Patent ID: 8622922

Claim:
A system for monitoring a patient's respiratory rate, comprising: an impedance pneumography sensor comprising at least two electrodes configured to measure thoracic electrical impedance indicative of respiration and processing circuitry configured to process signals from the two electrodes and to generate therefrom an impedance pneumography waveform from the patient; a motion sensor configured to attach to the patient's torso and to measure breathing-induced movements of the torso, and to generate therefrom a motion waveform from the patient a processing system configured to be worn on the patient's body and to receive the impedance pneumography waveform, and the motion waveform, the processing system further configured to: i) process the impedance pneumography waveform to determine therefrom an initial respiratory rate estimate by filtering the impedance pneumography waveform with a 0.01-12 Hz bandpass filter, derivatizing the filtered impedance pneumography waveform, and identifying features in the derivatized impedance pneumography waveform corresponding to respiration events; ii) process the motion waveform by filtering the motion waveform with an adaptive digital filter determined from the initial respiratory rate estimate, derivatizing the filtered motion waveform, and identifying features in the derivatized motion waveform corresponding to respiration events to determine a final value for the patient's respiration rate.