From the Research
Double lumen tubes (DLTs) should be sized based on the outer diameter of the tracheal and bronchial cuffs when they are inflated, matched with the inner diameter of the trachea and bronchus measured on chest CT slice, to minimize airway complications. When selecting the size of a DLT, several factors should be considered, including patient gender, height, and tracheal diameter.
- For adult males, a 37 Fr tube is typically appropriate, as recommended by a study published in the Saudi journal of anaesthesia 1.
- For adult females, a 35 Fr tube is generally recommended, also based on the study published in the Saudi journal of anaesthesia 1. However, the most recent and highest quality study, published in Scientific reports in 2024, suggests that the method which matched the inner diameter of the trachea and bronchus measured on chest CT slice with the outer diameter of the tracheal and bronchial cuffs when they were inflated to select an appropriate size of LDLT can reduce the incidence of airway complications 2. During placement, the bronchial cuff should pass through the vocal cords with minimal resistance. If significant resistance is encountered, downsize immediately to prevent airway trauma. After placement, proper positioning should be confirmed with fiberoptic bronchoscopy. Having multiple sizes available before attempting placement is advisable, as anatomical variations may necessitate adjustments from these general guidelines. Correct sizing is crucial to ensure adequate ventilation while minimizing the risk of airway trauma during thoracic procedures requiring one-lung ventilation. Other studies, such as those published in the British journal of anaesthesia 3, Anaesthesia and intensive care 4, and Annals of cardiac anaesthesia 5, provide additional information on the selection of DLT size, but the study published in Scientific reports in 2024 provides the most recent and highest quality evidence.