A prospective, randomised, cross-over trial comparing two standard polyvinyl chloride tracheal tubes. Are all the tubes the same?

Background: A randomised study was conducted on the number of attempts made during the conventional endotracheal intubation of a mannequin using two polyvinyl (PVC) tracheal tubes, apparently similar but from different manufactures: INTERSURGICAL (IS; Intersurgical S.L., Madrid, Spain) and Mallinckrodt (ML; Mallinkrodt Medical S.A., Madrid, Spain).

Methods: A total of 26 anaesthesiologists, in randomly established order (generated by Epidat 3.1) intubated a mannequin twice using a different tube each time. The tubes were masked by painting them to prevent recognition. The main outcome of the study was to compare the number of attempts needed to complete the manoeuvre for each tube. Data on intubation time and failed intubations were also collected.

Results: The number of attempts with the ML tube was significantly lower than with the IS tube. Intubation was completed on the first attempt with the ML tube in 93.3% of cases, while using the IS tube the percentage fell to 30.8% (Fisher exact test, P<.001). The time required to complete the manoeuvre was greater with the IS tube (median 10.8seconds, interquartile range 6-22) than with the ML tube (median 4.4seconds, interquartile range 3.5 to 6.3).

Conclusions: The PVC tube from the ML manufacturer was superior when compared with the IS, the latter was also associated with a larger number of attempts to complete intubation using a conventional Macintosh blade.