The authors are to be congratulated for comprehensive and practical guidelines on an important topic . We agree that re-intubation over an airway exchange catheter (AEC) can be a complex procedure. A small calibre (11-FG) AEC provides patient comfort and tolerability, but renders the relatively flimsy AEC prone to posterior displacement as the larger and stiffer adult tracheal tube is advanced during re-intubation, such that the tube may snag on the corniculate/arytenoid cartilages. However, the Difficult Airway Society (DAS) guidelines fail to mention intermediate use of an Aintree intubation catheter (William Cook Europe, Bjaeverskov, Denmark) during re-intubation. Whilst not appropriate for primary use as an AEC at extubation due to its larger (19-FG) diameter and stiffness, these same attributes temporarily stiffen and enlarge an 11-FG AEC (Fig. 1) during re-intubation, allowing for easier railroading of a the tube, with less likelihood of snagging.
In addition, mismatch between the external diameter of the small AEC and the internal diameter of the larger tracheal tube leaves a ‘lip’ of tracheal tube that can snag on glottic structures. Previous authors have recommended the use of a tracheal tube with a ‘beaked’ leading edge to avoid this problem . The DAS guidelines advise railroading a tube with the bevel facing anteriorly, achieved by clockwise rotation of the tube by 90 degrees from the beaked position, but this risks snagging. We suggest that counterclockwise rotation of the tube by 90 degrees over an AEC, with the bevel facing posteriorly, is more likely to avoid this problem .