A comparison between the GlideScope® classic and GlideScope® direct video laryngoscopes and direct laryngoscopy for nasotracheal intubation.

DESIGN: Prospective, randomized, clinical trial.

SETTING: University hospital operation room.

PATIENTS: 104 patients scheduled for elective dental or maxillofacial surgery were randomized to two groups: GlideScope® classic (GSc) and GlideScope® direct (GSd).

INTERVENTIONS: We compared the video laryngoscopes GSc and GSd with each other and with direct laryngoscopy (DL) for nasotracheal intubation with regard to visualization of the glottis, intubation success rate, and required time for and ease of intubation. The aim of the study was to determine whether the use of the video monitor alone reduced the difficulty of nasotracheal intubation, and also to investigate whether the GSc, with its blade designed for difficult airways, had an additional advantage over the video-assisted Macintosh blade (GSd). In both groups the investigators first performed laryngoscopy using the GSd blade, first with the monitor concealed and then with it visible. In the GSd group the tube was then inserted into the trachea with the video monitor screen visible. In the GSc group, the GSd blade was exchanged for the GSc blade, which was then used when inserting the tube with the screen visible.

RESULTS: The success rates and the times required for the video-assisted nasotracheal intubation did not differ significantly between the groups. A better view was obtained more often in the GSc group. In both groups there was a significant difference between direct laryngoscopy and the video-assisted intubation technique. Overall, using the video monitor improved the C-L scores by one grade in 52% and by two grades in 11% of the patients.

CONCLUSIONS: Video laryngoscopes increase the ease of nasotracheal intubation. The GSc blade might provide a better view of the laryngeal structures in case of a difficult airway than the GSd blade. Video laryngoscopy per se gives a better view of the glottis than direct laryngoscopy.