Back extrapolation is the method used to determine "time zero" when measuring which of the following parameters? A) FVC B) FEV₁ C) FEF_25%-75% D) MVV

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Back extrapolation is the method used to determine "time zero" when measuring FEV1. The test involves having the patient exhale as forcefully and quickly as possible, and the volume of air exhaled in the first second is measured. However, it is impossible to accurately measure the volume of air exhaled in the first instant of the test, so back extrapolation is used to estimate this value. By extrapolating the slope of the volume-time curve back to time zero, an estimated value for the volume exhaled in the first instant can be calculated.

Back Extrapolation Is the Method Used to Determine "Time Zero