Patent ID: 8747330

Claim:
A method for measuring respiratory rate from a patient, comprising the following steps: (a) measuring an impedance pneumography signal from the patient with an impedance pneumography sensor connected to at least two electrodes mounted on the patient's torso, the impedance pneumography signal representing a time-dependent capacitance change in the patient's torso; (b) measuring at least one motion signal with a three axis motion sensor mounted on the patient's torso and having an axis of measurement aligned into the patient's torso, the at least one motion signal comprising signal components corresponding to breathing-induced motion, posture of the patient, and degree of motion of the patient; (c) analyzing the motion signal with a first microprocessor located on the patient's body to determine a motion parameter indicative of the patient's degree of motion; (d) analyzing the motion parameter with the first microprocessor, wherein if the motion parameter exceeds a threshold which indicates that the impedance pneumography signal is not significantly corrupted by motion, determining a respiratory rate by identifying peaks in the impedance pneumography signal corresponding to respiration events with the first microprocessor, and wherein if the motion parameter does not exceeds the threshold which indicates that the impedance pneumography signal is significantly corrupted by motion, transmitting the impedance pneumography signal and the motion signal to a second microprocessor positioned at a different location than the first microprocessor and determining the respiratory rate by performing steps (e)-(h); (e) using the second microprocessor, collectively processing both the motion signal and impedance pneumography signal to determine coefficients corresponding to a digital filter; (f) transmitting the coefficients from the second microprocessor to the first microprocessor; (g) using the first microprocessor, processing one of the motion signal and impedance pneumography signal with the coefficients to determine a digitally filtered waveform; and (h) using the first microprocessor, analyzing the digitally filtered waveform to determine the respiratory rate.