Estimation of the depth of left-sided double-lumen endobronchial tube placement using preoperative chest radiographs.

Background: Accurate placement of the double-lumen endobronchial tube (DLETs) is essential for optimal gas exchange during one-lung ventilation. The present study was designed to estimate the insertion depth of left-sided DLET using a preoperative chest radiograph.
Methods: Forty-five patients who underwent thoracic operations requiring intubation of a DLET were studied. The distance between the cephalic edge of the sixth cervical vertebra and the carina of the trachea (Dc-c) was measured from the anterior-posterior view of preoperative chest radiograph. After the tube was positioned in the main bronchus, a fiberoptic bronchoscope was introduced into the tracheal lumen to ensure the appropriate position of the DLET. Simple regression analysis for the insertion depth of the DLETs and Dc-c was performed.
Results: There was a highly significant correlation between the insertion depth of the DLET and both the Dc-c (y = 0.5304x + 19.646) and the body height (y = 0.1022x + 10.525), with P < 0.001 and P < 0.01, respectively.
Conclusions: To get the distance from the cephalic edge of the 6th cervical vertebra to the Dc-c from the chest radiograph preoperatively would be helpful for the evaluation of the proper insertion depth of the placement of DLET.