Comparative effectiveness of McCoy laryngoscope and CMAC ^® videolaryngoscope in simulated cervical spine injuries

Abstract

BACKGROUND: Videolaryngoscopes are increasingly being used in potentially difficult airway. McCoy laryngoscope provides definitive advantage over conventional laryngoscopes in cervical spine patients. The aim of this study was to compare the performance of the CMAC(®) videolaryngoscope with the McCoy Laryngoscope in patients with a cervical collar. MATERIAL AND METHODS: Sample size of at least 22 patients in each group was calculated using Intubation Difficulty Scale (IDS) score as the primary outcome. 60 American Society of Anesthesiologists I and II patients requiring tracheal intubation for elective surgery were randomly allocated into the McCoy group (n = 30) and the CMAC(®) videolaryngoscope group (n = 30). Anesthesia was induced with fentanyl 2 mcg/kg, propofol 2-3 mg/kg and rocuronium 0.6 mg/kg. A rigid collar was applied to immobilize the cervical spine. Comparative data on the IDS scale, Cormack-Lehane (CL) laryngoscopic view, time taken for glottis visualization, time taken to pass endotracheal tube, total time to intubate, number of optimizing maneuvers and hemodynamic variables were recorded in the two groups. RESULTS: IDS score was significantly less in the CMAC(®) group compared to the McCoy group (median [interquartile range (IQR)], 1 [0-1] vs. 4 [3-6], P < 0.05). CMAC(®) videolaryngoscope required significantly less time for glottic visualization with median (IQR), 5 (5-7) versus 14 (8-15), P = 0.000 in McCoy laryngoscope, 29 (96.7%) patients in the CMAC(®) group had Modified CL Grade I compared with 16 (53.3%) patients in McCoy group. The hemodynamic variables, number of optimizing maneuvers and incidence of side effects were comparable in the two groups. CONCLUSION: CMAC(®) videolaryngoscope forms an effective tool for the airway management of cervical spine patients with a cervical collar.