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

Abstract

Context: Literature suggests glottic view is better with straight blades while tracheal intubation is easier with curved blades. Aims: To compare glottic view and ease of intubation with Macintosh, Miller, McCoy blades and the Trueview® laryngoscope. Settings and Design: This prospective randomised study was undertaken in operation theatres of a 550 bedded tertiary referral cancer centre after approval from the Institutional Review Board. Methods: 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. Statistical Analysis: Demographic data, Mallampati classification were compared using the Chi-square test. A P<0.05 was considered significant. Results: 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. Conclusions: 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.

Keywords

• Cormack lehane grade
• external laryngeal manipulation
• intubation
• laryngoscopy