Table 1 Characteristics of included studies
RCT | Sample size | Baseline FEV1 (ml/s) | He/O2 mixture | Ventilator type/helium canister connection | Ventilation mode/daily duration/study duration | Interface | Between NIV sessions gas | NIV failure criteria | Baseline pH | Baseline PaCO2 (mmHg) | Predicted mortality rate (%) | SMR | Predicted NIV failure rate (%) | Observed NIV failure rate (%) | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
He/O2 | Air/O2 | He/O2 | Air/O2 | He/O2 | Air/O2 | He/O2 | Air/O2 | |||||||||||
Jolliet_2003 | 59 | 64 | 740 ± 362 | 78/22 | ICU ventilator with connection to the air inlet | NIPSV/≥ 6H/until recovery | Oronasal mask | Air/O2 | Intubation | 7.32 ± 0.06 | 7.30 ± 0.07 | 65 ± 13 | 63 ± 15 | 24 | 0.33 | 45 | 13.5 | 20.3 |
Maggiore_2010 | 102 | 102 | 900 ± 400 | 65/35 | ICU ventilator with connection to the O2 inlet | NIPSV/≥ 6H/until recovery | Facial full mask | Air/O2 | Intubation | 7.28 ± 0.07 | 7.28 ± 0.06 | 73 ± 18 | 72 ± 15 | 15 | 0.67 | 40 | 24.5 | 30.4 |
Jolliet_2016 | 225 | 220 | 785 ± 360 | 78/22 | ICU ventilator with dedicated connection | NIPSV/≥ 6H/≤ 72H | Oronasal mask | He/O2 | Intubation or death in the ICU | 7.29 ± 0.05 | 7.30 ± 0.06 | 71 ± 16 | 68 ± 17 | 15 | 0.37 | 25 | 14.7 | 14.5 |