Which of the following statements are true of the FEF_25-75_%?
I.It is more sensitive to flow coming from medium to small airways.
II.Normal FEF_25-75% for a healthy young adult is approximately 4 to 5 L/sec.
III.It does not have more variance than other measures of flow.
IV.Because the FEF_25-75% is so variable, its validity is questionable.

Question

Quizplus · Accepted Answer

The average forced expiratory flow rate over the middle 50% of the FVC (FEF_25-75%) is more sensitive to flow coming from medium to small airways. The primary resistance to expiratory flow during the middle half of the FVC comes from rapid narrowing of small airways as the lung deflates. Normal FEF_25-75% for a healthy young adult is approximately 4 to 5 L/sec. Unfortunately, this test has more variance than other measures of flow, even in normal people. An FEF_25-75% equal to 65% of the predicted value may still be within statistically normal limits. Because the FEF_25-75% is so variable, its validity is questionable; the FEV₁ is more useful and reliable in assessing the response to bronchodilators.

Which of the Following Statements Are True of the FEF25-75%

Which of the Following Statements Are True of the FEF_25-75_%