In the bronchial blockers groups; all bronchial blockers will be placed via the ETT according to the manufacturers' recommended instructions. To achieve selective lobe collapse during surgery, the bronchial blocker will be advanced and directed to block selectively the desired operated lobe (or lobes) only; under vision with a pediatric FOB. The bronchial blocker will be placed deeply into the desired bronchus to minimize the chance of dislodgment back into the mainstem bronchus or trachea. If surgery will be performed in either the right middle or lower lobe, both lobes will be collapsed while the right upper lobe will be ventilated. If surgery will be performed in either the left lower or upper lobe, the left upper or lower lobe will be collapsed, respectively, while the remaining lobe will be ventilated. For the Arndt® blocker, once the blocker will be in an optimal position, the wire loop will be removed to use the wire channel for suction. To facilitate the selected lobar collapse, a barrel part of a 1-mL insulin syringe will be attached to the suction port of the bronchial blocker, and will be connected to suction.