One-lung ventilation in children using the single-lumen tracheal tube.

In children, it has been shown that the angles of the tracheobronchial bifurcation total approximately 80 degrees; the overall mean of the right bronchial angle is about 30o, while the left bronchial angle is about 50o. This tracheobronchial relationship may explain why the tracheal tube is more likely to enter the more vertical and wider right main stem bronchus than the more obliquely placed and narrower left main stem bronchus1. However, Block challenged this conclusion, suggesting that the tracheal tube invariably enters the right bronchus because the bevel of the tube faces the left following insertion, and its tip, therefore, lies to the right of the midline of the trachea2. This postulation has been confirmed by Baraka et al in children, who showed that the available left-bevelled tube enters the right main bronchus, while a right-bevelled tube whose tip lies to the left of the midline of the trachea enters the left main stem bronchus. Each child served as his own control, suggesting that the bevel of the tracheal tube, and not the tracheobronchial angle is the principal factor determining the side of bronchial intubation3.