Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
  • A61B5/7203—Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal
  • A61B5/7207—Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal of noise induced by motion artifacts
  • A61B5/7214—Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal of noise induced by motion artifacts using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• • 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
  • A61B5/024—Measuring pulse rate or heart rate
  • A61B5/02416—Measuring pulse rate or heart rate using photoplethysmograph signals, e.g. generated by infrared radiation
• • 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
  • A61B5/021—Measuring pressure in heart or blood vessels
  • A61B5/02108—Measuring pressure in heart or blood vessels from analysis of pulse wave characteristics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/08—Measuring devices for evaluating the respiratory organs
  • A61B5/0816—Measuring devices for examining respiratory frequency

Definitions

• the detection data comprises wavelength-dependent reflection or transmission information in at least two signal channels representative of respective wavelength portions.
• a signal mixer dynamically mixes the at least two signal channels into at least one mixed signal.
• a processor derives physiological information indicative of at least one vital sign from the at least one mixed signal, and a controller controls the signal mixer to limit the relative contributions of the at least two signal channels mixed into at least one mixed signal and/or the rate-of-change at which said relative contributions are allowed to dynamically change.
• predetermined index element having a set orientation indicative of a reference physiological information Details of the Pt, v method and the use of the normalized blood volume vector (called "predetermined index element having a set orientation indicative of a reference physiological information") have also been described in US 2013/271591 Al, which details are also herein incorporated by reference.
• the present invention is based on the idea to find the linear combination of the color channels (also called wavelength channels or frequency bands; colors are to be understood broadly here and may include wavelength channels in invisible parts of the spectrum), which suppresses the distortions best in a frequency band including the pulse rate, and consequently use this same linear combination to extract the desired vital sign information (e.g. represented by a vital sign information signal such as a respiration signal or Mayer waves) in a lower frequency band.
• a vital sign information signal such as a respiration signal or Mayer waves
• said input interface is configured to obtain different sets of at least two detection signals derived from detected electromagnetic radiation transmitted through or reflected from different skin regions of the subject, wherein said weight computation unit is configured to compute weights per set of at least two detection signals, wherein said vital sign signal computation unit is configured to compute, per set of at least two detection signals, a first preliminary vital sign signal by a weighted combination of said at least two first bandwidth-limited detection signals using the computed weights of the respective set of at least two detection signals and to compute said first vital sign signal by combining said first preliminary vital sign signals computed for the different sets of at least two detection signals.
• the device further comprises a second filter unit for filtering said first vital sign signal with a second filter to obtain said second vital sign signal.
• the order of weighing and the first filtering is, in general, arbitrary.
• the first filter may be configured to let frequencies pass including or excluding the frequencies of the desired vital sign information, in particular the frequencies of respiration information.
• the detector comprises one or more optical photoplethysmography sensor(s) 19 (also referred to as contact PPG sensor(s)) configured for being mounted to a skin portion of the subject 14 for acquiring photoplethysmography signals.
• the PPG sensor(s) 19 may e.g. be designed in the form of a patch attached to a subject's forehead for measuring the blood oxygen saturation or a heart rate sensor for measuring the heart rate, just to name a few of all the possible embodiments.
• the stable character of Pt, v can be used to distinguish color variations caused by blood volume change from variations due to alternative causes.
• the resulting pulse signal S using known methods can be written as a linear combination (representing one of several possible ways of "mixing") of the individual DC-free normalized color channels:
• a first filter unit 32 filter said at least two detection signals C with a first filter to obtain at least two first bandwidth-limited detection signals Cn .
• a vital sign signal computation unit 36 computes a second vital sign signal S2 using the computed weights w and said at least two second bandwidth-limited detection signals Co.
• the second vital sign signal S2 is hereby preferably computed by a weighted combination of the at least two second bandwidth-limited detection signals Ce using the computed weights w.
• a vital sign determination unit 38 finally determines vital sign information V from said second vital sign signal S 2 .
• the weights to minimize distortions are calculated for both the individual sub-regions and the entire skin area. These weights are consequently used to extract signals from these (sub-) regions including both respiration and pulse information. Selecting the best weights is accomplished by calculating the signal-to- noise ratio (SNR) of each region. By ranking the signals based on their SNRs, the final weights are selected, as either the weights corresponding to the signal with the highest SNR, or a combination of the weights corresponding to the signals (two or more) with the highest SNR. These final weights are then applied to the filtered, normalized traces of the entire skin region, containing only respiration information.
• SNR signal-to- noise ratio

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physiology (AREA)
• Cardiology (AREA)
• Public Health (AREA)
• Molecular Biology (AREA)
• Physics & Mathematics (AREA)
• Veterinary Medicine (AREA)
• Biophysics (AREA)
• Pathology (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Medical Informatics (AREA)
• General Health & Medical Sciences (AREA)
• Surgery (AREA)
• Animal Behavior & Ethology (AREA)
• Signal Processing (AREA)
• Psychiatry (AREA)
• Artificial Intelligence (AREA)
• Computer Vision & Pattern Recognition (AREA)
• Pulmonology (AREA)
• Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
• Measuring And Recording Apparatus For Diagnosis (AREA)

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Cited By (4)

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Citations (3)

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• 2016
  • 2016-12-01 CN CN201680077231.XA patent/CN108471962B/zh active Active
  • 2016-12-01 WO PCT/EP2016/079390 patent/WO2017093379A1/en not_active Ceased
  • 2016-12-01 JP JP2018527954A patent/JP6654700B2/ja active Active
  • 2016-12-01 US US15/777,231 patent/US20180333102A1/en not_active Abandoned
  • 2016-12-01 EP EP16805781.8A patent/EP3383258B1/en active Active

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