Risk of bias domain | Taher et al 19 | Barzilay et al 20 * | ||
Judgement | Support for judgement | Judgement | Support for judgement | |
Random sequence generation (selection bias) | Unclear |
Quote: ‘…patients were divided in two groups…’. Comment: Not a random component in the sequence generation process. | Unclear | Comment: No description of a random component in the sequence generation process. |
Allocation concealment (selection bias) | Unclear | Comment: No description of allocation concealment. | High |
Quote: ‘Patients were assigned alternately to two groups’. Comment: Investigators had the possibility of foreseeing the assignment. |
Blinding of participants and personnel (performance bias) | Low |
Quote: ‘In this double blind clinical trial…’. Comment: Probably done. | Low | Comment: No blinding is described, but the relevant outcomes are not likely to be influenced by lack of blinding. |
Blinding of outcome assessment (detection bias) | Low | Comment: No blinding of outcome assessment is described, but the relevant outcomes are not likely to be influenced by lack of blinding. | Low | Comment: No blinding of outcome assessment is described, but the relevant outcomes are not likely to be influenced by lack of blinding. |
Incomplete outcome data (attrition bias) | Low | Comment: Outcome is reported for all included patients. | Unclear | Comment: The outcomes are not described as being defined before commencing the study. |
Selective reporting (reporting bias) | Unclear | Comment: No protocol is available and the reported outcomes are not prespecified in the methods section. | Unclear | Comment: As outcomes are not described as being defined before commencing the study, there is insufficient information to assess this domain. |
Other bias | Unclear | Comment: There is insufficient information on the study design to assess whether an important risk of bias exists. | High |
Quote: ‘Those in the study group were connected to a two-ventilator HFPPV system of our own design’. Comment: The authors are likely to have a preference for their own design. |
↵*This study did not strictly meet the inclusion criteria, however, it was included for descriptive purposes.
HFPPV, high-frequency positive-pressure ventilation.