Villar 2006.
| Study characteristics | ||
| Methods | Multi‐centre randomised controlled trial conducted in 8 ICUs in Spain Time period of study: March 1999 through March 2001 |
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| Participants | 95 participants aged ≥ 15 Included: established ARDS Excluded: patients with acute cardiac clinical conditions, pregnancy, neuromuscular disease, high risk of mortality within 3 months for reasons other than ARDS (severe neurological damage, age > 80 years, cancer patients in terminal stage of disease), more than 2 extrapulmonary organ failures Sample size was estimated considering that the intervention group would produce 20% reduction in ICU mortality vs control. Power calculations assumed 20% reduction in mortality rate from 50% in the control group to 30% in the intervention group (with an α level of.05 at power of 80%, requiring a sample size of 74 patients in each group). 50% mortality was based on previous studies (Lewandowski 1995; Villar 1999). There was justification for stopping the study in the presence of efficacy (when there were ≥ 45 participants per group and difference in ICU mortality was ≥ 20%) |
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| Interventions | Control (45) and intervention (50): MV ventilator mode (both groups): volume‐assist control, respiratory rate to maintain PaCO₂ between 35 and 50 cmH₂O Control: TV 9 to 11 mL/kg PBW, PEEP ≥ 5 cmH₂O and FIO₂ to optimise SpO₂ > 90% and PaO₂ between 70 and 100 mmHg. Mean PEEP 8.8 cmH₂O during first 72 hours Intervention: TV 5 to 8 mL/kg PBW, PEEP 2 cmH₂O above Pflex or 15 cmH₂O if no Pflex; FIO₂ to optimise SpO₂ > 90% and PaO₂ between 70 and 100 mmHg. Mean PEEP 12.6 cmH₂O during first 72 hours |
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| Outcomes | Primary: mortality in ICU Secondary: mortality before hospital discharge, VFDs, extrapulmonary organ failure, barotrauma |
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| Notes | Discontinued prematurely because absolute mortality difference between control and intervention groups satisfied the stopping rule This study was funded in part by the Fondo de Investigación Sanitaria of Spain |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Study authors used blocked randomisation (restricted randomisation) 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 5 out of 50 participants missing from control group because a centre failed to adhere to the randomisation method. Final analysis was performed with remaining 95 participants |
| Selective reporting (reporting bias) | Low risk | Published reports included all expected outcomes |
| Other bias | Low risk | Review authors believed the study to be free of other sources of bias |
AECC: American‐European Consensus Conference.
ALI: acute lung injury.
APACHE II: Acute Physiologic Assessment and Chronic Health Evaluation II.
ARDS: acute respiratory distress syndrome.
ECMO: extracorporeal membrane oxygenation.
FIO₂: fraction of inspired oxygen.
HFO: high‐frequency oscillatory therapy.
ICU: intensive care unit.
LIS: Lung Injury Scale.
LOS: length of stay.
MAP: mean arterial pressure.
MV: mechanical ventilation.
OLA: Open Lung Approach.
PaO₂: partial pressure of oxygen.
PBW: predicted body weight.
PEEP: positive end‐expiratory pressure.
SOFA: Sequential Organ Failure Assessment.
SpO₂: oxygen saturation.
TV: Tidal Volume.
VFDs: ventilator‐free days.