A Comparison Of The Truview^TM EVO₂ Laryngoscope With The Macintosh Laryngoscope In Patients With Cervical Vertebral Diseases

Part 1:A comparison of the Truview^TM EVO₂ laryngoscope with the Macintosh laryngoscope in patients scheduled for cervical vertebral surgeryObjective:The aim of this study was to prospectively compare laryngoscopy and intubation of Truview laryngoscope with that of Macintosh laryngoscope in patients scheduled for cervical vertebral surgery.Methods:One hundred patients scheduled for elective cervical vertebral surgery were enrolled in this randomised crossover study.After induction,the Macintosh laryngoscope and Truview laryngoscope were used in turn for direct laryngoscopy.The order of laryngoscope used was randomized by a random table list.The view of glottis at laryngoscopy was scored according to the Cormack-Lehane(C/L) grading criteria.The trachea was intubated after the second grading at laryngoscopy was completed.Relevant parameters were recorded,including demographics,airway assessment features(BMI, mouth opening,thyromental distance,Mallampati oropharyngeal scale,neck movement), C/L grade,the time to intubation(TTI),difficult laryngoscopy and related complications.Results:Of the 100 patients,34 had the same C/L grade score with both laryngoscopes.Of the remaining patients,64 showed improvement and 2 showed deterioration in C/L grade when the Truview laryngoscope was used compared to the Macintosh laryngoscope (Wilcoxon test,P<0.001).The proportion of difficult laryngoscopy was 5%obtained with the Truview laryngoscope,and was significantly lower than 28%with the Macintosh laryngoscope(McNemar test,P<0.001).Of the 100 patients,only 2 patients in Macintosh group required more than one attempt at intubation(two attempts) and were not included in the final TTI analysis.The TTI(28.6±9.0 s )in Macintosh group was significantly lower than that(33.4±8.6 s) in Truview group(independent-samples t test,P=0.008, 95%CI 1.3～8.3).There were significant association between airway assessment features and C/L grade(Spearman test,P<0.05).2 patients had a small cut on the lips and 3 patients had slight sore throat.Conclusion:The Truview^TM EVO₂ laryngoscope could give a better glottic view and easier intubation than those by Macintosh laryngoscope in patients scheduled for cervical vertebral surgery.Part 2:A comparison of the Truview^TM EVO₂ laryngoscope with the Macintosh laryngoscope in patients with ankylosing spondylitisObjective:The aim of this study was to prospectively compare laryngoscopy and intubation of Truview laryngoscope with that of Macintosh laryngoscope in patients with ankylosing spondylitis.Methods:32 patients with ankylosing spondylitis who presenting for hip replacement surgery were chosen to undergo tracheal intubation by Truview laryngoscope.Following induction, all patients underwent an intial direct laryngoscopy by Macintosh laryngoscope.After intial laryngoscopy,positive pressure ventilation was continued using a facemask and then laryngoscopy and tracheal intubation was performed by Truview laryngoscope.The tracheal intubation would be performed directly by fibreoptic bronchoscope if the view of glottis with Truview laryngoscopy was C/L gradeâ…£or trachea could not be intubated successfully within three intubation attempts by Truview laryngoscope.Recorded relevant parameters included demographics,airway assessment features,C/L grade,difficult laryngoscopy,difficult intubation and related complications.Results:The preoperative airway assessment features of 32 patients included:Mallapati scoreⅢ～Ⅳ71.9%,mouth opening<3.5cm 21.9%,thyromental distance< 6.5cm 53.1%,neck movement<90°100%,neck movement < 30°43.7%.Of the 32 patients,5 patients had the same C/L grade scoreâ…£with both laryngoscopes,and remaining 27 patients showed improvement in C/L grade with Yruview laryngoscope compared to the Macintosh laryngoscope(Wilcoxon test,P<0.001).There was significant statistic difference in difficult laryngoscopy between Macintosh laryngoscope(81.3%) and Truview laryngoscope(37.5%)(McNemar test,P<0.001).There was significant difference in difficult intubation between Macintosh laryngoscope(56.2%) and Truview laryngoscope (25%)(McNemar test,P<0.001).There were significant association between airway assessment features and C/L grade(Spearman test,P<0.001).9 patients(28.1%) suffered slight sore throat and 3 patient(9.4%) suffered slight soft tissue damage,but all healed in next day.Conclusion:The Truview^TM EVO₂ laryngoscope could give a better glottic view and easier intubation than those by Macintosh laryngoscope in patients with ankylosing spondylitis who might expect difficult intubation,and might have potential advantages for managing difficult airway.