Effect Of Stylet On Tracheal Intubation Under Video Laryngoscope

Objective: With the development of visualization technology,the use of visual laryngoscope is more and more widely,visual laryngoscope brings better glottic visual field exposure,but there are still some limitations.However,in recent years,studies have shown that the use of the core may also hinder successful intubation,because the shape is too rigid and may cause tracheal injury.At present,there has been a controversy about the use of intubation core in clinic.This study explored the effect of stylet on video laryngoscope tracheal intubation through difficult airway simulation experiments and clinical trials.Methods: Part Ⅰ: twenty experts(experts refer to the doctors in charge of anesthesia or above or those with five years of clinical experience in anesthesia)and twenty non experts(non experts refer to clinical medical students or clinical interns)were recruited for airway simulation experiment.Simman3 G human simulator system was used to set up three difficult simulated airway(no tongue edema,50% degree tongue edema,100%degree tongue edema)in advance to complete the intubation attempt with or without stylet under direct or video laryngoscope.The intubation time and the success rate of the first intubation were recorded.Part Ⅱ: a total of 160 ASA Ⅰ-Ⅱ patients who need general anesthesia intubation for elective surgery and signed informed consent were included in the clinical randomized controlled study.They were randomly divided into four experimental groups: group A direct laryngoscope with stylet,group B direct laryngoscope without stylet,group C video laryngoscope with stylet and group D video laryngoscope without stylet.The main outcome measures were success rate of first intubation,intubation time,and postoperative complications related to intubation.Results: 1.In the airway simulation experiment,there was no significant difference in the first intubation success rate and intubation time between video laryngoscope and direct laryngoscope when using the stylet(P = 0.678 and 0.34 respectively);in the case of no stylet,the intubation success rate of direct laryngoscope was higher than that of video laryngoscope(91.7% vs 55.0% respectively)The intubation time of direct laryngoscope was similar to that of video laryngoscope(P = 0.933 and 0.535,respectively)in conventional airway and medium difficulty,but the intubation time of direct laryngoscope was better than that of video laryngoscope(35.64 ± 10.359 vs35.64 ± 10.359,respectively)when airway difficulty increased to severe difficulty In the case of using video laryngoscope,the use of stylet can significantly improve the success rate of the first intubation(P < 0.001)and significantly optimize and shorten the intubation time(P < 0.001),and as the difficulty of simulating airway increases,the success rate of the first intubation without using stylet will continue to decline,and the intubation time required will continue to rise.2.In the clinical observation trial,there was no significant difference in the success rate of first intubation between video laryngoscope and direct laryngoscope when the stylet was used(P = 1.0),but the intubation time of direct laryngoscope was shorter;in the case of no stylet,the success rate of first intubation of direct laryngoscope was better than that of video laryngoscope(85.0% vs 65.0%,P = 0.039).For video laryngoscope,the success rate of first intubation was significantly increased by using the stylet(90.0%vs 65.0%,P = 0.007),and the intubation time was shortened by using the stylet(42.14± 9.59 vs 51.19 ± 7.56,P < 0.001).There was no significant difference in the incidence of postoperative complications between the four groups(P = 0.853).Conclusion: Through the experiment,it can be concluded that when using video laryngoscope,the use of stylet can significantly improve the success rate of the first intubation and shorten the intubation time,and as the difficulty of airway increases,the success rate of the first intubation without stylet decreases.There was no significant difference in hemodynamic changes and 24-hour postoperative complications between the two groups.