BODY-WORN MONITOR FOR MEASURING RESPIRATORY RATE
First Claim
1. A method for measuring respiratory rate from a patient, comprising the following steps:
- (a) measuring a time-dependent impedance pneumography signal from the patient with an impedance pneumography sensor connected to at least two electrodes, the impedance pneumography signal representing a time-dependent capacitance change in the patient'"'"'s torso;
(b) measuring at least one time-dependent motion signal with a motion sensor connected to the patient, the at least one motion signal corresponding to motion of a portion of the patient'"'"'s body to which the motion sensor is attached;
(c) transforming the time-dependent impedance pneumography signal into a frequency-dependent impedance pneumography spectrum;
(d) transforming the time-dependent motion signal into a frequency-dependent motion spectrum;
(e) determining motion components from the frequency-dependent motion spectrum that correspond to the patient'"'"'s motion;
(f) removing the motion components, or components calculated therefrom, from the frequency-dependent impedance pneumography spectrum to generate a processed frequency-dependent impedance pneumography spectrum; and
(g) analyzing the processed frequency-dependent impedance pneumography spectrum to determine the patient'"'"'s respiratory rate.
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Accused Products
Abstract
The invention provides a system for measuring respiratory rate (RR) from a patient. The system includes an impedance pneumography (IP) sensor, connected to at least two electrodes, and a processing system that receives and processes signals from the electrodes to measure an IP signal. A motion sensor (e.g. an accelerometer) measures at least one motion signal (e.g. an ACC waveform) describing movement of a portion of the patient'"'"'s body to which it is attached. The processing system receives the IP and motion signals, and processes them to determine, respectfully, frequency-domain IP and motion spectra. Both spectra are then collectively processed to remove motion components from the IP spectrum and determine RR. For example, during the processing, an algorithm determines motion frequency components from the frequency-domain motion spectrum, and then using a digital filter removes these, or parameters calculated therefrom, from the IP spectrum.
109 Citations
21 Claims
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1. A method for measuring respiratory rate from a patient, comprising the following steps:
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(a) measuring a time-dependent impedance pneumography signal from the patient with an impedance pneumography sensor connected to at least two electrodes, the impedance pneumography signal representing a time-dependent capacitance change in the patient'"'"'s torso; (b) measuring at least one time-dependent motion signal with a motion sensor connected to the patient, the at least one motion signal corresponding to motion of a portion of the patient'"'"'s body to which the motion sensor is attached; (c) transforming the time-dependent impedance pneumography signal into a frequency-dependent impedance pneumography spectrum; (d) transforming the time-dependent motion signal into a frequency-dependent motion spectrum; (e) determining motion components from the frequency-dependent motion spectrum that correspond to the patient'"'"'s motion; (f) removing the motion components, or components calculated therefrom, from the frequency-dependent impedance pneumography spectrum to generate a processed frequency-dependent impedance pneumography spectrum; and (g) analyzing the processed frequency-dependent impedance pneumography spectrum to determine the patient'"'"'s respiratory rate. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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2. A method for determining a respiratory rate value from a patient, comprising the following steps:
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(a) measuring a first time-dependent signal by detecting a modulated electrical current passing through the patient'"'"'s torso; (b) measuring a second time-dependent signal by detecting movements in the patient'"'"'s torso with at least one motion sensor; (c) transforming the first time-dependent signal into a first frequency-domain signal and the second time-dependent signal into a second frequency-domain signal; (d) determining a motion-related event not related to the patient'"'"'s respiratory rate value by analyzing the second frequency-domain signal; and (e) collectively processing both the first and second frequency-domain signals to remove motion artifacts from the first frequency-domain signal to determine the respiratory rate value.
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3. A method for determining a respiratory rate value from a patient, comprising the following steps:
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(a) measuring at least one electrical signal affected by both respiratory rate and motion with a first sensor; (b) measuring a motion signal affected by the patient'"'"'s motion with a second sensor; (c) transforming the motion signal into the frequency domain to determine frequency components corresponding to the patient'"'"'s motion; and (d) removing the frequency components corresponding to the patient'"'"'s motion from a transform of the at least one electrical signal to determine a respiratory rate value for the patient.
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Specification