Effect of the size of a tracheal tube and the efficacy of the use of the laryngeal mask for fibrescope-aided tracheal intubation

We randomly allocated 60 patients with normal airways into three groups to compare the ease of fibrescope-aided tracheal intubation using 8.0-mm internal diameter (group F-8) and 6.0-mm (group F-6) reinforced tracheal tubes and to evaluate the efficacy of the laryngeal mask as an aid for fibreoptic tracheal intubation (group L). In group F-8 tracheal intubation was optimal in 2 of 20 patients and in two patients in whom intubation over the fibrescope was difficult the attempts resulted in inadvertent oesophageal intubation. In group Fg intubation was always successful and significantly easier than in group F-8 (p < 0.005; 95% confidence interval for the difference in the proportion of the optimal intubation grade: 20-70%). In group L tracheal intubation was optimal in 18 of 20 patients and easier than in group F-6 (p = 0.014; 95% confidence interval for difference: 10-60%). In both groups F-6 and L tracheal intubation was completed within less than about 1 min. We conclude that conventional fibrescope-aided tracheal intubation with a 6.0-mm tracheal tube is easier than with an 8.0-mm tube and that the laryngeal mask facilitates fibrescope-aided tracheal intubation.