Background: Absence of interlobar collateral ventilation is essential to achieve lobar volume reduction after endobronchial valve (EBV) treatment and can be assessed using the Chartis measurement. However, especially in lower lobe measurements, Chartis can be complicated by the “no-flow phenomenon”, during which a sudden cessation of flow is observed, leading to an unreliable measurement. If this phenomenon occurs in the right lower lobe, when measuring collateral flow over the right major fissure, the entrance to the right middle lobe should be occluded, and the Chartis balloon should be placed in the right upper lobe. Both Watanabe spigots and balloon catheters can be used to achieve occlusion. Objective: Our aim was to demonstrate that right middle lobe occlusion with a blocking device is helpful in obtaining a reliable Chartis outcome in case of the no-flow phenomenon in the right lower lobe. Methods: We performed a retrospective analysis of patients scheduled for EBV treatment in an EBV registry between September 2016 and September 2019. Results: We included 15 patients with severe emphysema (median age 63 years [range 47–73], 73% female, and FEV1 24% [range 19–36] of predicted), who required temporary middle lobe occlusion (12 Watanabe spigot, 3 balloon catheter). After occlusion, a reliable Chartis outcome was obtained in all patients. Conclusion: Temporary middle lobe occlusion using a blocking device is helpful in obtaining a reliable Chartis outcome in case of a right lower lobe no-flow phenomenon.