Fall in vital capacity with posture.
In a study of 147 subjects (50 normals, 50 with obstructive, and 47 with restrictive lung function), the mean reduction in forced vital capacity from standing to supine (delta FVC) was 7.5% (SD +/- 5.7), 11.2% (+/- 13.4), and 8.2% (+/- 7.7) respectively, with no significant difference between groups. The respective 95% upper confidence limits were 19%, 38% and 24%. We conclude that delta FVC greater than 25% associated with normal or restrictive lung function or greater than 35% associated with airways obstruction should be an indication for further study of diaphragm function.
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011187:Posture; D012140:Respiratory Tract Diseases / Q000503:physiopathology*; D014797:Vital Capacity