Villar 2006.
| Methods | Randomized controlled trial. Time period of study: March 1999 through March 2001. | |
| Participants | 95 participants, aged > 15. Included: persistent ARDS. Excluded: patients with acute cardiac clinical conditions, pregnancy, neuromuscular diseases, high risk of mortality within 3 months for reasons other than ARDS (severe neurologic damage, age > 80 years, and cancer patients in the terminal stage of their disease), or more than two extrapulmonary organ failures. | |
| Interventions | Control (45) and intervention (50): MV: ventilator mode (both groups): volume‐assist control, respiratory rate to maintain PaCO2 between 35 and 50 cm H2O. Control: VT: 9 to 11 mL/kg PBW, PEEP ≥ 5 cm H2O and FIO2 to optimize SpO2 > 90% and PaO2 between 70 and 100 mm Hg. Intervention: VT: 5 to 8 mL/kg PBW, PEEP: 2 cm H2O above Pflex or 15 cm H2O if no Pflex; FIO2 to optimize SpO2 > 90% and PaO2 between 70 and 100 mm Hg. |
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| Outcomes | Primary: mortality in the ICU. Secondary: hospital mortality (mortality before hospital discharge), VFD, extrapulmonary organ failure, and barotrauma. |
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| Notes | Discontinued prematurely because the absolute mortality difference between control and intervention groups satisfied the stopping rule. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Authors used blocked randomization (restricted randomization) stratified by centre. |
| Allocation concealment (selection bias) | Low risk | Opaque sealed envelopes that were randomly ordered. |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Incomplete blinding (blinding of participants but not of personnel), but outcomes not influenced. |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | No blinding, but outcomes not influenced. |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Three out of 53 participants missing from intervention group and five out of 50 participants missing from control group, because a centre failed to adhere to the randomization methodology. The final analysis was performed with the remaining 95 participants. |
| Selective reporting (reporting bias) | Low risk | Published reports included all expected outcomes. |
| Other bias | Low risk | Review author believed the study to be free of other sources of bias. |