The Flex-Tip™ tracheal tube does not reduce the incidence of postoperative sore throat: a randomized controlled trial

Sore throat after tracheal intubation is common with an incidence of 30-70%. The Parker Flex-Tip™ endotracheal tube (ETT) is designed to reduce trauma during ETT placement. This randomized single-blinded trial was designed to assess whether using the Flex-Tip ETT would reduce the incidence of postoperative sore throat and/or vocal change.

A Flex-Tip or a Mallinckrodt Hi-Lo® cuffed ETT was used by random allocation in 200 patients with normal-appearing airways requiring elective orotracheal intubation. On the second postoperative day, a blinded assessor recorded the incidence and severity of postoperative sore throat and voice alteration. The primary outcome was the incidence of moderate or severe sore throat. Secondary outcomes included vocal change, time to intubation, number of attempts/failures, incidence of oropharyngeal bleeding, and subjective ease of intubation.

Demographic data were similar between the two groups. Moderate or severe sore throat was observed in 12% of patients with the Flex-Tip ETT and 6% of patients with the Mallinckrodt Hi-Lo ETT (odds ratio [OR] 2.1; 95% confidence intervals [CI] 0.70 to 7.1; P = 0.14). The incidence of moderate or severe vocal change was 6% and 3%, respectively (OR 2.0; 95% CI 0.42 to 12.9; P = 0.50). Time to intubation, number of intubation attempts, incidence of oropharyngeal bleeding, and ease of intubation did not differ significantly between groups.

In this study involving experienced clinicians, no significant difference was observed in the incidence of postoperative sore throat or vocal change between the Flex-Tip ETT and the standard Mallinckrodt Hi-Lo cuffed ETT. This trial was registered at www.clinicaltrials.gov , NCT01095861.