Adaptive Frequency Domain Filtering for Improved Non-Invasive Blood Pressure Estimation
First Claim
1. A method of computing an oscillometric envelope for use in determining the blood pressure of a patient, the method comprising:
- receiving an oscillometric signal from a blood pressure cuff connected to a patient;
receiving an indication of the heart rate of the patient;
computing the fundamental frequency of the heart rate;
computing at least one harmonic frequency of the heart rate;
converting the oscillometric signal to the frequency domain;
filtering the frequency domain oscillometric signal using a band pass filter comprising the fundamental frequency of the heart rate to produce a first filtered frequency domain signal;
filtering the frequency domain oscillometric signal using a band pass filter comprising the at least one harmonic frequency of the heart rate to produce a second filtered frequency domain signal;
reconstructing the oscillometric signal from the first and second filtered frequency domain signals to produce a reconstructed oscillometric signal;
computing an oscillometric envelope data point from the reconstructed oscillometric signal.
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Abstract
A system for processing oscillometric data from a plurality of pressure steps to determine the blood pressure of a patient as disclosed herein. A heart rate monitor connected to the patient acquires the patient'"'"'s heart rate. A time to frequency domain converter receives oscillometric data and converts the oscillometric data into the frequency domain. A harmonic frequency calculator is connected to the heart rate monitor and derives at least the heart rate fundamental frequency. A filter connected to the time to frequency domain converter and the harmonic frequency calculator that produces a filter frequency domain oscillometric signal. A reconstruction calculator receives the filtered frequency domain oscillometric signal and reconstructs a time domain oscillometric signal. A method of computing an oscillometric envelope for use in determining the blood pressure of a patient is also disclosed herein.
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Citations
20 Claims
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1. A method of computing an oscillometric envelope for use in determining the blood pressure of a patient, the method comprising:
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receiving an oscillometric signal from a blood pressure cuff connected to a patient; receiving an indication of the heart rate of the patient; computing the fundamental frequency of the heart rate; computing at least one harmonic frequency of the heart rate; converting the oscillometric signal to the frequency domain; filtering the frequency domain oscillometric signal using a band pass filter comprising the fundamental frequency of the heart rate to produce a first filtered frequency domain signal; filtering the frequency domain oscillometric signal using a band pass filter comprising the at least one harmonic frequency of the heart rate to produce a second filtered frequency domain signal; reconstructing the oscillometric signal from the first and second filtered frequency domain signals to produce a reconstructed oscillometric signal; computing an oscillometric envelope data point from the reconstructed oscillometric signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of processing oscillometric data for use in determining the blood pressure of a patient, the method comprising:
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receiving an oscillometric signal from a blood pressure cuff connected to a patient; receiving an indication of the heart rate of the patient; computing the fundamental frequency of the heart rate; computing at least one harmonic frequency of the heart rate; converting the oscillometric signal to the frequency domain; filtering the frequency domain oscillometric signal with at least one band pass filter comprising the fundamental frequency of the heart rate and the at least one harmonic frequency of the heart rate; and reconstructing the oscillometric signal from the filtered frequency domain signal to produce a reconstructed oscillometric signal. - View Dependent Claims (12, 13, 14, 15)
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16. A system for processing an oscillometric signal from a plurality of pressure steps of a blood pressure cuff to determine the blood pressure of a patient, the system comprising:
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a heart rate monitor connected to the patient, the heart rate monitor acquiring the patient'"'"'s heart rate at each pressure step; a time-to-frequency domain converter that receives the oscillometric signal acquired at each pressure step and converts the oscillometric data into the frequency domain; a harmonic frequency calculator connected to the heart rate monitor, the harmonic frequency calculator deriving at least the heart rate fundamental frequency; a filter connected to the time-to-frequency domain converter and the harmonic frequency calculator, the filter comprising at least the fundamental frequency, the filter producing a filtered frequency domain oscillometric signal; a reconstruction calculator that receives the filtered frequency domain oscillometric signal and reconstructs a time domain oscillometric signal from the filtered frequency domain oscillometric signal; an oscillometric envelope calculator that processes the time domain oscillometric signal at each pressure step to produce an oscillometric envelope from envelope data points corresponding to each pressure step; and a blood pressure determination calculator connected to the oscillometric envelope calculator, the blood pressure determination calculator analyzes the oscillometric envelope to determine the blood pressure of the patient. - View Dependent Claims (17, 18, 19, 20)
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Specification