Figure 2 –

A, B, Time courses of V_rc,p, V_rc,a, V_ab, and V_cw during a typical respiratory cycle during quiet breathing at rest in a representative patient before (A) and after (B) lung volume reduction surgery (LVRS). Black line represents the inspiratory portion of the respiratory cycle, and asynchronous movement of abdominal ribcage compartment (RC,a) before LVRS is clearly demonstrated, as is the improvement thereof after LVRS. Lissajou figures of the dynamic loops of ΔV_rc,p vs ΔV_rc,a (θRC) and ΔV_rc,a vs ΔV_ab (θDIA) during quiet breathing are used to calculate θ. m = line parallel to the x axis at 50% of one compartment’s tidal volume; s = the second compartment’s tidal volume. Phase shift is calculated as θ = sin⁻¹ (ms⁻¹). θDIA = phase shift angle between V_rc,p and V_rc,a; θRC = phase shift angle between V_rc,p and V_rc,a. See Figure 1 legend for expansion of other abbreviations.