gms | German Medical Science


Figure 9: Schematic drawing of the sequence of events in the obstructive sleep apnea, measured by the EEG, the heart rate (HR), the oxygen saturation (SaO 2 ), the airflow (Flow), the breathing movements (Effort) and the snoring (Micro). A: Onset of the apnea, pharyngeal collapse. B: Vain respiratory efforts against the obstructed pharynx. C: Drop of the oxygen saturation due to the interruption of the alveolar ventilation. D: Increase of the vain respiratory effort. E: Arousal reaction. F: Sudden increase in pharyngeal muscle tone, re-opening of the upper airways, short hyperventilation accompanied by loud snoring and tachycardia. G: Normalization of the oxygen saturation.