A comparative evaluation of King Vision video laryngoscope (channelled blade), McCoy, and Macintosh laryngoscopes for tracheal intubation in patients with immobilized cervical spine

Background: Cervical spine immobilization results in a poor laryngeal view on direct laryngoscopy leading to difficulty in intubation. This randomized prospective study was designed to compare the laryngeal view and ease of intubation with the Macintosh, McCoy, and King Vision video laryngoscopes in patients with immobilized cervical spine. Method: Ninety adult patients of ASA grade I-II with immobilized cervical spine using manual inline axial cervical spine stabilization technique, undergoing elective cervical surgery were enrolled. The patients were randomly allocated into three groups to achieve tracheal intubation with Macintosh (MAC group n=30), McCoy (MCC group n=30), or King Vision video laryngoscopes (KVL group). When the best possible view of the glottis was obtained, the Cormack-Lehane laryngoscopy grade and the percentage of glottic opening (POGO) score were assessed. Other measurements included the intubation time, the intubation difficulty score, and the intubation success rate. Haemodynamic parameters and any airway complications were also recorded. Result: King Vision video laryngoscope reduced the intubation difficulty score, improved the Cormack and Lehane glottic view, and the POGO score compared with the McCoy and Macintosh laryngoscopes. The first attempt intubation success rate was also high in the King Vision video laryngoscope group. However, there were no statistically significant differences in the time required for successful intubation and the overall success rates between the devices tested. No dental injury or hypoxia occurred with either device. Conclusion: The use of a King Vision video laryngoscope resulted in better glottis visualization, easier tracheal intubation, and higher first attempt success rate as compared to Macintosh and McCoy laryngoscopes in immobilized cervical spine patients.