WO2015123606A2 - Procédé et appareil permettant une surveillance optique en temps réel et non invasive d'un état de mal de décompression - Google Patents

Procédé et appareil permettant une surveillance optique en temps réel et non invasive d'un état de mal de décompression Download PDF

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WO2015123606A2
WO2015123606A2 PCT/US2015/015964 US2015015964W WO2015123606A2 WO 2015123606 A2 WO2015123606 A2 WO 2015123606A2 US 2015015964 W US2015015964 W US 2015015964W WO 2015123606 A2 WO2015123606 A2 WO 2015123606A2
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ppg
sensor
optical
light
ppg sensor
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WO2015123606A3 (fr
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Boris Tverskoy
Leonid Shvartsman
Irina MASSOVA
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    • 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 or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
    • A61B5/0205—Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
    • A61B5/026—Measuring blood flow
    • A61B5/0261—Measuring blood flow using optical means, e.g. infrared light
    • 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
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/6813—Specially adapted to be attached to a specific body part
    • A61B5/6814—Head
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63C—LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS; LIFE-SAVING IN WATER; EQUIPMENT FOR DWELLING OR WORKING UNDER WATER; MEANS FOR SALVAGING OR SEARCHING FOR UNDERWATER OBJECTS
    • B63C11/00—Equipment for dwelling or working underwater; Means for searching for underwater objects
    • B63C11/02—Divers' equipment
    • B63C11/12—Diving masks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63C—LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS; LIFE-SAVING IN WATER; EQUIPMENT FOR DWELLING OR WORKING UNDER WATER; MEANS FOR SALVAGING OR SEARCHING FOR UNDERWATER OBJECTS
    • B63C11/00—Equipment for dwelling or working underwater; Means for searching for underwater objects
    • B63C11/02—Divers' equipment
    • B63C11/32—Decompression arrangements; Exercise equipment
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2503/00—Evaluating a particular growth phase or type of persons or animals
    • A61B2503/10—Athletes
    • 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
    • A61B2562/02—Details of sensors specially adapted for in-vivo measurements
    • A61B2562/0233—Special features of optical sensors or probes classified in A61B5/00
    • A61B2562/0238—Optical sensor arrangements for performing transmission measurements on body tissue
    • 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 or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • 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 or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A61B5/14552—Details of sensors specially adapted therefor

Definitions

  • Embodiments of the invention relate to the detection of naturally occurring gas bubbles in the bloodstream. More particularly, the present invention relates to an optical device to detect Caisson's disease (decompression sickness) in situations where gas bubbles are released in body tissues and fluids upon a too rapid decrease in surrounding pressure after the body's stay in a compressed atmosphere.
  • Caisson's disease compression sickness
  • Additional aspects relate generally to the field of non-invasive monitoring of decompression sickness (DCS) and relates to a method and apparatus for determining the actual fraction of gas phase in a diver's blood.
  • DCS decompression sickness
  • DCS Decompression sickness
  • the actual challenge is to measure non-invasively the real-time fraction of the gas phase in blood both in the process of diving and in the post-diving period.
  • Existing techniques utilize a handheld or portable ultrasound device comprising a transducer propagating and receiving sound signals to/from a blood vessel and a controller receiving the sound signals from the transducer to determine/monitor presence of naturally occurring bubbles in the blood vessel because of decompression sickness.
  • Many existing devices require a significant power source. As a result, there is a need for a smaller, energy efficient device that would that provide the above features and offer additional vital measurements.
  • a method of determining an initiation or progression of decompression sickness in an individual using an in-vivo measurement of time-dependence of optical density of at least one irradiated body part including irradiating a portion of at least one body part with a photoplethysmography (PPG) sensor; collecting a time dependent optical signal from the sensor; and analyzing the collected system to determine the initiation or progression of decompression sickness in the individual.
  • PPG photoplethysmography
  • the irradiating step can be performed using a light in the yellow - green region. In another aspect, the irradiating step can be performed using a light in the near infrared region. In a further aspect, the analyzing step can be performed to determine an indicia of an optical scattering characteristic indicating the presence of a gas. In an alternative aspect, the method can further include irradiating another portion of a body part spaced apart from the portion of at least one body part and the analyzing step can be performed by comparing a blood velocity measurement at the portion and the another portion to determine an indicia of the presence of a gas influencing blood velocity.
  • the irradiated portions can be spaced apart by a distance of 6 inches to 12 inches.
  • the portion or the another portion of at least one body part can be within the mouth, on a lip, on a cheek, on a forehead, on a face, on an ear, on a wrist, on an elbow, on an arm, on a leg, on a finger or on a hand.
  • the irradiating step or the collecting step can be performed using a PPG sensor wherein at least one element of an emitter or a detector can be mounted on, in or within a respirator or SCUBA mouth piece or a diving mask.
  • the irradiating step or the collecting step can be performed using a PPG sensor configured as one emitter and multiple detectors. In a further aspect, the irradiating step or the collecting step can be performed using a PPG sensor configured as one detector and multiple emitters. In an alternative aspect, the method performed using at least one PPG sensor can be configured for transmission mode operation. In yet another aspect, the method performed using at least one PPG sensor can be configured for reflectance mode operation.
  • a PPG sensor enabled diving mask includes a face piece having a lens and a seal or skirt; and at least one PPG sensor on, in or within a portion of the seal or the skirt such that in use on a diver the at least on PPG sensor is positioned to irradiate a desired portion of a region of blood perfusion on the diver.
  • the at least one PPG sensor can be adapted and configured to irradiate a desired portion using a light in the yellow - green region. In another aspect, the at least one PPG sensor can be adapted and configured to irradiate a desired portion using a light in the near infrared region. In a further aspect, the at least one PPG sensor can be configured as one emitter and multiple detectors. In an alternative aspect, the at least one PPG sensor can be configured as one detector and multiple emitters. In yet another aspect, the at least one PPG sensor can be configured for transmission mode operation. In still another aspect, the at least one PPG sensor can be configured for reflectance mode operation.
  • a PPG sensor enabled respirator mouthpiece includes a respirator mouthpiece having a connector to attachment to a respirator supply and a portion for placement within the mouth of a user having an inner surface and an outer surface; and at least one PPG sensor on, in or within a portion of the respirator mouthpiece positioned to irradiate a desired portion of a region of blood perfusion on the user having the mouthpiece in his mouth.
  • the at least one PPG sensor can be adapted and configured to irradiate a desired portion using a light in the yellow - green region. In another aspect, the at least one PPG sensor can be adapted and configured to irradiate a desired portion using a light in the near infrared region. In a further aspect, the at least one PPG sensor can be configured as one emitter and multiple detectors. In an alternative aspect, the at least one PPG sensor can be configured as one detector and multiple emitters. In yet another aspect, the at least one PPG sensor can be configured for transmission mode operation. In still another aspect, the at least one PPG sensor can be configured for reflectance mode operation.
  • a method of real-time non-invasive monitoring of the actual state of decompression sickness including the steps of: obtaining reference data indicative of the spectral behavior of time-variant optical response modulated by heartbeats of diver; irradiating any part of diver's body with at least one light source with the wavelength belonging to the red - near infrared (RNIR) spectral range or the yellow green spectral range; measuring the optical response by at least one optical sensor of the same wavelength to obtain a first set of photoplethysmographic (PPG) data; performing the irradiating and the measuring steps with at least one additional light source and optical sensor to obtain a second set of photoplethysmographic (PPG) data; and combining said first set and said second set of photoplethysmographic (PPG) data from at least two different PPG units obtaining PPG information from different locations on the body.
  • RNIR red - near infrared
  • the said at least two PPG units or the first and second set of data can be synchronized with the common clock.
  • the method can further include comparing the first and the second data from the at least two said different PPG units to measure a phase shift in the PPG signal between two different locations on the body.
  • the method can further include analyzing the PPG data to determine changes in the relative amplitudes of the main peak "1" and secondary peak "3" of said PPG signals between said different locations on the body.
  • at least one PPG data collection unit can operate with reflected or/and back-scattered light.
  • At least one PPG data collection unit can operate in a transmission mode. In still another aspect, at least one PPG data collection unit can operate in a reflectance mode.
  • the measurements and analysis can be performed by said modified PPG unit having more than one detector optically coupled to the same light source. In another aspect, the analyzing and measuring the data where at least two of said optical detectors belonging to the same PPG unit can have different distance from the light source of the same modified PPG unit. In a further aspect, said measurements can be performed during a time interval exceeding the period of one heartbeat of a diver. In an alternative aspect, said measurements can be performed for multi-period PPG or providing for measuring to the slow trend of PPG.
  • said measurements and further analysis can define one or more slow frequency components when their frequencies are lower than the frequency of heartbeats.
  • when the existence of a measured slow frequency can be a basis or indication of a cognitive distortion caused by decompression sickness.
  • a measured slow trend cannot be periodic or can be non-repeating or can have an irregular occurrence.
  • the measured slow trends can relate to PPG or oximetry data taken at the same depth of a diving event or can be related to collection during the process of descent or can be related to collection during the process of ascent and thereafter one or more of the measured slow trends can be compared.
  • the measured slow trends can deal with any PPG data taken at the same depths but in the processes of descent and ascent and then compared.
  • the method can further include determining an actual state of decompression sickness based on the comparison steps.
  • the method can further include comparing between the optical signals of two sets of light detectors coupled to the same light source and tuned to the same wavelength but can have different distances from the said light source for obtaining an angular distribution of the out- coming light thus providing information about the existence of additional centers of light scattering in the diver's blood.
  • the method can further include synchronizing to a common clock the one or the more than one PPG units can be used for performing any of the steps located at different points of diver's body.
  • the wavelength of light used to perform a step or provided in a PPG sensor can be within the range of 300nm to l,300nm or is 660nm or is 940nm in any combination.
  • a method of real-time non-invasive monitoring of the actual state of decompression sickness including the steps of: providing reference data indicative of the spectral behavior of time-variant optical response modulated by heartbeats of diver; irradiating any part of diver's body with at least one light source with the wavelength belonging to the red - near infrared (RNIR) spectral range and measuring the optical response by at least one optical sensor of the same wavelength to get a photoplethysmographic (PPG) signal, and creating a basic configuration "light source - light detector" of the same wavelength that is further called the "PPG unit” or "light source - several light detectors" of the same wavelength that is further called the " modified PPG unit”; combining said photoplethysmographyc (PPG) data from at least two different PPG units located in different points of the body; keeping said at least two PPG units synchronized with the common clock; comparing the data from at least two said different PPG units to measure the phase shift
  • At least one of said PPG units or modified PPG units can work with reflected or/and back-scattered light.
  • at least one of said modified PPG units can have more than one detector optically coupled to the same light source.
  • at least two of said optical detectors belonging to the same PPG unit can have different distance from the light source of the same modified PPG unit.
  • a time interval can exceed the period of one heartbeat of a diver.
  • a multi-period PPG can measure the slow trend of PPG.
  • said measurement and further analysis can define one or more slow frequency components when their frequencies are lower than the frequency of heartbeats.
  • the existence of slow frequency can be the basis to suspect the cognitive distortion caused by DCS.
  • the measured slow trend cannot be periodic.
  • the measured slow trends can deal with oximetry data taken at the same depths but in the processes of descent and ascent and then compared.
  • the measured slow trends can deal with any PPG data taken at the same depths but in the processes of descent and ascent and then compared.
  • the basis of said comparison the conclusions can be drawn on the actual state of DCS.
  • the comparison between the optical signals of two sets of light detectors can be coupled to the same light source and tuned to the same wavelength but can have different distances from the said light source which can reveal the angular distribution of the out-coming light an can inform about the existence of additional centers of light scattering in the diver's blood.
  • the apparatus can include
  • the apparatus can include at least one modified PPG unit of the sort "several optical sensors coupled optically to the same light source” located at different distances from the same light source.
  • a real-time picture of gas bubbles distribution monitored by the change in the angular distribution of the out-coming light can be done in the reflective geometry of PPG sensors.
  • the PPG sensors of an apparatus have several light detectors optically bound to the same light source but placed in different distances from this light source. The comparison of PPG measured by these sensors is translated into the angular distribution of light, and thus contains information about the existence of the additional scatterers in blood like gas bubbles.
  • a method and apparatus is adapted and configured for multi-period PPG signal processing.
  • steps for analyzing the slow trend phenomena of measured PPG may be subdivided into two groups and each may be monitored for non- periodic slow trends in PPG signals in alike though non-identical conditions.
  • the conditions may be those of a diver during one or several different phases of a diving event (i.e., surfaced, descent, at depth, at different depth, and or ascent).
  • blood oximetry data are compared for the same depths but the one in the processes of descent with the oximetry data in the process of ascent.
  • the amount of gas phase differs in these cases, so will the measured oximetry data.
  • the second group of measurements deals with low frequency slow modulation of PPG signals.
  • the existence of clear low frequency component is indicative of certain sleep phases like REM-sleep phase.
  • EEG electroencephalography
  • the method or system is configured to perform the same procedure with the PPG signals obtained as described herein.
  • Figure 1 shows the typical single period PPG signal of healthy person where one can easily identify both: the major peak 1 , and the secondary peak 3, and the deep 2 between them. Timing of these features depends on the location of the PPG unit on the body, and the measured phase shift is the difference between corresponding features in different locations.
  • Figure 2 demonstrates the typical multi-period PPG feature measured by our system. The presence of low frequency modulation and its expression is suggested in this invention as an indication of risk of cognitive distortions.
  • Figure 3A demonstrates the layout of the one-wavelength part of our modified PPG unit. Such a layout provides in reflection the optical coupling between the light source and two sets of light detectors. All the detectors of each particular set, either the first set (detectors LD 1.1 - LD1.4) or the second set (detectors LD1.5 -LD1.8) have the same distance from the light source LS, while these distances for the first set and for the second set of detectors differ considerably.
  • Figure 3B demonstrates the layout of the one-wavelength part of a modified PPG unit. Such a layout provides in reflection the optical coupling between a single optical detector and two or more sets of optical light sources. All the light sources of each particular set, either the first set (sources LS 1_1- LS 1 4) or the second set (sources LS 1 5-LS 1_8) have the same distance from the light detector, while these distances for the first set and for the second set of sources differ.
  • Figure 4 is flow diagram showing the signal path from the optical transmitter to the CPU
  • Figure 5 is a perspective view of a respirator or SCUBA mouthpiece showing seven different exemplary PPG sensor mounting or integration locations.
  • Figure 6 is a perspective view of a respirator or SCUBA mouthpiece showing six different exemplary PPG sensor mounting or integration locations. .
  • Figure 7 is a perspective view of a respirator or SCUBA mouthpiece showing eight different exemplary PPG sensor mounting or integration locations.
  • Figure 8 is a rear view of the sealing rim of a dive mask showing six different exemplary PPG sensor mounting or integration locations.
  • Figure 9 is a view of an arm of a diver show two spaced apart PPG sensor locations on the arm between about 6 inches to 12 inches apart. In the illustrated embodiment, there is one sensor near the wrist and another sensor near the elbow.
  • PPG signals are analyzed for determining or detecting the onset of or progression of or degree of decompression sickness (i.e., caisson's disease).
  • PPG sensor data is analyzed for optical variations and mechanical variations as part of the method of determining the onset of or progression of or degree of decompression sickness (i.e., caisson's disease).
  • multiple PPG sensors are used in combination and may also be linked to a diver's watch or device for determining dive time overall, time at depth, descent rate, ascent rate and other parameters of a diving event in combination with one or more signals collected from one or more PPG sensors during the descent, dive duration or ascent phases of a scuba diving event.
  • PPG data collected during descent phase is compared to PPG data collected during ascent phase as part of a method of determining or detecting the onset of or progression of or degree of decompression sickness (i.e., caisson's disease).
  • PPG sensors may be placed in any location suited to measuring blood perfusion based on the activity being undertaken. Exemplary areas for sensor placement would be on the head such as forehead or the cheeks, in the mouth, on a finger or on the chest, to name a few.
  • Photoplethysmography is the in-vivo measurement of time-dependence of optical density of irradiated body part.
  • This optical density quasi-periodically oscillates with the heartbeats following an oscillating behavior of arterial blood.
  • the amplitudes of oscillations are wavelength dependent, and the resulting changes may be reliably observed in the red-near infrared (RNIR) spectral range.
  • RNIR red-near infrared
  • the actual magnitude of the PPG signal in the RNIR spectral range depends crucially both on absorption of blood key ingredients and on light scattering from blood.
  • the time dynamics of the PPG signal depends also on the velocity of the pulse wave in large arteries.
  • the existence of gas fraction in blood crucially changes both the scattering and the absorption of blood. Besides, it also changes the pulse wave velocity.
  • the actual state of DCS can be monitored by PPG techniques if certain modifications of this technique are applied.
  • such a monitoring system also known as a photoplethysmograph
  • a monitoring system includes a transmitter utilizing a probe attached to a part of the body (e.g., a finger, forehead, ear pinna or an earlobe) that includes an optical source, e.g., a light emitting diode (LED) or a laser, for irradiating the body part with light and a receiver utilizing an optical photodetector (e.g., a photo diode) positioned in an optical path so that it has a field of view which ensures the capture of a portion of the light which is transmitted, reflected or scattered from the body part.
  • an optical source e.g., a light emitting diode (LED) or a laser
  • an optical photodetector e.g., a photo diode
  • Resulting PPG signal depends on wavelength of the optical signal, refractive index and absorption coefficients of blood serum, red blood cells, water and hemoglobin. Additional details of PPG sensors and signal processing are provided in "Wearable Photoplethysmographic Sensors - Past and Present" by T. Tamura, Y. Meada, M. Sekine, and M.
  • a wireless optical device may be placed on various parts of the body including a finger or earlobe or is coupled with the SCUBA mouthpiece and detects certain vital signs such as heart rate, blood oxygen saturation (Sp02) and respiration rate by analyzing the photoplethysmogram (PPG) from a miniature sensor.
  • PPG photoplethysmogram
  • Photoplethysmography is the in-vivo measurement of time-dependence of optical density of irradiated body part.
  • PPG signals may be obtained using one or more or combinations of either reflection or transmission geometry configurations between the optical emitter and detector.
  • Optical density quasi-periodical ly oscillates with the heartbeats following an oscillating behavior of arterial blood.
  • the amplitudes of oscillations are wavelength dependent, and the resulting changes may be reliably observed in the red-near infrared (RNIR) spectral range.
  • the actual magnitude of the PPG signal in the RNIR spectral range depends both on absorption of blood key ingredients and on light scattering from blood.
  • the time dynamics of the PPG signal depends also on the velocity of the pulse wave in large arteries.
  • the existence of gas fraction in blood crucially changes both the scattering and the absorption of blood. Besides, it also changes the pulse wave velocity.
  • the actual state of DCS can be monitored utilizing embodiments of the modified PPG techniques described herein.
  • a method for a comparison of PPG signal from different PPG sensors located on a diver's body Such an approach enables simultaneous real time analysis of a variety of phase shifts between the single-period PPG signals collected from the different locations. This phase shift corresponds to the changes in the arterial pulse wave velocity when the blood gas phase becomes significant.
  • there is an apparatus that includes one or more PPG sensors operating in reflection geometry. In one configuration, the sensors are synchronized with a common clock of the signal processing system.
  • aspects of the system processing PPM data also detects the actual manifestations of basic and secondary peaks in the different locations of diver's body.
  • the basic and the secondary peaks and comparisons are indicative on the cases of small vessel embolism.
  • the real-time characterization of gas bubble distribution is also detected and/or monitored by the change in the angular distribution of the out-coming light.
  • angular light distribution may also be performed in a PPG sensor reflective geometry configuration.
  • the PPG sensors of our apparatus have several light detectors in varied spatial arrangement and distances but optically bound to the same light source. The comparison of PPG measured by these sensors is translated into the angular distribution of light. The angular distribution of light thus contains information about the existence of the additional optical scatterers in blood like gas bubbles.
  • Figure 1 shows the typical single period PPG signal of healthy person where one can easily identify both: the major peak 1, and the secondary peak 3, and the deep valley 2 between them. Timing of these features depends on the location of the PPG unit on the body, and the measured phase shift is the difference between corresponding features in different locations.
  • Figure 2 demonstrates the typical multi-period PPG feature measured by our system.
  • the presence of low frequency modulation and its expression is suggested in this invention as an indication of risk of cognitive distortions.
  • Figure 3A demonstrates the layout of the one-wavelength part of our modified PPG unit. Such a layout provides in reflection the optical coupling between the light source and two sets of light detectors. All the detectors of each particular set, either the first set (detectors LD 1.1 - LD 1.4) or the second set (detectors LD1.5 -LD1.8) have the same distance from the light source LS, while these distances for the first set and for the second set of detectors differ.
  • the spacing between the light source and the various detectors may range from about 2 mm to about 20 mm. In one aspect, there is a spacing of about 3 mm for the first set in a spatial array and about 5 mm for the second set in a spatial array.
  • Figure 3B demonstrates the layout of the one-wavelength part of a modified PPG unit.
  • Such a layout provides in reflection the optical coupling between a single optical detector and two or more sets of optical light sources. All the light sources of each particular set, either the first set (sources LS 1_1- LS 1 4) or the second set (sources LS 1 5-LS 1 8) have the same distance from the light detector, while these distances for the first set and for the second set of sources differ.
  • the spacing between the detector and the various emitters may range from about 2 mm to about 20 mm. In one aspect, there is a spacing of about 3 mm for the first set in a spatial array and about 5 mm for the second set in a spatial array.
  • Figure 4 is flow diagram showing the signal path from the optical transmitter to the CPU. It is to be appreciated that the proposed optical system is much smaller, energy efficient and may be placed on a finger, forehead, ear pinna, earlobe, cheek. In addition or optionally, the optical system may be inside the diver's mouth, in which case sensor may be mechanically combined with or integrated into a scuba mouthpiece. In addition or optionally, the optical system may be adapted and configured for placement along a portion of a diver's forehead in which case the sensor may be mechanically combined with or integrated into a dive mask.
  • a system that combines detection of decompression sickness with detection of such vital signs as heart rate, blood oxygen saturation (Sp02), respiration rate of a diver by analyzing photoplethysmogram (PPG) from a single miniature sensor and presents a significant improvement over existing ultrasound systems.
  • the optical transmitter 1 that includes an optical emitter comprises at least one light source configured for generating and applying an optical signal to a measurement location in a blood perfused body tissue.
  • the optical receiver 2 includes an optical detector comprises at least one photodiode, configured for receiving light originated back from at least a portion of the measurement location and generating a photocurrent signal including response of the blood perfused body tissue to the optical signal.
  • Signal amplifier 3 for amplification of the photocurrent signal generated by the optical detector 2.
  • Analog to digital converter 4 to convert analog output of the signal amplifier 3 to digital domain for the further processing.
  • CPU 5 for processing the amplified and digitized photocurrent signal generated by the optical detector 2.
  • the CPU 5 may include software, firmware or hardware for synchronized operation of one or more optical transmitters and/or received in accordance with the methods described herein.
  • the present invention can be attained by optical monitoring techniques that use light as an optical signal transmitted through a medium, such as a portion of a blood perfused body tissue for determining the vital signs and/or onset of or degree of decompression sickness.
  • the optical detector converts the light (i.e., optical signal) into an analog electrical signal, which is subsequently amplified, digitized and provided to a CPU to retrieve information that was present in the optical signal.
  • the information present in the optical signal may contain be both the information inserted by the transmitter as well as the information about the medium.
  • Figures 5 - 7 illustrate various locations where one or more PPG sensors may be mounted on or integrated to a portion of a mouth worn respirator.
  • one or more PPG sensors are placed on, in or within a mouth worn respirator so that the PPG sensor may operate in transmission or reflectance mode with the vascular beds of the lips, gums, and/or cheeks in any combination.
  • Figure 5 is a perspective view of a respirator or SCUBA mouthpiece showing seven different exemplary PPG sensor mounting or integration locations.
  • Figure 6 is a perspective view of a respirator or SCUBA mouthpiece showing six different exemplary PPG sensor mounting or integration locations.
  • Figure 7 is a perspective view of a respirator or SCUBA mouthpiece showing eight different exemplary PPG sensor mounting or integration locations.
  • Figure 8 is a rear view of the sealing rim of a dive mask showing six different exemplary PPG sensor mounting or integration locations.
  • Figure 8 illustrates various locations where one or more PPG sensors may be mounted on or integrated with a portion of a diving mask face piece or other sealing surface.
  • one or more PPG sensors are placed on, in or within a sealing surface or skirt portion of a mask such that the PPG sensor is in contact with the skin of the diver as appropriate to a transmission or reflection PPG sensor configuration.
  • the mask born PPG sensor(s) may operate in transmission or reflectance mode with the vascular beds of the lips, forehead, temple or face, and/or cheeks in any combination.
  • Figure 9 is a view of an arm of a diver show two spaced apart PPG sensor locations on the arm between about 6 inches to 12 inches apart. In the illustrated embodiment, there is one sensor near the wrist and another sensor near the elbow. The spacing of the sensors is particularly useful when analyzing PPG signal information for pulse wave comparisons as part of the mechanical indicia evaluation of detecting decompression sickness. While desiring not to be bound by theory, measuring blood speed at two different PPG sensors spaced apart permits comparison of differences in blood velocity from a reference blood speed of a user before a dive, during the descent stage of a dive, while at depth during a dive or during the ascent stage of a dive event.
  • comparisons of blood velocity from at least two PPG sensors on a user may be used to determine the presence or increasing presence or decreasing presence of gas or bubbles in the blood stream of the user.
  • One or more sensors with the same or different wavelength of the optical signal can be used in order to give a greater level of accuracy to the sensor readings.
  • one or more PPG sensors may be operating in the green - yellow region (between 500-600 nm) while another may be operating in the red or infrared region.
  • a suitable display for use in an underwater environment may be used which provides an output of PPG information related to one or more methods to the diver, or to another diver(s) or device which advises the diver, another diver or a safety monitor of the sensors analysis pertaining to the onset of or level of the caisson's disease and/or other vital signs.
  • a radio if a radio is required then an appropriate radio technology might be integrated. The invention may be used for monitoring underwater diver's vital signs and stage of decompression sickness in real time for safety purposes.
  • a numeric value may have a value that is +/- 0.1% of the stated value (or range of values), +/- 1% of the stated value (or range of values), +/- 2% of the stated value (or range of values), +/- 5% of the stated value (or range of values), +/- 10% of the stated value (or range of values), etc. Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

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Abstract

L'invention concerne un dispositif et un système ainsi qu'un procédé permettant la détection de bulles de gaz qui se produisent naturellement dans la circulation sanguine; selon un mode de réalisation, un dispositif optique sans fil peut être placé sur diverses parties du corps comprenant un doigt ou un lobe d'oreille ou est couplé avec l'embout buccal d'un scaphandre autonome et détecte certains signes vitaux tels que le rythme cardiaque, la saturation en oxygène dans le sang (Sp02) et le rythme respiratoire par analyse du photopléthysmogramme (PPG) à partir d'un capteur miniature. L'invention concerne également un procédé et un appareil permettant une surveillance optique en temps réel et non invasive de l'état actuel du mal de décompression. Le procédé est basé sur des mesures simultanées de signaux PPG à différents endroits du corps humain et sur l'analyse d'un facteur tel que des déphasages entre différents endroits, le changement de la forme du signal PPG entre différents endroits, l'existence et la modification de lentes tendances et des modulations basse fréquence et des distributions angulaires de la lumière réfléchie.
PCT/US2015/015964 2014-02-16 2015-02-13 Procédé et appareil permettant une surveillance optique en temps réel et non invasive d'un état de mal de décompression Ceased WO2015123606A2 (fr)

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CN105662367A (zh) * 2016-02-25 2016-06-15 北京航空航天大学 一种头戴式多点脉搏波检测方法及装置
WO2017078637A1 (fr) * 2015-11-03 2017-05-11 Ergun Onur Équipement de plongée en apnée
IT201700011204A1 (it) * 2017-02-03 2018-08-03 Oxama Srl Dispositivo per la misurazione della saturazione di ossigeno nel sangue durante immersioni subacquee in apnea
CN108937957A (zh) * 2018-06-05 2018-12-07 武汉久乐科技有限公司 检测方法、装置及检测设备
CN105769151B (zh) * 2016-02-25 2019-01-04 北京航空航天大学 一种多点脉搏波检测方法及装置
CN109310352A (zh) * 2016-07-01 2019-02-05 索尼公司 信息处理装置、信息处理方法及程序
CN109512417A (zh) * 2018-10-19 2019-03-26 天津大学 一种多位置动态光谱差值提取法
CN109589107A (zh) * 2018-10-19 2019-04-09 天津大学 一种双位置动态光谱差值提取法
IT201800003058A1 (it) * 2018-02-27 2019-08-27 Pumpo Fabio Di maschera subacquea con sensore per pulsossimetro integrato
EP3888530A1 (fr) * 2020-03-30 2021-10-06 Oxama S.r.l. Dispositif facial de surveillance de paramètres biomédicaux d'un utilisateur
JP2023533362A (ja) * 2020-07-14 2023-08-02 先陽科技有限公司 位置決め方法、装置、電子機器、記憶媒体及びコンピュータプログラム
CN118121154A (zh) * 2024-02-07 2024-06-04 中国海洋大学 一种潜水员氮醉状态检测方法及检测系统
US12350009B2 (en) 2021-10-25 2025-07-08 Samsung Electronics Co., Ltd. Electronic device including sensor module

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EP2451344B1 (fr) * 2009-07-10 2019-02-20 Cas Medical Systems, Inc. Procédé de surveillance spectrophotométrique de l'oxygénation sanguine du tractus gastro-intestinal inférieur
WO2011048556A2 (fr) * 2009-10-20 2011-04-28 Reuven Gladshtein Photopléthysmographe à profondeurs multiples
US8801183B2 (en) * 2009-11-30 2014-08-12 The Board Of Trustees Of The University Of Illinois Assessment of microvascular circulation
US20120220844A1 (en) * 2011-02-28 2012-08-30 Nellcor Puritan Bennett Llc Regional Saturation Using Photoacoustic Technique
WO2012149227A2 (fr) * 2011-04-26 2012-11-01 Incube Labs, Llc Embout buccal pour la mesure de données biométriques d'un plongeur et pour la communication sous l'eau

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WO2017078637A1 (fr) * 2015-11-03 2017-05-11 Ergun Onur Équipement de plongée en apnée
CN105662367A (zh) * 2016-02-25 2016-06-15 北京航空航天大学 一种头戴式多点脉搏波检测方法及装置
CN105769151B (zh) * 2016-02-25 2019-01-04 北京航空航天大学 一种多点脉搏波检测方法及装置
CN109310352B (zh) * 2016-07-01 2022-05-31 索尼公司 信息处理装置、信息处理方法及程序
CN109310352A (zh) * 2016-07-01 2019-02-05 索尼公司 信息处理装置、信息处理方法及程序
IT201700011204A1 (it) * 2017-02-03 2018-08-03 Oxama Srl Dispositivo per la misurazione della saturazione di ossigeno nel sangue durante immersioni subacquee in apnea
IT201800003058A1 (it) * 2018-02-27 2019-08-27 Pumpo Fabio Di maschera subacquea con sensore per pulsossimetro integrato
CN108937957B (zh) * 2018-06-05 2021-11-09 武汉久乐科技有限公司 检测方法、装置及检测设备
CN108937957A (zh) * 2018-06-05 2018-12-07 武汉久乐科技有限公司 检测方法、装置及检测设备
CN109589107A (zh) * 2018-10-19 2019-04-09 天津大学 一种双位置动态光谱差值提取法
CN109512417A (zh) * 2018-10-19 2019-03-26 天津大学 一种多位置动态光谱差值提取法
CN109512417B (zh) * 2018-10-19 2021-04-20 天津大学 一种多位置动态光谱差值提取法
CN109589107B (zh) * 2018-10-19 2021-05-07 天津大学 一种双位置动态光谱差值提取法
EP3888530A1 (fr) * 2020-03-30 2021-10-06 Oxama S.r.l. Dispositif facial de surveillance de paramètres biomédicaux d'un utilisateur
WO2021198896A1 (fr) * 2020-03-30 2021-10-07 Oxama S.R.L. Dispositif pour le visage destiné à surveiller des paramètres biomédicaux d'un utilisateur
JP2023533362A (ja) * 2020-07-14 2023-08-02 先陽科技有限公司 位置決め方法、装置、電子機器、記憶媒体及びコンピュータプログラム
JP7580838B2 (ja) 2020-07-14 2024-11-12 先陽科技有限公司 位置決め方法、装置、電子機器、記憶媒体及びコンピュータプログラム
US12350009B2 (en) 2021-10-25 2025-07-08 Samsung Electronics Co., Ltd. Electronic device including sensor module
CN118121154A (zh) * 2024-02-07 2024-06-04 中国海洋大学 一种潜水员氮醉状态检测方法及检测系统

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