×

Detection of aortic coarctation using photoplethysmography

  • US 10,376,154 B2
  • Filed: 03/12/2015
  • Issued: 08/13/2019
  • Est. Priority Date: 03/18/2014
  • Status: Active Grant
First Claim
Patent Images

1. A method for detecting an aortic coarctation in an infant comprising:

  • a) obtaining photoplethysmographic (PPG) signals from a right hand and from a foot of the infant using a photoplethysmograph of at least two channels;

    b) selecting a section of the PPG signals without movement noise for analysis, low-pass filtering the PPG signals to reduce high frequency noise, and smoothing the PPG signals using a moving average filter;

    c) identifying end-diastolic maxima and minima of systolic decrease for hand PPG pulses and for the foot PPG pulses from the PPG signals, and using the end-diastolic maxima and minima of systolic decrease to determine one or both of the following;

    c1) time delay (TD) between the end-diastolic maxima for the hand PPG pulses and the end-diastolic maxima for the foot PPG pulses (f-hTD), and/orc2) PPG pulse amplitude (AM) between the end-diastolic maxima and minima of systolic decrease for the hand PPG pulses and for the foot PPG pulses;

    d) if PPG pulse amplitude (AM) is determined, determining a relative pulse amplitude (rAM) by dividing the AM by the minima of systolic decrease to obtain a rAM for the foot (rAM-F) PPG pulses and a rAM for the hand (rAM-H) PPG pulses;

    e) calculating mean and standard deviation (SD) of f-hTD, and/or rAM for the foot (rAM-F) and rAM for the hand (rAM-H) for the PPG pulses in a selected section of PPG pulses, and discarding values deviating from the mean by 2 standard deviations or more from the calculation of the mean;

    f) if mean foot rAM-F and mean hand rAM-H are calculated, determining a ratio F/H between mean foot rAM-F and mean hand rAM-H, and/or determining a ratio H/F between mean hand rAM-H and mean foot rAM-F; and

    optionally, obtaining a multiplication product of H/F times f-hTD and/or a multiplication product of F/H times f-hTD; and

    g) detecting the aortic coarctation in the infant if one or more of;

    the f-hTD is elevated above normal, orthe ratio F/H is decreased below normal, orthe ratio H/F is increased above normal, orthe product H/F times f-hTD is increased above normal.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×