4 Variables reflecting dynamic pulmonary hyperinflation and variables determined during passive expiration from end-expiratory lung volume (EELV) to functional residual capacity (FRC)
| Baseline semirecumbent | Prone | Post-prone semirecumbent | |
| EELV computed L | 5.65±0.65 | 4.92±0.49# | 5.52±0.59 |
| EELV measured L | 5.71±0.65 | 4.94±0.49# | 5.56±0.60 |
| FRC measured L | 5.24±0.63 | 4.60±0.47 | 5.13±0.57 |
| ΔFRC measured L | 0.47±0.04 | 0.35±0.03¶,§ | 0.44±0.03 |
| ΔFRC computed L | 0.41±0.04 | 0.32±0.03¶,§ | 0.39±0.03 |
| Static PEEPi,RS cmH2O | 8.9±1.7 | 6.7±1.1#,+ | 8.2±1.2 |
| Static PEEPi,Lung cmH2O | 7.8±1.1 | 5.4±0.6#,+ | 7.1±0.7 |
| Static PEEPi,cw cmH2O | 1.1±0.6 | 1.3±0.6 | 1.1±0.6 |
| Expiratory Raw at EELV cmH2O·L−1·s−1 | 31.6±2.6 | 18.3±1.4¶,§ | 28.4±1.9 |
| Dynamic PEEPi cmH2O·L−1·s−1 | 3.0±0.3 | 2.3±0.3¶,+ | 2.9±0.3 |
| Mean end-expiratory flow mL·s−1 | 47.9±4.0 | 63.9±4.2¶,§ | 51.2±4.7 |
| Time of ΔFRC expiration s | 24.1±3.3 | 11.5±1.6¶,§ | 21.1±2.9 |
Data are presented as mean±sd. ΔFRC: change in FRC; PEEPi: intrinsic positive end-expiratory pressure; RS: respiratory system; cw: chest wall; Raw: airway resistance. Measured EELV/FRC refers to helium dilution determinations; measured ΔFRC refers to volume determination carried out during passive exhalation from EELV to FRC; computed EELV = measured FRC plus measured ΔFRC; computed ΔFRC = measured EELV–measured FRC. #: p<0.05 versus baseline semirecumbent; ¶: p<0.01 versus baseline semirecumbent; +: p<0.05 versus post-prone semirecumbent; §: p<0.01 versus post-prone semirecumbent.