that may be fluidly coupled to the regulator  118  for purging fluids from the therapy cavity  403 . 
     In some embodiments, the component cavity  404  containing the electrical devices may be open to the ambient environment such that the electrical devices are exposed to the ambient environment. In other example embodiments, the component cavity  404  may be closed by a cover such as, for example, a cap  411  to protect the electrical devices. In still other embodiments, the component cavity  404  covered by the cap  411  may still be vented to the ambient environment to provide cooling to the electrical devices and a source of ambient pressure for a pressure sensor disposed in the therapy cavity  403  as described in more detail below. The first dressing may further comprise a drape ring  413  covering the circumference of the flange  409  and the adjacent portion of the drape  406  to seal the therapy cavity  403  of the housing  401  over the manifold  408  and the tissue site  410 . In some embodiments, the drape ring  413  may comprise a polyurethane film including and an attachment device such as, for example, an acrylic, polyurethane gel, silicone, or hybrid combination of the foregoing adhesives (not shown) to attach the drape ring  413  to the flange  409  and the drape  406 . The attachment device of drape ring  413  may be a single element of silicon or hydrocolloid with the adhesive on each side that functions as a gasket between the drape  406  and the flange  409 . In some embodiments, the drape ring  413  may be similar to the cover  106  and/or the attachment device described above in more detail. 
     In some embodiments, a pressure sensor  416 , a temperature and humidity sensor  418 , and a pH sensor  420  (collectively referred to below as “the sensors”) may be disposed in the housing  401  with each one having a sensing portion extending into the therapy cavity  403  of the housing  401  and associated electronics disposed within the component cavity  404 . The housing  401  may include other types of sensors, or combinations of the foregoing sensors, such as, for example, oxygen sensors. In some example embodiments, the sensors may be coupled to or mounted on the wall  402  and electrically coupled to electrical components and circuits disposed within the component cavity  404  by electrical conductors extending through the wall  402 . In some preferred embodiments, the electrical conductors extend through pathways in the wall  402  while keeping the therapy cavity  403  electrically and pneumatically isolated from the component cavity  404 . For example, the wall  402  may comprise a circuit board  432  on which the electrical circuits and/or components may be printed or mounted. In some other examples, the circuit board  432  may be the wall  402  that covers an opening between the therapy cavity  403  and the component cavity  404 , and pneumatically seals the therapy cavity  403  from the component cavity  404  when seated over the opening. 
     In some embodiments, the electrical circuits and/or components associated with the sensors that are mounted on the circuit board  432  within the component cavity  404  may be electrically coupled to the controller  110  to interface with the rest of the therapy system  100  as described above. In some embodiments, for example, the electrical circuits and/or components may be electrically coupled to the controller  110  by a conductor that may be a component of the conduit  405 . In some other preferred embodiments, a communications module  422  may be disposed in the component cavity  404  of the housing  401  and mounted on the circuit board  432  within the component cavity  404 . Using a wireless communications module  422  has the advantage of eliminating an electrical conductor between the dressing interface  400  and the integrated portion of the therapy system  100  that may become entangled with the conduit  405  when in use during therapy treatments. For example, the electrical circuits and/or components associated with the sensors along with the terminal portion of the sensors may be electrically coupled to the controller  110  by wireless means such as an integrated device implementing Bluetooth® Low Energy wireless technology. More specifically, the communications module  422  may be a Bluetooth Low Energy system-on-chip that includes a microprocessor (an example of the microprocessors referred to hereinafter) such as the nRF51822 chip available from Nordic Semiconductor. The wireless communications module  422  may be implemented with other wireless technologies suitable for use in the medical environment. 
     In some embodiments, a voltage regulator  423  for signal conditioning and a power source  424  may be disposed within the component cavity  404  of the housing  401 , mounted on the circuit board  432 . The power source  424  may be secured to the circuit board  432  by a bracket  426 . The power source  424  may be, for example, a battery that may be a coin battery having a low-profile that provides a 3-volt source for the communications module  422  and the other electronic components within the component cavity  404  associated with the sensors. In some example embodiments, the sensors, the electrical circuits and/or components associated with the sensors, the wall  402  and/or the circuit board  432 , the communications module  422 , and the power source  424  may be integrated into a single package and referred to hereinafter as a sensor assembly  425  as shown in  FIG. 6B . In some preferred embodiments, the wall  402  of the sensor assembly  425  may be the circuit board  432  itself as described above that provides a seal between tissue site  410  and the atmosphere when positioned over the opening between the therapy cavity  403  and the component cavity  404  of the housing  401  and functions as the wall  402  within the housing  401  that forms the therapy cavity  403 . 
     Referring now to  FIGS. 8A and 8B , a perspective view and a bottom view, respectively, of a bottom surface of the flange  409  facing the manifold  408  is shown. In some embodiments, the bottom surface may comprise features or channels to direct the flow of liquids and/or exudates away from the sensors out of the therapy cavity  403  into the primary lumen  430  when negative pressure is being applied to the therapy cavity  403 . In some embodiments, these channels may be molded into the bottom surface of the flange  409  to form a plurality of serrated guide channels  437 , perimeter collection channels  438 , and intermediate collection channels  439 . The serrated guide channels  437  may be positioned and oriented in groups on bottom surface to directly capture and channel at least half of the liquids being drawn into the therapy cavity  403  with the groups of serrated guide channels  437 , and indirectly channel a major portion of the balance of the liquids being drawn into the therapy cavity  403  between the groups of serrated guide channels  437 . In addition, perimeter collection channels  438  and intermediate collection channels  439  redirect the flow of liquids that are being drawn in between the groups of radially-oriented serrated guide channels  437  into the guide channels  437 . An example of this redirected flow is illustrated by bolded flow arrows  436 . In some example embodiments, a portion of the housing  401  within the therapy cavity  403  may comprise a second set of serrated guide channels  427  spaced apart and radially-oriented to funnel liquids being drawn into the therapy cavity  403  from the flange  409  into the primary lumen  430 . In other example embodiments of the bottom surface of the flange  409  and that portion of the housing  401  within the therapy cavity  403 , the channels may be arranged in different patterns. 
     As indicated above, the sensor assembly  425  may comprise a pressure sensor  416 , a humidity sensor  418 , a temperature sensor as a component of either the pressure sensor  416  or the humidity sensor  418 , and a pH sensor  420 . Each of the sensors may comprise a sensing portion extending into the therapy cavity  403  of the housing  401  and a terminal portion electrically coupled to the electrical circuits and/or components within the component cavity  404 . Referring more specifically to  FIGS. 4, 6A, 6B, and 7A-7D , the housing  401  may comprise a sensor bracket  441  that may be a molded portion of the housing  401  within the therapy cavity  403  in some embodiments. The sensor bracket  441  may be structured to house and secure the pressure sensor  416  on the circuit board  432  within the therapy cavity  403  of the sensor assembly  425  that provides a seal between tissue site  410  and the atmosphere as described above. In some embodiments, the pressure sensor  416  may be a differential gauge comprising a sensing portion  442  and a terminal portion or vent  443 . The vent  443  of the pressure sensor  416  may be fluidly coupled through the circuit board  432  to the component cavity  404  and the atmosphere by a vent hole  444  extending through the circuit board  432 . Because the component cavity  404  is vented to the ambient environment, the vent  443  of the pressure sensor  416  is able to measure the wound pressure (WP) with reference to the ambient pressure. The sensing portion  442  of the pressure sensor  416  may be positioned in close proximity to the manifold  408  to optimize fluid coupling and accurately measure the wound pressure (WP) at the tissue site  410 . In some embodiments, the pressure sensor  416  may be a piezo-resistive pressure sensor having a pressure sensing element covered by a dielectric gel such as, for example, a Model  1620  pressure sensor available from TE Connectivity. The dielectric gel provides electrical and fluid isolation from the blood and wound exudates in order to protect the sensing element from corrosion or other degradation. This allows the pressure sensor  416  to measure the wound pressure (WP) directly within the therapy cavity  403  of the housing  401  proximate to the manifold  408  as opposed to measuring the wound pressure (WP) from a remote location. In some embodiments, the pressure sensor  416  may be a gauge that measures the absolute pressure that does not need to be vented. 
     In some embodiments, the pressure sensor  416  also may comprise a temperature sensor for measuring the temperature at the tissue site  410 . In other embodiments, the humidity sensor  418  may comprise a temperature sensor for measuring the temperature at the tissue site  410 . The sensor bracket  441  also may be structured to support the humidity sensor  418  on the circuit board  432  of the sensor assembly  425 . In some embodiments, the humidity sensor  418  may comprise a sensing portion that is electrically coupled through the circuit board  432  to a microprocessor mounted on the other side of the circuit board  432  within the component cavity  404 . The sensing portion of the humidity sensor  418  may be fluidly coupled to the space within the therapy cavity  403  that includes a fluid pathway  445  extending from the therapy cavity  403  into the primary lumen  430  of the conduit  405  as indicated by the bold arrow to sense both the humidity and the temperature. The sensing portion of the humidity sensor  418  may be positioned within the fluid pathway  445  to limit direct contact with bodily fluids being drawn into the primary lumen  430  from the tissue site  410 . In some embodiments, the space within the therapy cavity  403  adjacent the sensing portion of the humidity sensor  418  may be purged by venting that space through the auxiliary lumens  435  as described in more detail below. As indicated above, the humidity sensor  418  may further comprise a temperature sensor (not shown) as the location within the fluid pathway  445  is well-suited to achieve accurate readings of the temperature of the fluids. In some embodiments, the humidity sensor  418  that comprises a temperature sensor may be a single integrated device such as, for example, Model HTU28 humidity sensor also available from TE Connectivity. 
     Referring now to  FIGS. 9A and 9B , the pH sensor  420  may comprise a sensing portion disposed within the therapy cavity  403  that is electrically coupled through the circuit board  432  to a front-end amplifier  421  mounted on the other side of the circuit board  432  within the component cavity  404 . The front-end amplifier  421  comprises analog signal conditioning circuitry that includes sensitive analog amplifiers such as, for example, operational amplifiers, filters, and application-specific integrated circuits. The front-end amplifier  421  measures minute voltage potential changes provided by the sensing portions to provide an output signal indicative of the pH of the fluids. The sensing portion of the pH sensor  420  may be fluidly coupled to the space within the therapy cavity  403  by being positioned in the fluid pathway  445  that extends into the primary lumen  430  as described above to sense the pH changes. The sensing portion of the pH sensor  420  may be formed and positioned within the fluid pathway  445  so that the sensing portion directly contacts the wound fluid without contacting the wound itself so that the sensing portion of the pH sensor  420  does not interfere with the wound healing process. In some embodiments, the space within the therapy cavity  403  adjacent the sensing portion of the pH sensor  420  also may be purged by venting that space through the auxiliary lumens  435  as described in more detail below. In some embodiments, the pH sensor  420  may be, for example, pH sensor  450  shown in  FIG. 9A  that comprises a pair of printed medical electrodes including a working electrode  451  and a reference electrode  452 . In some embodiments, the working electrode  451  may have a node being substantially circular in shape at one end and having a terminal portion at the other end, and the reference electrode  452  may have a node being substantially semicircular in shape and disposed around the node of the working electrode  451 . 
     In some example embodiments, the working electrode  451  may comprise a material selected from a group including graphene oxide ink, conductive carbon, carbon nanotube inks, silver, nano-silver, silver chloride ink, gold, nano-gold, gold-based ink, metal oxides, conductive polymers, or a combination thereof. This working electrode  451  further comprise a coating or film applied over the material wherein such coating or film may be selected from a group including metal oxides such as, for example, tungsten, platinum, iridium, ruthenium, and antimony oxides, or a group of conductive polymers such as polyaniline and others so that the conductivity of the working electrode  451  changes based on changes in hydrogen ion concentration of the fluids being measured or sampled. In some example embodiments, the reference electrode  452  may comprise a material selected from a group including silver, nano-silver, silver chloride ink, or a combination thereof. The pH sensor  450  may further comprise a coating  453  covering the electrodes that insulates and isolates the working electrode  451  from the reference electrode  452  and the wound fluid, except for an electrical coupling space  454  between the nodes of the working electrode  451  and the reference electrode  452 . The coating  453  does not cover the terminal portions of the working electrode  451  and the reference electrode  452  to form terminals  455  and  456 , respectively, adapted to be electrically coupled to the front-end amplifier  421 . 
     In some example embodiments, the terminal portion of the working electrode  451  and the reference electrode  452  may extend through the circuit board  432  and electrically coupled to the front-end amplifier  421  of the pH sensor  450 . As indicated above, the front-end amplifier  421  of the pH sensor  450  measures minute potential changes between the working electrode  451  and the reference electrode  452  that result from a change in hydrogen ion concentration of the wound fluid as the pH of the wound fluid changes. The front-end amplifier  421  may be, for example, an extremely accurate voltmeter that measures the voltage potential between the working electrode  451  and the reference electrode  452 . The front-end amplifier  421  may be for example a high impedance analog front-end (AFE) device such as the LMP7721 and LMP91200 chips that are available from manufacturers such as Texas Instruments or the AD7793 and AD8603 chips that are available from manufacturers such as Analog Devices. 
     In some other embodiments, the pH sensor  420  may include a third electrode such as, for example, pH sensor  460  shown in  FIG. 9B  that comprises a third electrode or a counter electrode  462  in addition to the working electrode  451  and the reference electrode  452  of the pH sensor  450 . The counter electrode  462  also comprises a node partially surrounding the node of the working electrode  451  and a terminal  466  adapted to be electrically coupled to the front-end amplifier  421 . Otherwise, the pH sensor  460  is substantially similar to the pH sensor  450  described above as indicated by the reference numerals. The counter electrode  462  is also separated from the working electrode  451  and is also insulated from the wound fluid and the other electrodes by the coating  453  except in the electrical conductive space  454 . The counter electrode  462  may be used in connection with the working electrode  451  and the reference electrode  452  for the purpose of error correction of the voltages being measured. For example, the counter electrode  462  may possess the same voltage potential as the potential of the working electrode  451  except with an opposite sign so that any electrochemical process affecting the working electrode  451  will be accompanied by an opposite electrochemical process on the counter electrode  462 . Although voltage measurements are still being taken between the working electrode  451  and the reference electrode  452  by the analog front-end device of the pH sensor  460 , the counter electrode  462  may be used for such error correction and may also be used for current readings associated with the voltage measurements. Custom printed electrodes assembled in conjunction with a front-end amplifier may be used to partially comprise pH sensors such as the pH sensor  450  and the pH sensor  460  may be available from several companies such as, for example, GSI Technologies, Inc. and Dropsens. 
     As described above, the sensing portions of the sensors may all be disposed within the therapy cavity  403  and electrically coupled through the circuit board  432  to the front-end amplifier  421  and the communications module  422  mounted on the other side of the circuit board  432  within the component cavity  404 . In some embodiments, sensor assembly  425  may comprise a processing element that may include the communications module  422  which may include the microprocessor and/or the wireless communications chip described above. The processing element may further include the front-end amplifier  421  and any other components that are disposed within the component cavity  404 . The processing element may be electrically coupled to the sensing portions of the sensors for receiving property signals from the sensing portions that are indicative of the pressure, humidity, temperature, and the pH of the fluid at the tissue site in order to determine the flow characteristics of the system and the progression of wound healing as described in more detail below. 
     The systems, apparatuses, and methods described herein may provide other significant advantages. For example, some therapy systems are a closed system wherein the pneumatic pathway is not vented to ambient air, but rather controlled by varying the supply pressure or the pump pressure (PP) to achieve the desired target pressure (TP) in a continuous pressure mode, an intermittent pressure mode, or a variable target pressure mode as described above in more detail with reference to  FIGS. 2A and 2B . In some embodiments of the closed system, the wound pressure (WP) being measured in the dressing interface  107  may not drop in response to a decrease in the supply pressure or the pump pressure (PP) as a result of a blockage within the dressing interface  107  or other portions of the pneumatic pathway. In some embodiments of the closed system, the supply pressure or the pump pressure (PP) may not provide airflow to the tissue interface  108  frequently enough that may result in the creation of a significant head pressure or blockages within the dressing interface  107  that also would interfere with sensor measurements being taken by the dressing interface  400  as described above. The head pressure in some embodiments may be defined as a difference in pressure (DP) between a negative pressure set by a user or caregiver for treatment, i.e., the target pressure (TP), and the negative pressure provided by a negative pressure source that is necessary to offset the pressure drop inherent in the fluid conductors, i.e., the supply pressure or the pump pressure (PP), in order to achieve or reach the target pressure (TP). For example, the head pressure that a negative pressure source needs to overcome may be as much as 75 mmHg. Problems may occur in such closed systems when a blockage occurs in the pneumatic pathway of the fluid conductors that causes the negative pressure source to increase to a value above the normal supply pressure or the pump pressure (PP) as a result of the blockage. For example, if the blockage suddenly clears, the instantaneous change in the pressure being supplied may cause harm to the tissue site. 
     Some therapy systems have attempted to compensate for head pressure by introducing a supply of ambient air flow into the therapeutic environment, e.g., the therapy cavity  403 , by providing a vent with a filter on the housing  401  of the dressing interface  400  to provide ambient air flow into the therapeutic environment as a controlled leak. However, in some embodiments, the filter may be blocked when the interface dressing is applied to the tissue site or when asked at least blocked during use. Locating the filter in such a location may also be problematic because it is more likely to be contaminated or compromised by other chemicals and agents associated with treatment utilizing instillation fluids that could adversely affect the performance of the filter and the vent itself. 
     The embodiments of the therapy systems described herein overcome the problems associated with having a large head pressure in a closed pneumatic environment, and the problems associated with using a vent disposed on or adjacent the dressing interface. More specifically, the embodiments of the therapy systems described above comprise a pressure sensor, such as the pressure sensor  416 , disposed within the pneumatic environment, i.e., in situ, that independently measures the wound pressure (WP) within the therapy cavity  403  of the housing  401  as described above rather than doing so remotely. Consequently, the pressure sensor  416  is able to instantaneously identify dangerously high head pressures and/or blockages within the therapy cavity  403  adjacent the manifold  408 . Because the auxiliary lumens  435  are not being used for pressure sensing, the auxiliary lumens  435  may be fluidly coupled to a fluid regulator such as, for example, the regulator  118  in  FIG. 1 , that may remotely vent the therapeutic environment within the therapy cavity  403  to the ambient environment or fluidly couple the therapeutic environment to a source of positive pressure. The regulator  118  may then be used to provide ambient air or positive pressure to the therapeutic environment in a controlled fashion to “purge” the therapeutic environment within both the therapy cavity  403  and the primary lumen  430  to resolve the problems identified above regarding head pressures and blockages, and to facilitate the continuation of temperature, humidity, and pH measurements as described above. 
     Using a regulator to purge the therapeutic environment is especially important in therapy systems such as those disclosed in  FIGS. 1 and 3  that include both negative pressure therapy and instillation therapy for delivering therapeutic liquids to a tissue site. For example, in one embodiment, fluid may be instilled to the tissue site  150  by applying a negative pressure from the negative-pressure source  104  to reduce the pressure at the tissue site  150  to draw the instillation liquid into the dressing  102  as indicated at  302 . In another embodiment, liquid may be instilled to the tissue site  150  by applying a positive pressure from the negative-pressure source  104  (not shown) or the instillation pump  116  to force the instillation liquid from the solution source  114  to the tissue interface  108  as indicated at  304 . Such embodiments may not be sufficient to remove all the instillation liquids from the therapeutic environment, or may not be sufficient to remove the instillation liquids quickly enough from the therapeutic environment to facilitate the continuation of accurate temperature, humidity, and pH measurements. Thus, the regulator  118  may be used to provide ambient air or positive pressure to the therapeutic environment to more completely or quickly purge the therapeutic environment to obtain the desired measurements as described above. 
     In embodiments of therapy systems that include an air flow regulator comprising a valve such as the solenoid valve described above, the valve provides controlled airflow venting or positive pressure to the therapy cavity  403  as opposed to a constant airflow provided by a closed system or an open system including a filter in response to the wound pressure (WP) being sensed by the pressure sensor  416 . The controller  110  may be programmed to periodically open the solenoid valve as described above allowing ambient air to flow into the therapy cavity  403 , or applying a positive pressure into the therapy cavity  403 , at a predetermined flow rate and/or for a predetermined duration of time to purge the pneumatic system including the therapy cavity  403  and the primary lumen  430  of bodily liquids and exudates so that the humidity sensor  418  and the pH sensor  420  provide more accurate readings and in a timely fashion. This feature allows the controller to activate the solenoid valve in a predetermined fashion to purge blockages and excess liquids that may develop in the fluid pathways or the therapy cavity  403  during operation. In some embodiments, the controller may be programmed to open the solenoid valve for a fixed period of time at predetermined intervals such as, for example, for five seconds every four minutes to mitigate the formation of any blockages. 
     In some other embodiments, the controller may be programmed to open the solenoid valve in response to a stimulus within the pneumatic system rather than, or in addition to, being programmed to function on a predetermined therapy schedule. For example, if the pressure sensor is not detecting pressure decay in the canister, this may be indicative of a column of fluid forming in the fluid pathway or the presence of a blockage in the fluid pathway. Likewise, the controller may be programmed to recognize that an expected drop in canister pressure as a result of the valve opening may be an indication that the fluid pathway is open. The controller may be programmed to conduct such tests automatically and routinely during therapy so that the patient or caregiver can be forewarned of an impending blockage. The controller may also be programmed to detect a relation between the extent of the deviation in canister pressure resulting from the opening of the valve and the volume of fluid with in the fluid pathway. For example, if the pressure change within the canister is significant when measured, this could be an indication that there is a significant volume of fluid within the fluid pathway. However, if the pressure change within the canister is not significant, this could be an indication that the plenum volume was larger. 
     The systems, apparatuses, and methods described herein may provide other significant advantages over dressing interfaces currently available. For example, a patient may require two dressing interfaces for two tissue sites, but wish to use only a single therapy device to provide negative pressure to and collect fluids from the multiple dressing interfaces to minimize the cost of therapy. In some therapy systems currently available, the two dressing interfaces would be fluidly coupled to the single therapy device by a Y-connector. The problem with this arrangement is that the Y-connector embodiment would not permit the pressure sensor in the therapy device to measure the wound pressure in both dressing interfaces independently from one another. A significant advantage of using a dressing interface including in situ sensors, e.g., the dressing interface  400  including the sensor assembly  425  and the pressure sensor  416 , is that multiple dressings may be fluidly coupled to the therapy unit of a therapy system and independently provide pressure data to the therapy unit regarding the associated dressing interface. Each dressing interface  400  including in situ sensors that is fluidly coupled to the therapy unit for providing negative pressure to the tissue interface  108  and collecting fluids from the tissue interface  108  has the additional advantage of being able to collect and monitor other information at the tissue site including, for example, humidity data, temperature data, and the pH data being provided by the sensor assembly  425  in addition to the pressure data and other data that might be available from other sensors in the sensor assembly  425 . 
     Another advantage of using the dressing interface  400  that includes a pressure sensor in situ such as, for example, the pressure sensor  416 , is that the pressure sensor  416  can more accurately monitor the wound pressure (WP) at the tissue site and identify blockages and fluid leaks that may occur within the therapeutic space or other distribution components of the system as described in more detail above. Another advantage of using the dressing interface  400  that includes a pressure sensor in situ is that one of the auxiliary lumens  435  are freed up to vent or actively purge the sensing portions of the sensors within the therapeutic cavity  403  so that meaningful data regarding the sensing properties can be obtained on a timely basis for providing the therapy and detecting the flow characteristics of the system and the status of wound healing. Yet another advantage of using a dressing interface including in situ sensors, e.g., the dressing interface  400 , is that the sensor assembly  425  provides additional data including pressure, temperature, humidity, and pH of the fluids being drawn from the tissue site that facilitates improved control algorithms for detecting flow characteristics within the system and profiling the status of wound healing. Such improvements further assist the caregiver with additional information provided by the therapy unit of the therapy system to optimize the wound therapy being provided and the overall healing progression of the tissue site when combined with appropriate control logic. 
     As indicated above, the processing element of the sensor assembly  425  may receive property signals indicative of the pressure, the humidity, the temperature, and the pH within the therapy cavity  403  that may be transmitted to the controller  110  of the system for applying therapy to the tissue site and detecting the flow characteristics of the system and the status of wound healing at the tissue site. In some embodiments, the flow characteristics may include the detection of blockages, fluidly leaks, air leaks, and desiccation conditions associated with the dressing interface and the system. The property signals associated with the fluids at a specific time may be processed and logged by the controller  110  and assessed with previous property signal measurements. The controller  110  may also be programmed with a negative pressure control algorithm that assesses the logged property signals to assess the status of wound healing and with that assessment adjust the pump pressure (PP) and/or the pump duty cycle (PD) if necessary to maintain the wound pressure (WP) proximate the desired target pressure (TP). 
     Referring to  FIG. 10 , a flowchart is shown that illustrates a method for treating a tissue site in some embodiments of therapy systems including, for example, the therapy system  100 . More specifically, such method may utilize a dressing interface or sensing pad such as, for example, the dressing interface  400  of  FIG. 4 , for applying negative-pressure therapy with fluid instillation therapy and sensing properties of wound exudates extracted from a tissue site as shown at  600 . A tissue interface such as the tissue interface  108  may be placed within, over, on, or otherwise proximate a tissue site at  601 . A cover such as the cover  106  may be placed over the tissue interface  108  and sealed to an attachment surface near the tissue site  150 . For example, the cover  106  may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing  102  provides a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, while the negative-pressure source  104  reduces the pressure within the sealed therapeutic environment and the instillation pump  116  provides fluids to the sealed therapeutic environment as described above. In some embodiments, the method may further comprise applying the sensing pad or dressing interface to the tissue interface at  602 . More specifically, applying the sensing pad may include positioning the housing on the dressing interface so that the aperture of the housing is in fluid communication with the tissue interface. The dressing interface may comprise a wall disposed within the housing to form a therapy cavity within the housing and a component cavity fluidly sealed from the therapy cavity, wherein the therapy cavity opens to the aperture as described above. Such dressing interface may further comprise a negative-pressure port fluidly coupled to the therapy cavity and adapted to be fluidly coupled to a negative-pressure source as described above. The dressing interface may further comprise a processing element disposed in the component cavity or outside the therapy cavity, similar to the processing element described above. 
     Still referring to  602 , the method may further comprise connecting the sensing pad to a wound therapy device such as, for example, the therapy system  100 . Connecting the sensing pad may include coupling the therapy cavity of the sensing pad to a negative-pressure source and to a vent as described above, and electrically coupling the processing element to a controller of the therapy system such as, for example, the controller  110 . The sensing pad or the dressing interface may further comprise a pH sensor, a temperature sensor, a humidity sensor, and a pressure sensor, each having a sensing portion disposed within the therapy cavity and each electrically coupled to the processing element through the wall as described above. 
     Referring now to  603 , the method may further comprise initializing therapy settings for both the negative pressure therapy and the fluid instillation therapy to be provided for treatment. The therapy settings may include, for example, the initial settings for the sensor readings of the pH sensor, the temperature sensor, the humidity sensor, and the pressure sensor that may be stored on the controller  110 . The therapy settings for the negative pressure therapy phase may also include, for example, any initial values associated with the pump pressure (PP), the pump duty cycle (PD), or the desired target pressure (TP) of the negative-pressure source  104 . The therapy settings for the fluid instillation therapy phase may further include any initial values associated with the fill volume and the soak time, as well as an instillation pump pressure (IP), an instillation duty cycle (ID), and a desired fluid pressure (FP) of the instillation pump  116  for the fluid instillation therapy phase of the therapy treatment. 
     After the therapy settings are initialized, the method may further comprise a caregiver or patient turning on the therapy system  100  to begin applying a desired therapy treatment at  604 . The desired therapy treatment may include negative pressure therapy, instillation therapy, or other therapy for treating the tissue site as indicated. In some embodiments, for example, the method may comprise applying negative-pressure therapy at  605  to the therapy cavity of the dressing interface to draw fluids from the tissue interface into the therapy cavity and exiting out of the reduced-pressure port. The method may further comprise sensing the pH, temperature, humidity, and pressure properties of the fluids flowing through therapy cavity utilizing the sensing portion of the sensors which may provide property signals indicative of such properties to the processing element. Applying negative-pressure therapy may further comprise providing the property signals from the processing element to the controller of the therapy system for processing the property signals and treating the tissue site in response to the property data being collected and processed by the therapy system. 
     In some embodiments, the method may further comprise applying fluid instillation therapy at  606  to the therapy cavity of the dressing interface to provide fluids to the therapy cavity either directly to the therapy cavity of the dressing interface or indirectly from another location on the dressing as described above, and ultimately exiting out of the reduced-pressure port. In some embodiments, fluid instillation therapy may be provided prior to or concurrent with negative pressure therapy as described in more detail above. The method may further comprise sensing the pH, temperature, humidity, and pressure properties of the fluids flowing through therapy cavity utilizing the sensing portion of the sensors which may provide property signals indicative of such properties to the processing element. Applying fluid instillation therapy may further comprise providing the property signals from the processing element to the controller of the therapy system for processing the property signals and treating the tissue site in response to the sensor data being collected and processed by the therapy system. 
     Referring to decision block  607 , the method may further comprise turning off the therapy treatment when receiving a signal from a caregiver, a patient, or from a control algorithm stored on the controller of the therapy system for assessing the sensor data and corresponding health of the tissue site as described in more detail below. If the therapy system is turned off (YES) ending the therapy treatment at  608 , the method may further comprise removing the dressing interface, the cover, and the sensing pad at  609  after the therapy system is turned off as indicated. If no such signal is received to turn off the therapy treatment, the method in some embodiments may loop back to  605  to continue applying the negative-pressure therapy with fluid instillation to the dressing interface and the tissue site. When the method loops back to  605 , the method may include commands provided by the control algorithms to continue controlling the negative pressure therapy by increasing the pump pressure (PP) or the pump duty cycle (PD) along with the fluid instillation therapy by adjusting the instillation pump pressure (IP) or the instillation duty cycle (ID). 
       FIG. 11  is a schematic block diagram illustrating an embodiment of a control algorithm that may comprise a negative pressure control algorithm that may be utilized when applying the negative-pressure therapy within the tissue treatment method  600 , hereinafter referred to as the negative pressure control algorithm  605 . The negative pressure control algorithm  605  may include the detection of dressing flow characteristics within the system and an assessment of sensor properties based on the property data stored on the controller of the therapy system.  FIGS. 13A-13C  show flow charts illustrating various methods of some embodiments that may be configured to operate within the negative pressure control algorithm  605  of  FIG. 11 . The negative pressure therapy algorithm  605  may commence by initializing the therapy settings at  603  including the sensor settings by setting initial values of the property signals provided by the sensors to the processing element of the dressing interface and ultimately to the controller of the therapy system as indicated for processing and assessment. 
     The negative pressure control algorithm  605  may include a wound pressure control  610  as shown in  FIG. 11  that compares wound pressure (WP) to the target pressure (TP), and then provides commands to increase or decrease the pump duty cycle (PD) accordingly and/or log the sensor readings of the sensor properties at  650 . Referring more specifically to  FIG. 13A , if the wound pressure (WP) is greater than the target pressure (TP) at  611  (YES), the wound pressure control  610  may generate a command to vent the therapy cavity at  612  as described above and a command to reduce the pump duty cycle (PD) at  613 . After the pump duty cycle (PD) is reduced, the property signals may then be logged in the controller of the therapy system as indicated at  650  for further processing by a set of assessment algorithms as indicated at  651 . If the wound pressure (WP) is not greater than the target pressure (TP) at  611  (NO), the wound pressure (WP) is again compared to the target pressure (TP) at  614 . If the wound pressure (WP) is not less than the target pressure (TP), i.e., greater than or equal to the target pressure (TP), the wound pressure control  610  may generate a command to maintain or reduce the pump duty cycle (PD) at  615  and the property signals may then be logged in the controller of the therapy system as indicated at  650  for further processing by the assessment algorithms  651 . However, if the wound pressure (WP) is less than or equal to the target pressure (TP), the wound pressure control  610  may generate a command to increase the pump duty cycle (PD) at  616 . When the pump duty cycle (PD) is increased, the negative pressure control algorithm  605  in some embodiments may proceed to dressing-alert algorithms including, for example, a blockage detection algorithm and fluid leak detection algorithm shown generally at  620  in  FIG. 11  (shown more specifically in  FIG. 13B ), and an air leak detection algorithm and desiccation detection algorithm shown generally at  640  in  FIG. 11  (shown more specifically in  FIG. 13C ). 
     In some embodiments of a therapy system such as, for example, therapy system  100 , the therapy system may comprise a user interface coupled to the controller  110 . Referring more specifically to  FIG. 12 , a block diagram of one example embodiment of a user interface, user interface  660 , that may comprise a variety of alerts and alarms associated with the dressing flow characteristics of  FIG. 11 . These alerts and/or alarms associated with the dressing flow characteristics may comprise, for example, alerts and/or alarms for a blockage condition  661 , a fluid leak condition  662 , an air leak condition  663 , or a desiccation condition  664 . The negative pressure control algorithm may be programmed to generate an alarm based on the occurrence of a predetermined number of alerts such as, for example, generating alarm after the occurrence of three alerts. The user interface  660  may also provide alerts and/or alarms that may be associated with wound progress  665  and/or canister-full alert  667  based on the fluid properties being provided by the sensing pad or the dressing interface  400 , for example. All of the fluid properties and associated alerts and/or alarms identified above may be selectively provided for each wound dressing (WD #1, WD #2 or WD #3) such as, for example, wound dressings substantially similar to the dressing  102 , that may be fluidly and electrically coupled to the therapy system  100 . For example, a patient or caregiver may select a desired wound dressing by setting a wound dressing selection switch  668 . Alternatively, the controller of the therapy system may be programmed to selectively collect the fluid properties and provide alerts and/or alarms based on a predetermined order with times designated for each wound dressing. 
     After the negative pressure control algorithm  605  proceeds to the dressing-alert algorithms including, for example, the blockage detection algorithm and fluid leak detection algorithm shown generally at  620  in  FIG. 13B , the algorithm may commence with determining whether the wound pressure (WP) is increasing at  621  after increasing the pump duty cycle (PD) at  616  by a predetermined increment as an output of the wound pressure control  610 . If the wound pressure (WP) responds and is increasing, the algorithm may increment an air leak counter at  622  and proceed to the air leak detection algorithm and desiccation detection algorithm at  640 . However, if the wound pressure (WP) does not increase, the blockage/leak detection algorithm  620  determines whether the property signals associated with the humidity, i.e., the humidity data, is rising at a relatively low rate within the therapy cavity at  623 . If the humidity data is rising at a relatively low rate, the blockage/leak detection algorithm  620  increments a blockage counter  624  and inquires whether the blockage counter is less than a predetermined blockage count threshold at  625  such as, for example, less than three, to determine whether a blockage alert or alarm should be generated. If the blockage counter number is less than the blockage count threshold, the blockage/leak detection algorithm  620  generates a blockage alert at  626  and progresses to log a new set of sensor readings at  650 . If the blockage counter number is greater than or equal to the blockage count threshold, the negative pressure control algorithm generates a blockage alarm at  627  and progresses to log a new set of sensor readings at  650 . 
     If the humidity data is not rising at a relatively low rate at  623 , the negative pressure control algorithm inquires whether the humidity data is increasing at a high rate at 628. If the humidity data is not increasing at such a high rate, the blockage/leak detection algorithm  620  increments the air leak counter  622  and proceeds to the air leak detection algorithm and desiccation detection algorithm at  640 . However, if the humidity data is increasing above the high rate, the blockage/leak detection algorithm  620  increments or increases a fluid leak counter at  629  and inquires whether the fluid leak counter is less than a predetermined leakage count threshold at  630  such as, for example, less than three. If the fluid leak counter number is not less than the leakage count threshold, alternatively greater than or equal to the leakage count threshold, the blockage/leak detection algorithm  620  generates a fluid leak alarm at  631  and progresses to log a new set of sensor readings at  650 . If the fluid leak counter number is less than the leakage count threshold, the blockage/leak detection algorithm  620  checks the dead space detection at  632  that may be associated with the amount of gas or space that may be present in the container of the therapy system such as, for example, the container  112 , after collecting liquids in the container. The blockage/leak detection algorithm  620  determines whether there is a dead space detection variance of less than a predetermined value, e.g., 200 cc, at  633 . If the variance is not less than the predetermined value, i.e., if the variance is greater than the predetermined value, the blockage/leak detection algorithm  620  generates a fluid leak alarm at  631 . If the blockage/leak detection algorithm  620  determines that the variance is less than the predetermined value, the blockage/leak detection algorithm  620  generates a canister full alert  667  (not shown in  FIG. 13A ) and then progresses to log a new set of sensor readings at  650 . 
     After the negative pressure control algorithm  605  proceeds to the dressing-alert algorithms including, for example, the air leak detection algorithm and desiccation detection algorithm at  640 , or a desiccation/leak detection algorithm, shown generally at  640  in  FIG. 13C , the algorithm may commence by determining at  641  whether the air leak counter at  622  is less than a predetermined air count threshold at  641  such as, for example, less than three, after incrementing the air leak counter as described above. If the air leak counter  641  is less than the air count threshold, the negative pressure control algorithm may generate an air leak alert at  642  and progress to log a new set of sensor readings at  650 . If the air leak counter  641  is not less than the air count threshold, alternatively if the air leak counter is greater than or equal to the air count threshold, the desiccation/leak detection algorithm  640  may generate an air leak alarm at  643  and proceed to inquire whether the humidity is less than about a predetermined internal humidity value at  644 . More specifically, if the humidity within the therapy cavity of the sensing pad is less than a percentage value of the ambient humidity such as, for example, a percentage value of 25%, the desiccation/leak detection algorithm  640  may generate a desiccation alert at  645  and proceed to log new set of sensor readings at  650 . Alternatively, if the humidity within the therapy cavity of the sensing pad is greater than a humidity percentage of 25%, for example, the desiccation/leak detection algorithm  640  would not generate a desiccation alert, but rather would proceed to log new set of sensor readings at  650 . 
     Referring back to  FIG. 11 , a new set of property signals indicative of the sensor properties may be logged at  650  into the controller of the therapy system as a result of the alerts, alarms, and other events described above with respect to the negative pressure control algorithm  605  including the wound pressure control  610 , the blockage detection and fluid leak detection algorithms  620 , and the air leak detection algorithm and desiccation detection algorithm at  640 . Logging these property signals along with contemporaneous readings of the wound pressure (WP), the pump pressure (PP), and the pump duty cycle (PD) generates sets of property data that may include humidity data, temperature data, and pH data being provided by the processing element such as, for example, the sensor assembly  425  in addition to the pressure data, duty cycle data, and other data that might be available from other sensors in the therapy system  100 . Such other sensors also may be coupled to the controller or other distribution components in the therapy system. In some embodiments, the negative pressure control algorithm  605  may be configured to assess the pH data at  652 , the humidity data at  654 , and the temperature data at  656 , and use such data to assess the status of wound health of the tissue site at  658 , and further configured to return to the wound pressure control  610  after the assessments have been completed. In some embodiments, the assessments may include an analysis of whether the data is increasing or decreasing and how rapidly the data may be increasing or decreasing. In some embodiments, the assessments may further include an analysis of whether the data may increase or decrease and how rapidly that data may fluctuate in each direction. In some embodiments, the assessment may further include a determination that the relevant data is simply not affected. 
     The assessments of the pH data, the humidity data, and the temperature data along with contemporaneous wound pressure (WP) data, pump pressure (PP) data, and the pump duty cycle (PD) data may be utilized to determine how the flow characteristics of the therapy system  100  may be affected by a blockage, a fluid leak, an air leak, or desiccation within the system including the sensor pad or dressing interface  400 . Referring more specifically to Table 1, the flow characteristics may include a blockage state condition within the therapy system that may be identified by the assessment of the pH data, the humidity data, and the temperature data along with contemporaneous wound pressure (WP) data, pump pressure (PP) data, and the pump duty cycle (PD) data. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                   
                 Dressing State: Flow Characteristics 
               
            
           
           
               
               
               
               
            
               
                 Inputs 
                 Blockage 
                 Fluid Leak (Bolus) 
                 Air Leak 
               
               
                   
               
               
                 Wound Pressure 
                 WP may slowly decrease 
                 WP will decrease 
                 WP may decrease 
               
               
                 (WP) 
                 
                   
                 
                 
                   
                 
                 
                   
                 
               
               
                 Sensor Assembly 
                   
                   
                   
               
               
                 Wound Humidity 
                 Humidity may 
                 Humidity will  
                 Humidity may change  
               
               
                 (Hum) 
                 increase slowly     
                 increase    
                 rapidly     
               
               
                 Sensor Assembly 
                   
                   
                   
               
               
                 Wound Temperature 
                 Temperature may  
                 Temperature may  
                 Temperature may 
               
               
                 (Temp) 
                 increase slowly     
                 increase     
                 change     
               
               
                 Sensor Assembly 
                   
                   
                   
               
               
                 Pump Duty 
                 PD will increase     
                 PD may  
                 PD will  
               
               
                 (PD) 
                   
                 increase     
                 increase     
               
               
                 System 
                   
                   
                   
               
               
                 Pump Pressure 
                 PP will increase     
                 PP may increase  
                 PP may  
               
               
                 (PP) 
                   
                 for a short 
                 increase     
               
               
                 System 
                   
                 time     
               
               
                   
               
            
           
         
       
     
     For example, a blockage state condition may be identified in the system (e.g., a substance blocking a tube or a kink in the tube) when the pump pressure (PP) data increases and the pump duty cycle (PD) data increases. In some embodiments, the blockage state condition may be identified further if the wound pressure (WP) data slowly decreases. In yet other embodiments, the blockage state condition may be identified further if the humidity data slowly increases, especially if the wound dressing is saturated with fluids. In yet other embodiments, the blockage state condition may be identified further if the temperature data slowly increases. In still other embodiments, the blockage state condition may be identified further when the pH data is not affected. Referring to  FIG. 14  as an example, a graph is shown illustrating test results using the dressing interface  400  for the detection of blockages based on the assessment of humidity data and wound pressure over time generated by the negative pressure control algorithm  605  of  FIG. 11 . The wound pressure (WP) being applied at the tissue site is set as a target pressure (TP) of 125 mmHg. As can be seen, a blockage state condition is identified at approximately 1.50 minutes when the wound pressure (WP)  701  begins to decrease and the dressing humidity  702  slowly increases over the ambient humidity  703  as described above. In some embodiments, the negative pressure control algorithm  605  may generate a command to provide an alarm  661  and shut down the pump  104 , for example, until the blockage can be removed. When the blockage is removed at 3.67 minutes, the wound pressure (WP) returns to the target pressure (TP) and the dressing humidity converges back to the ambient humidity. 
     Still referring more specifically to Table 1, the flow characteristics may include a fluid leak state within the therapy system that also may be identified by the assessment of the pH data, the humidity data, and the temperature data along with contemporaneous wound pressure (WP) data, pump pressure (PP) data, and the pump duty cycle (PD) data. For example, a fluid leak state may be identified in the wound dressing if the pump duty cycle (PD) data and the pump pressure (PP) data increase depending on the severity of a fluid bolus trapped in the wound dressing. The pump pressure (PP) data may increase for only a short period of time. In some embodiments, the fluid leak state may be identified further if the wound pressure (WP) data decreases, but will typically track with the pump pressure (PP) data. In yet other embodiments, the fluid leak state may be identified further if the humidity data increases as a result of higher exudates or blood volumes collecting at the tissue site. The temperature data may also increase in a corresponding fashion. In still other embodiments, the fluid leak state may be identified further when the pH data is not affected. Referring to  FIG. 15  as an example, a graph is shown illustrating test results using the dressing interface  400  for the detection of fluid leaks based on the assessment of humidity data and wound pressure data over time generated by the negative pressure control algorithm of  FIG. 11 . The wound pressure (WP) being applied at the tissue site is set as a target pressure (TP) of 125 mmHg. A bolus of 60 cc of simulated wound fluid with a viscosity of about 16 cP was rapidly introduced into the wound dressing. As can be seen, a fluid leak state is identified at approximately 0.50 minutes when the wound pressure (WP)  711  begins to decrease and the dressing humidity  712  slowly increases over the ambient humidity  713  as described above. In some embodiments, the negative pressure control algorithm  605  may generate a command to provide an alarm  662  and shut down the pump  104 , for example, until the fluid leak can be corrected. Clearly, such assessment facilitates the detection of liquid boluses or potentially adverse events such as a blood vessel that bursts, so that a caregiver may be alerted to a potentially dangerous situation so that a timely intervention is possible. 
     Referring more specifically to Table 2, the flow characteristics may include an air leak state within the therapy system that may be identified by the assessment of the pH data, the humidity data, and the temperature data along with contemporaneous wound pressure (WP) data, pump pressure (PP) data, and the pump duty cycle (PD) data. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
             
            
               
                   
                   
               
               
                   
                   
                 Dressing State: Flow Characteristics 
               
            
           
           
               
               
               
               
            
               
                   
                 Inputs 
                 Air Leak 
                 Desiccation 
               
               
                   
                   
               
               
                   
                 Wound Pressure 
                 WP may  
                 WP likel unaffected 
               
               
                   
                 (WP) 
                 decrease     
                 
                   
                 
               
               
                   
                 Sensor Assembly 
                   
                   
               
               
                   
                 Wound Humidity 
                 Humidity may  
                 Humidity will  
               
               
                   
                 (Hum) 
                 change rapidly 
                 decrease 
               
               
                   
                 Sensor Assembly 
                 
                   
                 
                 
                   
                 
               
               
                   
                 Wound Temperature 
                 Temperature  
                 Temperature may  
               
               
                   
                 (Temp) 
                 may change 
                 change 
               
               
                   
                 Sensor Assembly 
                 
                   
                 
                 
                   
                 
               
               
                   
                 Pump Duty 
                 PD will  
                 PD likely  
               
               
                   
                 (PD) 
                 increase 
                 unaffected 
               
               
                   
                 System 
                 
                   
                 
                 
                   
                 
               
               
                   
                 Pump Pressure 
                 PP may  
                 PP likely  
               
               
                   
                 (PP) 
                 increase  
                 unaffected 
               
               
                   
                 System 
                 
                   
                 
                 
                   
                 
               
               
                   
                   
               
            
           
         
       
     
     For example, an air leak state within the therapy system that may be identified when the pump duty cycle (PD) data increases proportionally with the severity of the leak, and wherein the pump pressure (PP) data may increase or nonresponsive to an increase in the pump duty cycle (PD) data again depending on the severity of the leak. The air leak may be sufficiently severe to require an increase in both the pump duty cycle (PD) and the pump pressure (PP). In some embodiments, the air leak state may be identified further if the wound pressure (WP) begins to decrease proportionally with the severity of the leak, but will track with the pump pressure (PP). In yet other embodiments, the air leak state may be identified further if the humidity data changes rapidly depending upon the environmental humidity measured by the system and the saturation level of the wound dressing. For example, if the air is drier than the saturation level of the wound dressing, then the humidity of the dressing may decrease. The air leak state may also be identified further if the temperature data changes depending on the environmental temperature and the saturation level of the wound dressing. For example, the temperature data will decrease if the environmental temperature is cooler than the temperature at the tissue site. In still other embodiments, the air leak state may be identified further when the pH data is not affected. Referring to  FIG. 16  as an example, a graph is shown illustrating test results using the dressing interface  400  for the detection of air leaks based on the assessment of humidity data, wound pressure data, and pump pressure data over time generated by the negative pressure control algorithm of  FIG. 11 . The wound pressure (WP) being applied at the tissue site is set as a target pressure (TP) of 125 mmHg. A small leak was introduced into the wound dressing such that the pump pressure (PP) had to be elevated to approximately 140 mmHg in order to maintain a wound pressure (WP) at the target pressure (TP). As can be seen, an air leak state is identified at approximately 0.2 minutes when the wound pressure (WP)  721  decreases and the pump pressure (PP)  722  increases to compensate for the decreasing wound pressure (WP). In some embodiments, the air leak state also may be identified by the dressing humidity  723  which slowly increases to converge with the ambient humidity  724 . In this example, the tissue interface was dry, so that the humidity increased with the introduction of the leak (ambient humidity). In other embodiments, the air leak state also may be identified by the dressing humidity  723  which slowly decreases to converge with the ambient humidity  724 . 
     In some embodiments where the humidity data decreases indicating that the wound is drying out, the negative pressure control algorithm  605  may generate a command to provide an alarm  663  and shut down the pump  104  until the air leak can be corrected. In other embodiments where the humidity does not decrease or is at an acceptable level, the negative pressure control algorithm  605  may generate a command to provide an alarm or an alert  663 , but continue providing therapy by increasing the pump duty cycle (PD) to compensate for the air leak. Referring back to Table 1, an air leak state may be distinguished from a fluid leak state because the humidity data will increase in the presence of a fluid leak, but will not increase in the presence of an air leak (although it may fluctuate rapidly). Clearly, such assessment facilitates the detection of air leaks by differentiating them from fluid leaks, so that the therapy system may continue providing negative pressure therapy by increasing the pump duty cycle (PD) to compensate for the air leak rather than discontinuing the therapy being provided. 
     Still referring more specifically to Table 2, the flow characteristics may include a desiccation state within the wound dressing that also may be identified by the assessment of the pH data, the humidity data, and the temperature data along with contemporaneous wound pressure (WP) data, pump pressure (PP) data, and the pump duty cycle (PD) data. For example, a desiccation state may be identified if the pump pressure (PP) data and the pump duty cycle (PD) data remain unchanged, unless there is an air leak present which causes a moisture drop. In some embodiments, the desiccation state may be identified further if the wound pressure (WP) the also remains unchanged, unless there is an air leak present. In yet other embodiments, the desiccation state may be identified further if the humidity data decreases longitudinally over time. The humidity data may be tracked and compared to a minimum threshold value to prevent or avoid wound desiccation. The negative pressure control algorithm may be configured to provide an alert and/or an alarm in the event that the humidity data falls below the minimum threshold value. In still other embodiments, the desiccation state may be identified further if the pH data decreases slightly as the tissue site becomes slightly more acidic from drying. The temperature data also may change based on drying and the lack of sufficient exudation of the at the tissue site. Referring to  FIG. 17  as an example, a graph is shown illustrating test results using the dressing interface  400  for the detection of desiccation conditions based on the assessment of humidity data over time generated by the negative pressure control algorithm of  FIG. 11 . The tissue interface such as, for example, tissue interface  108 , was filled in saturated with simulated wound fluid. After the tissue interface was saturated with the wound fluid, the wound pressure (WP) was set as a target pressure (TP) of 125 mmHg and applied to the tissue interface. As can be seen, a desiccation state may be identified a decreasing dressing humidity  731  compared to the ambient humidity by tracking the humidity data and comparing it to a minimum threshold value as described above. In some embodiments, the negative pressure control algorithm  605  may generate a command to provide an alert  664  and shut down the pump  104 , for example, until the desiccation can be corrected. 
     The assessments of the pH data at  652 , the humidity data at  654 , and the temperature data at  656  along with contemporaneous wound pressure (WP) data, pump pressure (PP) data, and the pump duty cycle (PD) data may be utilized to assess the health of the wound at  658  including, for example, the progression of wound healing, i.e., the wound status. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                   
                 Wound Status: 
               
               
                   
                 Inputs 
                 Wound Health/Progression 
               
               
                   
                   
               
             
            
               
                   
                 Wound Pressure 
                 Critically affected 
               
               
                   
                 (WP) 
                 (May Increase or Decrease) 
               
               
                   
                 Wound Humidity 
                 May increase or decrease 
               
               
                   
                 (Hum) 
                 slowly 
               
               
                   
                 Wound pH 
                 Will change with wound 
               
               
                   
                   
                 regression or progression 
               
               
                   
                   
                 (May Increase or Decrease) 
               
               
                   
                 Wound 
                 May increase or  
               
               
                   
                 Temperature 
                 decrease 
               
               
                   
                 (Temp) 
                 slowly 
               
               
                   
                   
               
            
           
         
       
     
     Referring more specifically to Table 3, the wound status may include a determination of the progression of wound healing that may be identified by the assessment of the pH data, the humidity data, and the temperature data along with contemporaneous wound pressure (WP) data, pump pressure (PP) data, and the pump duty cycle (PD) data. For example, a wound healing state may be identified when the pH data changes in response to wound healing regression or progression. For example, in some embodiments, the wound may be considered in a healthy state if the wound fluids have a pH of approximately 7.4 and the pH data indicates that the pH has held at that value over a predetermined time period. In some other embodiments, the wound may be considered in a healthy state if the wound fluids have a pH that stays within a range from about 5.0 to about 8.0 and remains within that range over a predetermined time period. More specifically, if the pH data exceeds 8.0, the wound may be considered to be in a chronic state. Additionally, if the pH data is less than about 6.0, the wound may be considered to be in an inflammatory state. In some embodiments, the wound healing state may be identified when the humidity data and the temperature data both increase or decrease slowly at predetermined rates. For example, if the temperature data indicates that the temperature is increasing, the increasing temperature may be an indication that the wound is infected. Additionally, the wound pressure (WP) or the pump pressure (PP) may critically affect the healing progression or regression. For example, if the pressure is not within the therapeutic range that was prescribed, then the patient is not getting the benefit of the therapy. However, wound progression or regression does not necessarily affect the wound pressure (WP) or the pump pressure (PP). In some embodiments, the negative pressure control algorithm  605  may generate a command to provide an alert  665  and continue providing therapy including, for example, the instillation of fluids that may include medication until the pH returns to an acceptable range. 
       FIG. 18  is a schematic block diagram illustrating an embodiment of a control algorithm that may comprise a fluid instillation control algorithm that may be utilized when applying the fluid instillation therapy  606  within the tissue treatment method  600 , hereinafter referred to as the fluid instillation control algorithm  706 . The fluid instillation control algorithm  706  may include the detection of dressing flow characteristics within the system and an assessment of sensor properties based on the property data stored on the controller of the therapy system.  FIGS. 19A-19B  show flow charts illustrating various methods of some embodiments that may be configured to operate within the fluid instillation control algorithm  706  of  FIG. 18 . The fluid instillation therapy algorithm  706  may commence by initializing the therapy settings at  603  including logging the baseline readings of the sensors at  703  and setting the initial values of the property signals provided by the sensors. In some embodiments, the property signals may be sent to the processing element of the dressing interface and ultimately to the controller of the therapy system as indicated for processing and assessment. 
     A tissue interface such as the tissue interface  108  may be placed within, over, on, or otherwise proximate a tissue site as described above, and may include an accelerometer or other device for determining whether the sensors within the dressing interface are properly oriented at the tissue site. The fluid instillation control algorithm  706  may include a dressing orientation process at  708  that processes data from the accelerometer to determine whether sensors in the dressing interface are correctly oriented with respect to the tissue interface at the tissue site. If the sensors are not correctly oriented (NO), the fluid instillation control algorithm  706  in some embodiments may proceed to a dressing-fill assist subroutine at  710  shown more specifically in  FIG. 19A . When the dressing-fill assist subroutine is completed, the sensor readings may be logged and assessed at  720  along with a measurement of the amount of fluid dispensed to the tissue interface, i.e., the dispensed fill volume, as a result of the dressing-fill assist subroutine. After the sensor readings and the dispensed fill volume have been logged and assessed, the fluid instillation control algorithm  706  may further comprise providing wound pressure alerts at  721  similar to those described above. 
     Referring back to  708 , if the tissue interface is correctly oriented (YES), the fluid instillation control algorithm  706  in some embodiments may proceed to a pump control routine the compares the relative dressing humidity to a target humidity, and then provides commands to start or stop the instillation pump depending on the results of the comparison. More specifically, the pump control routine may compare the relative dressing humidity to the target humidity at  722  and stop the instillation pump at  723  (YES) if the relative dressing humidity exceeds the target humidity. After the instillation pump has been stopped at  723 , the sensor readings and the dispensed fill volume may be logged and assessed at  720  and wound pressure alerts may be provided at  721 . The pump control routine may include a redundant check of the role dressing humidity in comparison to the target humidity at  724  and stop the instillation pump at  725  (NO) if the relative dressing humidity is less than the target humidity. After the instillation pump has been stopped at  725 , the sensor readings and the dispensed fill volume may be logged and assessed at  720  and wound pressure alerts may be provided at  721 . Thus, if the relative dressing humidity is not greater than the target humidity at  722  and less than the target humidity at  724 , then the fluid instillation control algorithm  706  in some embodiments may proceed to dressing-alert algorithms including, for example, a blockage detection algorithm and fluid leak detection algorithm shown generally at  730  shown more specifically in  FIG. 19B . After either a blockage or dressing leak has been identified, the fluid instillation control algorithm  706  in some embodiments may log the sensor readings at  750  and loop back to  722  for further comparisons of the relative dressing humidity to the target humidity. However, if the relative dressing humidity is greater than the target humidity at  722  and not less than the target humidity at  724 , the pump may be stopped to log and assess the sensor readings and the dispensed volume. 
     After the fluid instillation control algorithm  706  proceeds to the dressing-alert algorithms including, for example, the blockage detection algorithm and fluid leak detection algorithm shown generally at  730  in  FIG. 19A , the algorithm may provide a command to continue operating the instillation pump at  731  and proceed to determine whether the relative dressing humidity is increasing at  732 . If the relative dressing humidity is not increasing (NO), the fluid instillation control algorithm  706  may proceed to determine whether the duty cycle (ID) of the instillation pump is increasing at  733 . The algorithm may proceed to implement the fluid leak detection algorithm if the duty cycle (ID) is not increasing (NO), or to implement the blockage detection algorithm if the duty cycle (ID) is increasing (YES). When the fluid instillation algorithm proceeds with the blockage detection algorithm, the algorithm may increment a blockage counter at  734  and proceed to determine whether the blockage counter is less than a predetermined blockage count threshold at  735  such as, for example, less than three increments to determine whether a blockage alert or alarm should be generated. If the blockage counter is less than the blockage count threshold, the blockage detection algorithm may generate a blockage alert at  736  and proceed to log a new set of sensor readings at  750 , e.g., pH, temperature, and humidity readings. If the blockage counter number is greater than or equal to the blockage count threshold, the blockage detection algorithm may generate a blockage alarm at  737  and proceed to log a new set of sensor readings at  750 . The blockage detection algorithm may then loop back to check the relative dressing humidity with respect to the target humidity at  722  as described above. 
     As indicated above, the fluid instillation control algorithm may proceed to implement the fluid leak detection algorithm if the duty cycle (ID) of the instillation pump is not increasing (NO) at  733  and proceed to increment a leakage counter at  738 . The leakage detection algorithm may then proceed to determine whether the leakage counter is less than a predetermined leakage count threshold at  740  such as, for example, less than three increments to determine whether a leakage alert or alarm should be generated. If the fluid leak counter is not less than the leakage count threshold, alternatively greater than or equal to the leakage count threshold, the leak detection algorithm may generate a fluid leak alarm at  741  and proceed to log a new set of sensor readings at  750 . However, if the fluid leak counter number is less than the leakage count threshold, the leak detection algorithm may generate a dressing leak alert at  742  and proceed to check a dead space detection algorithm at  743  that may be associated with the amount of gas or space that may be present in the tissue interface of the dressing such as, for example, the tissue interface  108  of the dressing  102  after instilling liquids into the tissue interface. The leak detection algorithm may determine whether there is a dead space detection variance of less than a predetermined value, e.g., 200 cc, at  744 . If the variance is not less than the predetermined value, i.e., if the variance is greater than the predetermined value, the leak detection algorithm may generate a fluid leak alarm at  741 . If the leak detection algorithm may determine that the variance is less than the predetermined value, the leak detection algorithm may generate a canister-full alert  667  (not shown in  FIG. 19A ) and then proceed to log a new set of sensor readings at  750 . Returning back to the decision at  732  of the fluid instillation control algorithm, the algorithm proceeds to log a new set of sensor readings at  750  if the relative dressing humidity is increasing and then loops back to check the relative dressing humidity with respect to the target humidity at  722  as described above. 
     Referring back to  FIG. 18 , the fluid instillation control algorithm  706  may further comprise a fill assist algorithm  710  that may facilitate determining whether the tissue interface has been instilled with a volume of fluids desired for the instillation therapy, i.e., a desired fill volume. Referring more specifically to  FIG. 19B , the fill assist algorithm  710  may comprise a dead space detection algorithm  711  that may be similar to the dead space detection algorithm  743  described above. The fill assist algorithm  710  may then proceed to provide a command to a controller to evacuate a therapy cavity of a dressing interface such as, for example, the controller  110  evacuating the therapy cavity  403  of the dressing interface  400 , to a negative pressure sufficient to commence instillation of the fluids at  712 . For example, a negative pressure of about 25 mmHg, which is well below the negative pressure therapy level of negative pressure, may be applied to the therapy cavity to commence instillation of the fluids. The negative pressure may be provided by the suction of a negative pressure pump such as, for example, the negative pressure pump  104 , as described in more detail above. 
     In some embodiments, providing this suction may be sufficient for instilling fluid into the therapy cavity. In other embodiments, an instillation pump such as, for example, the instillation pump  116 , may be used in conjunction with the suction to commence instillation. For example, the instillation pump may provide a positive force to instill the fluids into the therapy cavity as shown at  713  and may be supplemented by continuing to provide negative pressure from the negative pressure pump. The fill assist algorithm  710  may also include a pressure check algorithm at  714  for determining whether pressure changes within the therapy cavity are within an acceptable range, while instilling fluids into the therapy cavity and allowing those fluids to soak for a desirable so time. If the pressure measured is not within the acceptable range (NO), the fill assist algorithm  710  may generate a dressing leak alarm at  741 . However, if the pressure measured is within the acceptable range (YES), the fill assist algorithm  710  may provide a command to a controller to generate a command to open a pressure relief valve at  715  such as, for example, the controller  110  generating a command to the regulator  118  as described above, in order to further evacuate gases from the therapy cavity and draw liquids into the therapy cavity. The controller may be programmed to open the pressure relief valve for a fill period sufficient to provide the therapy cavity and the tissue interface with a desired fill volume. The fill assist algorithm  710  may also continue providing fill assist at  716  by refilling the therapy cavity until previous fill volumes are achieved for another cycle of instillation therapy. Whenever the desired fill volume or fill volumes are achieved, the fill assist algorithm  710  may proceed back to the fluid instillation control algorithm  706  so that the sensor readings may be logged and assessed at  720  along with a measurement of the amount of fluid dispensed to the tissue interface, i.e., the dispensed fill volume. After the sensor readings and the dispensed fill volume have been logged and assessed, the fluid instillation control algorithm  706  may continue by providing wound pressure alerts at  721  similar to those described above. 
     Referring back to  FIG. 18 , a new set of sensor readings indicative of the sensor properties and dispensed volumes may be logged at  720  into the controller of the therapy system as a result of the alerts, alarms, and other events described above with respect to the fluid instillation control algorithm  706  including the dressing orientation control  708 , the fill assist algorithm  710 , and the blockage detection and fluid leak detection algorithms  730 . Logging these property signals along with contemporaneous readings of the wound pressure (WP), the instillation pump pressure (IP), and the instillation pump duty cycle (ID) generates sets of property data that may include humidity data, temperature data, and pH data being provided by the processing element such as, for example, the sensor assembly  425 , in addition to the pressure data, duty cycle data, and other data that might be available from other sensors in the therapy system  100 . Such other sensors also may be coupled to the controller or other distribution components in the therapy system. For example, some embodiments may include an occlusion sensor (not shown), such as the fluid connections located in the therapy device shown in  FIG. 1 , that independently checks the possibility of a blockage or kink in the conduits or tubing coupled to the dressing interface. In some embodiments, the fluid instillation control algorithm  706  may be configured to assess the pH data, the humidity data, the temperature data, and the dispensed volume of fluids, and then use such assessment data to evaluate the status of wound health of the tissue site at  721 . The fluid instillation control algorithm  706  may be configured further to return to the wound pressure control algorithm  605  after such assessments have been completed. In some embodiments, the assessments may include an analysis of whether the data is increasing or decreasing and how rapidly the data may be increasing or decreasing. In some embodiments, the assessment may further include a determination that the relevant data is simply not affected 
     The assessments of the pH data, the humidity data, the temperature data, and the dispensed volume data, along with contemporaneous wound pressure (WP) data, instillation pump pressure (IP) data, and the instillation pump duty cycle (ID) data may be utilized to determine how the flow characteristics of the therapy system  100  may be affected by a blockage, a fluid leak, or a full canister within the system including the sensor pad or dressing interface  400 . Referring more specifically to Table 4 and  FIG. 20 , the flow characteristics may include a blockage state condition within the therapy system that may be identified by the assessment of the humidity data and the temperature data of the tissue site or the wound, along with contemporaneous wound pressure (WP) data, instillation pump pressure (IP) data, the instillation pump duty cycle (ID) data, and the occlusion sensor. 
     
       
         
           
               
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                   
                 Dressing State: Flow Characteristics 
               
            
           
           
               
               
               
               
            
               
                 Inputs 
                 Blockage 
                 Fluid Leak (Bolus) 
                 Fill Status 
               
               
                   
               
               
                 Wound Pressure 
                 WP may  
                 WP may  
                 WP may increase 
               
               
                 (WP) 
                 increase     
                 not change 
                 
                   
                 
               
               
                 Sensor Assembly 
                   
                   
                   
               
               
                 Wound Humidity 
                 Humidity will  
                 Humidity may  
                 Humidity will  
               
               
                 (Hum) 
                 not increase 
                 not increase 
                 increase     
               
               
                 Sensor Assembly 
                   
                   
                   
               
               
                 Wound  
                 Temperature  
                 Temperature may  
                 Temperature will  
               
               
                 Temperature 
                 will not  
                 decrease     
                 decrease     
               
               
                 (Temp) 
                 decrease 
                   
                   
               
               
                 Sensor Assembly 
                   
                   
                   
               
               
                 Instillation Pump  
                 ID will  
                 ID will not  
                 N/A 
               
               
                 Duty (ID) 
                 increase     
                 increase 
                   
               
               
                 System 
                   
                   
                   
               
               
                 Instillation Pump  
                 IP will  
                 IP may increase 
                 N/A 
               
               
                 Pressure (IP) 
                 increase     
                 
                   
                 
                   
               
               
                 System 
                   
                   
                   
               
               
                 Occlusion Sensor  
                 May trip 
                 N/A 
                 N/A 
               
               
                 (System) 
               
               
                   
               
            
           
         
       
     
     For example, a blockage state condition may be identified in the system (e.g., a substance blocking a tube or a kink in the tube) when the instillation pump pressure (IP) data increases and the instillation pump duty cycle (ID) data increases. In some embodiments, the blockage state condition may be identified further if the relative dressing humidity does not increase toward a target humidity such as, for example, a target humidity threshold which in some embodiments corresponds to a condition of the tissue interface being instilled to a desired fill volume.  FIG. 20  is a graph illustrating an instillation response curve  760  including data associated with the relative humidity percentage of a dressing in response to the fluid instillation control algorithm of  FIG. 18 . The graph includes, for example, a target humidity threshold  762  that is about 90% which may be determined to be an indication that the tissue interface is fully saturated with fluids as a result of instilling the desired fill volume. In this example, the relative humidity data is increasing at  761  of the response curve  760  toward the target humidity threshold  762  so that a blockage condition might not exist apart from other information. In yet other embodiments, the blockage state condition may be identified further if the temperature data does not decrease. For example, in some embodiments the temperature data does not decrease because the fluid simply does not reach into the tissue interface. Normally, the body temperature of the patient is warmer than the temperature of the fluids being instilled so that the temperature of the instillation fluid should drop if the fluid reached the tissue interface. In some other embodiments, the blockage state condition may be identified further if the wound pressure (WP) increases. In still other embodiments, the blockage state condition may be identified further when the occlusion sensor located in the fluid conduits of the therapy device is tripped. In some embodiments, the fluid instillation control algorithm  706  may generate a command to provide an alarm  661  and shut down the pump  116 , for example, until the blockage can be removed and the relative dressing humidity begins to increase toward the target humidity threshold such as, for example, toward 90% as shown in  FIG. 20 . 
     Still referring more specifically to Table 4, the flow characteristics may include a fluid leak state within the therapy system that also may be identified by the assessment of the humidity data and the temperature data, along with contemporaneous wound pressure (WP) data, instillation pump pressure (IP) data, the instillation pump duty cycle (ID) data, and the occlusion sensor. For example, a fluid leakage state may be identified in the wound dressing if the instillation pump duty cycle (ID) data does not increase. This may result from a fluid bolus trapped in the wound dressing that does not fill the therapeutic cavity, a closed volume, resulting in the lack of a back pressure that should have resulted from filling the therapeutic cavity. In some embodiments, the fluid leak state may be identified further if the humidity data increases, but does not increase fully toward the target threshold humidity of 90% to satisfy an assessment that the tissue interface is full. In still other embodiments, the fluid leak state may be identified further if the temperature data changes depending on the size of the leak. For example, if the body temperature is warmer than the temperature of the instillation fluid, then the temperature of the instillation fluid will decrease provided that the fluid does contact the tissue interface before leaking out of the dressing. In some embodiments, the fluid instillation control algorithm  706  may generate a command to provide an alarm  662  and shut down the pump  116 , for example, until the fluid leak can be corrected. Clearly, such assessment facilitates the detection of liquid boluses or potentially adverse events such as a blood vessel that bursts with the addition of instillation fluid in a fixed volume, so that a caregiver may be alerted to a potentially dangerous situation and/or the controller can quickly shut down the pump  116 . 
     Still referring to Table 4, the flow characteristics may include a dressing fill status for the therapy system to assist a caregiver by the assessment of the humidity data and the temperature data, along with contemporaneous wound pressure (WP) data. For example, a dressing fill status may be identified in the wound dressing if the humidity data increases to the target threshold humidity such as, for example, toward the 90% humidity as shown in  FIG. 20  indicating that the therapy cavity and/or the tissue interface is saturated with the instillation liquid as metered out by desired fill volume. In some embodiments, the fluid instillation control algorithm  706  may generate a command to provide a canister full alert  667  and/or shut down the pump  116 , for example, because the relative dressing humidity increased to a target humidity threshold such as, for example, 90% to detect a fully saturated dressing at a predetermined desired fill volume of about 38 ml at  764 . Once the dressing is fully saturated to this predetermined value, the relative dressing humidity remains substantially constant as shown by the flat portion  763  of the response curve  760 . In still other embodiments, a dressing fill status may be identified if the temperature decreases as instillation fluid is introduced into the dressing. For example, if the body temperature is warmer than the temperature of the instillation fluid, then the temperature of the instillation fluid will decrease provided that the fluid does contact the tissue interface before leaking out of the dressing. In yet other embodiments, a dressing fill status may be identified if the wound pressure (WP) increases to a pressure slightly higher than the ambient pressure, or if the wound pressure (WP) does not increase or decrease after the dressing is saturated with the instillation fluids. Such assessment facilitates the identification of a dressing fill status to assist a caregiver&#39;s visual monitoring of the dressing so that the caregiver may be alerted to a potentially dangerous situation and the controller can quickly shut down the relation pump  116  after the desired fill volume has been achieved. 
       FIG. 21  is a block diagram of a wireless architecture of another embodiment of a sensor assembly, sensor assembly  2125 , which may be substantially similar to the sensor assembly  425 . For example, the sensor assembly  2125  may be coupled to the sensors including the pressure sensor  416 , the temperature and humidity sensor  418 , and the pH sensor  420 , in the therapy cavity  403  and be configured to read the sensors in substantially the same way as the sensor assembly  425 . The wireless module architecture comprises a core module  2105  implemented on circuit board  2132  of sensor assembly  2125 . The core module  2105  comprises a system-on-a-chip (SoC) module  2110  that includes a central processor unit (CPU)  2115  and a Bluetooth low energy (BLE) transceiver (X-CVR)  2120  with built-in analog front end. By way of example, SoC module  2110  may be a Nordic© nRF51 series SoC or a Rigado© BMD-200 SoC. Both of these SoC devices are flexible, multi-protocol, wireless circuits for ultra-low power wireless applications, such as Bluetooth low energy (BLE) applications. Both SoC devices include processors, Bluetooth transceivers, antennas, and analog front ends. Those skilled in the art will understand that other types of SoC modules may be used and may communicate according to other wireless protocols, including WiFi, cellular, and the like. 
     The core module  2105  further comprises a general purpose input-output (GPIO) bus  2155 , the pressure sensor  416 , the temperature/humidity sensor  418 , the pH sensor  420 , a light-emitting diode (LED)  2130 , and at least one peripheral device  2135 . The GPIO bus  2155  comprises an internal bus  2155 A that is part of SoC module  2110  and an external bus  2155 B that is implemented on circuit board  2132  outside of SoC module  2110 . Bus  2155 A and bus  2155 B may be, for example, an inter-integrated circuit (I 2 C) connection bus used for coupling lower speed peripheral integrated circuits to SoC module  2110  for short-distance, intra-board communication. The I 2 C connection bus is a de facto standard interface protocol for many currently available sensors. Thus, internal bus  2155 A couples SoC module  2110  to the pressure sensor  416 , the temperature/humidity sensor  418 , the pH sensor  420 , a light emitting diode (LED) indicator  2130 , and at least one peripheral device  2135 . Similarly, external bus  2155 B couples SoC module  2110  and core module  2105  to additional peripherals  2160  and  2165  that are in expansion slots or daughter boards external to core module  2105 . 
     In an exemplary embodiment, the pressure sensor  416  may comprise a TE Connectivity© 1620 sensor, an Amphenol© NPC-120 sensor, or a Merit© BP0002 sensor. Similarly, the temperature/humidity sensor  418  may comprise a TE Connectivity© HTU21D sensor or a Sensirion© SHT31-DIS-F sensor. Finally, the pH sensor  420  may comprise a direct input passive electro-chemical sensor that measures subtle changes in voltage potential and is manufacture by screen-printing electrodes onto a polyamide or equivalent film substrate. Sensor assembly  2125  may comprise an activation switch or a plastic tab insulating battery  424  from creating a power connection. When the plastic tab is pullet to activate, LED indicator  430  may illuminate once sensor assembly  2125  is powered up and BLE transceiver  2120  has paired with an external control device used by an operator. 
     The core module  2105  further comprises a high-speed bus  2150  and USB 3.0 type-C microconnector  2140 . Bus  2150  comprises an internal bus  2150 A within SoC module  2110  and an external bus  2150 B that is implemented on circuit board  2132  outside of SoC module  2110 . Bus  2150  provides 2-way communications and may be used for connection, communication, and power supply between sensor assembly  2125  and add-on devices, such as WiFi, 3G, 4G or 5G GSM cellular communications, Bluetooth communications modules, additional Serial Peripheral Interface bus (SPI) connections, graphical user interface (GUI) or pointing devices, digital cameras, daughter boards with additional electro-chemical sensors, and additional power sources for the addition of therapy supply/control. 
     By way of example, bus  2150  may couple core module  2105  to USB 3.0 daughter boards  2170  and  2180 . Daughter board  2170  couples SoC module  2110  to an exemplary serial device  2175 . Daughter board  2180  couples SoC module  2110  to a plurality of expansion devices, including cellular transceiver  2181 , display/GUI device  2182 , WiFi transceiver  2183 , firmware updating device  2184 , and secondary sensor  2185 . A single USB 3.0 port is able to permit the connection of at least 127 separate devices through a system of hubs. 
     Core module  2105  may be connected to a range of external interfaces and extended systems but provides key features in such a system. It is also intended that these external devices may not be just “data-out” systems, but may facilitate two-way communications such that control (or limited control) of the therapy system may be made by an operator via the peripherals. These peripherals may include: i) a display or user interface, such as a LCD, touch screen, LED membrane; ii) a cellular (3G, 4G, 5G) mobile communication module to allow the system to communicate via a mobile phone network with, for example, a smartphone or the like, iii) a GPS circuit for tracking the operator, iv) movement sensors such as accelerometers (for measuring patient activity levels or patient compliance); v) VoC sensors or other sensors of biologic activity or byproducts of biological processes which may indicate the presence of a disease state; and vi) WiFi communications to a facility or home network. 
     It is anticipated that core module  2105  may not have sufficient power capacity to run all but the most basic peripheral systems. Thus, any external peripherals may require further power supply and power management which can be managed by an appropriate power module connected via USB to the core module  2105 . In such a scenario, the core module  2105  would derive power from the peripheral. By way of example, USB 3.0 microconnector  2140  may be coupled to communication port  412  in  FIG. 5B  and receive power from an external peripheral device. Furthermore, it is considered advantageous to restrict software and firmware upgrades to core module  2105  to a hard-wired USB connection (via firmware device  2184 ) and to prohibit access to the system core from the peripherals. This should prevent external access to the core system, which could prove problematic if accessed by an unauthorized external agent. 
       FIG. 22  is a first wireless network topology for controlling the therapy system according to an exemplary embodiment of the disclosure. In  FIG. 22 , dressing interface  400  is controlled by and in communication with therapy controller  2210 . Therapy controller  2110  is similar to and performs the same functions as controller  110  in  FIG. 1 . Dressing interface  400  is similar to and performs the same functions as dressing  102  in  FIG. 1 . For simplicity, the remaining components of  FIG. 1  are omitted. 
     The therapy controller  2210  comprises a wireless transceiver (WT)  2211  for communicating with the core module  2105  on sensor assembly  2125  in dressing interface  400 . In an advantageous embodiment, WT  2211  communicates with core module  2105  on sensor assembly  2125  according to the Bluetooth low energy (BLE) protocol. Alternatively, therapy controller  2210  may use a wireline, such as a USB cable, coupled to communication port  412  to communicate with dressing interface  400 . In such an embodiment, power may be supplied from the therapy controller  2210  to dressing interface  400  via the USB cable. Therapy controller  2210  further comprises a wireline interface, such as input-output (I/O) interface  2212 , to communicate with an external IP network  2205 , such as the Internet. By way of example and without limitation, I/O interface  2212  may be coupled to an Ethernet cable  2206 . Because of the use of a short range wireless protocol (i.e., BLE) or a USB cable, it will be understood that dressing interface  400  and therapy controller  2110  may be co-located with each other. 
     As described above in  FIGS. 1-20 , therapy controller  2110  controls the operation of dressing interface  400  by performing negative pressure would therapy (NPWT) and instillation therapy to the wound site. Therapy controller  2110  receives from core module  2105  the sensor data readings from pressure sensor  416 , the temperature/humidity sensor  418 , the pH sensor  420 , and from other peripherals that may be coupled to core module  2105  on sensor assembly  2125  in dressing interface  400 . 
     Therapy controller  2210  may also be in communication via IP network  2205  with a remote monitor  2220  that is more remotely located, such as in another room, another building, of another city. Remote monitor  2220  comprises a wireline interface, such as input-output (I/O) interface  2221 , configured to communicate with the IP network  2205 . By way of example and without limitation, I/O interface  2221  may be coupled to an Ethernet cable  2207 . Remote monitor  2220  may also be coupled to a storage device  2230  that stores the sensor readings that are captured and logged by dressing interface  400  and therapy controller  2110 . 
     The network topology in  FIG. 22  enables the dressing interface  400  to be controlled directly by therapy controller  2210  and also remotely by remote monitor  2220 . Furthermore, if a display/GUI device  2182  is coupled to core module  2105 , the operator may also control and/or interact with dressing interface  400  and therapy controller  2210  directly via the display/GUI device  2182 . 
       FIG. 23  is a second wireless network topology for controlling the therapy system according to an exemplary embodiment of the disclosure. In  FIG. 23 , dressing interface  400  is controlled by and in communication with therapy controller  2310  via IP network  2305  using wireless communication links. In this embodiment, while the air pressure and fluid components in  FIG. 1  may still be co-located with dressing interface  400 , therapy controller  2110  may be more remotely located, such as in another room or another building. The therapy controller  2310  comprises a wireless transceiver (WT)  2311  for communicating with the IP network  2305 . In an advantageous embodiment, both core module  2105  and WT  2311  communicates with IP network  2305  according to the WiFi protocol. In such an embodiment, core module  2105  on sensor assembly  2125  may be coupled to a WiFi transceiver  2183  in sensor assembly  2125 . It will be understood by those skilled in the art that IP network  2305  may include cellular base stations or similar facilities capable of supporting cellular communication links, such as 3G, 4G, or 5G GSM cellular communication links. 
     Therapy controller  2310  may also be in communication with a remote monitor  2320  that may be collocated with therapy controller  2310  or may be more remotely located, such as in another room, another building, or another city. The therapy controller  2310  comprises a wireline interface, such as input-output (I/O) interface  2312 , configured to communicate with an input-output (I/O) interface  2321  in remote monitor  2320 . By way of example and without limitation, I/O interfaces  2312  and  2321  may be coupled via an Ethernet cable  2315 . Remote monitor  2320  may also be coupled to a storage device  2330  that stores the sensor readings that are captured and logged by dressing interface  400  and therapy controller  2310 . 
       FIG. 24  is a third wireless network topology for controlling the therapy system according to an exemplary embodiment of the disclosure. In  FIG. 24 , dressing interface  400 , therapy controller  2410 , and remote monitor  2420  are all remotely located with respect to each other and communicate via wireless links to IP network  2405 . It will be understood by those skilled in the art that IP network  2405  may include cellular base stations or similar facilities capable of supporting cellular communication links, such as 3G, 4G, or 5G GSM cellular communication links. 
     The therapy controller  2410  comprises a wireless transceiver  2411  that may be, for example, a WiFi transceiver or a cellular transceiver. Similarly, the remote monitor  2420  comprises a wireless transceiver  2421  that may be, for example, a WiFi transceiver or a cellular transceiver. Likewise, core module  2105  on sensor assembly  2125  may communicate with IP network  2405  using a WiFi link or a cellular link. In such an embodiment, core module  2105  may be coupled to a WiFi transceiver  2183  or may be coupled to cellular transceiver  2181 , or both, in sensor assembly  2125 . Remote monitor  2420  may also be coupled to a storage device  2430  that stores the sensor readings that are captured and logged by dressing interface  400  and therapy controller  2410 . 
       FIG. 25  is a method  2500  for wirelessly controlling the dressing interface  400  and the therapy system according to an exemplary embodiment of the disclosure. Initially, dressing interface  400  is powered up at  2505 . This may be performed by using an activation switch or removing an insulating tab from battery  424 . Alternatively, power may be applied by port  412  from an external source. Once power is applied, sensor assembly  2125  is initialized at  2510  and sets up a communication link (e.g., BLE, WiFi, cellular) to the therapy controller  2210 ,  2310 , or  2410  in any of  FIGS. 22-24 . Once a communication link is successfully established, the core module  2105  on sensor assembly  2125  illuminates the LED indicator  2130  to provide a visual indicator to the operator that the dressing interface  400  is ready to perform therapy operations. 
     Under the direction of the operator of the therapy controller, the core module  2105  begins to capture sensor data in dressing IF  400  at  2520 . The core module  2105  then transmits the sensor data to therapy controller  2210 ,  2310 , or  2410  and may optionally receive operator inputs and display operator information at  2525 . Next, at  2530 , dressing interface  400  and the other components of  FIG. 1  perform NPWT therapy and instillation therapy as described above in  FIGS. 1-20  under control of therapy controller  2210 ,  2310 ,  2410  and/or the operator. Throughout such NPWT and instillation therapy operations, remote monitor  2202 ,  2320 ,  2420  may log sensor data in storage  2230 ,  2330 ,  2430 . The therapy system then continues to capture sensor and perform NPWT and instillation therapy operations until a predetermined threshold value is reached or predetermined time period has elapsed. 
     One of the advantages of the core module  2105  described above is that, on its own, it covers at least 80% of the likely wireless communication needs of different types of dressing interfaces  400 , particularly for low-end therapy systems and therapy peripherals. By the addition of generic peripheral modules, it is possible to configure the core module  2105  to be able to meet quickly the wireless needs of any other future product. By populating only the components needed for a given application, it is possible to reduce the cost to the point that having the wireless capability in every device is attainable. Key to achieving this is to choose components and modular connections which do not consume needless space and power. 
     In an advantageous embodiment of the present disclosure, the therapy controllers  2210 ,  2310 , or  2410  in  FIGS. 22-24  are configured to automatically detect and identify a plurality of different types of dressing interfaces  400 . Based on the identification of the dressing  400 , the therapy controllers  2210 ,  2310 , or  2410  are further configured to select the correct therapy protocol(s) and operating parameters for the identified dressing interface. This prevents the operator from selecting an inappropriate therapy for a specific dressing  400 , thereby reducing potential harm to a patient. 
       FIG. 26  is a method for wirelessly controlling the dressing interface and the therapy system according to an exemplary embodiment of the disclosure. In  FIG. 26 , therapy controller  2610  is similar to any one of therapy controllers  2210 ,  2310 , or  2410 . In the specific embodiment in  FIG. 26 , therapy controller is implements in the form of a tablet device, such as an iPad tablet or an Android tablet. However, this is by way of illustration only and should not be construed to limit the scope of the disclosure. In alternate embodiments, therapy controller  2610  may be an embedded controller in therapy device  100 . 
     Therapy controller  2610  comprises a product detection circuit that detects and identifies dressing interface  400 , either automatically or in response to a user input command on the touch screen of therapy controller  2610 . According to the principles of the present disclosure, each dressing interface  400  comprises one or more types of product identifiers  499  that are printed, adhered or otherwise attached to the housing  401  of the dressing interface  400 . By way of example and not limitation, the product detection circuit in therapy controller  2610  may be a near-field communication (NFC) transceiver that detects and identifies a near-field communication (NFC) tag  499 A. Alternatively, the product detection circuit in therapy controller  2610  may be an RFID transceiver that detects and identifies an RFID tag (passive or active)  499 B. In still another embodiment, the product detection circuit in therapy controller  2610  may be a camera that detects and identifies a Q code  499 C or a bar code  499 D, or both. 
     The therapy controller  2610  is simply brought within close proximity of the product identifier  499  in order to automatically read the product and model information and thereby select, for example, the proper graphical user interface (GUI) to allow an operator to follow the correct therapy protocol(s) and operating parameters for dressing interface  400 . If the therapy controller  2610  is an embedded controller in therapy device  100 , the dressing interface  400  may be brought within close proximity of the therapy controller  2610  to enable the therapy controller  2610  to read the product and model information automatically. 
       FIG. 27  is a block diagram of the wireless therapy controller  2610  according to an exemplary embodiment of the disclosure. The therapy controller  2610  comprises the conventional components of a tablet device including a cellular transceiver (as described above). In an exemplary embodiment, the cellular transceiver includes an antenna  2705 , an RF front-end block  2710 , a digital to analog converter/analog to digital converter (DAC/ADC) block  2715 , and a baseband processing and audio processing block  2720 , which may typically be implemented as a digital signal processor (DSP). The therapy controller  2610  further comprises a central processing unit (CPU)  2725 , a memory  2730 , an RFID/NFC transceiver  2735 , a Bluetooth (BT) transceiver  2740 , a microphone (MIC)  2745 , a speaker  2750 , a display  2755 , which includes a integral touchscreen  2760 , a camera  2765 , a WiFi transceiver  2770 , and a USB connector  2775 . In an alternate embodiment, a physical keyboard may be implemented in place of a touchscreen  2760  that is part of the display  2755 . 
     Memory  2730  stores an operating system (not shown) that is executed by CPU  2725  in order to control the overall operation of the therapy controller  2610 . According to the principles of the present disclosure, memory  2730  further stores a therapy application program  2731  and a database file  2732  of selected therapy protocols and operating parameters. During a therapy procedure, the CPU  2725  executes the therapy application program  2731  to cause the therapy controller  2610  to identify the exact product and model of the dressing interface  400  using RFID/NFC transceiver  2735  or camera  2765 , or both, depending on the type of product identifier  499  attached to or printed on dressing interface  400 . After identifying the correct dressing interface  400 , the CPU  2725 , under control of the therapy application program  2731 , then selects the correct therapy protocol(s) and operating parameters for dressing interface  400  from the database file  2732 . CPU  2725  then presents, for example, the proper graphical user interface (GUI) to allow an operator to follow the correct therapy protocol(s) and use the correct operating parameters for the identified dressing interface  400 . 
       FIG. 28  is a method for wirelessly controlling the dressing interface  400  and the therapy system according to an exemplary embodiment of the disclosure. Initially, in  2805 , the operator presents the disposable (i.e., dressing interface  400 ) to the therapy controller  2610 , which then reads the product identifier  499 . Based on the product identifier and the information in database file  2732 , the therapy controller  2610  determines in  2810  if the disposable is genuine and not expired. If the disposable is not genuine or is expired, the therapy controller  2610  in  2815  alerts the user (or operator) and disables therapy until a correct disposable is presented in  2805  and  2810 . 
     If the disposable is genuine and not expired, the therapy controller  2610  in  2820  determines if the disposable is part of an instillation system. If the disposable is part of an instillation system, the therapy controller  2610  in  2825  will select the correct GUI, the correct help information, and the correct parameter settings for an instillation therapy. 
     Next, the therapy controller  2610  in  2830  determines if the disposable is part of a negative pressure wound therapy (NPWT) system. If the disposable is part of an NPWT system, the therapy controller  2610  in  2835  will select the correct GUI, the correct help information, and the correct parameter settings for an NPWT therapy. 
     Next, the therapy controller  2610  in  2840  determines if the disposable is part of a wound specific system (e.g., surgical incision, burn, blunt trauma, laceration, etc.). If the disposable is part of a wound specific system, the therapy controller  2610  in  2845  will select the correct GUI, the correct help information, and the correct parameter settings for a wound specific therapy, such as incision management therapy. 
     If the disposable is not for an instillation system or an NPWT system, the therapy controller in  2860  will alert user to try again or try different disposable. Otherwise, once the therapy controller  2610  has determined is the disposable is part of an instillation system and/or a NPWT system, the therapy controller in  2865  may allow the user (or operator) to adjust the settings to suit the specific application and commence therapy. 
     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. For example, certain features, elements, or aspects described in the context of one example embodiment may be omitted, substituted, or combined with features, elements, and aspects of other example embodiments. 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 be also be combined or eliminated in various configurations for purposes of sale, manufacture, assembly, or use. For example, in some configurations the dressing  102 , the container  112 , or both may be eliminated or separated from other components for manufacture or sale. In other example configurations, the controller  110  may also be manufactured, configured, assembled, or sold independently of other components. 
     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 herein may also be 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.