Question - nilakash

[ArchivalUser]

A 72 year old man is diagnosed with interstitial lung disease. His PaO2 is 51 on room air. The FEV1/FVC ratio is 0.90. The diffusion capacity (DLCO) is only 20% of what is predicted for someone of his age, height, weight and sex. How do you explain his blood gas and DLCO measurements?
A. The disease process has destroyed pulmonary capillaries
B. Fibrosis has thickened the interstitium and impeded diffusion
C. His airways are scarred and obstructed
D. Lung restriction prevents adequate ventilation

[ArchivalUser]

bbb

[ArchivalUser]

Thank you, A is correct.

[ArchivalUser]

can you please explain? I mean what's the Dx?

[ArchivalUser]

thanks, dx was given in the question stem interstitial lung disease, question asks explanation of his blood gas and DLCO measurement,that is why his dif usion capacity so low. DLCO measures how much carbon monoxide binds to pulmonary capillary blood, and that the thickened interstitium is not nearly the barrier to CO that it would be to oxygen. It is the loss of pulmonary capillary bed that lowers the DLCO.

[ArchivalUser]

thank you!