Total lung capacity and subdivisions, seated and supine
| Parameter | Normal group, seated | Obese group, seated | p Value | Normal group, supine | Obese group, supine | p Value |
|---|---|---|---|---|---|---|
| TLC (L) | 6.8 (1.7) | 5.1 (1.9) | 0.065 | 6.5 (1.7) | 4.8 (1.9) | 0.058 |
| TLC (%pred) | 104.4 (12.3) | 88.6 (16.9) | 0.033 | N/A | N/A | N/A |
| VC (L) | 5.3 (1.3) | 3.6 (1.8) | 0.035 | 5.2 (1.2) | 3.4 (1.8) | 0.030 |
| FRC (L) | 3.2 (0.9) | 1.8 (0.5) | 0.002 | 2.7 (0.7) | 1.8 (0.4) | 0.004 |
| FRC/TLC (%) | 46.9 (4.6) | 37.5 (6.9) | 0.004 | 41.5 (4.3) | 39.4 (7.7) | 0.477 |
| ERV (L) | 1.7 (0.6) | 0.4 (0.4) | <0.001 | 1.1 (0.3) | 0.3 (0.4) | <0.001 |
| ERV/TLC (%) | 25.8 (6.3) | 6.1 (6.4) | <0.001 | 17.5 (6.4) | 4.2 (6.4) | <0.001 |
| RV (L) | 1.5 (0.6) | 1.5 (0.3) | 0.979 | 1.4 (0.6) | 1.4 (0.3) | 0.872 |
| RV/TLC (%) | 21.2 (4.9) | 31.4 (10.1) | 0.015 | 20.4 (5.1) | 32.2 (11.1) | 0.010 |
| IC (L) | 3.6 (0.9) | 3.2 (1.4) | 0.564 | 4.1 (1.2) | 3.3 (1.5) | 0.227 |
| Change of volumes with recumbency | Normal group | Obese group | p Value |
|---|---|---|---|
| Δ TLC (L) | −0.24 (0.08) | −0.25 (0.08) | 0.695 |
| Δ IC (L) | 0.36 (0.59) | −0.19 (0.15) | <0.016 |
| Δ FRC (L) | −0.51 (0.42) | −0.04 (0.13) | 0.05 |
Lung volumes in obese and normal subjects, seated and supine. Δ indicates the change of volume with recumbency (+, increased volume in supine posture; −, loss of volume in supine posture).
ERV, expiratory reserve volume; FRC, functional residual capacity; IC, inspiratory capacity; RV, residual volume; TLC, total lung capacity.