What is a significant change for a given test?

There are two ways of looking for a significant change.

I was taught to use the last criteria. 2 standard deviation for repetetive performance of these tests is 10%. Hence it stands to reason that we can consider a change as significantr only when it is over 10% of predicted change. Most of the Pulmonologists will use a combination first two criteria to assess a significant change.

Some patients can deflate following relief of obstruction and can increase inspiratory flow rates. Look at the flow volume loop for these changes.