Determination of the True Inclination Angle of the Main Bronchi Relative to the Median Sagittal Plane for Placement of a Left-Sided Double-Lumen Tube

Objectives This study aimed to determine the true inclination angle of the main bronchi relative to the median sagittal plane, using CT imaging to help increase accuracy of double-lumen tube (DLT) placement. Design In this retrospective study, 2 investigators independently measured normal chest CT scans from 50 male and 50 female patients. To determine the true AP axis, a mid-sagittal plane reference line (MSPRL) was drawn, intersecting the midsternum and the vertebral spinous process at the level of mid-carina. Lines were drawn through the center of each main bronchus to determine the inclination angle with regard to the MSPRL. Setting Research was conducted at a single institution, the Los Angeles County and University of Southern California Medical Center. Participants Normal chest CT images from 50 women and 50 men. Main Results The mean true inclination angle between the main bronchi and trachea in the mid-sagittal plane was 108.4° on the left compared with 96.2° on the right (p