In a patient with worsening hypoxia, which value or condition should the nurse anticipate to be consistent with ARDS?

In a patient with worsening hypoxia consistent with Acute Respiratory Distress Syndrome (ARDS), a PaO2/FiO2 ratio below 300 is indicative of this condition. ARDS is characterized by significant impairment in gas exchange due to inflammation and fluid accumulation in the alveoli, leading to decreased lung compliance and hypoxemia. The PaO2/FiO2 ratio is a critical measurement used to assess the severity of the impairment in oxygenation. A value below 300 mmHg signifies mild to moderate ARDS, while a ratio below 200 mmHg indicates severe ARDS.

The rationale for recognizing that a PaO2/FiO2 below 300 is consistent with ARDS lies in how oxygenation is affected by the disease process. As ARDS progresses, the ability to oxygenate the blood decreases significantly, thereby lowering this ratio. Monitoring this value helps in determining the extent of respiratory failure and guiding treatment strategies, such as the use of mechanical ventilation and the application of PEEP (positive end-expiratory pressure).

In contrast, normal arterial blood gases would not be expected in ARDS, as this condition typically results in significant abnormalities. Additionally, increased lung compliance is contrary to what occurs in ARDS; instead, lung