Figure 2. Flow volume loops show (A) early closure of the expiratory curve in a patient with air leaking from both lungs after surgery;(B) air leak reduced when chest suction was removed, (C) a persistent and increasing leak from the patient's left lung; and (D) a flow volume loop after surgical closure of a tear in the left lung. V^Tinsp= inspired tidal volume, V (^Texp)= expired tidal volume.