A Clinical Assessment of Macintosh Blade, Miller Blade and King Visiontm Videolaryngoscope for Laryngeal Exposure and Difficulty in Endotracheal Intubation

Abstract

Previous studies suggest glottic view is better achieved with straight blades while tracheal intubation is easier with curved blades and videolaryngoscope is better than conventional laryngoscope. AIMS Comparison of conventional laryngoscope (Macintosh blade and Miller blade) with channelled videolaryngoscope (King Vision TM) with respect to laryngeal visualisation and difficulty in endotracheal intubation. SETTINGS AND DESIGN This prospective randomised comparative study was conducted at a tertiary care hospital (in ASA I and ASA II patients) after approval from the Institutional Ethics Committee. METHODS We compared Macintosh, Miller, and the King Vision-TM videolaryngoscope for glottic visualisation and ease of tracheal intubation. Patients undergoing elective surgeries under general anaesthesia requiring endotracheal intubation were randomly divided into three groups (N=180). After induction of anaesthesia, laryngoscopy was performed and trachea intubated. We recorded visualisation of glottis (Cormack-Lehane grade-CL), ease of intubation, number of attempts, need to change blade, and need for external laryngeal manipulation. STATISTICAL ANALYSIS Demographic data, Mandibular length, Mallampati classification were compared using ANOVA, Chi-square test, Kruskal-Wallis Test, where P value <0.005 is statically significant. RESULTS CL grade 1 was most often observed in King Vision-TM VL group (90%) which is followed by Miller (28.33%), and Macintosh group (15%). We found intubation was to be easier (grade 1) with King Vision-TM VL group (73.33%), followed by Macintosh (38.33%), and Miller group (1.67%). External manipulation (BURP) was needed more frequently in patients in Miller group (71.67%), followed by Macintosh (28.33%) and in King Vision-TM VL group (6.67%). All (100%) patients were intubated in the 1 st attempt with King Vision-TM VL group, followed by Macintosh group (90%) and Miller group (58.33%). CONCLUSIONS In patients with normal airway, glottis direct laryngoscope with Miller blade may provide better glottis view than Macintosh blade, but intubation was easier with Macintosh blade laryngoscope. Our study supports the superior performance of King Vision TM videolaryngoscope for both glottis visualisation and ease to intubate.

Comparison of Laryngeal Visualisation and Ease of Intubation Between Macintosh and Medan Video Laryngoscope

“…In a study by Teoh et al, 12 there was a greater need of external laryngeal pressure with Macintosh (38%) and C-Mac (31%) as compared with GlideScope (11%) or Airway scope (0%) and the difference was statistically significant. In a study by Garhwal AM et al, 16 the need for external laryngeal manipulation was more frequent in Macintosh laryngoscope (71.67%) than with video laryngoscope (6.67%).…”

Evaluation of Glottic Visualization and Ease of Intubation at Induction of General Anesthesia

“…The McGrath video laryngoscope (aircraft Medical, Ltd, Edinburgh, UK) is equipped with a liquid-crystal display (LCD) screen on the top of its handle and a thin acrylic cover with a 60° angle that allows an indirect vision of glottis. 10 Garhwal AM and his associate has found in a study that better glottic visualization was 15% with Macintosh and ease of intubation was 38.33% 11 .…”