A Prospective Crossover Study Evaluating the Efficacy of King Vision Video Laryngoscope in Patients Requiring General Anesthesia with Endotracheal Intubation

BACKGROUND: Direct laryngoscopy used for tracheal intubation requires aligning the pharyngeal, laryngeal and oral axes to achieve a line of sight. Video laryngoscopy provides a better view of the glottis without the need for aligning the three axes. AIMS: To evaluate the effectiveness of King vision laryngoscope over Macintosh laryngoscope in visualizing the glottis and intubating the trachea, when used on a same patient as in a cross over manner. SETTINGS AND DESIGN: Department of Anaesthesia, Mediciti Institute of Medical Sciences, prospective crossover study conducted over a period of six months. SUBJECTS AND METHODS: Sixty adult patients belonging to ASA physical status class I-II, requiring tracheal intubation were randomly assigned to intubation by King vision or Macintosh laryngoscope. Improvement, if any, in the Cormack-Lehane grading using the King vision scope, following initial grading with the Macintosh blade in the same patient was analyzed. STATISTICAL ANALYSIS: Mean and Standard deviation were calculated for different parameters under the study. Where appropriate, results were analyzed using the Mc Nemar χ2 test. A ‘p’ value less than 0.05 was considered statistically significant. RESULTS: In the King Vision group, Cormack and Lehane grade improved in the majority (9/12) of patients in whom the initial Cormack and Lehane grade was >1 using the Macintosh blade. CONCLUSIONS: The use of the King vision blade significantly improved the laryngoscopic view over the Macintosh blade but the time for intubation was prolonged.