Double-Lumen Endotracheal Tube Placement: Knowing Depth of Insertion Firsthand May Make a Difference

Expert opinion on the use of fiberoptic bronchospe to check the insertion depth of the left-sided double-lumen tube

Left-sided double-lumen tube (LDLT) is commonly used to achieve one lung isolation in most thoracic surgical procedures. Traditionally, the LDLT is blindly placed using direct or video laryngoscopy. In this brief report, we highlight the importance of using our novel insertion depth formula to predict the appropriate LDLT insertion depth and demonstrate the current evidence supporting the efficacy of the formula. Also, we will discuss two relatively new devices of LDLTs: one with an embedded camera at the distal end of the tracheal lumen and the other with a carinal cuff between the bronchial cuff and the tracheal lumen in reducing the incidence of too deep inserted LDLT. We advocate that using our novel formula and these two new devices may reduce but not eliminate the need for FOB to check the insertion depth of LDLT.

Efficacy of height-based formula to predict insertion depth of left-sided double lumen tube: A prospective observational study

The insertion depth of the left-sided double-lumen tube needs careful positioning and bronchoscopic confirmation. Several formulae based on body height have been used for estimating the optimal insertion depth of a left-sided double-lumen tube. We conducted this prospective study to test the hypothesis that our earlier developed height-based formula (0.25 × body height^0.916) could predict the accurate insertion depth of a left-sided double-lumen tube. After obtaining ethical approval, 66 patients who underwent thoracic surgery were included. A left-sided double-lumen tube was advanced blindly to the predicted depth of insertion calculated using our formula. The optimal position of the left-sided double-lumen tube was confirmed using a fibreoptic bronchoscope. The primary outcome was the percentage of tubes placed in the optimal position without the need for further adjustments. The secondary outcomes included the need for bronchoscopic adjustments and the final correct insertion depth of the left-sided double-lumen tube. The formula resulted in an optimum position of the left-sided double-lumen tube without further adjustments in 45 patients (70%) (95% confidence interval 58%-80%). The left-sided double-lumen tube was withdrawn or advanced in 18.2% and 12.1%, respectively, to achieve the optimal insertion depth. We found that our formula provided satisfactory positioning in about 70% of patients and that in the remaining patients, the adjustments required to achieve satisfactory positioning under fibreoptic bronchoscope guidance were minimal. Nevertheless, as it is not possible to predict which patients will have a satisfactory tube position, bronchoscopic confirmation for the final positioning is still required.