Ventilation corrected oxygen tension in lethal pulmonary embolism.

Lethal pulmonary embolism is associated with hypoxemia and hypocapnia in the vast majority of cases. The easily calculated ventilation corrected oxygen tension was a very sensitive test in patients breathing air. It yielded no normals, four percent mild hypoxemia, and 96 percent moderate to extreme hypoxemia. The alveolar-arterial oxygen tension difference and oxygen ratio were equally sensitive during air breathing. During oxygen inhalation, alveolar-arterial oxygen difference was most sensitive; oxygen ratio was second best; and oxygen saturation was the least sensitive test.