The effects of posture on total respiratory compliance

In 6 subjects, a minimum of 10 determinations of total respiratory compliance by the weighed spirometer technique was made in four different body positions: seated, supine, right lateral decubitus, and left lateral decubitus. The mean total respiratory compliance was 0.097 ± 0.018 1/cmH₂O; the mean individual coefficient of variation was 8%. There was no significant change in the total respiratory compliance with change in posture in any individual or in the group as a whole. In 6 patients with pulmonary disease, the total respiratory compliance determined by this technique and derived from measurements using the esophageal balloon was not significantly different. It is concluded that total thoracic compliance does not vary with posture in normal subjects, and that the weighed spirometer technique is reproducible and clinically applicable.