CPC A61B 5/0816 (2013.01) [A61B 5/0803 (2013.01); A61B 5/085 (2013.01); A61B 5/7203 (2013.01); A61B 5/7225 (2013.01); A61B 5/7235 (2013.01)] | 14 Claims |
1. A non-transitory computer readable storage medium encoded with a computer program, the program comprising instructions that when executed by one or more data processing apparatus cause the one or more data processing apparatus to perform operations comprising:
receiving a signal corresponding to impedance across a patient's chest cavity;
filtering the signal using one or more filters that reduce noise and center the signal around a zero baseline;
adjusting an amplitude of the filtered signal based on a threshold value;
separating the amplitude-adjusted signal into component signals, wherein each of the component signals represents a frequency-limited band;
detecting a fractional phase transition of a component signal of the component signals;
selecting a dominant component signal from the component signals based on amplitudes of the component signals at a time corresponding to the detected fractional phase transition;
determining a frequency of the dominant component signal at the time corresponding to the detected fractional phase transition; and
determining a respiratory rate of the patient based on the determined frequency.
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