system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Which of the following will have the highest magnitude of the increased Alveolar aeriolar gradient at rest?
assistant
The correct answer is  Normal alveolar aeriolar gradient is 5-15 mm Hg. In interstitial lung disease, diffusion effect is present but PO2 can be normal and decreases in exercise. Hence in ILD A-a gradient is normal at rest and increases in exercise Massive pulmonary embolism, the increased dead space leads to very low PO2 and an increase of A-a gradient. Choice C and D are easily ruled out as both leads to hypoventilation leading to normal A-a gradient.