A 22 years old male patient was hospitalized with complaints of obesity, daytimesomnolence and snorring during sleep. Physical examination revealed slight ptosis in eyelidsand grade III tonsillar hypertrophy, however, no other abnormalities were observed. The chest X-ray film showed slight cardiomegaly. Laboratory tests were all within normal limit.Pulmonary function test was normal except slight reduction of RV and elevation of CV. Theventilatory response tests of respiratory center revealed blunt responce to the lowered oxygenconcentration of inhaled gas and weak response to the higher concentration of CO2 in the inhaledgas. The distribution of the sleep stage analyzed with EEG showed stage W of 25%, stage I of 11%, stage II of 36%, stage III of 10%, stage IV of 1% and stage REM of 17%, and the marked reduction of deep sleep was clearly demonstrated. The pattern of respirationwas continuously monitored during sleep by means of the capacitance pneumograph, andperiodic apnea lasting for about 60 seccnds was observed. The arterial oxygen saturationmonitored by an earoxymeter droped to 76%, and ECG recording indicated the occurrence ofsinus bradycardia and premature ventricular contraction during the apnea periods. Thecapacitance pneumograph, which was devised to record chest and abdominal wall movementsseparately, initially showed complete cessation and then paradoxical movement of chest andabdominal wall during apnea. This indicated that the apnea was initially central then followedby obstruction. After reduction of body weight and tonsillectomy, daytime somnolenceand snor on sleep were markedly improved and the period of apnea reduced to 35-45 seconds and reduction of SaO2 was about 90%. The capacitance pneumograph is non-invasive and useful tool for the investigation of sleep induced apnea.
