WO2018064569A1 - Moniteur de pression de contact et d'état de tissu à résolution de profondeur multimodale - Google Patents

Moniteur de pression de contact et d'état de tissu à résolution de profondeur multimodale Download PDF

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Publication number
WO2018064569A1
WO2018064569A1 PCT/US2017/054491 US2017054491W WO2018064569A1 WO 2018064569 A1 WO2018064569 A1 WO 2018064569A1 US 2017054491 W US2017054491 W US 2017054491W WO 2018064569 A1 WO2018064569 A1 WO 2018064569A1
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Prior art keywords
light
tissue
photodetector
sensor
emitting elements
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PCT/US2017/054491
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English (en)
Inventor
Warren S. Grundfest
George N. SADDIK
James Dunn
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The Regents Of The University Of California
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Publication of WO2018064569A1 publication Critical patent/WO2018064569A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/44—Detecting, measuring or recording for evaluating the integumentary system, e.g. skin, hair or nails
    • A61B5/441—Skin evaluation, e.g. for skin disorder diagnosis
    • A61B5/445—Evaluating skin irritation or skin trauma, e.g. rash, eczema, wound, bed sore
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/03—Detecting, measuring or recording fluid pressure within the body other than blood pressure, e.g. cerebral pressure; Measuring pressure in body tissues or organs
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A61B5/14552—Details of sensors specially adapted therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/1459—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters invasive, e.g. introduced into the body by a catheter
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/42—Detecting, measuring or recording for evaluating the gastrointestinal, the endocrine or the exocrine systems
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
    • A61B5/6885—Monitoring or controlling sensor contact pressure
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
    • A61B2562/04—Arrangements of multiple sensors of the same type
    • A61B2562/046—Arrangements of multiple sensors of the same type in a matrix array

Definitions

  • the properties inside a human tissue as well as how those properties vary over time can include information of great importance to a healthcare provider. For example, the concentration of hemoglobin, oxygenated or non-oxygenated, blood flow velocity, body temperature, and even change in size of the tissue, can all be relevant to a doctor's
  • the tissue of interest may not be easily accessible, as a tissue that is under a cast or beneath a bandage, or may be beneath a layer of skin that makes it difficult to evaluate the tissue visually or in a non-invasive manner.
  • Necrotizing enterocolitis is a life-threatening gastrointestinal disease most commonly found in neonates. There are approximately 40,000 babies that suffer from NEC every year, and another 400,000 at risk. NEC can be the result of a number of factors, including premature birth, low oxygen or intestinal blood flow, and heavy bacterial growth in the intestine. Any of these conditions can trigger an array of complications, ranging from necrosis and bowel perforation to gut ischemia. The clinical diagnosis for NEC is difficult due to nonspecific symptoms and great patient variation. Earlier detection of ischemia and necrosis in the bowel before perforation could greatly reduce the morbidity of the disease. Thus, quantitative approaches to prediction of NEC at earlier stages are needed.
  • a device for monitoring oxygenation of tissue comprises a tissue contact surface having disposed thereon a first photodetector, a contact pressure sensor, and a plurality of light sources.
  • the plurality of light sources is disposed in a predetermined configuration relative to the first photodetector.
  • Each of the plurality of light sources has an associated target depth.
  • the photodetector is adapted to receive light emitted from each of the plurality of light sources after propagating through tissue to the associated target depth.
  • the contact pressure sensor is adapted to measure contact pressure between the tissue contact surface and tissue.
  • a data connection is operably coupled to the first photodetector and the contact pressure sensor. The data connection is adapted to provide signals indicative of the received light and the measured contact pressure.
  • the first photodetector comprises a charge-coupled device, a photodiode, a phototransistor, or a photoresistor.
  • each of the plurality of light sources comprises a light-emitting diode.
  • each of the plurality of light sources is adapted to emit light at about a predetermined wavelength.
  • the predetermined wavelength is about 660nm or about 880nm.
  • the predetermined wavelength is between about 650nm and about 2500nm.
  • the predetermined wavelength is between about 650nm and about 1400nm.
  • the device includes an adhesive layer disposed on the tissue contact surface. In some embodiments, the device includes a retention band adapted to maintain contact between the tissue contact surface and tissue. In some embodiments, the device is flexible
  • the predetermined arrangement of the light sources is substantially hexagonal about the first photodetector. In some embodiments, the
  • predetermined arrangement is substantially linear, extending from the first photodetector.
  • the signals indicative of the received light are normalized based on the measured contact pressure.
  • the device includes at least one additional photodetector. In some embodiments, the device includes at least one one additional contact pressure sensor.
  • the device includes a visual pressure indicator adapted to indicate to a user when the contact pressure is between predetermined upper and lower thresholds.
  • the data connection comprises a wired connection. In some embodiments, the data connection comprises a wireless connection.
  • a method for monitoring oxygenation of tissue is provided.
  • a sensor device is brought into contact with a tissue.
  • the sensor device comprises a first photodetector, a contact pressure sensor, and a plurality of light sources.
  • the plurality of light sources is disposed in a predetermined configuration relative to the first photodetector.
  • Each of the plurality of light sources has an associated target depth.
  • Light is emitted from each of the plurality of light sources.
  • Light is measured at the photodetector from each of the plurality of light sources after propagating through tissue to the associated target depth. Based on the measured light and the measured contact pressure, an oxygenation of the tissue is determined at the associated target depth of each of the plurality of light sources.
  • the first photodetector comprises a charge-coupled device, a photodiode, a phototransistor, or a photoresistor.
  • each of the plurality of light sources comprises a light-emitting diode.
  • each of the plurality of light source emits light at about a predetermined wavelength.
  • the predetermined wavelength is about 660nm or about 880nm.
  • the predetermined wavelength is between about 650nm and about 2500nm.
  • the predetermined wavelength is between about 650nm and about 1400nm.
  • the sensor device further comprises an adhesive layer disposed on a tissue contact surface. In some embodiments, the sensor device is affixed to a tissue by the adhesive layer. In some embodiments, the sensor device is affixed to a tissue by a retention band. In some embodiments, the sensor device is flexible.
  • the predetermined arrangement of the light sources is substantially hexagonal about the first photodetector. In some embodiments, the
  • predetermined arrangement is substantially linear, extending from the first photodetector.
  • the measured light is normalized based on the measured contact pressure.
  • the sensor device further comprises at least one additional photodetector. In some embodiments, the sensor device further comprises at least one additional contact pressure sensor.
  • a visual pressure indicator is provided to a user when the contact pressure is between predetermined upper and lower thresholds.
  • the oxygenation of the tissue is sent via a wired connection. In some embodiments, the oxygenation of the tissue is sent via a wireless connection. In some embodiments, a 3D map of oxygenation is generated based on the oxygenation of the tissue at the associated target depth of each of the plurality of light sources.
  • a system for monitoring tissue at a plurality of depths can include a sensor strip, a data acquisition module and analysis software.
  • the sensor strip can have a first side including a first photodetector element, one or more force sensor elements, and a plurality of light-emitting elements, wherein the plurality of light- emitting elements are disposed in a predetermined configuration relative to the photodetector element.
  • the data acquisition module can be capable of being coupled to the sensor strip, wherein the data acquisition module is configured to control the sensor strip and store signals received from the light-emitting elements.
  • the analysis software can analyze and/or display the received signals.
  • the system can be adapted to be placed on the surface of a patient's skin, e.g., under a cast, splint, or dressing.
  • the sensor strip can be adapted to be placed over an area of a patient's body, e.g., that has suffered trauma.
  • each of the one or more force sensor elements is positioned in proximity to one of the plurality of light-emitting elements. In some embodiments, each of the one or more force sensor elements is positioned in proximity to a pair of the plurality of light-emitting elements. In some embodiments, the one or more force sensor elements and the plurality of light-emitting elements are arranged in a plurality of rows, each row having a predetermined number of the plurality of force sensor elements and a predetermined number of the plurality of light-emitting elements. In some embodiments, each of the plurality of rows comprises alternating force sensor elements and light-emitting elements. In some embodiments, each row has three of the one or more force sensors and two of the plurality of light-emitting elements
  • such systems can also include an analog-to-digital converter (ADC), wherein the system differentiates signals received from the light-emitting elements by using the ADC in conjunction with a first photodetector element, and activating only a subset (e.g., one) of the plurality of light-emitting elements at any single point in time.
  • ADC analog-to-digital converter
  • such systems can include processing circuitry configured to modulate and demodulate light emitted by the plurality of light-emitting elements.
  • the data acquisition module can include a sensor strip control unit configured to control the plurality of light-emitting elements and the first photodetector element.
  • the sensor strip control unit can be configured to generate a modulation sequence for each of the plurality of light-emitting elements that can be differentiated from the modulation sequence for each of the other light-emitting elements activated simultaneously with that light-emitting element.
  • a first photodetector element can be configured to detect only a specific wavelength that matches a wavelength of one or more of the plurality of light- emitting elements. In some such systems, all of the light-emitting elements emit substantially the same wavelength of light, or emit light across substantially the same range of
  • each of the plurality of light-emitting elements emits a different wavelength of light, or emits different ranges of wavelengths, in some cases, non-overlapping ranges of wavelengths.
  • the light-emitting elements can emit ultraviolet, visible, and/or near-infrared light. Any, some or all of the light emitting elements can be, for example, a light-emitting diode (LED), including a constant current LED.
  • LED light-emitting diode
  • such a system can include two or more photodetector elements.
  • a wavelength of light emitted by the light-emitting element(s) and detectable by the photodetector(s) can be selected to detect a chromophore of interest to be found in tissue to be monitored. Not all the photodetectors need be capable of detecting light selected to detect the chromophore of interest.
  • one or more photodetectors can be a photodiode or a phototransistor.
  • a sensor strip can include an ultrasound transducer and/or an ultrasound acquisition unit.
  • Such a sensor strip can include a plurality of ultrasound transducers, e.g., wherein each of the plurality of ultrasound transducers emits a different frequency.
  • a first side of the sensor strip can include at least one of electrical traces, electrical components, pressure sensors, and stretch sensors.
  • the sensor strip can also or alternatively include an accelerometer, gyroscope, and temperature sensor.
  • the sensor strip can also include one or more of analog signal processing circuitry, signal filtering circuitry, sensor-driving circuitry, analog-to-digital conversion circuitry, power supply circuitry, digital data processing circuitry, and data communication unit.
  • the first side of the sensor strip can include a connector for the data acquisition module.
  • the sensor strip can include a flexible substrate, optionally with a biocompatible adhesive. Such films include polyimide films or other similar flexible materials.
  • a data acquisition module can include signal-processing circuitry and communication modules.
  • the data acquisition module can be configured by the analysis software.
  • the data acquisition module can include a printed circuit board, battery pack, and/or an enclosure.
  • Such a printed circuit board can include at least one of power supply circuitry, a data communication unit, a wireless module, sensor strip control circuitry, a user interface control unit, and a power on/off control.
  • Such a printed circuit board can include at least one of a data-processing unit, an algorithm for data processing and analysis, embedded control software, and/or a memory unit.
  • Such a printed circuit board can include a connector for the sensor strip allowing the sensor strip to be operably connected to the data acquisition module.
  • Such a printed circuit board can include at least one of a visual status indicator, a visual alarm indicator, and an audio alarm indicator.
  • Such a printed circuit board can include a connector for a battery charger and wired communication.
  • analysis software is adapted to: view, download, store, and analyze data from the data acquisition module; or create and upload, into the data acquisition module, a data acquisition configuration file specific to a patient.
  • a configuration file can include, for example, a patient number, a length of a recording session, alarm threshold levels, and communication parameters.
  • a method of monitoring a patient can include 1) positioning the first side of a sensor strip of a system of any preceding claim adjacent to a tissue of a patient; 2) activating one or more light-emitting elements; 3) detecting light emitted by the activated elements to generate one or more signals representative of a characteristic of the tissue; and 4) processing the signals to determine the characteristic of the tissue.
  • the characteristic of the tissue can include one or more of: oxygenation state, levels of oxygenated and/or deoxygenated hemoglobin, ratio of oxygenated :deoxygenated hemoglobin, total hemoglobin level, carboxyhemoglobin level, tissue saturation, cardiovascular pulse,
  • hypovolemic/hypervolemic states muscle intracompartmental pressure, temperature, blood flow velocity, and change in size of tissue under observation.
  • a calibration pad can be used for calibrating a sensor strip.
  • the sensor strip can have a first side including a photodetector element and a plurality of light- emitting elements.
  • the calibration pad can include a test pattern within the calibration pad or on an exterior surface of the calibration pad, wherein the test pattern can be detected by one or more wavelengths of light.
  • the test pattern can detectable by positioning the sensor strip adjacent to a surface of the calibration pad, activating one or more of the light-emitting elements, detecting light emitted by the activated elements to generate one or more signals representative of a characteristic of the test pattern, and processing the signals to determine the characteristic of the test pattern.
  • Such calibration pads can be used to determine the positions of the light-emitting elements on the sensor strip relative to the photodetector by processing light emitted from the light-emitting elements, the light having interacted with the test pattern before being received by the photodetector element while the sensor strip is in photocommuni cation with the calibration pad.
  • such calibration pads can be part of a kit including the calibration pad with a sensor strip, a data acquisition module and analysis software as described above.
  • such a kit can be used for calibration by 1) positioning the first side of the sensor strip adjacent to and in photocommuni cation with a surface of the calibration pad, 2) activating one or more of the light-emitting elements, 3) detecting, with the first photodetector element, light emitted by the activated one or more light-emitting elements and reflected, refracted, or diffracted by the test pattern, thereby generating one or more signals representative of a characteristic of the test pattern, 4) storing a representation of the signals in the data acquisition module, and 5) by operation of the analysis software, comparing the stored representations to a template, thereby determining one or more response characteristics of the sensor strip. In some such methods, comparing the stored
  • representations to a template can include fitting the stored representations to predetermined signals representative of the test pattern, thereby determining the relative locations of the activated one or more light-emitting elements and the first photodetector.
  • Fig. 1 schematically shows potential paths taken by light propagating through tissue.
  • Fig. 2 schematically shows the locations of various components on a particular sensor strip having a single photodetector.
  • Fig. 3 schematically shows the locations of various components on a particular sensor strip having two photodetectors.
  • Fig. 4 schematically shows the locations of various components on a particular sensor strip having a single photodetector.
  • Fig. 5 schematically shows various parts that can make up a data acquisition module.
  • Fig. 6 depicts an exemplary sensor strip and data acquisition module.
  • Fig. 7 depicts an exemplary hard case device according to embodiments of the present disclosure.
  • Fig. 8 depicts an exemplary soft case device according to embodiments of the present disclosure.
  • Fig. 9 depicts an exemplary flexible strip device according to embodiments of the present disclosure.
  • Fig. 10 depicts an exemplary flexible strip device according to embodiments of the present disclosure.
  • Fig. 11 depicts an exemplary flexible strip device according to embodiments of the present disclosure.
  • Fig. 12 depicts an exemplary flexible strip device according to embodiments of the present disclosure.
  • Fig. 13 is a front view of an exemplary device for near-infrared spectroscopy (NIRS) according to embodiments of the present disclosure.
  • NIRS near-infrared spectroscopy
  • Fig. 14 is a side view of an exemplary device for near-infrared spectroscopy (NIRS) according to embodiments of the present disclosure.
  • NIRS near-infrared spectroscopy
  • Fig. 15 is a schematic block diagram of a near-infrared spectroscopy (NIRS) system.
  • NIRS near-infrared spectroscopy
  • Fig. 16 is an X-Ray image of an exemplary device of the present disclosure in use.
  • Fig. 17 is a graph presenting depth-resolved data illustrating optical readings by an exemplary embodiment of the present disclosure.
  • Fig. 18 is a graph presenting data collected using 660nm LEDs during an in-vivo ischemic animal model experiment.
  • Fig. 19 is a graph presenting data collected using 880nm LEDs during an in-vivo ischemic animal model experiment.
  • Fig. 20 depicts a computing node according to embodiments of the present disclosure.
  • devices that make use of Near Infrared Spectroscopy (RS) are provided for the detection of oxy- and deoxy- hemoglobin in tissue and with depth resolution. Because NEC is often a result of too little oxygen or blood flow to the intestine at birth, this issue can be identified using devices according to the present disclosure before bowel wall perforation. Devices according to the present disclosure obtain depth-resolved information regarding bowel tissue oxygen and hydration status in newborn babies and separates out the oxygenation of the abdominal wall form the bowel.
  • RS Near Infrared Spectroscopy
  • Near Infrared Spectroscopy is a non-invasive, non-ionizing imaging technique that uses light in the 650 nm to 2,500 nm region of the electromagnetic spectrum.
  • optical devices utilize what is known as the biologic window (i.e., "therapeutic window”). This window encompasses the light from about 600 nm to about 1400 nm.
  • Tissue proteins are relatively transparent at these wavelengths, with the exception of certain chromophores such as oxygenated and deoxygenated hemoglobin, melanin, fat, and water.
  • Light is highly scattered by the cells and organelles in tissues, as well as absorbed by certain chromophores. Understanding scattering, absorption, and penetration of light in tissue allows extraction of information from different tissue depths. Modeling tissue scattering and absorption helps analyze light being detected at the surface.
  • Multi -photon depth resolved tissue status and contact pressure monitor techniques use multiple wavelength LEDs to interrogate a target of interest and ascertain the oxygenation level through the detection and analysis of the received optical intensity modified by the properties of the tissue.
  • the received optical intensity is a function of the distance between the light source and the detector, and the physiologic or disease state of the tissue of interest.
  • Pressure sensors are also present to monitor and ensure appropriate contact between the LEDs, detector and the skin surface, and to ensure proper and constant contact between the optical detectors and the skin.
  • Various systems as set forth herein comprise a flexible substrate with an array of multiple wavelength LEDs and pressure sensors. Each LED is sequentially turned on/off by the accompanying electronics. The light travels through the targeted tissue and is detected by a photodetector. Depending on the physiological state of the tissue and the depth of penetration, this results in a variation in the detected optical intensity.
  • One or more pressure sensors are present in various embodiments to ensure the appropriate contact between the tissue surface, the photodetector and the LEDs.
  • contact pressure sensors or force sensors are suitable for use according to the present disclosure.
  • force collectors using piezoresistive strain gauge, capacitive force, electromagnetic force, piezoelectric, optical, and potentiometric approaches are known in the art.
  • any pressure/force sensor adapted to measure contact pressure between devices of the present disclosure and a subject at about atmospheric pressures is suitable.
  • photodetectors are suitable for use according to the present disclosure. Such sensors may be based on, for example, photoemission or photoelectric, photovoltaic, thermal, polarization, or photochemical mechanisms. For example, some embodiments include a charge-coupled device (CCD), a photodiode, a phototransistor, or a photoresistor.
  • CCD charge-coupled device
  • a visual indicator provides feedback to the user on the appropriate pressure range.
  • the visual indicator may include one or more lights, or a digital display. In some embodiments, three lights are included, one activating when pressure is below a predetermined lower threshold, one activating when pressure is above a
  • predetermined upper threshold and one activating when pressure is between the upper and lower thresholds.
  • the addition of the pressure sensors significantly improves consistency of tissue contact and removes variability in the pressure between the optical components and the tissue. While lack of contact may prevent accurate readings, excessive pressure may compress subject tissue, likewise resulting in inaccurate readings.
  • the optical emissions from the LEDs through the tissue are detected by a photodetector in intimate contact with the tissue.
  • a transimpedance amplifier is used to amplify the current produced by the photodetector and convert it to a voltage signal for processing by an analog digital converter (ADC).
  • ADC analog digital converter
  • the digital signals generated by the ADC are processed by a computer, and a percent oxygenation level may be displayed on a screen.
  • the pressure sensors are calibrated for the application and the measured pressure is processed by onboard electronics.
  • tissue sampling depth is defined by the photon-path-distribution function for photons migrating from a source to a detector on the surface of the skin.
  • the spatial photon distribution function has a banana-like shape. If one considers weak absorption within the tissue, then the banana-like shape of the photon propagation in tissue is approximated by Equation 1, which describes a curve of the most probable direction of photon migration. From Fig. 1 it is evident that the maximum sampled tissue depth, z max , occurs approximately at the mid-point between a light source (e.g. , LEDl, LED2, LED3) and a light detector (e.g.
  • Light-emitting diodes LEDl, LED2, and LED3 shown in Fig. 1 may or may not be of the same wavelength. Different surface positions of light-emitting elements such as LEDl, LED2, and LED3 with respect to a photodetector element affect sam ling from different tissue depths.
  • the present disclosure includes a portable, battery-operated, non-invasive, multimodal, depth-resolved, tissue status monitor.
  • Such monitors may include a multi-channel low-power depth-resolved near infrared spectroscopy module, ultrasound module, pressure sensors, temperature sensor, and stretch sensors. These physiological sensors, individually or in various different combinations, are used to obtain depth-resolved information about the tissue health status.
  • Some of the information that may be acquired from the patient to determine tissue health status include, but are not limited to: oxygenated and deoxygenated hemoglobin concentrations, total hemoglobin,
  • Some systems and methods of the present disclosure may be used to acquire and analyze signals representative of a physiological quantity, and to inform the clinician about the health status of tissues under observation.
  • a device is provided for use on the surface of the skin and placed under a cast or splint at the time of surgery to monitor tissue viability.
  • a patch such as a lightweight and/or adhesive patch, is placed over an area that has suffered trauma and the patch provides realtime physiologic monitoring data of the affected area and can be used as an acute
  • compartment syndrome detector or tissue flap monitor Some other examples where systems and methods of the present disclosure may be used include, but are not limited to: monitoring of tissue after vascular surgery; monitoring of lower or upper limb tissue viability during prolonged surgeries; or monitoring of skin flaps after mastectomy.
  • Certain monitors of the present disclosure allow the clinician to obtain depth-resolved information. This is useful, for example, in cases where tissue is very thin or consists of multiple layers. Such monitors can be set to allow differentiation of signals from different layers. Technology described herein is also capable of including a variety of other sensor modalities to complement this information.
  • a monitor consists of three main components: (1) a sensor strip to be placed on patient skin, the strip containing physiological and other sensors; (2) a data acquisition module, which contains signal processing circuitry as well as storage and communication modules; and (3) analysis software, which can be used to analyze signals collected from the sensor strip, to view and analyze patient data, and to configure the data acquisition module for different recording sessions.
  • the sensor strip can include a flexible substrate (e.g., polyimide film or similar material) with biocompatible adhesive on bottom side (toward patient skin) and electrical components, sensors, and electrical traces on the opposite side.
  • the sensor strip contains multiple pressure sensors, light sources (e.g., light-emitting diodes, LEDs), stretch sensors, and one or more photodetectors (e.g., photo diode, photo transistor).
  • Fig. 2 schematically shows a sensor strip 201 with a single photodetector (PD) 202.
  • PD photodetector
  • single or plural numbers of PDs may be used in different geometric configurations to obtain depth-resolved RS information from underlying tissues. Any photodetector capable of detecting the emitted light as it emerges from the tissue can be used. The number of photodetectors and light sources can depend on the clinical application.
  • Figs. 2-4 Examples of different geometric configurations are shown in Figs. 2-4.
  • Fig. 3 includes two photodetectors 302 on strip 301.
  • Fig. 4 includes one photodetector 402 on strip 401
  • Depth-resolved information may be obtained either using a single photodetector element and multiple light-emitting elements, or with multiple photodetector elements.
  • Embodiments having only a single photodetector typically make use of one or more methods of discriminating between the signals associated with different light-emitting elements. The following are examples of how to effect such discrimination. While some of the following methods apply only to single photodetector embodiments or multiple photodetector embodiments, other methods apply to both.
  • a single light-emitting element is turned on (i.e., emits light) at a single point in time. It may be desirable to convert an analog signal acquired by the photodetector element into a digital signal to facilitate a determination of which light- emitting element corresponds to the acquired signal.
  • the photodetector element may be used in conjunction with an analog-to-digital converter (ADC).
  • ADC analog-to-digital converter
  • Analog circuitry may be used to process the analog signal acquired by the photodetector element, and the ADC may digitize the analog signal into digital data for further analysis to determine which light- emitting element was on at which time.
  • a sensor strip control unit may be responsible for both emitter and photodetector/ ADC control.
  • light from the emitters may be modulated and then demodulated by processing circuitry.
  • each light-emitting element would have its own unique modulation sequence generated by a sensor strip control unit.
  • each photodetector element may detect only a specific wavelength that matches a specific emitter wavelength, or a single photodetector element may detect multiple wavelengths and distinguish each source light-emitting element based on the wavelength of the received signal.
  • any combination of the above techniques may be adopted in various embodiments e.g., turning on a subset of the light-emitting elements, each of the light-emitting elements having a unique modulation sequence relative to the other light-emitting elements activated at the same time; activating subsets of light-emitting elements such that each of the simultaneously-activated light-emitting elements emits a different wavelength; having the some light-emitting elements emit signals of the same wavelength, but using different modulation sequences for different emitters that are operating at the same wavelength; etc.
  • Light-emitting elements may be selected based on the clinical application of the monitor. For example, emitters having a particular output ⁇ e.g., emitted wavelength), or several emitters collectively having a range of wavelengths, may be selected depending on the specific chromophore of interest that is to be investigated. The selection of light-emitting elements may guide the selection of an appropriate photodetector element or elements. A photodetector element may be selected that best matches the output of the emitters ⁇ e.g., a detector that detects a particular wavelength or range of wavelengths), or that best matches only a subset of the emitters. A wide variety of light emitting elements is known in the art, and any appropriate light emitter may be used.
  • the sensor strip may include two or more photodetector elements. Multiple emitters and one or more detectors may be used in different
  • detectors and emitters could be arranged to probe only a narrow range of depths over a large area if the tissue to be investigated a relatively shallow, flap-type incision or wound.
  • the tissue is known to include a deep, generally vertical incision or wound, i.e., a cut that is along a plane perpendicular to the exterior surface of the tissue, a sensor strip with emitters and detectors may be arranged so as to probe a larger variety of depths along a single plane.
  • the sensor strip may include one or more ultrasound transducers.
  • a single ultrasound transducer may be sufficient. Multiple ultrasound transducers, however, may provide better depth-resolved information compared to a single transducer.
  • each transducer may emit a different frequency in order to preferentially obtain information from different depths of tissue (e.g., higher frequency transducers have shorter penetration depth but better resolution and vice versa).
  • the information from the ultrasound transducer(s) may be used to complement information obtained from light-emitting elements, or may be processed as a stand-alone modality. The ultrasound information is not necessary for operation of the light- emitting elements.
  • the ultrasound transducer module(s) are an optional part of the sensor strip depending on the clinical application of the device.
  • the sensor strip may include a single or plural number of
  • the sensor strip may contain analog signal processing circuitry, signal filtering circuitry, sensor driving circuitry, analog-to-digital conversion circuitry, power supply circuitry, an ultrasound acquisition unit, digital data processing circuitry, a data communication unit, and connector for operably connecting to a data acquisition module.
  • the sensors and electrical components may be placed in any number of geometric
  • the information from each sensor may be used individually or in combination with any or all other sensor data to monitor tissue viability, and/or tissue flap status, and detect acute compartment syndrome.
  • An operable connection between the sensor strip and the data acquisition module can be a wired connection or can be wireless.
  • a wired connection might be convenient where the sensor strip is placed on an in-patient or other person confined to a bed. Wireless connections between the various parts of the system may be preferable where the patient is mobile. However, even for mobile patients, a wired connection may be useful, since the entire system can be designed to be light-weight and easily transportable. Different portions of the system may be designed to be carried on the patient' s person.
  • the sensor strip itself may have a wireless connection to the rest of the system, in which case the patient need only keep the sensor strip.
  • the sensor strip can be wired to the data acquisition module where signals are stored.
  • the data acquisition module can include a wired or wireless connection to a computer on which analysis software can be executed.
  • the data acquisition module can store data on a removable memory medium, such as flash memory, which can then be physically removed to a computer that is not otherwise connected to the data acquisition module.
  • the data acquisition module can have a wired or wireless connection directly into a network, such as a LAN, so as to transmit received and stored data in real-time to a computer.
  • the data can be analyzed and compared to criteria designed to detect one or more pathologies in the patient's tissue. As described in more detail below, the analysis of the data can trigger an alarm if a criterion is met or if a pathology is detected or inferred.
  • a data acquisition module 500 can include a printed circuit board (flexible or solid), a primary or secondary battery pack, and an enclosure.
  • the printed circuit board can include power supply circuitry 501 (including, e.g., a battery charger 502), a data communication unit 503, a wireless module 504, sensor strip control circuitry 505, a user interface control unit 506, a data processing unit 507, memory media 508 (e.g., an SD card or other data storage unit, possibly removable), a connector 509 for the sensor strip, a visual status indicator(s) 510, a visual alarm indicator(s) 511, an audio alarm indicator 512, a power 'on/off control 513, and/or a connector 514 for battery charger and/or wired communication.
  • the above units such as the sensor strip control circuitry, the user interface control unit the data processing unit, and the memory media, are capable of storing software.
  • Such stored software can be used, for example, for data processing and/or analysis, or operational control and can include algorithms specific to those or other tasks.
  • a personal computer or similar mobile device is provided with analysis software that includes computer code programmed with a series of instructions that allow a user to view, download, store, and analyze data from the data acquisition module.
  • analysis software can be used to create and upload one or more data acquisition
  • configuration file may contain information such as, but not limited to, patient number, length of the recording session, alarm threshold levels, communication parameters and relevant elements of patient history.
  • a particular aspect of the present disclosure is the use of a series of emitters and at least one photodetector sensor to obtain depth-resolved information in a substrate, such as living tissue.
  • the emitters may be constant current LEDs and a detector is chosen to match the outputs of the LEDs. This unique combination of inputs and outputs is combined with geometric placement of the emitters on the sensor strip to achieve differentiation in signals from various tissue layers.
  • Monitors and systems disclosed herein can be used in a variety of methods. For example, in an exemplary method, a reusable or single-use sensor strip is attached to the patient skin and a data acquisition module is connected to the strip. A clinician or authorized person powers-up the data acquisition module and loads the appropriate data acquisition configuration file.
  • the data acquisition module initializes and verifies proper state of the sensors embedded in the sensor strip, for example by calibration as explained below. After the successful start-up, the data acquisition module goes into acquisition mode for the duration of a session (e.g., according to a predetermined acquisition routine or as determined by the clinician). Data acquired during the session may be stored onto a device-based memory medium for later retrieval and analysis. At the discretion of the clinician, real-time physiological data may be viewed on a designated platform via wireless or wired interface.
  • the data acquisition module may utilize an embedded processing unit to process the acquired physiological signals and determine if, for example, any of the pre-selected physiological abnormalities or conditions are present in tissues under observation. If no abnormalities are present, the unit does not alarm. If the algorithm determines that there may be an abnormality present, it alarms by either visual, audio, or both means.
  • An optional communication link may be established with a server at a healthcare center that would enable real-time viewing of patient acquired data by trained healthcare providers, or that may send an alarm signal or other appropriate notice to the patient's physician or other healthcare provider. For outpatients, if necessary, the monitoring center personnel may contact the patient and instruct them to call their clinician for follow-up or observation, or may contact the patient's physician or other healthcare provider directly.
  • data acquisition module finalizes the recorded data file on the local memory medium and then powers-down.
  • the clinician removes the sensor strip from the patient and either discards it (if it is a single-use strip) or disinfects it for the next patient (if a reusable strip).
  • the senor strip can be applied to a calibration pad. Data can be recorded, and characteristics of the calibration pad analyzed and compared to a template based on the calibration pad' s predetermined characteristics.
  • a device or kit includes a sensor strip, data acquisition module and receiver station.
  • the sensor strip can be either reusable or disposable.
  • the device may be used under a cast or dressings to monitor tissue viability. For example, if a patient has a complex lower limb fracture and a clinician is concerned about acute compartment syndrome, the device would be placed over the anterior compartment prior to casting or bandaging. The bandage or cast would be applied as usual and the data acquisition module would be monitored to provide real-time data. Depending on the condition of the patient, monitoring could be in real-time (e.g., continuous) or at various time increments.
  • inpatients data may be displayed on a monitor.
  • the technology allows for remote monitoring, for example over the Internet or a telephone line, allowing the clinician to obtain a range of physiologic data remotely. When the cast is removed the device can be recovered.
  • a calibration pad can be used to verify that the system is working properly before, after, and/or interleaved with data collection.
  • a calibration pad can be generally sized and shaped to be complementary to the sensor pad.
  • the calibration pad can include a test pattern in its interior or on its surface. The test pattern can be detectable in one or more wavelengths of light.
  • the calibration pad could have material with a first near infrared chromophore at a first depth and a second, different chromophore at a second different depth.
  • the calibration pad could have a wide variety of materials with different infrared properties throughout its interior and on its surface, e.g., arranged in a two or three-dimensional pattern, gradient or other suitable configuration.
  • the calibration pad can be used by positioning the sensor strip adjacent to the surface of the calibration pad, activating on or more light-emitting elements on the sensor strip, detecting light emitted by the activated light-emitting elements to generate one or more signals representative of the test pattern, and processing the signals to determine a
  • the characteristic could be, for example, a particular near infrared spectral response at a first depth within the calibration pad and a second, distinct near infrared spectral response at a second depth, for example on the surface of the calibration pad.
  • the calibration pad can include a test pattern that is designed to allow for
  • the sensor pad can be positioned on the calibration pad with light emitting element(s) and photodetector(s) facing the calibration pad, light emitting elements on the sensor pad activated, emitted light detected by a photodetector or photodetectors on the sensor strip, and the detected light translated in to signals that are transmitted to a data acquisition module or other processor where a representation of the signals is stored.
  • the stored representations can then be compared to a template based on the predetermined properties of the calibration pad, thereby determining one or more response characteristics of the sensor strip, or other component of the above system.
  • test pattern can have a predetermined form
  • analysis of the signals can be used to determine the location of a photodetector and/or light emitting elements of the sensor pad relative to the test pattern on the calibration pad, and thus to each other.
  • the detected characteristics of the calibration pad can also be used to determine other properties of a photodetector and light emitting elements, such as brightness or sensitivity.
  • a wide variety of characteristics of the system can be characterized and the system calibrated by comparing the known,
  • predetermined properties of the test pattern to how the test pattern is actually detected.
  • Comparing the data collected on the calibration pad to a template of the calibration pad can include, for example, determining how to best fit a predetermined model response function to the data, and inferring from that best fit the properties of the sensor strip and its components and/or other elements of the system.
  • the system can interpret the signals stored by the data acquisition module.
  • knowing how far a particular light emitter is from a particular photodetector is important in understanding what depth of tissue is being probed by the detected light.
  • the user can allow the software to take into account ordinary variations in the sizes and shapes of sensor strips. Such variations could result from differences within manufacturing tolerances, deformation (e.g., stretching) of the sensor strip over time, or other causes and need not be representative of any sort of defect.
  • any of a calibration pad, a sensor strip, a data acquisition module, and relevant software can be combined in a kit.
  • the kit can then be used as explained above to calibrate the response of the sensor strip, data acquisition module and/or software package.
  • the device of the present disclosure is applicable to all limbs and anywhere a cast or dressings are placed, in addition to other applications mentioned previously (e.g., tissue flaps, vascular surgery, etc.).
  • FIGs. 7-12 further embodiments of multi-modal depth- resolved tissue status monitors are illustrated.
  • various of these further embodiments include pressure sensors.
  • Combining near infrared technology according to the present disclosure with pressure sensing technology ensures proper contact between the optical sensor and the patient. Without combined pressure and optical data, inaccuracies may be introduced that lead to false positives and false negatives. Thus, combining both sensors improves performance. This improved performance significantly increases the utility of RS systems for monitoring the neonatal patient.
  • RS is a non-invasive, non-ionizing, harmless, imaging technique that uses light in the 650 nm to 2500 nm region of the electromagnetic spectrum.
  • Devices according to the present disclosure include wearable, portable embodiments that can be used for specifically providing depth resolved tissue measurements.
  • signals coming from the abdominal wall and the gut are differentiable.
  • information may be provided to the clinician regarding gut function based on the optical signals obtained through the abdominal wall.
  • the pressure sensors insure that the contacts are consistent over time. Without pressure sensors, readings may be variable and thus difficult to interpret.
  • devices according to the present disclosure are held in place by a Velcro sleeve that wraps around the abdomen of a patient. This may be either a thin strip or wide wrap or some combination of the two. Monitoring devices and techniques according to embodiments of the present disclosure are useful both as an initial diagnostic tool and as a method for following gut function post-operatively.
  • a hard case device 700 according to embodiments of the present disclosure is depicted.
  • Such a device includes at least one LED, a light sensor, and a pressure sensor.
  • Such a device may have a curvature suitable for applicant to the abdomen of a neonate.
  • a band is provided for holding device 700 flush with a patient' s body.
  • the band is elastic to ensure intimate contact between the light emitting components and the body.
  • an adjustable strap is provided.
  • the strap includes an adjustable connection such as Velcro.
  • a hard case device 800 includes at least one LED, a light sensor, and a pressure sensor.
  • a device may be flexible, allowing the device to conform to a range of abdominal curvatures in order to accommodate a range of abdomen sizes and patient ages.
  • a band is provided for holding device 800 flush with a patient's body.
  • the band is elastic to ensure intimate contact between the light emitting components and the body.
  • an adjustable strap is provided.
  • the strap includes an adjustable connection such as Velcro.
  • a flexible strip device 900 includes at least one LED, a light sensor, and a pressure sensor. Each component is arrayed on a flexible substrate, such as for example plastic substrates, such as polyimide, PEEK or transparent conductive polyester film. Such a device is lightweight, and may be attached directly to the abdomen using adhesive coating a portion of the substrate or by surgical tape or dressings.
  • one or more pressure sensor is paired with each LED. This configuration enables fine-grained correction to the data collected. In particular, by recording the pressure near to each LED, each individual light signal may be corrected separately for variable pressure.
  • feedback may be provided to a user at data collection time as to the degree of contact between the device and the patient. In some embodiments. The feedback comprises a light or audible signal that the pressure is too high or too low.
  • a schematic view of the device is presented to the user to indicate which portions of the device are in good contact, and which portions have a pressure out of the best operating range.
  • a pressure indicator is triggered when the pressure is outside of a given ideal operating range.
  • data that is within a correctable range may be corrected in post processing, while a user is prompted to take new readings or to adjust the device pressure at read time when the pressure is outside of the optimal range.
  • Feedback may be provided to a user throughout the examination procedure, to allow on the fly adjustments to device contact.
  • FIG. 10 an exemplary layout of sensors on a skin contact surface 1001 is depicted.
  • a plurality of rows 1011...1019 of LEDs and force sensors are provided.
  • Each row includes a Red LED 1002 and an IR LED 1003 separated by force sensors 1005, 1006, 1007.
  • a PEST photodetector 1007 is adapted to receive light emitted by the LEDs as set forth in further detail above.
  • LEDs 1002, 1003 measure about 2.0 x 1.2 x 0.76mm.
  • force sensors 1004, 1005, 1006 measure about 5.1 x 4.6 x 1.1mm.
  • PIN photodetector 1007 measures about 4.5 x 4.0 x 1.2mm.
  • FIG. 11 an exemplary layout of sensors on a skin contact surface 1101 is depicted.
  • a plurality of rows 1111...1119 of LEDs and force sensors are provided.
  • Each row includes integrated duel LED comprising Red LED portion 1102 and IR LED portion 1103 flanked by force sensors 1104, 1106.
  • a PIN photodetector 1107 is adapted to receive light emitted by the LEDs as set forth in further detail above.
  • integrated LED 1002, 1003 measures about 5.7 x 5.7x 1.5mm.
  • force sensors 1004, 1005, 1006 measure about 5.1 x 4.6 x 1.1mm.
  • PIN photodetector 1107 measures about 4.5 x 4.0 x 1.2mm.
  • FIG. 12 an exemplary layout of sensors on a skin contact surface 1201 is depicted.
  • a plurality of rows 1211...1219 of LEDs and force sensors are provided.
  • Each row includes an integrated component comprising Red LED 1202, IR LED 1203, and force sensor 1006.
  • a PIN photodetector 1207 is adapted to receive light emitted by the LEDs as set for in further detail above. In some embodiments, PIN photodetector 1207 measures about 4.5 x 4.0 x 1.2mm.
  • LEDs are suitable for use according to the present disclosure.
  • the distance between a given LED and the photodetector determines the amount of light reaching the photodetector (as illustrated by the graphs in Fig. 1).
  • LEDs may be activated one at a time (or several at a time) on a rolling basis, thereby taking measurements at different depths in sequence.
  • a 3D image may be reconstructed.
  • a comprehensive 3D image over a broad area such as the entire abdomen many be generated.
  • Various embodiments use hexagonal patterns of LEDs, circular patterns of LEDs, or grids of LEDs.
  • some embodiments use a flexible array of LEDs, such as that used in an LED display. Using a high-resolution grid of LEDs in this manner, a large number of readings at multiple depths may be collected.
  • the LEDs have an intensity that is dynamically configurable.
  • the intensity of each LED may be determined based on a calibration routine, such as those described above. Calibration data may be stored, enabling
  • Standard calibration profiles may be provided for various age ranges or physical attributes in order to shorten or eliminate the calibration process for a given subject. By reducing or increasing the intensity of a given LED, the amount of light, and therefore the saturation of the photodetector may be controlled.
  • various embodiments include a pressure sensor, which allows correction of the data for variations in applied pressure, such as that resulting from
  • pressure is evaluated and the baseline is reset when pressure stabilizes.
  • data are discarded when the pressure exceeds
  • the correlation between pressure and signal is determined in real time, and the signal is normalized to a predetermined pressure.
  • signal intensity is converted to an absolute oxygenation measurement.
  • the blood oxygenation values may be compared to existing clinical guidelines in order to arrive at a disease indication.
  • a form factor of a RS NEC device is illustrated.
  • device 1300 is adapted to be hand-held, and placed against a subject for data gathering.
  • planar patient-contact surface 1301 includes a plurality of LEDs 1302 and a photodetector 1303.
  • Device 1300 includes wired connection 1303 to receive control signals and to send data.
  • control signals may include indications to switch on or off individual LEDs, or to control wavelength or intensity of individual LEDs.
  • output signals may include intensity measurements collected by photodetector 1303.
  • LEDs 1302 are divided among two rows radiating from photodetector 1303.
  • the LEDs in one row emit light at about 660nm (red), while the LEDs in the other row emit light at about 880nm (NIR).
  • NIR 880nm
  • FIG. 14 a side view of device 1300 is shown.
  • Substantially cylindrical body 1305 is adapted to be held by a clinician. It will be appreciated that variety of form factors for body 1305 are suitable, for example a wand or handle.
  • System 1500 includes one or more optical sensor modules 1501. Each senor module includes at least one photodetector 1510 and at least one LED 1511...1518. Various exemplary embodiments of an optical sensor module are illustrated in prior figures.
  • Optical sensor module 1501 is operably coupled to data acquisition module 1502 by data connection 1504.
  • sensor module 1501 and data acquisition module 1502 are combined in a single case, such as a wearable sensor or a hand-held wand.
  • the data acquisition module is separated from the sensor module, for example allowing the sensor module to be affixed to a subject while the data acquisition module is held.
  • data connection 1504 is a wired connection, while in some embodiments data connection 1504 is a wireless connection.
  • LAN local area network
  • PAN personal area network
  • Suitable wireless technologies may use, e.g. , radio or light to communicate wirelessly.
  • a plurality of sensor modules 1501 can communicate with a single data acquisition module.
  • a plurality of sensor modules are affixed to a single patient.
  • the data acquisition module collects and aggregates the data received from these multiple sensor modules for further processing.
  • data acquisition module 1502 includes 1521 analog circuity for interfacing with the components of sensor module 1501.
  • analog circuitry 1502 may instead be included in optical sensor module 1501, and converted to digital form prior to transmission via connection 1504. Accordingly, connection 1504 may be digital or analog according to various embodiments.
  • data acquisition module 1502 includes a microcontroller 1525.
  • Microcontroller 1525 is operably coupled to analog circuitry 1521, and in various embodiments provides digital-to-analog conversion (DAC) and/or analog-to-digital conversion (ADC).
  • DAC digital-to-analog conversion
  • ADC analog-to-digital conversion
  • Microcontroller 1525 may also include a digital signal processor (DSP) and a communication interface.
  • DSP digital signal processor
  • Data acquisition module 1502 may be operably coupled to a computing node such as a personal computer 1503 via data connection 1505.
  • data connection 1505 is a wired connection, while in some embodiments data connection 1505 is a wireless connection.
  • the connected computing node may provide storage, display, and analysis of data collected. However, it will be appreciated that these functions may be separated among multiple computing nodes, for example a database server providing data storage, a web browser providing display, and an application server providing data analysis. It will be appreciated that these various functions may be provided via a cloud architecture.
  • NIRS near infrared spectroscopy
  • the RS system in this test consists of an optical sensor module, data acquisition and processing module, and a PC computer used for real-time data display, analysis, and storage.
  • the system consists of a custom-made optical sensor module, data acquisition unit, and a laptop PC.
  • a custom-made optical sensor module At the heart of the system is an ultra-low power microcontroller, MSP430- family by Texas Instruments.
  • MSP430 family was selected because of its ultra-low power requirements and processing capabilities.
  • the MSP430G461x was selected for the initial prototype.
  • This MSP430 device features a 16-bit RISC CPU, a high performance 12 channel 12-bit AID converter (with 610 ⁇ LSB) and one universal synchronous/asynchronous communication interface (USART). Digitized data is sent to the PC in binary format using the serial communication protocol.
  • Serial communication protocol i.e., serial port profile, SPP
  • SPP serial port profile
  • the MSP430FG461x series supports a liquid crystal display (LCD) option with its integrated LCD driver.
  • the system was designed to obtain information about various tissue chromophores at varying tissue depths. This has been achieved by using multiple source-detector distances to collect reflected light. Light obtained from a near source-detector pair samples tissue closer to the surface, while the light obtained from the source-detector pairs several centimeters apart is able to sample deeper sections of tissue. Understanding the results from these optodes requires careful modeling and algorithm development to interpret the data (see below).
  • the optical sensor module contains light sources, LEDs, and a photodetector, PD. The optical signal strength at the detector position on the surface of the skin is expected to be on the order of pico- to micro-watts, which depends on the actual radiant intensity of the source.
  • the initial system requirements were based on a need for a fully portable (i.e., light weight), compact multi-channel system capable of 36 hours standby time, 12 hours of continuous RS data acquisition at 20 samples per second using 700 mAh rechargeable lithium-polymer battery.
  • the sampling rate was based on the work by Saager, who found that 20 Hz offers more than sufficient sampling rate for characterizing hemodynamic fluctuations, which mostly occur in single- to sub-Hz range.
  • the current consumption in the ready (i.e., standby) mode would need to be 19 mA and 58 mA in the active mode.
  • the system would need to display multi -channel realtime acquired data and save it to the PC hard drive for offline analysis.
  • the initial version of the PC software for RS data acquisition, display, and storage utilizes custom-designed application developed with Microsoft® DirectX® technology.
  • the application is capable of displaying up to 64 channels of data with various user-configurable parameters such as display scale, signal grouping, and displayed data color.
  • display scale e.g., portrait
  • signal grouping e.g., textual data
  • displayed data color e.g., textual data
  • the acquired data is saved to a local hard drive for off-line analysis.
  • Initial signal processing algorithms have been developed and will be optimized pending the results of our clinical trials.
  • a NIRS NEC device according to an embodiments of the present disclosure was used in an in-vivo ischemic animal model experiment.
  • an X-ray image is provided of the procedure in progress.
  • a balloon catheter 1601 was placed to occlude blood flow to a segment of the intestines of the animal subject.
  • the sensor device 1602 (described in further detail above with regard to Figs. 13- 14), was placed in contact with the abdomen of the animal subject, and data was collected.
  • FIG. 17 depth resolved data is presented, illustrating optical reading from the gut and abdominal wall of a healthy animal (without occlusion).
  • LEDs are numbered based on proximity to the photodetector, with LEDi being closest to the photodetector.
  • NIRS NEC detector has five 660nm LEDs. LEDi is closest to the photodetector, thus having the shallowest penetration depth, and LEDs is the furthest from the photodetector, thus having the deepest penetration depth.
  • the balloon catheter was inflated and the blood flow was occluded.
  • t 2 lOOsec
  • the balloon was deflated and the oxygenation returned to baseline.
  • t 3 500secs, the balloon was inflated again.
  • Fig. 19 data collected from 880nm LEDs during the in-vivo ischemic animal model experiment are shown.
  • the NIRS NEC detector has five 880nm LEDs. LEDi is closest to the photodetector, thus having the shallowest penetration depth, and LEDs is the furthest from the photodetector, thus having the deepest penetration depth.
  • the balloon catheter was inflated and the blood flow was occluded.
  • t 2 lOOsec the balloon was deflated and the oxygenation returned to baseline.
  • t 3 500secs, the balloon was inflated again.
  • FIG. 20 a schematic of an example of a computing node is shown.
  • Computing node 10 is only one example of a suitable computing node and is not intended to suggest any limitation as to the scope of use or functionality of embodiments of the invention described herein. Regardless, computing node 10 is capable of being implemented and/or performing any of the functionality set forth hereinabove.
  • computing node 10 there is a computer system/server 12, which is operational with numerous other general purpose or special purpose computing system environments or configurations.
  • Examples of well-known computing systems, environments, and/or configurations that may be suitable for use with computer system/server 12 include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments that include any of the above systems or devices, and the like.
  • Computer system/server 12 may be described in the general context of computer system-executable instructions, such as program modules, being executed by a computer system.
  • program modules may include routines, programs, objects, components, logic, data structures, and so on that perform particular tasks or implement particular abstract data types.
  • Computer system/server 12 may be practiced in distributed cloud computing environments where tasks are performed by remote processing devices that are linked through a communications network.
  • program modules may be located in both local and remote computer system storage media including memory storage devices.
  • computer system/server 12 in computing node 10 is shown in the form of a general-purpose computing device.
  • the components of computer system/server 12 may include, but are not limited to, one or more processors or processing units 16, a system memory 28, and a bus 18 that couples various system components including system memory 28 to processor 16.
  • Bus 18 represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures.
  • bus architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.
  • ISA Industry Standard Architecture
  • MCA Micro Channel Architecture
  • EISA Enhanced ISA
  • VESA Video Electronics Standards Association
  • PCI Peripheral Component Interconnect
  • Computer system/server 12 typically includes a variety of computer system readable media. Such media may be any available media that is accessible by computer system/server 12, and it includes both volatile and non-volatile media, removable and non-removable media.
  • System memory 28 can include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and/or cache memory 32.
  • RAM random access memory
  • cache memory 32 can include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and/or cache memory 32.
  • Computer system/server 12 may further include other removable/non-removable,
  • storage system 34 can be provided for reading from and writing to a non-removable, non-volatile magnetic media (not shown and typically called a "hard drive”).
  • a magnetic disk drive for reading from and writing to a removable, non-volatile magnetic disk (e.g., a "floppy disk")
  • an optical disk drive for reading from or writing to a removable, non-volatile optical disk such as a CD-ROM, DVD-ROM or other optical media
  • each can be connected to bus 18 by one or more data media interfaces.
  • memory 28 may include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions of embodiments of the invention.
  • Program/utility 40 having a set (at least one) of program modules 42, may be stored in memory 28 by way of example, and not limitation, as well as an operating system, one or more application programs, other program modules, and program data. Each of the operating system, one or more application programs, other program modules, and program data or some combination thereof, may include an implementation of a networking environment.
  • Program modules 42 generally carry out the functions and/or methodologies of embodiments of the invention as described herein.
  • Computer system/server 12 may also communicate with one or more external devices 14 such as a keyboard, a pointing device, a display 24, etc.; one or more devices that enable a user to interact with computer system/server 12; and/or any devices (e.g., network card, modem, etc.) that enable computer system/server 12 to communicate with one or more other computing devices. Such communication can occur via Input/Output (I/O) interfaces 22. Still yet, computer system/server 12 can communicate with one or more networks such as a local area network (LAN), a general wide area network (WAN), and/or a public network (e.g., the Internet) via network adapter 20. As depicted, network adapter 20 communicates with the other components of computer system/server 12 via bus 18.
  • LAN local area network
  • WAN wide area network
  • public network e.g., the Internet
  • Various embodiments of the present disclosure may include a system, a method, and/or a computer program product.
  • a computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention.
  • the computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device.
  • the computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing.
  • a non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD- ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing.
  • RAM random access memory
  • ROM read-only memory
  • EPROM or Flash memory erasable programmable read-only memory
  • SRAM static random access memory
  • CD- ROM compact disc read-only memory
  • DVD digital versatile disk
  • memory stick a floppy disk
  • a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon
  • a computer readable storage medium is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiberoptic cable), or electrical signals transmitted through a wire.
  • Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network.
  • the network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers.
  • a network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.
  • Computer readable program instructions for carrying out operations of the present disclosure may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages.
  • the computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server.
  • the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
  • electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present disclosure.
  • These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for
  • These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks.
  • the computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks.

Abstract

Les propriétés internes d'un tissu humain ainsi que la façon dont ces propriétés varient dans le temps peuvent contenir des informations de grande importance pour un prestataire de soins de santé. Dans certains cas, le tissu d'intérêt peut ne pas être facile d'accès, tel qu'un tissu situé sous un plâtre ou sous un bandage, ou encore sous une couche de peau qui rend l'évaluation du tissu difficile à l'œil nu ou d'une manière non invasive. Les systèmes et les procédés de l'invention concernent la surveillance de tissus à une pluralité de profondeurs, et sont utiles pour la prédiction de NEC chez des nouveaux-nés à des stades précoces.
PCT/US2017/054491 2016-09-30 2017-09-29 Moniteur de pression de contact et d'état de tissu à résolution de profondeur multimodale WO2018064569A1 (fr)

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CN109464125A (zh) * 2018-12-27 2019-03-15 高腾飞 一种能够无线充电的组织状况监测系统
CN109549633A (zh) * 2018-12-27 2019-04-02 高腾飞 一种连续监测受试者的组织状况的监测系统
US11076997B2 (en) 2017-07-25 2021-08-03 Smith & Nephew Plc Restriction of sensor-monitored region for sensor-enabled wound dressings
GB2595778A (en) * 2020-06-01 2021-12-08 M2Jn Ltd Sensor and methods for sensing the oxygenation of tissue
US11324424B2 (en) 2017-03-09 2022-05-10 Smith & Nephew Plc Apparatus and method for imaging blood in a target region of tissue
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US11717447B2 (en) 2016-05-13 2023-08-08 Smith & Nephew Plc Sensor enabled wound monitoring and therapy apparatus
US11324424B2 (en) 2017-03-09 2022-05-10 Smith & Nephew Plc Apparatus and method for imaging blood in a target region of tissue
US11690570B2 (en) 2017-03-09 2023-07-04 Smith & Nephew Plc Wound dressing, patch member and method of sensing one or more wound parameters
US11883262B2 (en) 2017-04-11 2024-01-30 Smith & Nephew Plc Component positioning and stress relief for sensor enabled wound dressings
US11791030B2 (en) 2017-05-15 2023-10-17 Smith & Nephew Plc Wound analysis device and method
US11633153B2 (en) 2017-06-23 2023-04-25 Smith & Nephew Plc Positioning of sensors for sensor enabled wound monitoring or therapy
US11638664B2 (en) 2017-07-25 2023-05-02 Smith & Nephew Plc Biocompatible encapsulation and component stress relief for sensor enabled negative pressure wound therapy dressings
US11076997B2 (en) 2017-07-25 2021-08-03 Smith & Nephew Plc Restriction of sensor-monitored region for sensor-enabled wound dressings
US11925735B2 (en) 2017-08-10 2024-03-12 Smith & Nephew Plc Positioning of sensors for sensor enabled wound monitoring or therapy
US11759144B2 (en) 2017-09-10 2023-09-19 Smith & Nephew Plc Systems and methods for inspection of encapsulation and components in sensor equipped wound dressings
US11931165B2 (en) 2017-09-10 2024-03-19 Smith & Nephew Plc Electrostatic discharge protection for sensors in wound therapy
US11633147B2 (en) 2017-09-10 2023-04-25 Smith & Nephew Plc Sensor enabled wound therapy dressings and systems implementing cybersecurity
US11957545B2 (en) 2017-09-26 2024-04-16 Smith & Nephew Plc Sensor positioning and optical sensing for sensor enabled wound therapy dressings and systems
US11596553B2 (en) 2017-09-27 2023-03-07 Smith & Nephew Plc Ph sensing for sensor enabled negative pressure wound monitoring and therapy apparatuses
US11839464B2 (en) 2017-09-28 2023-12-12 Smith & Nephew, Plc Neurostimulation and monitoring using sensor enabled wound monitoring and therapy apparatus
US11559438B2 (en) 2017-11-15 2023-01-24 Smith & Nephew Plc Integrated sensor enabled wound monitoring and/or therapy dressings and systems
US11944418B2 (en) 2018-09-12 2024-04-02 Smith & Nephew Plc Device, apparatus and method of determining skin perfusion pressure
CN109044384A (zh) * 2018-09-26 2018-12-21 苏州大学附属第二医院 肢体肌肉软组织压力无创监测装置及监测方法
US11969538B2 (en) 2018-12-21 2024-04-30 T.J.Smith And Nephew, Limited Wound therapy systems and methods with multiple power sources
CN109549633A (zh) * 2018-12-27 2019-04-02 高腾飞 一种连续监测受试者的组织状况的监测系统
CN109464125A (zh) * 2018-12-27 2019-03-15 高腾飞 一种能够无线充电的组织状况监测系统
CN109549633B (zh) * 2018-12-27 2021-06-29 南华大学附属南华医院 一种连续监测受试者的组织状况的监测系统
WO2021245406A1 (fr) * 2020-06-01 2021-12-09 M2JN Limited Capteur et procédés de détection de l'oxygénation d'un tissu
GB2595778A (en) * 2020-06-01 2021-12-08 M2Jn Ltd Sensor and methods for sensing the oxygenation of tissue

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