Compatibility of left-sided double-lumen endobronchial tubes with tracheal and bronchial dimensions: a retrospective comparative study

Double-lumen endobronchial tubes (DLT) continue to be the most widely used method for obtaining lung isolation during anesthesia. We compared recommendations for DLT size selection with radiologically assessed lower airway dimensions gathered from a large patient population.For this retrospective comparative study, we assessed computed tomography (CT) scans of 150 adults with no known airway pathologies. Using these scans, we measured the diameter and length of the trachea and the diameter of the mainstem bronchi. These airway dimensions were then compared to the dimensions of left-sided DLTs of three different manufacturers. Size selection was based on one standard textbook's recommendations.We found the recommended DLT sizes were occasionally too small but more often too large, particularly in the endobronchial airway. With the DLT Vivasight-DL®, mismatching occurred in 28.7% (43/150) of the patients at the distal mainstem bronchus and 8% (12/150) at the tracheal level. This mismatching happened most often in females (left distal mainstem bronchus 34/68, 50%; trachea 9/68, 13.2%). Conversely, the DLT was more often too small for male patients in both the left main bronchus (SHER-I-BRONCH®: 8/82, 9.8%) and the trachea (SHER-I-BRONCH®: 2/82, 2.4%). The endobronchial tube portion was more often too long in females (Vivasight® DLT: 11/68, 16%) than males (9/82, 11%).A considerable proportion of the recommended DLT sizes from all three manufacturers was incompatible with individual patient's lower airway dimensions.