Comparing the performance of traditional direct laryngoscope with three indirect laryngoscopes: A prospective manikin study in normal and difficult airway scenarios

Objectives: The aim of the present study was to evaluate the performance of three indirect laryngoscopes, Truview EVO2 laryngoscope, Clarus Levitan fiberoptic stylet and AirwayScope AWS, in comparison with direct Macintosh laryngoscope (ML) when performed in normal and difficult airway scenarios. Methods: This prospective comparative study recruited 30 emergency physicians familiar with direct laryngoscopic intubation. Intubations were performed on manikin and were repeated twice for both scenarios. The primary end points were intubation time and rate of failed intubation. Glottis visualization was graded on Cormack and Lehane score and VAS. Results: In normal airway scenario: AWS had shortest intubation time (6.0 s) followed by ML (8.7 s); VAS score of ML and AWS was lower (easier to use) than the other two devices; Cormack and Lehane score was similar for all devices. In difficult airway scenario: AWS had shortest intubation time (5.9 s); VAS score of AWS was lower than the other three devices; TVL, FOS, AWS had better Cormack and Lehane score than ML. Intubation time, rate of failed intubation, and Cormack and Lehane score were similar between attempts in both scenarios. Learning effect was significant in FOS in both scenarios and in TVL in normal airway scenario. Conclusions: AWS performed best in normal and difficult airways. ML performed better than TVL and FOS in normal airways. Performances of ML, TVL and FOS were similar in difficult airways. Skills with AWS could be mastered rapidly. TVL and FOS required more practice to gain expertise.