Comparison of the king vision video laryngoscope with the Macintosh laryngoscope

Background Endotracheal intubation is a common procedure in the emergency department, and new devices may improve intubation time, success, or view. Objective We compared the King Vision video laryngoscope (KVVL; King Systems, Noblesville, IN) to the Macintosh direct laryngoscope (DL) in simulated normal and difficult airways. Methods Using manikins and clinical-grade cadavers, difficult airway scenarios were simulated using head movement restriction or a cervical spine collar. Four scenarios were studied using the KVVL and DL: normal manikin airway, difficult manikin airway, normal cadaver airway, and difficult cadaver airway. Primary outcomes were time to intubation and rate of successful intubation. Secondary outcomes were the percent of glottic opening and Cormack-Lehane grade visualized. Results Thirty-two paramedics participated in the study. In the normal manikin airway scenario, time to intubation was 3.4 s (99% confidence interval [CI] 0.1-6.6) faster with the KVVL compared with DL. Time to intubation was 11.3 s (99% CI 2.4-20.2) faster with the KVVL in the difficult cadaver airway scenario. There was no difference in time to intubation in the other 2 scenarios. In the difficult cadaver airway, 10 of 32 participants failed to successfully intubate the trachea using DL, whereas all KVVL intubations were successful. All scenarios found a lower Cormack-Lehane grade and higher percentage of glottic opening with the KVVL compared to DL. Conclusion The KVVL was slightly faster than Macintosh DL in two of four studied airway scenarios, and had a higher success rate in the difficult cadaver airway scenario. Further study is required in the clinical setting.