A randomized clinical trial comparing the King Vision (channeled blade) and the CMAC (D blade) videolaryngoscopes in patients with cervical spine immobilization

BACKGROUND AND AIMS: Cervical spine immobilization renders direct laryngoscopy difficult. The CMAC D blade and the channeled blade of the King Vision videolaryngoscopes, have both been used for difficult airway management. Our hypothesis is that the channeled blade of the King Vision would be superior to the CMAC D blade in terms of ease of intubation. We tested this hypothesis in a randomized comparison of the two videolaryngoscopes in patients with simulated cervical spine immobilization. MATERIAL AND METHODS: Hundred patients with no anticipated airway difficulty were randomly allocated to two groups after obtaining informed written consent. Following induction, manual inline stabilization (MILS) was applied to simulate a cervical spine injury and immobilzation. Patients were intubated with either of the two videolaryngoscopes. Time for visualization of the glottis, procedural time, intubation difficulty scale (IDS), and hemodynamic response were recorded. RESULTS: The time to visualize the glottis was shorter in the CMAC D group as compared to the King Vision group (P < 0.001). The incidence of external laryngeal manipulation was less in the King Vision group (P < 0.001). The ease of intubation was superior in the King Vision group, based on the IDS (P < 0.001). The haemodynamic response was similar between the groups. CONCLUSION: King Vision channeled videolaryngoscope was difficult to introduce into the mouth of the patient during laryngoscopy. Once introduced into the mouth, the time for intubation was less and less external laryngeal manipulation maneuvers were performed to achieve successful intubation. The ease of endotracheal intubation was superior for the King Vision videolaryngoscope. The King Vision videolaryngoscope with proper tranining, could be a safe and portable alternative in patients with cervical spine immobilization.