Fig. 3

The procedure for lung isolation. a. Measuring the DFC’s length and the distance from the left main bronchus to the proximal opening of the LMA. b. Inserting the modified DFC into the left main bronchus. The arrow “A” represented the proximal opening of the modified DFC’ drainage lumen, the arrow “B” represented the proximal end of DFC, which was also the air inlet of the DFC’ balloon. c-d. The proximal opening of the modified DFC’ drainage lumen (arrow “A”) was occluded with a sealing cap of a 20 G BD arterial cannula (arrow “C”) to prevent deflating (Becton Dickinson Infusion Therapy Systems Inc., Sandy, Utah, USA). e. Status before the breathing circuit and the LMA was connected. The arrow “D” represented the proximal opening of the LMA, the arrow “E” represented the corner of the breathing circuit, the arrow “F” represented the oesophageal drain tube. f-g. Connecting the breathing circuit and the LMA together. The part of the DFC that longer than the distance from the left main bronchus to the proximal opening of the LMA was the distance from arrow “B” to arrow “D”, which was about 3 centimeters so that the proximal end of the DFC (arrow “B”) could be fixed in the corner of the breathing circuit (arrow “E”)