What defines moderate ARDS?

Moderate ARDS is specifically defined by a PaO2/FiO2 ratio that falls between 100 mmHg and 200 mmHg. This classification is based on the Berlin definition of ARDS, which categorizes the severity of acute respiratory distress syndrome into three levels: mild, moderate, and severe. Each level is determined by the degree of hypoxemia indicated by the PaO2/FiO2 ratio.

In this context, the range from 100 to 200 mmHg indicates significant impairment of oxygenation, which is a hallmark characteristic of moderate ARDS. The lower ratio signifies a more severe level of hypoxemia than what is observed in mild ARDS (PaO2/FiO2 ratio of 200-300 mmHg) but is not as severely impaired as in severe ARDS (PaO2/FiO2 ratio of less than 100 mmHg). Understanding these classifications is crucial for guiding management and treatment strategies for patients with different levels of ARDS.