Biocapacitance sensor

Abstract

To provide apparatuses and methods for measurement of the biocapacitance of tissue.SOLUTION: An apparatus comprises: a sensor comprising two electrodes; a movable element coupled to the sensor; and a switch disposed between the movable element and a fixed element. The switch is electrically closed when a gap between the movable element and the fixed element is less than or equal to a pre-determined value. The device makes a measurement of the biocapacitance between the two electrodes when the switch is closed.SELECTED DRAWING: Figure 3B-3C

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Application No. 63 / 004,822, filed April 3, 2020, which is incorporated herein by reference in its entirety.

[0002] The present disclosure provides devices and methods for the non-invasive assessment of biocapacitance in biological tissue. [Background technology]

[0003] Current approaches to measuring biocapacitance require manual control of the applied force of the sensing device, resulting in measurements that vary with applied force. A means to automatically measure at the appropriate applied force without the user having to actively control the pressure would improve the reproducibility of measurements. Summary of the Invention

[0004] In one aspect, the present disclosure provides and includes an apparatus for measuring biocapacitance of tissue, the apparatus comprising: a sensor having two electrodes; a movable element coupled to the sensor; a switch disposed between the movable element and the fixed element and configured to electrically close when a gap between the movable element and the fixed element is less than or equal to a predetermined value; a device coupled to the sensor and configured to perform a measurement of capacitance between the two electrodes; and a processor coupled to the switch and the device and configured to receive a measurement from the device when the switch is electrically closed.

[0005] In one aspect, the electrodes are configured such that an electric field between the electrodes penetrates into the tissue when the sensor is positioned proximate to the tissue.

[0006] In one embodiment, the device is configured to repeatedly measure the capacitance between the two electrodes at predetermined intervals.

[0007] In one aspect, the sensor further comprises an insulating cover layer coupled to the electrode, the insulating cover layer configured to prevent conductive contact between the electrode and tissue when the sensor is positioned adjacent to the tissue.

[0008] In one aspect, the measurement involves comparing the capacitance between the electrodes to the capacitance of a reference capacitor.

[0009] In one embodiment, the comparison involves using a sigma-delta method to compare the capacitance between the electrodes to the capacitance of a reference capacitor.

[0010] In one aspect, the device further comprises a visual indicator coupled to the processor, the processor further configured to activate the visual indicator upon closure of the switch.

[0011] In one aspect, the movable element is configured to move along a translational axis relative to the fixed element, and the gap is disposed on the translational axis.

[0012] In one aspect, the device further comprises a spring positioned between the movable element and the fixed element and configured to provide a monotonically increasing force along the translational axis to separate the movable element and the fixed element.

[0013] In one aspect, the movable element is further configured to permit rotation about at least one of a first axis of rotation that is perpendicular to the translation axis and a second axis of rotation that is perpendicular to both the translation axis and the first axis of rotation.

[0014] In one aspect, the processor is further configured such that after the first measurement is received upon a first closure of the switch, the switch is electrically opened before the second measurement can be received.

[0015] In one aspect, the present disclosure provides and includes an apparatus for measuring biocapacitance of tissue, the apparatus comprising: a sensor having two electrodes; a device coupled to the sensor and configured to perform a capacitance measurement between the two electrodes; a barcode scanning engine configured to optically scan a machine-readable image to determine a first alphanumeric string encoded in the machine-readable image; and a processor coupled to the device and the engine and configured to receive measurements from the device and the first alphanumeric string from the engine.

[0016] In one aspect, the processor is further configured to receive a plurality of sequential alphanumeric strings and associate each of the sequential alphanumeric strings with one of a patient, a user, an encounter, an intervention, a wear factor, a durability factor, a location, and a time.

[0017] In one aspect, the processor is further configured to associate the first alphanumeric string of the patient with sequential alphanumeric strings.

[0018] In one aspect, the processor is further configured to transfer the associated alphanumeric string to a data system.

[0019] In one aspect, the present disclosure provides and includes a method for measuring biocapacitance of tissue, the method including positioning a sensor having a first electrode and a second electrode against a patient's skin above the tissue, measuring capacitance between the two electrodes, optically scanning a primary machine-readable image associated with the patient, determining a primary alphanumeric string encoded in the primary machine-readable image, and associating the capacitance with the primary alphanumeric string.

[0020] In one aspect, the method further includes optically scanning one or more secondary machine-readable images associated with one of a user, an encounter, an intervention, a wear element, a durability element, a location, and a time; determining a respective encoded secondary alphanumeric string in each of the one or more secondary machine-readable images; and associating the secondary alphanumeric string with the primary alphanumeric string.

[0021] In one aspect, the method further includes transmitting the primary alphanumeric string and the secondary alphanumeric string to a data system. [Brief explanation of the drawings]

[0022] Aspects of the present disclosure are described herein, by way of example only, with reference to the accompanying drawings. Referring now specifically to the drawings in detail, it is emphasized that the details shown are by way of example and for purposes of illustrative discussion of aspects of the present disclosure. In this regard, the description and drawings, taken both alone and together, will make apparent to those skilled in the art how aspects of the present disclosure may be practiced.

[0023] [Figure 1A] FIG. 1 is a plan view of a toroidal sensor according to the present disclosure. [Figure 1B] FIG. 10 is a plan view of another embodiment of a sensor according to the present disclosure. [Figure 1C] FIG. 1B is a cross-sectional view of the sensor of FIG. 1A according to the present disclosure. [Figure 1D] 1B shows an illustrative example of an electric field between two electrodes of the sensor of FIG. 1A in accordance with the present disclosure. [Figure 2] Shown is a classic model of a capacitor. [Figure 3A] 1 illustrates an embodiment of a biocapacitance scanner according to the present disclosure. [Figure 3B-3C] 1 shows structural details of a biocapacitance scanner according to the present disclosure. [Figures 4A-4C] 4 illustrates a sequence of states of a portion of the scanner of FIG. 3 in accordance with the present disclosure. [Figure 5] 4 illustrates a portion of an alternative embodiment of the scanner of FIG. 3 according to the present disclosure. [Figure 6] 1 illustrates certain aspects of a visual indicator according to the present disclosure. [Figure 7A] 1 illustrates another embodiment of a biocapacitance scanner according to the present disclosure. [Figure 7B] 1 shows an exploded view of components of a biocapacitance scanner according to the present disclosure. [Figures 8A-8D] 1 illustrates a series of states of an apparatus configured to implement a sigma-delta method for measuring capacitance according to the present disclosure. [Figure 9A] FIG. 1 shows a hardware block diagram for measuring the capacitance of a sensor according to the present disclosure. [Figure 9B] 1 shows a diagram of a system for measuring, storing, transferring, and accessing measurement data according to the present disclosure. [Figure 10] 1 illustrates a workflow including scanning primary and secondary barcodes according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present disclosure provides apparatus and methods for measuring biocapacitance of tissue. In one aspect, the present disclosure provides and includes an apparatus for measuring biocapacitance of tissue, the apparatus comprising: a sensor having two electrodes; a movable element coupled to the sensor; a switch disposed between the movable element and the fixed element and configured to electrically close when a gap between the movable element and the fixed element is equal to or less than a predetermined value; a device coupled to the sensor and configured to perform a capacitance measurement between the two electrodes; and a processor coupled to the switch and the device and configured to receive the measurement from the device when the switch is electrically closed.

[0025] In one aspect, the present disclosure provides and includes an apparatus for measuring biocapacitance of tissue, the apparatus comprising: a sensor having two electrodes; a device coupled to the sensor and configured to perform a capacitance measurement between the two electrodes; a barcode scanning engine configured to optically scan a machine-readable image to determine a first alphanumeric string encoded in the machine-readable image; and a processor coupled to the device and the engine and configured to receive measurements from the device and the first alphanumeric string from the engine.

[0026] In one aspect, the present disclosure provides and includes a method for measuring biocapacitance of tissue, the method including positioning a sensor having a first electrode and a second electrode against a patient's skin above the tissue, measuring capacitance between the two electrodes, optically scanning a primary machine-readable image associated with the patient, determining a primary alphanumeric string encoded in the primary machine-readable image, and associating the capacitance with the primary alphanumeric string.

[0027] This description is not intended to be a detailed listing of all the different ways in which the present disclosure can be implemented or all the features that can be added to the present disclosure. For example, features illustrated with respect to one embodiment may be incorporated into other embodiments, and features illustrated with respect to a particular embodiment may be omitted from that embodiment. Thus, the present disclosure contemplates that some embodiments of the present disclosure may exclude or omit any feature or combination of features described herein. Additionally, numerous modifications and additions to the various embodiments suggested herein will become apparent to those skilled in the art in light of the present disclosure without departing from the present disclosure. In other instances, well-known structures, interfaces, and processes have not been shown in detail so as not to unnecessarily obscure the present invention. No part of this specification is intended to result in a denial of any portion of the full scope of the present invention. Accordingly, the following description is intended to illustrate some specific embodiments of the present disclosure, but is not intended to exhaustively specify all permutations, combinations, and variations thereof.

[0028] 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 herein are for the purpose of describing particular aspects or embodiments only and are not intended to be limiting of the disclosure.

[0029] All publications, patent applications, patents, and other references cited herein are incorporated by reference in their entirety for the teachings related to the sentence and / or paragraph in which the reference is presented. References to techniques employed herein are intended to refer to techniques commonly understood in the art, including variations of those techniques or substitutions of equivalent techniques that would be apparent to those skilled in the art.

[0030] U.S. Patent Application Serial No. 14 / 827,375 discloses a device that uses radio frequency (RF) energy to measure subepidermal capacitance using a bipolar sensor similar to sensor 90 shown in FIG. 1A. The subepidermal capacitance correlates with the moisture content of a target area of ​​a patient's skin. The '375 application also discloses arrays of these bipolar sensors of various sizes.

[0031] U.S. Patent Application No. 15 / 134,110 discloses an apparatus for measuring subepidermal moisture (SEM) that emits and receives RF signals at a frequency of 32 kHz through a single coaxial sensor to generate a bioimpedance signal, which is then converted to generate an SEM value.

[0032] Both U.S. Patent Application Nos. 14 / 827,375 and 15 / 134,110 are incorporated herein by reference in their entirety.

[0033] Unless the context indicates otherwise, it is specifically contemplated that the various features of the present disclosure described herein can be used in any combination. Further, the present disclosure also contemplates that in some aspects of the disclosure, any feature or combination of features described herein can be excluded or omitted.

[0034] The methods disclosed herein comprise one or more steps or actions for achieving the described method. Method steps and / or actions may be interchanged with one another without departing from the scope of the invention. In other words, unless a specific order of steps or actions is required for proper operation of an aspect, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the invention.

[0035] 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 indicates otherwise.

[0036] As used herein, "and / or" and "or" refer to and include any and all possible combinations of one or more of the associated listed items.

[0037] As used herein, the terms "about" and "approximately," when referring to a length, time interval or period, frequency, or a measurable value such as an SEM value, are meant to encompass variations of ±20%, ±10%, ±5%, ±1%, ±0.5%, or ±0.1% of the specified amount.

[0038] 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 "about X to Y" mean "about X to about Y."

[0039] As used herein, the term "subepidermal moisture" or "SEM" refers to the level of moisture contained in tissues below the epidermis. Increased tissue fluid and local edema can be caused by vascular leakage and other changes that alter the underlying structure of injured tissue in the presence of continued pressure on the tissue, including, but not limited to, apoptosis, necrosis, and inflammatory processes.

[0040] As used herein, the term "tissue biocapacitance" refers to a biophysical marker for detecting early tissue damage based on increased levels of fluid accumulating in the interstitial space.

[0041] As used herein, a "system" may be a collection of devices that are physically coupled or in wired or wireless communication with each other.

[0042] As used herein, a "patient" can be a human or animal subject.

[0043] As used herein, "healthy" may describe tissue that does not show signs of damage to cell walls or blood vessels, the presence of increased amounts of extracellular fluid (ECF) being indicative of such damage.

[0044] As used herein, a "switch" refers to a device that selectively provides an electrical connection between two elements or contacts. In one aspect, "closing" or deforming a portion of the switch creates an electrical connection between the two contacts, thereby closing a circuit, and "opening" or reversing the switch to its original configuration breaks the electrical connection, thereby opening the circuit. In one aspect, an applied force creates the electrical connection, and removal of the force breaks the connection.

[0045] As used herein, "tissue" refers to a part of a living human or animal body. Tissue may include one or more layers from the outermost stratum corneum, subepidermis, epidermis, and deeper layers of muscle, fat, and bone, as well as internal structures such as veins, arteries, capillaries, lymphatic vessels, and nerves.

[0046] As used herein, "biocapacitance" refers to the capacitance of the sensor where the active field projects into the tissue.

[0047] As used herein, "spring" refers to an element that has force-deformation properties, where an applied force causes a deformation and / or the deformation causes a restoring force.

[0048] As used herein, "insulating" and like terms refer to the property of an element that prevents significant electrical conduction through the element.

[0049] As used herein, a "machine-readable image" refers to a pattern containing encoded information that can be observed by a machine and autonomously converted into information, for example, an alphanumeric string. In one aspect, the machine may project a light beam and capture a portion of the reflected light. In one aspect, the machine may capture a 2D recording of the image and process the image to thereby extract the encoded information. In one aspect, a "machine-readable image" may be a radio frequency sensing device, whether passive or active, such as a radio frequency identification (RFID) tag.

[0050] As used herein, an "alphanumeric string" refers to a sequence of characters, which may include uppercase or lowercase letters, in any language and numbers. An alphanumeric string may also be encoded in a digital form, for example, a string of 0s and 1s, that is uniquely associated with the alphanumeric string.

[0051] As used herein, "optical" refers, in one aspect, to a range of wavelengths of radiation that includes the "visible" spectrum from about 380 to 740 nanometers (nm). In one aspect, this range may include a portion of the infrared spectrum above about 740 nm. In one aspect, this range may include a portion of the ultraviolet spectrum below about 380 nm. In one aspect, radio frequency systems may be substituted as equivalents to optical systems.

[0052] As used herein, a "data system" refers to a system that includes one or more of data processing, data transmission, and / or data storage capabilities. The data system may be directly coupled to a first processor or may be coupled to a second processor that is communicatively coupled to the first processor. The storage elements may utilize any available volatile or non-volatile technology, including, but not limited to, solid-state drives (SSDs), spinning hard disk drives, and flash memory.

[0053] 1A is a plan view of one embodiment of a sensor 90 according to the present disclosure. The toroidal sensor 90 includes a first electrode 110 embodied as a circular pad and a second electrode 120 embodied as a toroid around the electrode 110. The embodiment of FIG. 1A is axisymmetric and therefore insensitive to angular rotation.

[0054] 1B is a plan view of another embodiment of a sensor 91 according to the present disclosure, in which two electrodes 111 and 121 are made up of interleaved fingers.

[0055] FIG. 1C is a cross-sectional view of the sensor 90 of FIG. 1A in accordance with the present disclosure. In this embodiment, the electrodes 110 and 120 are disposed on a common surface of the substrate 100 and are therefore coplanar with one another. In one embodiment, the electrodes may be disposed on different layers or non-planar surfaces of the substrate 100. In one embodiment, an insulating cover layer 130 may be disposed over the electrodes 110 and 120, as shown in FIG. 1C. The insulating cover layer 130 may prevent conductive contact between either of the electrodes 110, 120 and the skin when the sensor 90 is positioned against the skin. In one embodiment, one or more of the electrodes 110 and 120 are exposed and make conductive contact with the skin when the sensor 90 is positioned against the skin. In one embodiment, multiple electrodes (not shown in FIG. 1C) may be provided on the substrate 100, and the formation of the sensor 90 is controlled by selective connection of measurement circuitry (not shown in FIG. 1C) to first and second electrodes from the multiple electrodes.

[0056] 1D shows an illustrative example of an electric field 140 between two electrodes 110 and 120 of sensor 90 of FIG. 1A in accordance with the present disclosure. Electrodes 110 and 120 are positioned against skin 60 of patient tissue 50. Cover layer 130, omitted from FIG. 1D for clarity, may be disposed between electrodes 110, 120 and skin 60. Field 140 has an effective depth 150 below skin 60.

[0057] Without being bound by any theory, the capacitance measured between electrodes 110 and 120 depends in part on the dielectric constant of the tissue 50 that is within the effective field volume of field 140. Because water has a dielectric constant of approximately 81, while dry tissue has a dielectric constant of approximately 4, a small increase in the amount of water, also called subepidermal water, in the tissue can result in an increase in the capacitance measured by sensor 90.

[0058] 2 shows a classical model of a capacitor 200 according to the present disclosure. Capacitor 200 comprises a first planar electrode 210 and a second planar electrode 220 of the same dimensions placed parallel to electrode 210 with a separation distance "d". The space between electrodes 210 and 220 has a relative dielectric constant ε r The electrodes 210 and 220 are filled with a uniform material having a capacitance of 0.01 V, and the charges on the electrodes 210 and 220 are shown as "-" and "+" symbols, respectively. The science of capacitors is well known to those skilled in the art and can be found in standard electrical engineering reference books.

[0059] The capacitor 200 can hold a charge Q. The voltage difference V between the two electrodes 210 and 220 caused by the charge Q is proportional to the dielectric constant ε of the material between the electrodes. r The capacitance C of the capacitor 200 is determined by measuring the charge Q supplied to the capacitor 200 and the voltage difference V between the electrodes 210 and 220, as given by the equation

number

[0060] 3A illustrates one embodiment of a biocapacitance scanner 300 according to the present disclosure. A sensor 310 is located on the "nose" 325 of the body 320.

[0061] FIG. 3B shows structural details of a biocapacitance scanner 300 according to the present disclosure. The sensor 300, including the substrate and electrodes, is fixedly coupled to a carrier 330, including a top portion 332 and a shaft 334. The shaft 334 passes through a guide 350. In one embodiment, the shaft 334 is movable along an axis 336 relative to the guide 350. In one embodiment, the top portion 332 is rotatable relative to the shaft 334 about one or more intersecting axes (not shown in FIG. 3B) that are perpendicular to the axis 336. A printed circuit board assembly (PCBA) 340 includes a substrate 344 disposed below the carrier 330. In one embodiment, the substrate 344 is approximately perpendicular to the axis 336. In one embodiment, a switch 342 is coupled to the substrate 344 and disposed directly below the shaft 334. In one embodiment, the switch 342 is a dome switch that collapses upon application of a force above a predetermined value, thereby electrically closing a circuit, where the direction of the force is approximately perpendicular to the substrate 344. In one embodiment, switch 342 is configured to electrically close a circuit when the force between sensor 310 and the patient's skin is greater than a predetermined value. In one embodiment, switch 342 is configured to electrically close a circuit when the gap between a movable element, e.g., carrier 330, and a fixed element, e.g., guide 350, is less than or equal to a determined value.

[0062] In one embodiment, switch 342 is coupled to sensor 310 and coupled to a processor (not shown in FIG. 3B ) that is also coupled to a device (not shown in FIG. 3B ) configured to measure the capacitance detected by sensor 310, e.g., a capacitance-to-digital converter such as an Analog Devices AD7746. In one embodiment, the device is configured to repeatedly measure the capacitance between two electrodes of sensor 310 at predetermined intervals. In one embodiment, the device measures capacitance at a rate ranging from 1 to 1,000,000 times per second. In one embodiment, the device measures capacitance at a rate ranging from 1,000 to 100,000 times per second. In one embodiment, the device measures capacitance at a rate ranging from 10,000 to 50,000 times per second. In one embodiment, the device measures capacitance at a rate ranging from 20,000 to 40,000 times per second. In one embodiment, the device measures capacitance approximately 34,000 times per second. In one aspect, the device measures capacitance at this rate regardless of whether switch 342 is electrically open or closed. In one aspect, the processor accepts measurements from the device when switch 342 is closed. In one aspect, the processor records multiple measurements from the device after switch 342 is closed, e.g., 10 consecutive measurements. In one aspect, the processor combines the multiple recorded measurements, e.g., by averaging, to obtain a single representative "measurement" to be used for further processing. In one aspect, the processor is reset by the opening of switch 342 before the processor records another measurement from the device.

[0063] FIG. 3C shows structural details of a biocapacitance scanner 300 according to the present disclosure. In one embodiment, guide 350 is fixedly coupled to body 320. Bellows 360 (not shown in FIG. 3B) is coupled to guide 350 at its lower edge and to carrier 330 at its upper edge. In one embodiment, bellows 360 is constructed of a flexible material, e.g., silicone, rubber, or similar material, that resists compression and acts as a compression spring that applies a force separating carrier 330 and guide 350 along axis 336. In one embodiment, a spring is positioned between a movable element, e.g., carrier 330, and a fixed element, e.g., guide 350, and is configured to provide a monotonically increasing force along translation axis 336 to separate the movable and fixed elements.

[0064] In one embodiment, shaft 334 includes a nose 338 that is proximate to switch 342. In one embodiment, when sensor 310 is pressed against the patient's skin, carrier 330 (including shaft 334) is configured to move along axis 336 toward PCBA 344 until nose 338 contacts switch 342 and compresses switch 342 with sufficient pressure to close switch 342. In one embodiment, the capacitance measurement detected by sensor 310 occurs at a moment when applying a higher pressure on sensor 310 does not affect the capacitance measurement of sensor 310, such that the measurement is taken when the force first reaches a level sufficient to close switch 342.

[0065] 4A-4C illustrate a series of positional states that may be adopted by the portion of the scanner of FIG. 3C indicated by dashed circle 301, in accordance with the present disclosure.

[0066] 4A shows a first state of the configuration of scanner 300. In this first state, gap 335A between nose 338 and PCBA 344 has a first value. Switch 342 protrudes from the surface of PCBA 344 in the direction of nose 338, resulting in a smaller gap between switch 342 and nose 338. Flange 339 of carrier 330 contacts stop 352 of guide 350, which is the highest position of carrier 330 relative to guide 350.

[0067] Figure 4B shows a second state of the same scanner 300 of Figure 4A. A downward force is applied to carrier 330, causing carrier 330 to move downward toward PCBA 344. Gap 335B is smaller than gap 335A in Figure 4A, and switch 342 is under sufficient compression to electrically close switch 342. Further increases in applied force may cause carrier 330 to move further downward toward the surface of PCBA 344, but further compression of switch 342 does not affect the closure of switch 342. In this second state, flange 339 and stop 352 are not in contact with each other.

[0068] Figure 4C shows a third state of the same scanner 300 of Figure 4B after removing a portion of the force applied to separate nose 338 from switch 342 such that switch 342 is electrically open. In one embodiment, the third state is the same as the first state of Figure 4A, with flange 339 in contact with stop 352. In one embodiment, gap 335C is smaller than gap 335A, and there is a gap (not shown in Figure 4C) between flange 339 and stop 352.

[0069] 5 shows details of the construction of a biocapacitance scanner 500 according to the present disclosure. Scanner 500 has a head 525 comprising a sensor 510. In this embodiment, sensor 510 is mounted in a removable cap 512 that is removably coupled to a holder 540. In one embodiment, convex surface 532 of holder 540 has a radius of curvature "R" centered at center 538. In one embodiment, center 538 is on a surface of interface PCBA 550. In one embodiment, center 538 is on a surface of sensor 510. In one embodiment, center 538 is positioned on axis 526.

[0070] In one aspect, carrier 530 is constrained by guide mechanism 522 of body 520 to translate along axis 526. In one aspect, surface 532 of carrier 530 is concentric with surface 542, which has a radius of curvature slightly greater than R, thus allowing holder 540 to rotate about center 538 while maintaining partial contact between surfaces 532 and 542. Bellows 560 is flexible, allowing holder 540 to rotate about at least one of a first rotational axis 527 perpendicular to translational axis 526 and a second rotational axis 528 (not visible in FIG. 5 ) perpendicular to both translational axis 526 and first rotational axis 527. Because sensor 510 is secured to cap 512, which is also coupled to holder 540, rotation of holder 540 also rotates sensor 510. In one aspect, bellows 560 exerts a restoring rotational force on holder 540, guiding holder 540 back to a centered position relative to axes 527 and 528. In one aspect, this restoring rotational force increases monotonically with increasing rotational angle of holder 540 about one or both of axes 527 and 528.

[0071] FIG. 6 illustrates one embodiment of a visual indicator 627 according to the present disclosure. Body 620 includes a front portion 624 and a rear portion 626. In one embodiment, a translucent gasket 627 is positioned between front portion 624 and rear portion 626. In one embodiment, one or more light sources, e.g., one or more light-emitting diodes (LEDs), are positioned proximate the inside of gasket 627 such that, when the LEDs are activated, light from the LEDs passes through gasket 627, causing a portion of gasket 627 to appear to glow. This glowing mechanism is the visual indicator. In one embodiment, the LEDs are coupled to a processor (not visible in FIG. 6 ) of the scanner, which is also coupled to a switch, e.g., switch 342 of FIG. 4A . In one embodiment, the processor is configured to activate the LED, and thus the visual indicator, when switch 342 is closed. In one embodiment, the visual indicator is provided by internal illumination, e.g., a portion of body 620 illuminating from an internal LED.

[0072] FIG. 7A illustrates another embodiment of a biocapacitance scanner 700 according to the present disclosure. This embodiment includes a barcode scan engine 730 mounted within a body 720. The scan engine 730 includes an illuminator that emits radiation, e.g., in the frequency range of visible light, and an imager that is sensitive to radiation across the frequency range emitted by the illuminator. The body 720 includes a window 722 positioned so that a portion of the radiation projected by the illuminator passes outward through the window and the imager's field of view includes a portion of the window. In this manner, radiation from the illuminator can illuminate a machine-readable image printed on an object, e.g., a patient's wristband, and the imager can acquire an image of the object, e.g., a barcode. In other words, the scan engine 730 optically scans barcodes, 2D matrix codes, or other machine-readable encoded images. In one embodiment, the scan engine includes a signal processor that converts the image acquired by the imager into an alphanumeric string of characters. In one aspect, the scan engine 730 is coupled to a processor and provides the alphanumeric string to the processor, the processor being configured to receive the alphanumeric string from the scan engine. In one aspect, the alphanumeric string encodes one of a patient, a user, a consultation, an intervention, a wear element, a durability element, a location, and a time. In one aspect, the processor is further configured to receive a plurality of sequential alphanumeric strings. In one aspect, the processor is further configured to associate each of the sequential alphanumeric strings with one of a patient, a user, a consultation, an intervention, a wear element, a durability element, a location, and a time. In one aspect, the processor is further configured to associate a first alphanumeric string of the patient with the sequential alphanumeric string. In one aspect, the processor is further configured to transfer the associated alphanumeric string to a data system.

[0073] FIG. 7B shows an exploded view of a scanner 700 according to the present disclosure. The body 720 includes a front portion 721 and a rear portion 723, with a gasket 727 sandwiched between the front portion 721 and the rear portion 723 when they contact each other. In this embodiment, the front portion 721 is coupled to a guide 725, which is coupled to a bellows 726, and a carrier 728, which is coupled to the sensor 710. Two electrodes of the sensor 710 are coupled via electrical wires (not visible in FIG. 7B) to a device 744, e.g., a capacitance-to-digital converter (CDC), in this example, located on the main board 740. The device 744 is then communicatively coupled to a processor 742. The processor 742 is also coupled to a display 760, which may further comprise a touchscreen, via cables and wires (not visible in FIG. 7B). In one embodiment, the processor 742 may also be coupled to one or more of the barcode scan engine 730, a battery 764, a wirelessly powered receiving coil 766, and an audible indicator 768. In this embodiment, the audible indicator 768 is a piezoelectric buzzer. The display 760 is visible to the user through a transparent window 762 mounted within an opening in the front portion 721. The processor 744 is also operably coupled through a cable to a light emitting diode (LED) 752 mounted on the headboard 750 in this embodiment. The LED is positioned adjacent to the translucent gasket 727 so that when the scanner 700 is assembled, light from the LED 752 shines through the translucent gasket 727 to provide a visual indicator.

[0074] 8A shows a schematic diagram of a circuit 800 configured to implement the sigma-delta method of measuring capacitance according to the present disclosure. Because the sigma-delta method is well known to those skilled in the art and can be found in standard electrical engineering references, only a simplified description is provided here. In this diagram, the symbol [ka] represents a controllable switch. In one embodiment, the circuit 800 is part of another device, for example, the CDC 744 of FIG. 7B.

[0075] Voltage Reference V REF (+) and V REF (-) is connected to the reference capacitor C through the switch pair 850 REF and then coupled to a reference capacitor C REF is selectively coupled to either ground or the input of integrator 810. The operational configuration of these switches is described with reference to Figures 8C-8D. In this embodiment, an off-chip capacitor C SENSOR For example, a capacitor formed by the two electrodes of sensor 710 of scanner 700 of FIG. 7B is connected between a first terminal providing square wave excitation voltage 830 and the input of switch pair 854, which selectively couples the input to either ground or the input of integrator 810. The output of integrator 810 is coupled across integrating capacitor C INT and coupled to the input of comparator 820. The output of comparator 820 is provided to digital filter 840 to provide either a "0" or a "1" signal that controls the configuration of switch pair 850, as described with respect to Figures 8C-8D.

[0076] 8B illustrates the voltage state over a sample interval for the circuit of FIG. 8A in accordance with the present disclosure. The top line "ph1" indicates a configuration of switch pair 850, with a "1" configuration indicating V REF The switch connected to (+) is closed and V REF The bottom line "ph2" shows the configuration of switch pair 852, with a "1" configuration indicating that the switch connected to the input of integrator 810 is closed and the switch connected to ground is open, and a "0" configuration indicating vice versa.

[0077] Comparator 820 responds to the input voltage only when the "strobe" signal is "HI" and is inactive when the strobe signal is "LO." If the input is a positive voltage when the strobe is "HI," the output of comparator 820 is the voltage associated with a "1" state. If the input is a negative input when the strobe is "HI," the output is the voltage associated with a "0" state.

[0078] The sequence of states of circuit 800 during a single sampling cycle is as follows:

[0079] At time T0, as shown in Figure 8C, switch pair 850 is at a "1" state, while switch pairs 852 and 854 are in a "0" state, where the solid bars across the switch symbols indicate that the switches are closed. This state is maintained for a duration "D" long enough for the circuit voltage to settle to a steady state. During this time, C REF A charge Q1 is stored in C SENSOR A charge Q2 is stored in the capacitor. As Q=V×C, the amount of charge Q1 is REF (+) and C REF The value of Q1 is known because it is determined by the capacitance of the resistor C, both of which are known. Similarly, the value of Q2 is determined by the known excitation voltage 830 and the unknown capacitance C. SENSOR and is determined by.

[0080] At about time T1, switch pair 850 reverts to state "0," while the other switch pairs 852 and 854 remain in the "0" state. This buffer interval prevents both switches in each switch pair from conducting at the same time.

[0081] At time T2, switch pair 852 and 854 change to the "1" configuration, as shown in FIG. 8D, and shortly thereafter, charges Q1 and Q2 are both provided to the input of integrator 810. This configuration converts the reference capacitor C REF Let the known capacitance of C SENSORThe integrator 810 output is effectively compared to the unknown capacitance of Q1. If the sum of Q1 and Q2 is a positive voltage, i.e., greater than the ground connected to the other input of the comparator 810, the output of the integrator 810 will be negative. If the sum of Q1 and Q2 is a negative voltage, the output of the integrator 810 will be positive.

[0082] At time T3, the strobe goes high and comparator 820 may respond to its input voltage by changing its output to either a "1" or a "0". Over a series of sampling cycles, this creates a string of 1s and 0s as input to digital filter 840, which is processed within the filter to produce C SENSOR 7B, the digital value corresponding to the measured capacitance of the capacitor 742 is determined. This measurement may then be provided to an external device, such as the processor 742 of FIG. 7B.

[0083] 9A shows a hardware block diagram 900 for measuring the capacitance of a sensor 910 according to the present disclosure. The coupling of the sensor to a device 920, such as the CDC described with reference to FIG. 7B, can comprise an analog signal related to the capacitance measured by the sensor 910, as described with reference to FIGS. 8A-8D. A digital representation of the measured capacitance can be generated by an integrated circuit (IC) 2 C) It may be provided via communication line 925 to a host system 930, for example, processor 744 in FIG. 7B.

[0084] FIG. 9B shows a schematic diagram of an integrated system 950 for measuring, evaluating, storing, and transferring SEM values ​​according to the present disclosure. In this example, the system 950 includes a scanner 951 capable of wirelessly communicating with a WiFi access point 962, as discussed with respect to FIG. 7B. The scanner 951 may also communicate with one or more of an SEM application running on a server 960, an application running on a laptop computer 964, a smartphone 970, and other digital devices. In one aspect, the laptop computer 964 and the smartphone 970 are held by a user of the scanner 951, e.g., a nurse, and the application provides feedback and information to the user. In one aspect, information received from the scanner 951 regarding the patient is recorded in a database 954. In one aspect, the information received from the scanner 951 is transferred via a network 958 to another server 956, which stores a portion of the information in the patient's electronic health record (EMR) 952. In one embodiment, information from the scanner 951 or retrieved from the database 954 or EMR 952 is transferred to an external server 966 and then to a computer 968, for example, a computer in the office of a physician providing care for the patient.

[0085] 10 illustrates a workflow 1000 involving scanning primary and secondary barcodes in accordance with the present disclosure. The illustrated steps may be performed in any order, and any steps may be omitted or modified.

[0086] In this example, a first step 1010, 1020, and 1030 obtains identifying information associated with one or more of the patient, the caregiver, and the current date and time. In this example, this information is encoded in a barcode or other machine-readable image, such as a 2D matrix code, and obtained by scanning the barcode.

[0087] Step 1040 involves obtaining information, which may include, but is not limited to, physical examinations, health status, other measurements such as temperature or weight, and / or other physical artifacts such as photographs or data regarding nutritional intake and hydration. In this example, this information is obtained by scanning barcodes associated with various attributes, for example, a set of barcodes for each component of a meal where the user scans the barcodes for consumed items, or a series of barcodes for various amounts of liquid ingested. Step 1040 may also include scanning barcodes associated with other aspects of the patient's care, which may include, but are not limited to, barcodes associated with medications being administered to the patient, barcodes associated with gowns or other general clothing, equipment such as an intravenous (IV) pump being used to treat the patient, as well as barcodes associated with medical fluids or medications being administered with the IV pump, barcodes associated with treatment protocols, or other activities or items that can be identified with a machine-readable image, such as a barcode.

[0088] Step 1050 involves activities related to measuring subdural water (SEM) values ​​in a patient's body at various locations. Step 1050 includes multiple executable steps, shown in this example as steps 1051-1056. Step 1051 involves positioning a sensor, such as sensor 310 of scanner 300 of FIG. 3B, with first and second electrodes, such as electrodes 110 and 120 of FIG. 1A, against the patient's skin over an area of ​​tissue, such as the sacrum. Step 1052 involves increasing the pressure of the sensor on the patient's skin until an internal switch, such as switch 342 of FIG. 4B, closes, initiating step 1053 for recording the capacitance measured by the sensor. Step 1054 involves the user removing the sensor from the skin, thereby resetting the measurement circuitry. The user then decides, in step 1055, whether to take additional measurements or close the series of measurements at this location. In step 1056, the SEM measurements are transferred to a database that associates the capacitance measurements with the patient ID captured in step 1010. In one aspect, step 1056 may further include saving the data in non-volatile local memory. In one aspect, step 1056 may not save the data at all. In one aspect, step 1056 may further include saving other information obtained in one or more of steps 1010-1050 in a database or local memory.

[0089] Step 1060 involves branching activities depending on whether a treatment is being administered for this patient. These treatments may include, but are not limited to, the application of bandages, ointments, or other consumables, as well as the use of durable products such as foot orthotics or special mattresses. These treatments may also include, but are not limited to, manual treatments, such as repositioning the patient at two-hour intervals compared to the standard eight-hour interval. The treatment administered may be related to the tissue injury being assessed by the scanner, but does not exclude treatments related to other types of injury or health conditions. In step 1070, these treatments are identified, in this example, by scanning a barcode associated with starting, changing, or stopping a treatment. In step 1080, this information acquisition is repeated for all treatments.

[0090] While the present invention has been described with reference to particular embodiments, those skilled in the art will recognize that various modifications may be made and equivalents may be substituted for 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. Therefore, it is not intended that the invention be limited to the particular embodiments disclosed, but rather, the invention is intended to include all embodiments within the scope and spirit of the appended claims.

[0091] From the foregoing, it will be appreciated that the present disclosure can be embodied in a variety of ways, including but not limited to the following.

[0092] Embodiment 1: An apparatus for measuring biocapacitance of tissue, the apparatus comprising: a sensor having two electrodes; a movable element coupled to the sensor; a switch disposed between the movable element and the fixed element and configured to electrically close when a gap between the movable element and the fixed element is less than or equal to a predetermined value; a device coupled to the sensor and configured to perform a measurement of capacitance between the two electrodes; and a processor coupled to the switch and the device and configured to receive a measurement from the device when the switch is electrically closed.

[0093] Embodiment 2: The device of embodiment 1, wherein the electrodes are configured such that an electric field between the electrodes penetrates into the tissue when the sensor is positioned in proximity to the tissue.

[0094] Embodiment 3: An apparatus according to embodiment 1 or 2, wherein the device is configured to repeatedly measure the capacitance between the two electrodes at predetermined intervals.

[0095] Embodiment 4: A device described in any one of embodiments 1 to 3, wherein the sensor further comprises an insulating cover layer coupled to the electrode, the insulating cover layer configured to prevent conductive contact between the electrode and tissue when the sensor is positioned adjacent to the tissue.

[0096] Embodiment 5: A device according to any one of embodiments 1 to 4, wherein the measurement comprises comparing the capacitance between the electrodes with the capacitance of a reference capacitor.

[0097] Embodiment 6: The apparatus of embodiment 5, wherein the comparison comprises using a sigma-delta method to compare the capacitance between the electrodes with the capacitance of a reference capacitor.

[0098] Embodiment 7: The device of any one of embodiments 1 to 6, further comprising a visual indicator coupled to the processor, the processor further configured to activate the visual indicator upon closure of the switch.

[0099] Embodiment 8: A device described in any one of embodiments 1 to 7, wherein the movable element is configured to move along a translational axis relative to the fixed element, and the gap is disposed on the translational axis.

[0100] Embodiment 9: The device of embodiment 8, further comprising a spring positioned between the movable element and the fixed element and configured to provide a monotonically increasing force along the translational axis to separate the movable element and the fixed element.

[0101] Embodiment 10: The device described in embodiment 8, wherein the movable element is further configured to enable rotation about at least one of a first rotation axis that is perpendicular to the translation axis and a second rotation axis that is perpendicular to both the translation axis and the first rotation axis.

[0102] Embodiment 11: An apparatus described in any one of embodiments 1 to 10, wherein the processor is further configured to electrically open the switch after a first measurement value is received upon a first closure of the switch and before a second measurement value can be received.

[0103] Embodiment 12: An apparatus for measuring biocapacitance of tissue, the apparatus comprising: a sensor having two electrodes; a device coupled to the sensor and configured to perform a capacitance measurement between the two electrodes; a barcode scanning engine configured to optically scan a machine-readable image to determine a first alphanumeric string encoded in the machine-readable image; and a processor coupled to the device and the engine and configured to receive measurements from the device and receive the first alphanumeric string from the engine.

[0104] Embodiment 13: The device of embodiment 12, wherein the processor is further configured to receive a plurality of sequential alphanumeric strings and associate each of the sequential alphanumeric strings with one of a patient, a user, a consultation, an intervention, a wear element, a durability element, a location, and a time.

[0105] Embodiment 14: The device of embodiment 13, wherein the processor is further configured to associate the patient's first alphanumeric string with sequential alphanumeric strings.

[0106] Embodiment 15: The device of embodiment 13, wherein the processor is further configured to transfer the associated alphanumeric string to a data system.

[0107] Embodiment 16: A method for measuring biocapacitance of tissue, the method comprising: positioning a sensor having a first electrode and a second electrode against a patient's skin above the tissue; measuring capacitance between the two electrodes; optically scanning a primary machine-readable image associated with the patient; determining a primary alphanumeric string encoded in the primary machine-readable image; and associating the capacitance with the primary alphanumeric string.

[0108] Embodiment 17: The method of claim 16, further comprising: optically scanning one or more secondary machine-readable images associated with one of a user, an encounter, an intervention, a wear factor, a durability factor, a location, and a time; determining a respective encoded secondary alphanumeric string in each of the one or more secondary machine-readable images; and associating the secondary alphanumeric string with the primary alphanumeric string.

[0109] Embodiment 18: The method of claim 17, further comprising transmitting the primary alphanumeric string and the secondary alphanumeric string to a data system.

Claims

1. 1. An apparatus for measuring biocapacitance of tissue, said apparatus comprising: a sensor comprising two electrodes; a movable element coupled to the sensor; a switch disposed between the movable element and the fixed element, the switch being configured to electrically close when a gap between the movable element and the fixed element is equal to or smaller than a predetermined value; a device coupled to the sensor and configured to perform a measurement of capacitance between the two electrodes; a processor coupled to the switch and the device and configured to receive a measurement from the device when the switch is electrically closed.

2. The device of claim 1 , wherein the electrodes are configured such that an electric field between the electrodes penetrates into the tissue when the sensor is positioned proximate to the tissue.

3. The apparatus of claim 1 , wherein the device is configured to repeatedly measure the capacitance between the two electrodes at predetermined intervals.

4. 10. The device of claim 1, wherein the sensor further comprises an insulating cover layer coupled to the electrode, the insulating cover layer configured to prevent conductive contact between the electrode and the tissue when the sensor is positioned adjacent to the tissue.

5. The apparatus of claim 1 , wherein the measuring comprises comparing the capacitance between the electrodes to the capacitance of a reference capacitor.

6. 6. The apparatus of claim 5, wherein the comparison comprises using a sigma-delta method to compare the capacitance between the electrodes with the capacitance of the reference capacitor.

7. The apparatus of claim 1 , further comprising a visual indicator coupled to the processor, the processor further configured to activate the visual indicator upon closure of the switch.

8. the movable element is configured to move along a translational axis relative to the fixed element; The apparatus of claim 1 , wherein the gap is disposed on the translation axis.

9. 10. The apparatus of claim 8, further comprising a spring positioned between the movable element and the fixed element and configured to provide a monotonically increasing force along the translational axis to separate the movable element and the fixed element.

10. 9. The apparatus of claim 8, wherein the movable element is further configured to permit rotation about at least one of a first axis of rotation that is perpendicular to the translational axis and a second axis of rotation that is perpendicular to both the translational axis and the first axis of rotation.

11. 2. The apparatus of claim 1, wherein the processor is further configured such that after a first measurement is received upon a first closure of the switch, the switch is electrically opened before a second measurement can be received.

12. 1. An apparatus for measuring biocapacitance of tissue, said apparatus comprising: a sensor comprising two electrodes; a device coupled to the sensor and configured to perform a measurement of capacitance between the two electrodes; a barcode scan engine configured to optically scan a machine-readable image to determine a first alphanumeric string encoded in the machine-readable image; a processor coupled to the device and the engine, the processor configured to receive measurements from the device and receive the first alphanumeric string from the engine.

13. the processor: receiving a plurality of sequential alphanumeric strings; 13. The device of claim 12, further configured to associate each of the sequential alphanumeric strings with one of a patient, a user, a consultation, an intervention, a wear factor, a durability factor, a location, and a time.

14. the processor:

14. The device of claim 13, further configured to associate the first alphanumeric string of a patient with the sequential alphanumeric string.

15. the processor:

14. The apparatus of claim 13, further configured to transfer the associated alphanumeric string to a data system.

16. 1. A method for measuring biocapacitance of tissue, said method comprising: positioning a sensor comprising a first electrode and a second electrode against the patient's skin over the tissue; measuring the capacitance between the two electrodes; optically scanning a primary machine-readable image associated with the patient; determining an encoded primary alphanumeric string in the primary machine-readable image; and associating said capacitance with said primary alphanumeric string.

17. optically scanning one or more secondary machine-readable images associated with one of a user, an encounter, an intervention, a wear factor, a durability factor, a location, and a time; determining a respective encoded secondary alphanumeric string in each of the one or more secondary machine-readable images; 17. The method of claim 16, further comprising associating the secondary alphanumeric string with the primary alphanumeric string.

18. 18. The method of claim 17, further comprising transferring the primary alphanumeric string and the secondary alphanumeric string to a data system.

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