Method of operating a device for identifying damaged tissue

Abstract

To provide methods, apparatus and computer readable media for measuring sub-epidermal moisture in patients to determine damaged tissue for clinical intervention.SOLUTION: Apparatus for identifying damaged tissue is provided, the apparatus including: one or more coaxial electrodes for emitting and receiving a radiofrequency signal to generate a bioimpedance signal; a circuit that can be configured to convert the bioimpedance signal into a sub-epidermal moisture (SEM) value; and a processor electronically coupled to the circuit and can be configured to receive the SEM value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 521,837, filed June 19, 2017, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure provides an apparatus and computer readable medium for measuring subepidermal water in a patient for assessing damaged tissue for purposes of clinical intervention. The present disclosure also provides a method for assessing damaged tissue. [Background technology]

[0003] Skin is the largest organ in the human body. It is susceptible to many types of damage and injury. When the skin and surrounding tissues are unable to redistribute external pressure and mechanical forces, pressure ulcers can form. Pressure ulcers pose a significant health and economic concern internationally in both acute and long-term care settings. Pressure ulcers affect approximately 2.5 million people annually in the United States and an equal number in Europe. In long-term and acute care settings, up to 25% of elderly and bedridden patients develop pressure ulcers. Approximately 60,000 U.S. patients die each year from infections and other complications due to pressure ulcers.

[0004] Most pressure ulcers develop on bony prominences where there is less tissue to press against and pressure gradients within the vascular network are altered. Pressure ulcers are classified into one of four stages, ranging from the earliest stage currently recognized (Stage 1), where the skin remains intact but a patch of redness may be visible over the bony prominence, to the final stage (Stage 4), where tissue is destroyed and bone, tendon, or muscle is exposed. Detecting pressure ulcers before the skin is destroyed and treating them to prevent progression to later stages is the goal of policy makers and health care providers in major economies. Most pressure ulcers are preventable and if identified before the first stage of pressure ulcers, the deterioration of the underlying tissues can be halted.

[0005] Of the four major stages of pressure ulcers, the earliest stage currently recognized (Stage 1) is the least expensive to treat, costing an average of $2,000 per pressure ulcer, but is also the most difficult to detect. In many cases, damage above the epidermal cell layer is absent or invisible as the underlying subcutaneous tissue necroses. As a result, a clinician's first diagnosis of a pressure ulcer in a patient is typically made at a later stage of pressure ulcer development, at which point the average cost of treatment is $43,000 for a Stage 3 pressure ulcer or $129,000 for a Stage 4 pressure ulcer. If clinicians could identify and diagnose pressure ulcers at an early stage of development, the treatment process would be greatly shortened and the costs of treatment would be significantly reduced. Summary of the Invention [Problem to be solved by the invention]

[0006] To treat pressure ulcers in a timely and effective manner, clinicians need to accurately identify the area of ​​pressure ulcers, but the current standard for detecting pressure ulcers is by visual inspection, which is subjective, unreliable, untimely, and has low specificity. [Means for solving the problem]

[0007] In one aspect, the present disclosure provides and includes an apparatus for identifying damaged tissue. The device may include one or more coaxial electrodes capable of interrogating an anatomical site and surrounding tissue, each of the one or more coaxial electrodes may be configured to transmit and receive radio frequency signals to generate a bioimpedance signal; a circuit that may be electronically coupled to the one or more coaxial electrodes and configured to convert the bioimpedance signal into a subepidermal moisture ("SEM") value; a processor that may be electronically coupled to the circuit and configured to receive the SEM value; and a non-transitory computer readable medium that may be electronically coupled to the processor and may have stored thereon instructions that, when executed on the processor, perform the steps of receiving from the processor an SEM value measured at the anatomical site and at least two SEM values ​​measured around the anatomical site and their relative measurement locations, determining a maximum SEM value from the measurements around the anatomical site, determining a difference between the maximum SEM value and each of the at least two SEM values ​​measured around the anatomical site, and flagging relative measurement locations associated with a difference greater than a predetermined value as damaged tissue. In another embodiment, the difference between the maximum SEM value and the minimum SEM value measured around the anatomical site is determined.

[0008] In yet another aspect, the device may comprise one or more coaxial electrodes capable of interrogating an anatomical site and surrounding tissue, each of the one or more coaxial electrodes may be configured to transmit and receive radio frequency signals to generate a bioimpedance signal; a circuit that may be electronically coupled to the one or more coaxial electrodes and configured to convert the bioimpedance signal to an SEM value; a processor that may be electronically coupled to the circuit and configured to receive the SEM values; and a non-transitory computer readable medium that may be electronically coupled to the processor and may have stored thereon instructions that, when executed on the processor, perform the steps of receiving from the processor an SEM value measured at the anatomical site and at least two SEM values ​​measured around the anatomical site and their relative measurement locations, determining an average SEM value for each group of SEM values ​​measured generally equidistant from the anatomical site, determining a maximum SEM value from the average SEM values, determining a difference between the maximum SEM value and each of the average SEM values ​​measured around the anatomical site, and flagging relative measurement locations associated with a difference greater than a predetermined value as damaged tissue.

[0009] In yet another aspect, the present disclosure provides and includes a non-transitory computer readable medium for identifying damaged tissue. The non-transitory computer readable medium may have stored thereon instructions that, when executed on a processor, perform the steps of receiving an SEM value measured at an anatomical location and at least two SEM values ​​measured around the anatomical location and their relative measurement locations, determining a maximum SEM value from the measurements around the anatomical location, determining a difference between the maximum SEM value and each of the at least two SEM values ​​measured around the anatomical location, and flagging a relative measurement location associated with a difference greater than a predetermined value as damaged tissue. In another aspect, the difference between the maximum SEM value and the minimum SEM value measured around the anatomical location is determined.

[0010] In another aspect, a non-transitory computer readable medium may have stored thereon instructions that, when executed on a processor, perform the steps of receiving an SEM value measured at an anatomical location and at least two SEM values ​​measured around the anatomical location and their relative measurement locations, determining an average SEM value for each group of SEM values ​​measured generally equidistant from the anatomical location, determining a maximum SEM value from the average SEM values, determining the difference between the maximum SEM value and each of the average SEM values ​​measured around the anatomical location, and flagging relative measurement locations associated with a difference greater than a predetermined value as damaged tissue.

[0011] In yet another aspect, the present disclosure provides and includes a method for identifying damaged tissue. A method according to the present disclosure may include using a device to measure at least three subepidermal moisture values ​​at and around an anatomical site, the device may include one or more coaxial electrodes capable of probing tissue at and around the anatomical site, the one or more coaxial electrodes may be configured to transmit and receive radio frequency signals to generate a bioimpedance signal, a circuit may be electronically coupled to the one or more coaxial electrodes and configured to convert the bioimpedance signal to an SEM value, a processor may be electronically coupled to the circuit and configured to receive the SEM value, and a non-transitory computer readable medium having stored thereon instructions that, when executed on the processor, perform the steps of receiving from the processor an SEM value measured at the anatomical site and at least two SEM values ​​measured around the anatomical site and their relative measurement locations, determining a maximum SEM value from the measurements measured around the anatomical site, determining a difference between the maximum SEM value and each of the at least two SEM values ​​measured around the anatomical site, and flagging relative measurement locations associated with a difference greater than a predetermined value as damaged tissue. In another aspect, the difference between the maximum SEM value and the minimum SEM value measured around the anatomical site is determined. The method may further include obtaining from the device the relative measurement locations that are flagged as damaged tissue.

[0012] In another aspect, a method according to the present disclosure includes measuring at least three subepidermal water values ​​measured at and around an anatomical site using a device, the device including one or more coaxial electrodes capable of interrogating tissue at and around the anatomical site, the one or more coaxial electrodes may be configured to transmit and receive radio frequency signals to generate a bio-impedance signal, a circuit electronically coupled to the one or more coaxial electrodes and configured to convert the bio-impedance signal into a SEM value, a processor electronically coupled to the circuit and configured to receive the SEM value, and a processor electronically coupled to the processor, the processor may be configured to receive the SEM value, and the processor may be configured to receive the SEM value. The method may include a non-transitory computer readable medium having stored thereon instructions that, when performed as above, perform the steps of receiving from a processor an SEM value measured at the anatomical site and at least two SEM values ​​measured around the anatomical site and their relative measurement locations, determining an average SEM value for each group of SEM values ​​measured at generally equal distances from the anatomical site, determining a maximum SEM value from the average SEM values, determining a difference between the maximum SEM value and each of the average SEM values ​​measured around the anatomical site, and flagging relative measurement locations associated with a difference greater than a predetermined value as damaged tissue. The method may further include obtaining from the device the relative measurement locations flagged as damaged tissue.

[0013] In yet another aspect, the present disclosure provides and includes a method for generating an SEM image showing damaged tissue on an anatomical graphical display, the SEM image may be created by obtaining parameters of the anatomical site being interrogated, measuring at least three subepidermal water values ​​at and around the anatomical site using a device, the device including one or more coaxial electrodes capable of interrogating tissue at and around the anatomical site, the one or more coaxial electrodes may be configured to transmit and receive radio frequency signals to generate a bioimpedance signal, a circuit electronically coupled to the one or more coaxial electrodes and configured to convert the bioimpedance signal into an SEM value, and a process electronically coupled to the circuit and configured to receive the SEM value. The method may include a processor electronically coupled to a processor and a non-transitory computer readable medium having stored thereon instructions, when executed on the processor, for performing the steps of receiving from the processor an SEM value measured at the anatomical site and at least two SEM values ​​measured around the anatomical site and their relative measurement locations, determining a maximum SEM value from the measurements around the anatomical site, determining a difference between the maximum SEM value and each of the at least two SEM values ​​measured around the anatomical site, and flagging relative measurement locations associated with a difference greater than a predetermined value as damaged tissue. In another aspect, a difference between the maximum SEM value and a minimum SEM value measured around the anatomical site is determined. The method may further include displaying the measured SEM values ​​based on the relative measurement locations of the anatomical sites on a graph where an area defined by a parameter of the anatomical site is displayed, and indicating the measurement locations flagged as damaged tissue.

[0014] In yet another aspect, the SEM image may be created by obtaining parameters of the anatomical site being interrogated and measuring at least three subepidermal moisture values ​​at and around the anatomical site using a device, the device comprising: one or more coaxial electrodes capable of interrogating tissue at and around the anatomical site, the one or more coaxial electrodes may be configured to transmit and receive radio frequency signals to generate a bio-impedance signal; a circuitry electronically coupled to the one or more coaxial electrodes and configured to convert the bio-impedance signal into an SEM value; a processor electronically coupled to the circuitry and configured to receive the SEM value; and a processor electronically coupled to the processor. and a non-transitory computer readable medium having stored thereon instructions that, when executed on a processor, perform the steps of receiving from the processor an SEM value measured at the anatomical site and at least two SEM values ​​measured around the anatomical site and their relative measurement locations, determining an average SEM value for each group of SEM values ​​measured at generally equal distances from the anatomical site, determining a maximum SEM value from the average SEM values, determining a difference between the maximum SEM value and each of the average SEM values ​​measured around the anatomical site, and flagging relative measurement locations associated with a difference greater than a predetermined value as damaged tissue. The method may further include displaying the measured SEM values ​​based on the relative measurement locations of the anatomical sites on a graph in which an area defined by a parameter of the anatomical site is displayed, and indicating the measurement locations flagged as damaged tissue. [Brief description of the drawings]

[0015] Certain aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: Referring now in particular detail to the drawings, it is emphasized that the details shown are by way of example and are for the purpose of illustrating the discussion of embodiments of the present disclosure, however, that taken in conjunction with the drawings, it will be apparent to one skilled in the art how aspects of the present disclosure can be practiced. [Figure 1]FIG. 1 illustrates an example device according to the present disclosure having one coaxial electrode. [Diagram 2] FIG. 2 illustrates a detection unit of a device according to the present disclosure, comprising one or more coaxial electrodes. [Figure 3A] FIG. 3A illustrates an example of a coaxial electrode according to the present disclosure. [Figure 3B] FIG. 3B illustrates an example coaxial electrode according to the present disclosure, which is comprised of a point source electrode surrounded by six hexagonal pad electrodes. [Figure 3C] FIG. 3C illustrates a set of hexagonal pad electrodes, each of which can be programmed to function as a different portion of a coaxial electrode in accordance with the present disclosure. [Figure 3D] FIG. 3D illustrates an example of electronic connections for a set of hexagonal pads to enable coaxial electrode emulation in accordance with the present disclosure. [Figure 3E] FIG. 3E is a diagram illustrating a set of coaxial electrodes that are electronically interconnected. [Figure 4] FIG. 4 illustrates an example measurement scheme according to the present disclosure. [Figure 5A] FIG. 5A shows an example of an SEM measurement obtained by the method of the present disclosure displayed as an SEM map. [Figure 5B] FIG. 5B is a graph showing an example of SEM measurements taken along the x-axis of FIG. 5A. [Figure 5C] FIG. 5C is a graph showing an example of SEM measurements taken along the y-axis of FIG. 5A. [Figure 6A] FIG. 6A illustrates a method for making SEM measurements starting from the rear of the heel. [Figure 6B] FIG. 6B illustrates a method for performing SEM measurements starting from the side of the heel. [Figure 6C] FIG. 6C illustrates a method for taking SEM measurements starting from the mid-heel. [Figure 7A] FIG. 7A shows an example of visual assessment of damaged tissue around the sacrum. [Figure 7B] FIG. 7B shows an example of an SEM measurement of damaged tissue obtained using the methods of the present disclosure. [Figure 8A] FIG. 8A shows an example of visual assessment of healthy tissue around the sacrum. [Figure 8B] FIG. 8B shows an example of a SEM measurement of healthy tissue obtained using the method of the present disclosure. [Figure 9A] FIG. 9A shows an example of an SEM map obtained by the method of the present disclosure. [Figure 9B] FIG. 9B is a corresponding view of the visual assessment of damaged tissue in FIG. 9A. [Figure 10] FIG. 10 shows an example of an SEM image obtained by the method of the present disclosure. [Figure 11] FIG. 11 shows example time-lapse SEM images illustrating the sensitivity of the detection apparatus and methods of the present disclosure. [Figure 12A] FIG. 12A shows an example of a graphical representation of a finite element model illustrating the depth of various SEM levels according to the detection apparatus and methods of the present disclosure. [Figure 12B] FIG. 12B shows example plots of SEM measurements at various depths in a skin-like material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] This specification is not intended to describe in detail all of the various ways in which the disclosure may be implemented or all of the features that may be added to the disclosure. For example, features described with respect to one embodiment may be incorporated into other embodiments, and features described with respect to a particular embodiment may be omitted from that embodiment. Thus, the disclosure contemplates that in some embodiments of the disclosure, any feature or combination of features described herein may be excluded or omitted. Also, numerous modifications and additions to the various embodiments proposed herein will be apparent to those skilled in the art in light of this disclosure and do not depart from the disclosure. In other instances, well-known structures, interfaces, and processes have not been shown in detail so as not to unnecessarily obscure the invention. No part of this specification is intended to be construed as denying any portion of the full scope of the invention. Thus, the following description is intended to illustrate some specific embodiments of the disclosure, and is not intended to exhaustively specify all permutations, combinations, and variations thereof.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terms used in the description of the disclosure set forth herein are for the purpose of describing particular embodiments only and are not intended to be limiting of the disclosure.

[0018] All publications, patent applications, patents, and other references cited herein are incorporated by reference in their entirety for the teachings relevant to the sentence and / or paragraph in which the reference is presented. References to technology used herein are intended to refer to technology as commonly understood in the art, including modifications of those technologies or substitutions of equivalent technologies that are apparent to those skilled in the art.

[0019] It is specifically contemplated that the various features of the present disclosure described herein can be used in any combination, unless the context indicates otherwise. Further, the present disclosure contemplates that in some embodiments of the present disclosure, any feature or combination of features described herein can be excluded or omitted.

[0020] The methods disclosed herein consist of one or more steps or activities for achieving the described method. The steps and / or activities of the methods may be interchanged with one another without departing from the scope of the invention. That is, unless a specific order of steps or activities is required to properly use an embodiment, the order and / or use of specific steps and / or activities may be changed without departing from the scope of the invention.

[0021] As used in the description of this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0022] As used in this specification, "and / or" refers to and covers any and all possible combinations of one or more of the associated listed items, not just the lack of combination ("or") when interpreted in the alternative.

[0023] As used herein, the terms "about" and "approximately" when referring to a measurable value such as a length, frequency, or SEM value are meant to encompass variations of ±20%, ±10%, ±5%, ±0.5%, ±1%, or even ±0.1% of the stated amount.

[0024] As used herein, phrases such as "between X and Y" and "between about X and Y" should be interpreted to include X and Y. As used herein, phrases such as "between about X and Y" mean "between about X and about Y," and phrases such as "from about X to Y" mean "from about X to about Y."

[0025] As used in this specification, the words "comprise", "comprises" and "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0026] As used herein, the transitional phrase "consisting essentially of" means that the claims are to be construed to include the specific materials or steps recited in the claims, and those that do not materially affect the basic and novel characteristics of the claimed disclosure. Thus, the term "consisting essentially of" as used in the claims of this disclosure is not intended to be construed as equivalent to "comprising."

[0027] As used herein, the term "subepidermal moisture" refers to an increase in tissue fluid and local edema caused by vascular leakage and other changes that alter the underlying structure of damaged tissue in the presence of ongoing pressure on the tissue, apoptosis, necrosis, and inflammatory processes.

[0028] As used herein, a "system" may be a collection of devices that communicate with each other in a wired or wireless manner.

[0029] As used herein, "probing" refers to the use of radio frequency energy to penetrate the patient's skin.

[0030] As used herein, a "patient" may be a human or animal subject.

[0031] Exemplary devices according to the present disclosure are shown in Figures 1 and 2. It will be understood that these are examples of devices for measuring subepidermal moisture ("SEM"). In some embodiments, devices according to the present disclosure may be handheld devices, portable devices, wired devices, wireless devices, or devices suitable for measuring a portion of a human patient. U.S. Publication No. 2014 / 0288397 A1 to Sarrafzadeh et al. is directed to an SEM scanning device and is incorporated herein by reference in its entirety.

[0032] In certain embodiments according to the present disclosure, the device may include one or more electrodes. In one aspect according to the present disclosure, it may be preferable to use a coaxial electrode on an electrode such as a quadripolar ECG electrode, since the coaxial electrode is generally isotropic, thereby allowing the SEM value to be obtained regardless of the electrode placement orientation. The SEM value measured by the coaxial electrode may represent the water content of the tissue under the coaxial electrode, rather than the water content of the tissue surface across two spaced bipolar electrodes.

[0033] In some embodiments, the device may include two or more coaxial electrodes, three or more coaxial electrodes, four or more coaxial electrodes, five or more coaxial electrodes, ten or more coaxial electrodes, fifteen or more coaxial electrodes, twenty or more coaxial electrodes, twenty five or more coaxial electrodes, or thirty or more coaxial electrodes. In some embodiments, the coaxial electrodes may be configured to transmit and receive RF signals at a frequency of 32 kilohertz (kHz). In other embodiments, the coaxial electrodes may be configured to transmit and receive RF signals at a frequency of about 5 kHz to about 100 kHz, about 10 kHz to about 100 kHz, about 20 kHz to about 100 kHz, about 30 kHz to about 100 kHz, about 40 kHz to about 100 kHz, about 50 kHz to about 100 kHz, about 60 kHz to about 100 kHz, about 70 kHz to about 100 kHz, about 80 kHz to about 100 kHz, or about 90 kHz to about 100 kHz. In yet another embodiment, the coaxial electrodes may be configured to transmit and receive RF signals at frequencies of about 5 kHz to about 10 kHz, about 5 kHz to about 20 kHz, about 5 kHz to about 30 kHz, about 5 kHz to about 40 kHz, about 5 kHz to about 50 kHz, about 5 kHz to about 60 kHz, about 5 kHz to about 70 kHz, about 5 kHz to about 80 kHz, or about 5 kHz to about 90 kHz. In further embodiments, the coaxial electrodes may be configured to transmit and receive RF signals at frequencies less than 100 kHz, less than 90 kHz, less than 80 kHz, less than 70 kHz, less than 60 kHz, less than 50 kHz, less than 40 kHz, less than 30 kHz, less than 20 kHz, less than 10 kHz, or less than 5 kHz. In certain embodiments, all coaxial electrodes of the device may operate at the same frequency. In some embodiments, some of the coaxial electrodes of the device may operate at different frequencies. In certain embodiments, the frequency of the coaxial electrodes may be changed by programming certain pins on the integrated circuit to which they are connected.

[0034] In some embodiments according to the present disclosure, the coaxial electrodes may comprise a bipolar configuration having a first electrode comprising an outer annular ring disposed around a second inner circular electrode. Referring to FIG. 3A, the outer ring electrode is spaced apart from the outer diameter D of the circular inner electrode.C Outside diameter D is larger than O and inner diameter D I Each of the inner circular electrode and the outer electrode may be electrically coupled to one or more circuits capable of applying a voltage waveform to each electrode, generating a bio-impedance signal, and converting the capacitance signal to an SEM value. In certain embodiments, the bio-impedance signal may be a capacitance signal generated, for example, by measuring the difference in current waveforms applied between the central electrode and the annular ring electrode. In some embodiments, the conversion may be performed by a 24-bit capacitance-to-digital converter. In other embodiments, the conversion may be a 16-bit capacitance-to-digital converter, a charge-timed capacitance-to-digital converter, or a sigma-delta capacitance-to-digital converter. The one or more circuits may be electronically coupled to a processor. The processor may be configured to receive the SEM values ​​generated by the circuits.

[0035] In certain embodiments, the coaxial electrodes may be of the same size. In other embodiments, the coaxial electrodes may be of different sizes and may be configured to interrogate the patient's skin at different depths. The dimensions of the coaxial electrodes may be tailored to the depth at which the patient's skin is to be interrogated. Thus, electrodes with larger diameters may penetrate deeper into the skin than smaller pads. The desired depth may vary depending on the area of ​​the body being scanned, or the patient's age, skin texture, or other characteristics. In some embodiments, the coaxial electrodes may be coupled to two or more separate circuits such that each coaxial electrode can operate independently. In another embodiment, all or a portion of the coaxial electrodes may be coupled to the same circuit.

[0036] In some embodiments, the one or more coaxial electrodes may be capable of emitting RF energy to a skin depth of 4 millimeters (mm), 3.5 mm, 3.0 mm, 2.5 mm, 2.0 mm, 1.0 mm, or 0.5 mm. In further embodiments, the one or more coaxial electrodes have an outer diameter D of about 5 mm to about 55 mm, about 10 mm to about 50 mm, about 15 mm to about 45 mm, or about 20 mm to about 40 mm. O In another embodiment, the outer ring of the one or more coaxial electrodes may have an inner diameter D of about 4 mm to about 40 mm, about 9 mm to about 30 mm, or about 14 mm to about 25 mm. I In yet another embodiment, the inner electrode of the one or more coaxial electrodes may have a diameter D of about 2 mm to 7 mm, 3 mm to 6 mm, or 4 mm to 5 mm. C may have the following structure:

[0037] In further embodiments, the one or more coaxial electrodes may be spaced apart at a distance that avoids interference between the electrodes. The distance may be a function of the size of the sensor and the applied frequency. In some embodiments, each of the one or more coaxial electrodes may be activated sequentially. In certain embodiments, multiple coaxial electrodes may be activated simultaneously.

[0038] In certain embodiments according to the present disclosure, the coaxial electrode may comprise a point light source surrounded by hexagonal pad electrodes spaced approximately equidistant apart, as shown in FIG. 3B. The point light source may comprise a hexagonal pad electrode. In some embodiments, the point light source may comprise two, three, four, five, or six hexagonal pad electrodes. In certain embodiments, the point light source may be surrounded by six hexagonal pad electrodes. In some embodiments, the coaxial electrodes may be emulated from a group of hexagonal pad electrodes, each of which is programmable to be electronically coupled to a floating ground, a capacitive input, or a capacitive excitation signal, as shown in FIGS. 3C and 3D. In further embodiments, each hexagonal pad electrode may be connected to a multiplexer, which may have a select line that controls whether the hexagonal pad electrode is connected to a capacitive input or a capacitive excitation signal. The multiplexer may also have an enable line that controls whether the hexagonal pad electrode is connected to a floating ground. In certain embodiments, the multiplexer may be a pass-gate multiplexer. In some embodiments, one or more coaxial electrodes may be arranged as shown in Figure 3E to take advantage of multiplexer technology. Without being limited to theory, the arrangement shown in Figure 3E may limit interference between one or more coaxial electrodes.

[0039] In certain embodiments, the one or more coaxial electrodes may be embedded in a first side of a non-conductive substrate. In some embodiments, the substrate may be flexible or rigid. In certain embodiments, the flexible substrate may be comprised of Kapton, polyimide, or a combination thereof. In further embodiments, a top coverlay may be placed directly over the one or more coaxial electrodes. In certain embodiments, the top coverlay may be comprised of an all-polyimide composite of a double-sided copper clad laminate and a polyimide film bonded to a copper foil. In some embodiments, the top coverlay may include Pyralux 5 mil FR0150. Without being limited by theory, the use of this top coverlay may avoid parasitic charges naturally present on the skin surface from interfering with the accuracy and precision of the SEM measurements. In some embodiments, the one or more coaxial electrodes may be spring-mounted to the substrate in a device according to the present disclosure.

[0040] In some embodiments, the device may include a non-transitory computer-readable medium electronically coupled to the processor. In certain embodiments, the non-transitory computer-readable medium may have stored thereon instructions operable, when executed on the processor, to (1) receive at least one SEM value at an anatomical location, (2) receive at least two SEM values ​​measured around the anatomical location and their relative measurement locations, (3) determine a maximum SEM value from the measurements around the anatomical location, (4) determine a difference between the maximum SEM value and each of the at least two SEM values ​​measured around the anatomical location, and (5) flag as damaged tissue any relative measurement location associated with a difference greater than a predetermined value. In another embodiment, the non-transitory computer-readable medium may have stored thereon instructions that, when executed by a processor, are operable to: (1) receive at least one SEM value at an anatomical location; (2) receive at least two SEM values ​​measured around the anatomical location and their relative measurement locations; (3) determine an average SEM value for each group of SEM values ​​measured generally equidistant from the anatomical location; (4) determine a maximum SEM value from the average SEM values; (5) determine the difference between the maximum SEM value and each of the average SEM values ​​measured around the anatomical location; and (6) flag as damaged tissue any relative measurement locations associated with a difference greater than a predetermined value. In yet another embodiment, a non-transitory computer-readable medium may have stored thereon instructions that, when executed on a processor, are operable to: (1) receive at least one SEM value at an anatomical location; (2) receive at least two SEM values ​​measured around the anatomical location and their relative measurement locations; (3) determine a maximum SEM value from the measurements around the anatomical location; (4) determine a minimum SEM value from the measurements around the anatomical location; (5) determine the difference between the maximum SEM value and the minimum SEM value; and (6) flag as damaged tissue any relative measurement location associated with a difference greater than a predetermined value.In some embodiments, the predetermined value is 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, The predetermined value may be 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, or 7.5. It will be appreciated that the predetermined value is not limited by design, but rather, one of ordinary skill in the art may select the predetermined value based on the predetermined units of SEM.

[0041] One or more regions may be defined on the body. In one aspect, measurements within a region are considered comparable to one another. A region may be defined as an area on the skin of the body, and measurements may be taken at any point within the area. In one aspect, a region corresponds to an anatomical region (e.g., heel, ankle, lower back). In one aspect, a region may be defined as a set of two or more specific locations relative to an anatomical feature, and measurements are taken only at the specific locations. In one aspect, a region may include multiple, discontinuous areas on the body. In one aspect, a set of specific locations may include locations in multiple, discontinuous areas.

[0042] In one embodiment, the region is defined by a surface area. In one embodiment, the region is, for example, between 5 and 200 cm. 2 , 5~100cm 2 , 5~50cm 2 , or 10~50cm 2 , 10~25cm 2 , or 5~25cm 2 That's fine too.

[0043] In one embodiment, measurements may be taken in a specific pattern or at a site. In one embodiment, a pattern of readings is created in a pattern that includes a central area of ​​interest. In one embodiment, measurements are taken in one or more circular patterns of increasing and decreasing size, T-shaped patterns, at a set of specific locations, or randomly across a tissue or region. In one embodiment, a pattern may be placed on the body by defining a first measurement location of the pattern with respect to an anatomical feature, and the remaining measurement locations of the pattern may be defined as offsets from the first measurement location.

[0044] In one embodiment, multiple measurements are taken across a tissue or region and the difference between the lowest and highest measurement of the multiple measurements is recorded as the delta value of the multiple measurements, hi one embodiment, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more measurements are taken across a tissue or region.

[0045] In one embodiment, one threshold may be set for at least one region. In one embodiment, a threshold of 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or other numeric value may be set for at least one region. In one embodiment, a delta value is identified as significant if the delta values ​​of multiple measurements made within a region match or exceed the threshold associated with that region. In one embodiment, each of the multiple regions has a different threshold. In one embodiment, two or more regions may have a common threshold.

[0046] In one aspect, the threshold has both a delta value component and a time series component, and a delta value is identified as significant if the delta value is greater than a predetermined number for a predetermined portion of the time interval. In one aspect, the predetermined portion of the time interval is defined as at least X days, where a number of measurements taken on those days produce a delta value equal to or greater than the predetermined number within a total of Y consecutive measurement days. In one aspect, the predetermined portion of the time interval may be defined as 1, 2, 3, 4, or 5 consecutive days, where a number of measurements taken on those days produce a delta value equal to or greater than the predetermined number. In one aspect, the predetermined portion of the time interval may be defined as a portion of a different specific period (week, month, hour).

[0047] In one aspect, the threshold has a trend aspect where the change in delta value of consecutive measurements is compared to one another. In one aspect, the trend threshold is defined as a predetermined change in delta value over a predetermined period of time and it is important to determine if the threshold is met or exceeded. In one aspect, once the importance is determined, an alert is generated. In one aspect, a trend line may be calculated from a portion of the individual measurements of the consecutive measurements. In one aspect, a trend line may be calculated from a portion of the delta values ​​of the consecutive measurements.

[0048] In one aspect, the number of measurements taken within a single region may be less than the number of measurement locations defined in the pattern. In one aspect, a delta value is calculated after a predetermined initial number of readings, less than the number of measurement locations defined in the pattern, are taken within a region and each additional reading is taken within the same region, where once the delta value meets or exceeds a threshold value associated with that region, no additional readings are taken.

[0049] In one aspect, the number of measurements taken within a single area may be greater than the number of measurement locations defined in the pattern, hi one aspect, a delta value is calculated after each additional reading.

[0050] In one embodiment, a quality metric may be generated for each of the measurements. In one embodiment, the quality metric is selected to assess the reliability of the measurements. In one embodiment, the quality metric is selected to assess the skill of the clinician who performed the measurements. In one embodiment, the quality metric may include one or more statistical parameters, such as an average, mean, or standard deviation. In one embodiment, the quality metric may also include one or more comparisons of individual measurements to predefined regions. In one embodiment, the quality metric may include a comparison of individual measurements to a pattern of values, such as a comparison of measurements at predefined locations to a range associated with each predefined location. In one embodiment, the quality metric may include a determination of which measurements to make on healthy tissue and one or more assessments of consistency within this subset of "healthy" measurements, such as a "range," standard deviation, or other parameter.

[0051] In one embodiment, the measurements, e.g., the threshold values, are determined by a SEM scanner model 200 (Bruin Biometrics, LLC, Los Angeles, Calif.). In one embodiment, the measurements are determined by other SEM scanners.

[0052] In one aspect, the measurements are based on capacitance measurements by referencing a reference device. In one aspect, the capacitance measurements may be affected by the location of any electrodes in the device and other aspects. Such variations may be compared to a reference SEM device, such as a SEM Scanner Model 200 (Bruin Biometrics, LLC, Los Angeles, Calif.). Those skilled in the art will appreciate that the measurements described herein can be adjusted to accommodate different capacitance ranges by referencing a reference device.

[0053] In further embodiments, inflammation at the leading edge may be indicated by an SEM difference equal to or greater than a predetermined value, hi some embodiments, inflammation at the leading edge may be identified by the maximum value of a set of SEM measurements.

[0054] In certain embodiments, the anatomical site may be a bony prominence. In further embodiments, the anatomical site may be the sternum, sacrum, heel, scapula, elbow, ear, or other fleshy tissue. In some embodiments, one SEM value is measured at the anatomical site. In other embodiments, the average SEM value is obtained from two, three, four, five, six, seven, eight, nine, ten, or more than ten SEM values ​​measured at the anatomical site.

[0055] The device of the present disclosure may allow a user to control the pressure applied to the patient's skin to allow for optimized measurement conditions. In certain embodiments, the first pressure sensor may be disposed on a second side of the substrate opposite the first side on which the coaxial electrode is disposed. In further embodiments, the second pressure sensor may be disposed on a second side of the substrate opposite the first side on which the coaxial electrode is disposed. In certain embodiments, the first pressure sensor may be a low pressure sensor and the second pressure sensor may be a high pressure sensor. Together, the first and second pressure sensors may allow measurements to be made at a predetermined range of target pressures. In some embodiments, the target pressure may be about 500 g. It will be appreciated that the high and low pressure sensors are not limited by design, but rather, one of ordinary skill in the art may select these sensors based on a predetermined range of target pressures. The first and second pressure sensors may be resistive pressure sensors. In some embodiments, the first and second pressure sensors may be sandwiched between the substrate and a conformal pressure pad. The conformal pressure pad provides both support and conformance allowing measurement of body curvatures and bony prominences.

[0056] In one embodiment, the device may further comprise a plurality of contact sensors on the same planar surface and around each of the one or more coaxial electrodes to ensure that the one or more coaxial electrodes are in full contact with the skin surface. The plurality of contact sensors may be a plurality of pressure sensors, a plurality of light sensors, a plurality of temperature sensors, a plurality of pH sensors, a plurality of sweat sensors, a plurality of ultrasound sensors, a plurality of bone growth stimulation sensors, or a plurality of combinations of these sensors. In some embodiments, the plurality of contact sensors may consist of four, five, six, seven, eight, nine, ten or more contact sensors surrounding the one or more coaxial electrodes.

[0057] In certain embodiments, the device may include a temperature probe, hi some embodiments, the temperature probe may be a thermocouple or an infrared thermometer.

[0058] In some embodiments, the device may further comprise a display having a user interface. The user interface may allow a user to input measurement location data. The user interface may further allow a user to view the measured SEM values ​​and / or the location of the damaged tissue. In certain embodiments, the device may further comprise a transceiver circuit configured to receive and transmit data to and from a remote device, such as a computer, tablet, or other mobile or wearable device. The transceiver circuit may allow for any suitable form of wired or wireless data transmission, such as, for example, USB, Bluetooth, or Wifi.

[0059] A method according to the present disclosure provides for identifying damaged tissue. In some embodiments, the method may include using a device of the present invention to measure at least three SEM values ​​at and around an anatomical site and obtaining from the device a measurement location that is flagged as damaged tissue. In certain embodiments, measurements may be taken at locations on one or more concentric circles around the anatomical site. FIG. 4 illustrates a measurement method with a center defined by the anatomical site. In another embodiment, measurements may be taken spatially away from the anatomical site. In yet another embodiment, measurements may be taken on a straight line that crosses the anatomical site. In a further embodiment, measurements may be taken on a curved portion around the anatomical site. In certain embodiments, prior to the measuring step, surface moisture and material on the patient's skin surface may be removed. In some embodiments, the measuring step may take less than 1 second, less than 2 seconds, less than 3 seconds, less than 4 seconds, or less than 5 seconds.

[0060] Having now generally described the invention, the same will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended to limit the disclosure, unless otherwise specified. EXAMPLES

[0061] Example 1: Measurement of subepidermal moisture (SEM) values ​​at the sacral bony prominence Using the device of the present disclosure, SEM was measured multiple times on subjects with visually confirmed stage I or II pressure ulcers and intact skin at and around the sacral prominence. Prior to measurement, the subject's skin surface was cleaned of moisture and any deposits thereon. The electrodes of the device were applied to the desired anatomical site with sufficient pressure to ensure complete contact for approximately 1 second. Additional measurements were taken at the mapped locations as shown in FIG. 4.

[0062] Figure 5A shows an example of an SEM map centered on an anatomical site. Figure 5B is a plot of the individual SEM values ​​on the x-axis of the SEM map. Figure 5C is a plot of the individual SEM values ​​on the y-axis of the SEM map. Damaged tissue radiated from the central anatomical site to the edge of the erythema, defined by a difference in SEM values ​​of more than 0.5. Example 2: SEM measurements at the heel bone prominence

[0063] SEM measurements were performed at the heel, with the electrodes in full contact with the skin of human patients, using one of three methods:

[0064] 6A shows the method used to take SEM measurements starting from the rear of the heel using a device according to the present disclosure. First, the forefoot was dorsiflexed so that the toes were pointing toward the shin, and then the electrode was positioned at the base of the heel. After the electrode was aligned so that it was entirely in contact with the heel, multiple SEM measurements were taken in a straight line toward the toes.

[0065] 6B shows the method used to take SEM measurements starting from the lateral heel using the device of the present disclosure. First, the toes were turned inwards towards the middle of the body, pointing away from the body, and then the electrode was aligned to the lateral side of the heel. After the electrode was aligned so that it was entirely in contact with the heel, multiple SEM measurements were taken in a straight line down the sole of the foot.

[0066] 6C shows the method used to make SEM measurements starting from the mid-heel using a device according to the present disclosure. The toes were first rotated outward toward the side of the body, pointing away from the body, and then the electrode was aligned to the mid-heel. After the electrode was aligned so that it was entirely in contact with the heel, multiple measurements were taken in a curved line around the back of the heel. Example 3: Identification of areas of damaged tissue

[0067] SEM measurements were taken on the patient's sacrum in a line, each spaced 2 cm apart. Multiple measurements were taken at multiple times at a given measurement location. Figure 7A is an example of visual assessment of damaged tissue. Figure 7B is a corresponding plot of the average SEM measurements taken at each measurement location. Edge erythema is defined by a difference in SEM values ​​greater than 0.5. Example 4: SEM measurements of healthy tissue

[0068] SEM measurements were taken linearly on the patient's sacrum. Multiple measurements were taken multiple times at a given measurement location. Figure 8A is an example of a visual assessment of healthy tissue. Figure 8B is a corresponding plot of the average SEM measurements taken at each measurement location. Tissue is defined as "healthy" if the difference in SEM values ​​is less than 0.5. Example 5: SEM measurement maps of damaged tissue

[0069] SEM measurements were performed according to Example 1. Figure 9A is an example of a map of mean SEM values ​​plotted on concentric circles around an anatomical site. Figure 9B is a corresponding visual assessment of the patient's skin. Damaged tissue is identified with a solid circle and the difference in SEM value compared to the maximum SEM value is greater than 0.5. Apical inflammation is identified with a dotted circle and the difference in SEM value compared to the maximum SEM value is greater than 0.5. Apical inflammation is identified with a dotted line and shows the maximum value in the SEM map. Example 6: Example of image display of SEM measurement

[0070] SEM measurements were performed with multiple arrays of coaxial electrodes. Figure 10 shows an example of an SEM measurement image output showing the water content of skin over a defined area. Different SEM values ​​are displayed in different colors. Example 7: SEM measurement of skin moisture content over time

[0071] A moisturizer was used to simulate the development of a bedsore. 0.2 mL of moisturizer was applied to the subject's inner forearm for 60 seconds, and then the moisturizer was wiped off the skin. SEM measurements were performed with multiple arrays of coaxial electrodes for 10 minutes and 2 hours each. Figure 11 shows an example of the time course of SEM measurement images to observe the moisture content of a subject. Example 8: Selection of optimal electrodes for probing a patient's skin

[0072] 12A is an example of a graphical representation of a finite element model showing various SEM level depths according to the methods of the present disclosure. Each line represents the SEM value and water content depth.

[0073] The device according to the present disclosure was used to measure the actual SEM levels of various depths of the skin-like material. Specifically, the device includes one coaxial electrode. First, the thickness of a blister bandage simulating a skin-like material was measured, and the blister bandage was placed on the coaxial electrode. A downward force was then applied to the coaxial electrode through the metal within the tolerance range according to the present disclosure. The metal was fitted to a tubular second metal. The second metal was selected from brass, aluminum, and stainless steel, and SEM measurements were recorded. To record further SEM measurements, another blister bandage was placed on the coaxial electrode. FIG. 12B is an example of a plot of SEM measurements for blister bandages of various thicknesses. The variation in SEM values ​​in the presence of different tubular metals may be due to potential magnetic field interference, without being limited to theory. The maximum depth of the magnetic field generated by the coaxial sensor was determined at the distance from the coaxial sensor at which the metal tube no longer interferes with the magnetic field. In this example, the maximum depth ranged from 0.135 inches to 0.145 inches. Therefore, an electrode with an optimal penetration depth may be selected to probe a particular depth into the patient's skin.

[0074] While the invention has been described in terms of specific embodiments, those skilled in the art will recognize that various modifications can be made and equivalent substitutions can be made of elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope.

[0075] Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the spirit and scope of the appended claims.

Claims

1. 1. A method of operating an apparatus for identifying damaged tissue, comprising: the device acquiring at least three subepidermal moisture (SEM) values ​​at and around an anatomical site at four or more time points within a time interval, the time interval including at least two predetermined portions of the time interval, each predetermined portion of the time interval including at least two time points; the apparatus determining a maximum SEM value for each of the at least two time points within each of the predetermined portions of the time interval; the apparatus determining a SEM delta value for each of the at least two time points within each of the predetermined portions of the time interval, the SEM delta value being calculated from a difference between a maximum SEM value and a minimum SEM value of the at least three SEM values ​​obtained during the respective time point; identifying tissue as the damaged tissue at each location where any one of the SEM delta values ​​exceeds a predetermined threshold value corresponding to the predetermined portion of the time interval during the predetermined portion of the time interval; The apparatus, one or more coaxial electrodes configured to transmit and receive radio frequency signals to generate a biocapacitance signal; a circuit electronically coupled to the one or more coaxial electrodes and configured to convert the biocapacitance signal to the SEM value; a processor electronically coupled to the one or more coaxial electrodes and configured to receive the SEM value; and a non-transitory computer-readable medium electronically coupled to the processor and having instructions stored thereon that, when executed by the processor, perform the obtaining, determining, and identifying steps.

2. The method of claim 1 , wherein the anatomical site is a bony prominence.

3. The method of claim 2 , wherein at least two SEM values ​​measured around the anatomical site are recorded equidistant from the bony prominence.

4. The method of claim 3 further comprising measuring two or more SEM values ​​at locations located on one or more concentric circles around the bony prominence.

5. A method of operating the device described in claim 1, wherein the specified portion of the time interval is five days.

6. A method of operating the device described in claim 1, wherein the predetermined portion of the time interval is four days.

7. A method of operating the device described in claim 1, wherein the specified portion of the time interval is three days.

8. A method for operating the device described in claim 1, wherein the specified portion of the time interval is two days.

9. A method for operating the apparatus described in claim 1, wherein the predetermined portion of the time interval is one day.

10. A method of operating the apparatus of claim 1, further comprising the step of the apparatus transmitting the SEM value to a remote device.

11. The method of claim 10 , wherein the device further comprises a second circuit configured to receive and transmit wireless data.

12. The method of claim 10, wherein the remote device is selected from the group consisting of a computer, a tablet, a mobile device, and a wearable device.

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