Maximum alveolar aerial oxygen difference is seen in:
Pulmonary embolism
Severe asthma
Interstitial lung disease
Foreign body in upper airway
Ans: A. Pulmonary embolism (Ref: Ganong 25/e p634, 24/e p634)In pulmonary embolism gradient increases to very high level (I0 to 83 mm Hg from normal level of 5 mm Hg).But normal Pa02 level on aerial blood gas analysis does not exclude the diagnosis of acute pulmonary embolism.It is also increased in ILD.