BACKGROUND: We compared the ease of viewing the glottis under direct vision during conventional laryngoscopy with the quality of indirectly viewing on a monitor during laryngoscopy with a Macintosh videolaryngoscope in a multicenter study. PATIENTS AND METHODS: After ethical approval and written informed consent of 300 patients with no anticipated difficult airway, conventional laryngoscopy with a Macintosh videolaryngoscopy blade was performed and the quality of the view of the glottis was assessed and documented according to the Cormack and Lehane scoring system as modified by Yentis and Lee. Subsequently, the indirect viewing conditions on the monitor were documented without changing the position of the blade. Differences between both distributions were analyzed using the Bland-Altman Test. RESULTS: Videolaryngoscopy improved the laryngoscopy score by 1 grade in 72 cases, by 2 grades in 17 cases and by 3 grades in 2 cases. A relevant improvement (from grades III/IV to II) was found in 28 patients. Viewing conditions worsened in 3 cases by 1 grade, in 4 cases by 2 grades and in 3 cases by 3 grades. A statistical analysis of the data gave a bias of 0.31 and an SD bias of 0.77.The 95% confidence interval of the distribution ranged from -1.12 to 1.81. CONCLUSION: Videolaryngoscopy can lead to better viewing conditions but in rare cases it may result in worse viewing conditions.
BACKGROUND: We compared the ease of viewing the glottis under direct vision during conventional laryngoscopy with the quality of indirectly viewing on a monitor during laryngoscopy with a Macintosh videolaryngoscope in a multicenter study. PATIENTS AND METHODS: After ethical approval and written informed consent of 300 patients with no anticipated difficult airway, conventional laryngoscopy with a Macintosh videolaryngoscopy blade was performed and the quality of the view of the glottis was assessed and documented according to the Cormack and Lehane scoring system as modified by Yentis and Lee. Subsequently, the indirect viewing conditions on the monitor were documented without changing the position of the blade. Differences between both distributions were analyzed using the Bland-Altman Test. RESULTS: Videolaryngoscopy improved the laryngoscopy score by 1 grade in 72 cases, by 2 grades in 17 cases and by 3 grades in 2 cases. A relevant improvement (from grades III/IV to II) was found in 28 patients. Viewing conditions worsened in 3 cases by 1 grade, in 4 cases by 2 grades and in 3 cases by 3 grades. A statistical analysis of the data gave a bias of 0.31 and an SD bias of 0.77.The 95% confidence interval of the distribution ranged from -1.12 to 1.81. CONCLUSION: Videolaryngoscopy can lead to better viewing conditions but in rare cases it may result in worse viewing conditions.