Presently, the mortality of patients in the hospital with acute respiratory distress syndrome (ARDS) is higher than 40%. A sixteen month long observational study was conducted to determine if certain cutoff points of PaO2/FiO2 (less than or equal to 200 mmHg) and a positive end-expiratory pressure (PEEP) (greater than 5 cm H20) would identify patients with ARDS that have different prognoses.
The mechanically ventilated patients in the study were placed into four groups. Classification of ARDS is determined at 24 hours after onset.
|Group 1: PaO2/FiO2 ≥ 150 on PEEP<10||23.1%|
|Group 2: PaO2/FiO2 ≥ 150 on PEEP≥10||32.4%|
|Group 3: PaO2/FiO2 < 150 on PEEP<10||44.4%|
|Group 4: PaO2/FiO2 < 150 on PEEP≥10||60.3%|
Clearly, you can see that hospital mortality increases steadily as the severity of ARDS increases. This study can help clinicians talk with patients and their families about prognosis. Some controversies still exist with regards to ARDS management such as the potential benefit of corticosteroid therapy in early, severe ARDS. However, all patients with ARDS should be treated with lung-protective ventilation and conservative fluid management to optimize outcomes.
Villar J, et al. A clinical classification of the acute respiratory distress syndrome for predicting outcome and guiding medical therapy*. Critical Care Medicine. 2015; 43 (2): 346-353.