Characteristics by ventilation stages with spirometric data after 1, 3, 5 and 7 yrs of follow-up
| Characteristics | NIPPV | MIPPV | 1 yr | 3 yrs | 5 yrs | 7 yrs | ANOVA |
| Subjects n | 42 | 42 | 35 | 28 | 17 | 13 | |
| Age yrs*** | 19.4±4.2 | 23.5±4.4 | 24.8±4.7 | 27.1±5.0 | 29.2±4.9 | 32.5±4.4 | a, c, d, e |
| Height cm | 164±8 | 164±8 | 163±8 | 163±8 | 163±8 | 164±8 | |
| Weight kg | 52±15 | 47±16 | 49±13 | 49±13 | 47±11 | 46±12 | |
| BMI | 19.2±4.5 | 17.6±5.2 | 18.5±4.3 | 18.3±4.5 | 17.7±4.0 | 17.1±4.5 | |
| VC mL*** | 1016±399 | 534±200 | 582±198 | 488±178 | 412±173 | 354±129 | a, f |
| VC % pred*** | 21±8 | 11±4 | 13±4 | 11±4 | 9±4 | 8±3 | a |
| MIP cmH2O*** | 29±11 | 16±5 | 15±5 | 12±5 | 8±3 | 6±2 | a, c ,d, e |
| V’T mL*** | 281±87 | 217±64 | 199±46 | 181±57 | 168±58 | 137±75 | a, e |
| RR·mL-1# | 21±5 | 24±6 | 24±5 | 25±6 | 26±6 | 26±5 | a |
| V’E mL*** | 5692±1657 | 5027±1339 | 4688±1271 | 4466±1525 | 4292±1458 | 3396±1772 | a, e |
| V’E,alv mL*** | 3398±1058 | 2792±916 | 2509±848 | 2263±1011 | 2057±1112 | 1391±1278 | a, e, f |
| Free time h*** | 24.0±0 | 15.7±1.1 | 2.9±1.8 | 2.1±1.8 | 1.2±1.6 | 0.5±0.6 | a, b, c, d, e |
| Diurnal Pt,CO2mmHg | 62±17 | 43±10 | 39±10 | 39±10 | 43±12 | b | |
| Symptom score per 7 pts | 3.2±1.6 | 0.8±1.1 | b |
Data are presented as mean±sd, unless otherwise stated. NIPPV: start of nocturnal nasal intermittent positive pressure ventilation; MIPPV: start of diurnal mouthpiece intermittent positive pressure ventilation; BMI: body mass index; VC: vital capacity; % pred: percentage of predicted; MIP: maximal inspiratory pressure; V’T: tidal volume; RR: respiratory rate; V’E: spontaneous minute expiratory ventilation; V’E,alv: alveolar minute ventilation; Pt,CO2: transcutaceous CO2 tension; a: NIPPV/MIPPV; b: MIPPV/1 yr; c: MIPPV/3 yrs; d: MIPPV/5 yrs; e: MIPPV/7 yrs; f: 1 yr/7 yrs. #: p = 0.005; ***: p<0.001. 1 mmHg = 0.133 kPa.