Comparison of 2 Strategies of Adjustment of Mechanical Ventilation in Patients With Acute Respiratory Distress Syndrome

Primary Outcome Measures:

• Mortality at 28 days
  

Secondary Outcome Measures:

• Mortality at 60 days
  
• In hospital mortality
  
• Ventilator free Days through day 28
  
• Number of new organ failure before day 28
  
• Proportion of patients alive and unassisted breathing at 28 days
  
• Number of patients with pneumothorax
  
• Number of days alive between the first positive "potential weanability test" and day 28
  

Most patients suffering from acute lung injury or acute respiratory distress syndrome require mechanical ventilation. In this setting, positive end-expiratory pressure is used to improve arterial oxygenation. While the beneficial effect on clinical outcome of using low tidal volume is clearly proven, the best way to titrate PEEP is not known. Higher PEEP levels may better improve oxygenation and reduce ventilator-induced lung injury by reducing end-expiratory alveolar collapse but may also cause circulatory depression and aggravate lung injury from end-inspiratory overdistension. This trial compares the impact on outcome of two strategies for setting PEEP. In the "minimal alveolar distension" arm, PEEP is set for a total PEEP (PEEP + intrinsic PEEP) between 5 and 9 cm H20). In the "maximal alveolar recruitment" arm, PEEP is set for a plateau pressure between 28 and 30 cm H20. A tidal volume of 6 ml/kg predicted body weight is used in the two arms. The goals for arterial oxygenation and PaCO2 are the same in the two arms.