An Early PEEP/FiO2 Trial Identifies Different Degrees of Lung Injury in Patients with Acute Respiratory Distress Syndrome

Abstract

Rationale: Current American-European Consensus Conference definitions for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are inadequate for inclusion into clinical trials due to the lack of standardization for measuring the oxygenation defect.Objectives: We questioned whether an early assessment of oxygenation on specific ventilator settings would identify patients with established ARDS (persisting over 24 h).Methods: At the time of meeting ARDS criteria (Day 0) and 24 hours later (Day 1), arterial blood gases were obtained on standard ventilator settings, Vt 7 ml/kg predicted body weight plus the following positive end-expiratory pressure (PEEP) and FiO2 settings in sequence: (1) PEEP ≥ 5 cm H2O and FiO2 ≥ 0.5, (2) PEEP ≥ 5 cm H2O and FiO2 1.0, (3) PEEP ≥ 10 cm H2O and FiO2≥0.5, and (4) PEEP ≥ 10 cm H2O and FiO2 1.0.Measurements and Main Results: One hundred seventy patients meeting ARDS criteria (PaO2/FiO2 128 ± 33 mm Hg) were enrolled. Overall hospital mortality was 34.1%. The s...