Noninvasive Positive Pressure Ventilation in Moderate Acute Respiratory Distress Syndrome

In order to identify the effect of noninvasive positive pressure ventilation (NPPV) on decreasing inflammatory response, improving the pathophysiological manifestation and reducing the morbidity and mortality in the moderate acute respiratory distress syndrome (ARDS) patients, the investigators conduct this clinical trial comparing NPPV with invasive mechanical ventilation in more than twenty ICUs in China.