Patent ID: 8545417

Claim:
A system for monitoring a patient's respiratory rate, comprising: a first sensor selected from the group consisting of: i) an impedance pneumography sensor comprising at least two electrodes and an impedance pneumography processing circuit configured to process signals from the two electrodes to measure an impedance pneumography signal from the patient; ii) an ECG sensor comprising at least two electrodes and an ECG processing circuit configured to process signals from the two electrodes to measure an ECG signal from the patient; and iii) a PPG sensor comprising a light source, photodetector, and PPG processing circuit configured to process signals from the photodetector to measure a PPG signal from the patient; a second sensor comprising a motion sensor configured to attach to the patient's torso and measure a motion signal from the patient; a processing system configured to be worn on the patient's body and connect to the first sensor to receive a first signal representing at least one of the impedance pneumography, ECG, and PPG signals, and connect to the second sensor to receive a second signal representing the motion signal, the processing system configured to collectively process both the first and second signals to determine the patient's respiratory rate by determining an initial respiratory rate estimate using the first signal, determining a filtering function using the initial respiratory rate estimate, applying the filtering function to the second signal to provide a filtered motion waveform indicative of respiratory movements of the patient's torso, and processing the filtered motion waveform to determine the respiratory rate of the patient.