question about PFt's in restrictive lung ds

[HiddenTruth]

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So, do they have a normal FEV1: FVC ratio owing to a decrease in both PROPORTIONALLY? Or, does the FEV1:FVC ratio INCREASE (despite both individually being decreased) owing to a relative increase in FEV1 secondary to increased elasticity (normal 4L --> 3L) compare to FVC (normal 5--> now 3L)? My point is that with the increased elasticity, is your FEV1 very close to the FVC?

Normal FEV1: FVC = 75-80%. So, in ILD/RLD, does this ratio increase or stay the SAME? Thanks.

 

[omarsaleh66]

So, do they have a normal FEV1: FVC ratio owing to a decrease in both PROPORTIONALLY? Or, does the FEV1:FVC ratio INCREASE (despite both individually being decreased) owing to a relative increase in FEV1 secondary to increased elasticity (normal 4L --> 3L) compare to FVC (normal 5--> now 3L)? My point is that with the increased elasticity, is your FEV1 very close to the FVC?

Normal FEV1: FVC = 75-80%. So, in ILD/RLD, does this ratio increase or stay the SAME? Thanks.

i think both points are correct. Even tho the total lung capacity or FVC is lower, the FEV1/FVC is the same or higher in restrictive lung disease cuz most of the expiration in these patients occurs during the first second of expiration (I think this is abnormal).

Im not sure, but I think this is due to the higher radial traction and that opens up the airways so u can breathe out most of the air in that first second, but there's less compliance so that first second is all u got and total capacity remains low(this goes with ur second point)

Someone please correct me if this is wrong.
Later