Fig. 2

Respiratory system and lung pressure-volume curve. Mean (±standard deviation) pressure-volume curve of the total respiratory system (black line) and the lung (gray line) obtained by sigmoidal fitting (see text for method). The white dots indicate the upper corner points and the white squares the average inspiratory capacity (TLC-FRC) obtained by CT scan at 45 cmH₂O airway pressure. Horizontal dashed lines indicate the 95 % confidence limits of inspiratory capacity (mean ±2 standard deviations)