FACILITATION OF FIBEROPTIC OROTRACHEAL INTUBATION WITH A FLEXIBLE TRACHEAL TUBE

Advancement of a tracheal tube (TT) over a flexible fiberoptic bronchoscope (FOB) is often impeded by obstruction at the arytenoid cartilage or epiglottis. We tested the hypothesis that the use of a flexible, spiral-wound TT, rather than the standard, preformed TT would facilitate tube passage into the trachea over the FOB. Forty patients scheduled to undergo general anesthesia with tracheal intubation were randomized to two groups. Then the trachea was intubated with a FOB, followed by passage of either a standard, preformed TT or a flexible, spiral-wound TT over the FOB. Ease of TT advancement over the FOB into the trachea was graded on a 1 (easy) to 3 (difficult) scale, and differences between the two groups were compared with chi2 analysis. The overall scores were compared with Wilcoxon's ranked sum test. Statistical significance was defined as P < 0.05. In patients randomized to the regular TT, only 35% (7/20) of first attempts to advance the TT over the FOB were successful. In the patients randomized to the spiral-wound TT, 95% (19/20) of first attempts were successful (P < 0.0001). Of the 13 regular TTs that were not successfully advanced on the first attempt, seven could not be passed after the second or third attempt (necessitating the use of the cross-over spiral-wound TT). In the only instance in which a spiral-wound tube was not successfully passed into the trachea on the first attempt, passage also was not achieved after the second or third attempt. The median scores for ease of tracheal passage (and 25-75 percentiles) were 2 (1-3) when the initial attempt was with the regular TT and 1 (1-1) when the initial attempt was with the spiral-wound TT (P < 0.0002). The authors conclude that a spiral-wound, wire-reinforced TT is less likely to encounter obstruction on glottic structures than its preformed counterpart. We attribute this difference to the greater side-to-side flexibility of the spiral-wound tube when compared with the preformed tube. This increased flexibility allows the spiral-wound tube to bend more easily and thus conform to the acute angle which the stenting FOB may develop in the posterior pharynx. An additional advantage may be conferred by the more obtuse angle of the wire-reinforced TT's distal end, making it less likely to impinge on pharyngeal soft tissue during its advancement into the trachea.