Demographic and lung function information for each individual study
| Author [Ref.] | Subjects (M/F) | Age yrs | FEV1 % pred | FVC % pred | FEV1/FVC | TLC % pred | RV % pred | FRC % pred |
| Babb [28] | 10 (6/4) | 70±3 | 78±7 | 98±11 | 0.61±0.04 | 106±12 | ||
| Eves [29] | 10 (10/0) | 65±11 | 47±17 | 83±21 | 0.56±0.10 | 136±29 | 192±63 | 157±44 |
| Johnson [30] (Heliox) | 10 (4/6) | 62±9 | 34.1±12.8 | 57.3±16 | 108±23 | 291±66 | ||
| Johnson [30] (NIPPV) | 11 (8/3) | 69±9 | 31.6±9.3 | 56.9±14.5 | 111±17 | 203±63 | ||
| Laude [31] | 82 (57/25) | 69.7 | 42.6±15.5 | |||||
| Marciniuk [32] | 16 (7/9) | 67±8 | 55±13 | 89±12 | 0.48±0.08 | 130±15 | 175±37 | |
| Oelberg [33] (Control) | 10 (9/1) | 60.3±3.2 | 93±3 | 105±4 | ||||
| Oelberg [33] (COPD) | 8 (2/6) | 47±2.3 | 19±1 | 132±7 | ||||
| Palange [34] | 12 (12/0) | 68±8 | 38±10 | 76±14 | ||||
| Richardson [35] | 10 (4/6) | 64.7±7.62 | 40±11.9 |
Data are presented as n or mean±sd, when sd available. M/F: male/female; FEV1: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity; TLC: total lung capacity; RV: residual volume; FRC: functional residual capacity; NIPPV: noninvasive positive pressure ventilation; COPD: chronic obstructive pulmonary disease.