Comparison Of HC And Pentax-AWS,McGrath Video Laryngoscopes With Macintosh Laryngoscope In A Simulated Difficult Airway

Objective:This study assesses the effectiveness and potential trauma with four laryngoscopes, the Macintosh laryngoscope, HC video laryngoscope, Pentax-AWS and McGrath video laryngoscope in a simulated difficult airway with cervical spine immobilization.Methods:On the basic of volunteer,twenty-five first-year medical postgraduates with no experience using the four laryngoscopes studied were enrolled and successfully completed the study. A difficult airway was simulated through the use of SimMan manikin, which can provided a consistent Cormack and Lehane Grade III laryngeal inlet view by Macintosh laryngoscope. Prior to study, participants received a 3-minutes standardized introduction and demonstration about each devices, then were asked to intubate the manikin with different devices in the normal aiwway scenario and simulated difficult airway scenario respectively. Macintosh laryngoscope was used firstly, the order of the three video lanyngoscopes was in a random order.Times to achieve glottic view and successful intubation required were recorded, the number of additional discrete forward advances and Cormack and Lehane Grade were also recorded.After completion of intubation, participants were asked to fill out the visual analog scale(VAS) of force laid by blade and VAS of difficult of intubation and preference of each devices.Results:1. Normal aiwway scenario:In terms of times to achieve glottic view and times for successful intubation and overall success rate, There is no significant difference compared the three video laryngoscope with with Macintosh laryngoscope. The three video laryngoscopes provided superior Cormack and Lehane Grade and showed less VAS of force laid by blade compared with Macintosh laryngoscope (p<0.05), but there was no difference among the three video laryngoscopes. When used video laryngoscope, three video laryngoscopes showed less VAS of intubation difficulty than Macintosh laryngoscope. When asked the preference about devices.no one expressed a preference for Macintosh,11 participants expressed a preference for HC as their favored devices,13 preferred Pentax-AWS and only one for McGrath.2.Simulated difficult airway scenario:In terms of times to achieve glottic view and times for successful intubation、overall success rates,there was also no difference compared the three video laryngoscopes with Macintosh laryngoscope(p>0.05). The three video laryngoscopes also provided superior Cormack and Lehane Grade than Macintosh(p<0.05), but no difference among video laryngoscopes. The three video laryngoscopes showed less VAS of force laid by blade and intubation difficulty than Macintosh laryngoscope(p<0.05). When asked the preference about devices,9 participants expressed a preference for HC as their favored devices,16 preferred Pentax-AWS and no one for Macintosh and McGrath.Conclusion:Following a brief demonstration to participants naive to intubation devices,in both normal airway and simulated difficult airway scenario,the three video laryngoscopes can provide superior Cormack and Lehane Grade,reduced the VAS of force laid by blade and intubation difficulty compared with Macintosh, however,they can’t significantly shorten the times to achieve glottic view and time for successful intubation and reduce the number of additional discrete forward advances.In the both normal airway and simulated difficult airway scenarios,the overall success rate was not differ among the four laryngoscope devices.Participants expressed more preference towards HC and Pentax-AWS video laryngoscopes.