Question

PaO2/FiO2 ratio for ALI/ARDS?

< 300 *

Answer 1

The
`PaO2/FiO2` ratio less than
`300` is used to identify
`ALI/ARDS`, reflecting severe gas exchange impairment in the lungs. This ratio is clinically significant for diagnosing and managing patients with respiratory distress.

Step-by-step explanation:

The
`PaO2/FiO2` ratio is a crucial calculation used to assess lung function, particularly in patients with Acute Lung Injury (ALI) or Acute Respiratory Distress Syndrome (ARDS). In clinical settings, a
`PaO2/FiO2` ratio of less than
`300` is one of the criteria used to identify ALI/ARDS, indicating a severe impairment of gas exchange. As for the provided information regarding the calculation of the alveolar partial pressure of oxygen (
`PaO2`), it suggests that in the presence of an alveolar
`CO2`pressure (
`PCO2`) of
`40 mm Hg` and a respiratory quotient (RQ) of
`0.8` which are typical values, the alveolar
`PaO2` would be calculated using a specific formula involving these parameters.

The content loaded
`PaO2/FiO2` ratio helps determine the extent of lung compromise in ALI/ARDS and guides clinicians in management and therapeutic decisions. This ratio is derived from the arterial oxygen tension (
`PaO2`) to the fraction of inspired oxygen (
`FiO2`), indicating the level of hypoxemia and the patient's respiratory efficiency.