METHODS AND APPARATUS FOR DETERMINING ARTERIAL PULSE WAVE VELOCITY
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Abstract
Methods are presented for determining pulse transit time (PTT) and/or pulse wave velocity (PWV) of a subject by application of parametric system identification to proximal and distal arterial waveforms. The two waveforms are measured from the subject. A system is defined that relates the proximal arterial waveform to the distal arterial waveform (or vice versa) in terms of the unknown parameters of a parametric mathematical model. The model parameters are determined from the measured waveforms using system identification. PTT between the proximal and distal arterial sites is then determined from the system model. PWV may also be determined by dividing the distance between measurement sites (D) by PTT.
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Citations
53 Claims
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1-26. -26. (canceled)
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27. A method for determining an arterial pulse transit time of a subject, comprising:
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measuring a proximal waveform indicative of the arterial pulse at a proximal site of the subject; measuring a distal waveform indicative of the arterial pulse at a distal site of the subject; defining a dynamic system that relates one of the waveforms to the other waveform in terms of unknown parameters of a parametric mathematical model that assumes a specific structure for the system; determining the unknown parameters of the mathematical model from the measured proximal waveform and the measured distal waveform; and determining a pulse transit time between the proximal site and the distal site from the mathematical model. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 44)
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39. A method for determining an arterial pulse wave velocity of a subject, comprising:
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measuring a proximal waveform indicative of the arterial pulse at a proximal site of the subject; measuring a distal waveform indicative of the arterial pulse at a distal site of the subject; defining a dynamic system for the subject that relates one of the waveforms to the other waveform in terms of unknown parameters of a physical tube-load model transfer function in which pulse transit time is an explicit parameter of the model; determining the parameters of the transfer function from the measured proximal and the measured distal waveforms; and determining a pulse wave velocity from the pulse transit time parameter. - View Dependent Claims (40, 41, 42, 43, 45)
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46. A method for tracking blood pressure of a subject, comprising:
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measuring a proximal waveform indicative of the arterial pulse at a proximal site of the subject; measuring a distal waveform indicative of the arterial pulse at a distal site of the subject;
defining a dynamic system that relates the proximal arterial waveform to the distal arterial waveform in terms of a mathematical model;determining the mathematical model for the subject from the measured waveforms; determining a pulse transit time between the proximal site and the distal site from the mathematical model; and tracking blood pressure using the pulse transit time. - View Dependent Claims (47, 48)
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49. A method for improving a cardiac output measure of a subject, comprising:
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measuring a waveform indicative of the arterial pulse at a proximal site of the subject; measuring a waveform indicative of the arterial pulse at a distal site of the subject; defining a dynamic system that relates the proximal arterial waveform to the distal arterial waveform in terms of a mathematical model; determining the mathematical model from the measured waveforms; determining a pulse transit time between the proximal site and the distal site from the mathematical model; and improving a cardiac output measure for the subject using the pulse transit time. - View Dependent Claims (50, 51, 52)
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53. A method for determining an arterial pulse transit time of a subject, comprising:
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measuring a proximal waveform indicative of the arterial pulse at a proximal site of the subject; measuring a distal waveform indicative of the arterial pulse at a distal site of the subject sequentially with the measurement of the proximal waveform; measuring an electrocardiograph (ECG) of the subject concurrently with the measurements of the proximal and distal waveforms; determining a first impulse response relating a waveform derived from the ECG to the proximal waveform; determining a second impulse response relating a waveform derived from the ECG to the distal waveform; defining a dynamic system that relates the first impulse response to the second impulse response in terms of unknown parameters of a parametric mathematical model that assumes a specific structure for the system; determining the unknown parameters of the mathematical model from the first and second impulse response; and determining a pulse transit time between the proximal site and the distal site from the mathematical model.
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Specification