Title: Comparison of C-MAC video-laryngoscope with D-Blade, C-MAC video-laryngoscope with standard blade, and Macintosh Laryngoscopes for intubation with cervical spine immobilization: a randomized study.

             Macintosh laryngoscope is the most commonly used device for intubation in anesthesia practice. Difficult intubation still a major cause of morbidity and mortality associated with anaesthesia. Recently, viedeolaryngoscopes are becoming very popular for difficult intubation management because it increases glottic view and the success of intubation. There are many studies which show C-MAC viedeolaryngoscopes improves laryngeal view compared to direct laryngoscopy. Manual in-line stabilization (MILS) is used during procedures like airway management in patients with C-spine injury to minimize cervical movement. But MILS make the intubation difficult by decreasing the view of laryngoscopy.        A new C-MAC D-Blade is introduced which can be used as an alternative in difficult airway situations. The advantage of the C-MAC video-laryngoscope with a D-Blade in presence of cervical spine immobilization is not known. The purpose of this randomized controlled study is to com­pare the C-MAC video-laryngoscope with D-Blade, C-MAC video-laryngoscope with a standard blade, and Macintosh Laryngoscopes for intubation for endotracheal intubation under general anaesthesia with manual in-line stabilization (MILS).

The primary objective is to compare the Cormack Lehane (CL) grade of laryngoscopic view between C-MAC video-laryngoscope with D-Blade, C-MAC video-laryngoscope with standard blade, and Macintosh Laryngoscopes in patients undergoing general anesthesia (GA) using MILS. Following approval of Institute Ethics Committee, 123 patients in between the age group of 18-60 years, will be enrolled in a prospective, randomized, parallel group, multiple arm trial study. Patients aged between 18 and 60 years of either gender belonging to ASA physical status I–II undergoing elective cervical spine surgery requiring GA will be included.

         The patients will be randomized to one of the following three groups (41 each) on the basis of a computer-generated randomization chart: Group I: Macintosh laryngoscope (Group M), Group II: C-MAC videolaryngoscope (Group C), Group III: C-MAC D video laryngoscope (Group D).

            All patients enrolled for the study will receive general anesthesia with tracheal intubation. The neck will be immobilized using MILS by holding the sides of the neck and the mastoid processes, thus preventing flexion/extension or rotational movements of head and neck. Cormack Lehane (CL) grade will be assessed after the first attempt of laryngoscopy. Primary outcome measure will be Cormack Lehane (CL) grade of laryngoscopic view. The secondary outcome will be time taken for successful intubation, success rate of first attempt intubation, number of attempts of intubation, number of optimization maneuvers required to aid tracheal intubation, complication,  difficulty score and Hemodynamic changes during the intubation process.