Risk of bias in the included trials
| Study | Selection bias | Attrition bias (incomplete data) | Reporting bias (selective reporting) | |
|---|---|---|---|---|
| Random sequence generation | Allocation concealment | |||
| Girault et al. 201125 | Low | Low | Low | Low |
| Rabie Agmy et al. 201226 | Low | Low | Low | Low |
| Tawfeek et al. 201227 | Unclear | Low | Low | Low |
| Vaschetto et al. 201228 | Low | Low | Low | Low |
| Hill et al. 200029 | Unclear | Low | Low | Low |
| Rabie Agmy et al. 200430 | Unclear | Low | Low | Low |
| Chen et al. 200131 | High | High | Low | Unclear |
| Wang et al. 200432 | Unclear | Unclear | Low | Low |
| Zheng et al. 200533 | Unclear | Unclear | Unclear | Low |
| Zou et al. 200634 | Low | Unclear | Unclear | Low |
| Prasad et al. 200935 | Low | Unclear | Low | Low |
| Nava et al. 199836 | Unclear | Low | Low | Low |
| Collaborating Research Group for Noninvasive Mechanical Ventilation 200537 | Unclear | Unclear | Low | Low |
| Girault et al. 199938 | Unclear | Unclear | Low | Low |
| Ferrer et al. 200339 | Low | Low | Low | High |
| Trevisan et al. 200840 | Unclear | Unclear | Low | Low |