| CPC A61B 5/02028 (2013.01) [A61B 5/02444 (2013.01); A61B 5/6813 (2013.01); A61B 5/742 (2013.01)] | 9 Claims |
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1. A cardiac physiological parameter measuring method, comprising steps of:
acquiring vibration information of a subject to be tested in a supine state, comprising steps of:
providing a fiber-optic sensor including one optical fiber arranged in a pad and a control box connected with ends of the optical fiber;
connecting the control box of the fiber-optic sensor with a processor for data communication;
disposing the fiber-optic sensor under the back of the subject corresponding to the left shoulder of the subject, wherein a sensing area where the optical fiber is distributed in the fiber-optic sensor covers the back corresponding to the left shoulder blade of the subject; and micro body vibrations of the subject make the optical fiber micro bending;
processing and calculating, executed on a control processing module in the control box, changes in intensity of light passing through the optical fiber caused by the micro bending of the optical fiber; and
obtaining, executed on the control processing module, vibration information on the basis of the changes in intensity of light; wherein the vibration information containing breathing vibration, body vibration caused by contraction and relaxation of the heart of the subject, body vibration information caused by blood vessel wall deformation, and body movement;
acquiring, executed on the processor, synchronous electrocardiogram (ECG) of the subject through an electrocardiogram sensor while acquiring vibration information;
communicating the vibration information from the fiber-optic sensor and the synchronous ECG from the electrocardiogram sensor to the processor;
normalizing, executed on the processor, the vibration information and obtaining a waveform of the vibration information, where the waveform has a horizontal axis representing time, and a vertical axis representing normalized vibration information, which is dimensionless;
preprocessing, executed on the processor, the waveform of the vibration information to generate a waveform of hemodynamic related information with peaks and valleys; comprising:
filtering the vibration information below 1 Hz and above 45 Hz;
dividing, executed on the processor, cardiac cycles on the basis of the synchronous ECG; and
determining, executed on the processor, a Mitral Valve Closure (MC) feature point of an MC event on the basis of the waveform of the hemodynamic related information in one cardiac cycle; comprising steps of:
performing a second-order differential processing and a fourth-order differential processing on the waveform of the hemodynamic related information to generate a second-order differential graph and a fourth-order differential graph, respectively;
setting a highest peak in one cardiac cycle of the second-order differential graph as an auxiliary feature point;
synchronizing the second-order differential graph and the fourth-order differential graph on the horizontal axis representing time, and determining a time point of the fourth-order differential graph corresponding to the auxiliary feature point of the second-order differential graph; and
determining a first valley on the fourth-order differential graph before the time point in the same cardiac cycle as the MC feature point of the MC event.
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