Figure 3.

(A) Graphical depiction of the β-angle. The β-angle is calculated as β = 180 − tan^–1[(PEFR − MEF₅₀)/(0.5 × FVC)] + tan^–1[MEF₅₀/(0.5 × FVC)]. Values of β > 180° correspond to a configuration in which the curve is convex, whereas values of β < 180° correspond to a curve that is concave. The vertical dashed line represents the volume corresponding to 0.5 × FVC, and the intersecting horizontal line depicts the flow at this point (MEF₅₀). (B) Association between β-MMEF and mean expert score (MES).