| 摘要 |
A method and apparatus in an apnea detector monitor impedance pneumographic respiratory signals and heart rate of a patient. Magnitudes of excursions of the respiratory signals are monitored to resolve respiratory events, i.e. breaths, inhalations and exhalations. A counter will reach a threshold count and trigger an alarm if a selected interval lapses without a respiratory event being detected. If a respiratory event is detected, as by detecting successive peaks, a peak or a valley of the respiratory signal, the timer is reset. The method and apparatus reject artifact that would otherwise appear as breathing cycles in order to prevent false negative indications of apnea. Cyclically occurring peaks are rejected as being indicative of a breath if they are in a selected magnitude range compared to that of a normal breath and they approximate the patient's heart rate. Successive peaks due to sighs or of a baseline change are measured for average rate of change over the period it takes for the waveform to decrease from the second peak by of a selected level generally corresponding to of a normal inhalation or exhalation. They are rejected as artifact if the change is too slow. Consequently, sighs are not misinterpreted as breaths.
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