LOINC long common name : Arterial-alveolar oxygen Partial pressure ratio;
LOINC short name : a/A PO2 Rto;
LOINC description : The arterial/alveolar oxygen tension ratio, also known as a/APO2, is a measure of
gas-exchange. While it was originally believed to be less affected by the fraction
of inspired oxygen (FiO2) compared to other measures such as the alveolar-arterial
oxygen tension difference (PAO2-PaO2), the a/APO2 has been found to be somewhat dependent
on FiO2, especially with higher degrees of pulmonary shunting. [PMID: 3742320];
Has component