Comparison of glottic visualisation and ease of intubation with different laryngoscope blades

Literature suggests glottic view is better with straight blades while tracheal intubation is easier with curved blades.

To compare glottic view and ease of intubation with Macintosh, Miller, McCoy blades and the Trueview(®) laryngoscope.

This prospective randomised study was undertaken in operation theatres of a 550 bedded tertiary referral cancer centre after approval from the Institutional Review Board.

We compared the Macintosh, Miller, McCoy blades and the Trueview(®) laryngoscope for glottic visualisation and ease of tracheal intubation; in 120 patients undergoing elective cancer surgery; randomly divided into four groups. After induction of anaesthesia laryngoscopy was performed and trachea intubated. We recorded: Visualisation of glottis (Cormack Lehane grade), ease of intubation, number of attempts; need to change the blade and need for external laryngeal manipulation.

Demographic data, Mallampati classification were compared using the Chi-square test. A P<0.05 was considered significant.

Grade 1 view was obtained most often (87% patients) with Trueview(®) laryngoscope. Intubation was easier (Grade 1) with Trueview(®) and McCoy blades (93% each). Seven patients needed two attempts; one patient in Miller group needed three attempts. No patient in McCoy and Trueview(®) Groups required external laryngeal manipulation.

We found that in patients with normal airway glottis was best visualised with Miller blade and Trueview(®) laryngoscope however, the trachea was more easily intubated with McCoy and Macintosh blades and Trueview(®) laryngoscope.