welcome redditors!to snoo-finity ... and beyond!

NBME 20 Answers

nbme20/Block 2/Question#38

A 50-year-old woman with a restrictive pulmonary ...

Functional residual capacity: decreased; Residual volume: decreased; Vital capacity: decreased

Login to comment/vote.

 +0  upvote downvote
submitted by mbourne(8),

In restrictive lung disease, literally all lung values are DECREASED ("restricted") except for the FEV1/FVC ratio. FEV1/FVC ratio may be normal or increased (increased only if FEV1 decreases a bit less than the decrease in FVC, resulting in an increased ratio).





Ok, so you can reason this by drawing out REIT (sorry I can't draw it here). Anywho, you know its a restrictive disorder and will have a decreased RV, so automatically you know that RV is a component of FRC (FRC= RV+ERV). Thus, FRC should also be decreased. You also know that restrictive diseases are characterized by a steady decrease in FEV1/FVC since both components are decreasing. This leaves you with VC decreasing since FVC= forced vital capacity.

champagnesupernova3  FEV1 and FVC both decrease but FEV1/FVC actually increases because FVC decreases more than FEV1 so the ratio increases +  
fluentinwhale  Excuse my stupidity but what is REIT? +  
eliassam1  REIT, Residual volume, ERV, IRV, TV R E = FRC E I T = VC I T = IC REIT = TLC total lung capci I +  
eliassam1  Residual volume, ERV, IRV, TV R E = FRC E I T = VC I T = IC REIT = TLC total lung capci +