A Randomized Controlled Comparison Of King Vision,Mcgrath Video Laryngoscope And Macintosh Direct Laryngoscope For Nasotracheal Intubation In Patients With Predicted Difficult Airways

Objective: King Vision and McGrath MAC video laryngoscopes(VLs)are increasingly used.The purpose of this study was to evaluate the performance of nasotracheal intubation in patients with predicted difficult intubations using non-channeled King Vision VL,McGrath MAC VL or Macintosh laryngoscope by experienced intubators.Methods: The study included 99 patients requiring nasal endotracheal intubation for elective oral and maxillofacial surgery in our hospital from June 2017 to January 2018,aged 18-60 years with American Society of anesthesiologists(ASA)classification of I or II and El-Ganzouri risk index 1-7.Three groups were randomly assigned to perform nasotracheal intubation by experienced anesthesiologists guided by non-channeled King Vision video laryngoscope(K group),McGrath video laryngoscope(M group),and Macintosh laryngoscope(C group).Intubation time,success rate of primary intubation,exposure time of glottis,the view of glottis opening valued by Cormack-Lehane grade,the hemodynamic changes(MAP,HR),number of assist maneuvers and incidence of side effects were recorded.Results:The intubation time of King Vision and McGrath group was comparable(37.6±7.3 seconds vs.35.4±8.8 seconds)and both were shorter than Macintosh group(46.8±10.4 seconds,p<0.001).Both King Vision and McGrath groups had a 100% first attempt success rate,significantly higher than Macintosh group(85%,p < 0.05).The laryngoscopy time was comparable between King Vision and McGrath group(16.7±5.5 seconds vs.15.6±6.3 seconds)and was shorter than Macintosh group(22.8±7.2 seconds,p < 0.05)also.Compared with Macintosh laryngoscope,Glottis view was obviously improved when exposed with either non-channeled King Vision or McGrath MAC VL(p<0.001),and assist maneuvers required were reduced(p < 0.001).The maximum fluctuations of MAP were significantly attenuated in VL groups(47.7±12.5 mmHg and 45.1±10.3 mmHg vs.54.9±10.2 mmHg,p<0.05 and p<0.01).Most device insertions were graded as excellent in McGrath group,followed by Macintosh and King Vision group(p=0.0014).The tube advancements were easier in VLs compared with the Macintosh laryngoscope(p < 0.001).Sore throat was found more frequent in Macintosh group compared with King Vision group(p<0.05).Conclusions: Compared to Macintosh laryngoscope,both King Vision and McGrath video laryngoscopes facilitated nasotracheal intubation in managing predicted difficult airways.