초록 ▼

Methods and apparatus for determining the occurrence of an apnea, patency and/or partial obstruction of the airway are disclosed. Respiratory air flow from a patient is measured to give an air flow signal. The determination of an apnea is performed by calculating the variance of the air flow signal

Methods and apparatus for determining the occurrence of an apnea, patency and/or partial obstruction of the airway are disclosed. Respiratory air flow from a patient is measured to give an air flow signal. The determination of an apnea is performed by calculating the variance of the air flow signal over a moving time window and comparing the variance with a threshold value. One determination of partial obstruction of the airway is performed by detecting the inspiratory part of the air flow signal, scaling it to unity duration and area and calculating an index value of the amplitude of the scaled signal over a mid-portion. Alternatively, the index value is a measure of the flatness of the air flow signal over the mid-portion. One determination of patency of the airway is performed by applying an oscillatory pressure waveform of known frequency to a patient's airway, calculating the magnitude of the component of said air flow signal at the known frequency induced by the oscillatory pressure waveform and comparing the calculated magnitude with a threshold value. Alternatively, the air flow signal is analysed to detect the presence of a component due to cardiogenic activity.

대표청구항 ▼

[ What is claimed:] [12.] Apparatus for determining the occurrence of an apnea in a patient, the apparatus comprising;means for measuring respiratory airflow from the patient as a function of time;means for determining the variance of said measured airflow; andmeans for determining from said varianc

[ What is claimed:] [12.] Apparatus for determining the occurrence of an apnea in a patient, the apparatus comprising;means for measuring respiratory airflow from the patient as a function of time;means for determining the variance of said measured airflow; andmeans for determining from said variance that an apnea is occurring.