The effects of tracheal tube tip design and tube thickness on laryngeal pass ability during oral tube exchange with an introducer.

UNLABELLED: We compared the ease of passage through the glottis of two different tubes and two different sizes of tracheal tube exchanger (TE) during introducer-guided tracheal intubation. One tube was a polyvinyl chloride tube with a standard bevel, and the other was a newly designed tube with a hemispherical bevel. The outer diameters (OD) of the two TEs were 2.5 and 5.0 mm. After the standard induction of anesthesia, followed by vecuronium-induced paralysis, a TE was inserted into the trachea with a direct laryngoscope. By using the introducer as a guide, the tracheal tube was inserted into the trachea. The difficulty in passing the tube was assessed by a blinded observer and graded with a four-point scale. The newly designed tube was inserted more smoothly than was the conventional tube when the 2.5-mm-OD TE was used (P < 0.01). In situations such as those occurring after one-lung anesthesia, when use of a thicker TE is not applicable, this newly designed taper-tipped tube may be considered as an adjunct to oral tracheal tube exchange, using a thinner (smaller-OD) TE as the guide for tracheal intubation.

IMPLICATIONS: In situations such as after one-lung anesthesia, when use of a thicker tube exchanger (TE) is not applicable, a newly designed taper-tipped tube with the leading edge in the midline may be considered as an adjunct to an oral tracheal tube exchange, using a thinner TE as the guide for tracheal intubation.