Predicting the Size of a Left Double-Lumen Tube for Asian Women Based on the Combination of the Diameters of the Cricoid Ring and Left Main Bronchus: A Randomized, Prospective, Controlled Trial

BACKGROUND: There are limited data about how to choose the correct size of a double-lumen tube (DLT). It is especially difficult to select an appropriate DLT for Asian women because of their small stature. The primary aim of this study was to compare the overall accuracy of the DLT selected based on the combination of transverse diameter of cricoid ring and the equivalent diameter of the left main bronchus (ED-LMB) with that based on the ED-LMB alone for Asian women. METHODS: In this study, 80 consecutive and blinded female patients were assigned randomly to 2 groups. The overall accuracy of the selection of DLT was compared between the Combined group and LMB group. The accuracy of the selection of tracheal segment and bronchial segment was also compared between the 2 groups. The postoperative hoarseness and sore throat were investigated by blinded assessors. RESULTS: The overall accuracy of selection of the DLTs was higher in the Combined group than that in the LMB group (87.5% vs 60.0%; P = .010). The accuracy of selection of tracheal segment was also higher in the Combined group (92.5% vs 67.5%; P = .010). The accuracy of selection of bronchial segment was similar between the groups (95.0 % vs 86.1%; P = .246). The severity of sore throat was higher in the LMB group at 24 hours after the operation (P = .001). CONCLUSIONS: The correct size of DLT for Asian women should be selected based on the combination of transverse diameter of cricoid ring and the ED-LMB.