Comparison Of Exposure Of Glottis Between Improved And Classical Laryngoscopy

Objective: Endotracheal intubation is an essential skill for anesthesiologists.The classical method of tracheal intubation is that the laryngoscope blade is inserted into mouth from right side,then laryngoscope moves to the left side gradually and makes the tongue blocked.This method is the only one that has been mentioned in textbook for undergraduate so far,and has been used as a criterion for tracheal intubation.However,in the clinical practice we found that inserting the blade into mouth from middle(improved method)is another good method.In addition,with the extensive application of video laryngoscope,clinicians also found that the application of the improved method for tracheal intubation has more clinical advantages.Therefore,we supposed that the classical method to expose glottis is not the only standard for tracheal intubation,and the improved method is not absolutely inferior to the classical approach.This study aims to investigate the effects of the improved method on the exposure of glottis by comparing difference in laryngoscope exposure time,Cormack and Lehane laryngoscope grade,intubation time,hemodynamic changes and complications between improved and classical method.Methods: Two hundred and forty patients,ASA I-II,aged 18-65 years old,who were administered tracheal intubations for elective surgery under general anesthesia,were enrolled.Patients with severe systemic diseases,obvious tracheal or bronchial injury and potentially difficult airway were excluded.Patients included were randomly di vided into four groups(60 patients in each group),A1: ordinary laryngoscope for classicalmethod,A2: video laryngoscope for classical method,B1: ordinary laryngoscope for improved method,B2: video laryngoscope for improved method.Endotracheal tube was inserted after induction of general anesthesia.The classical method group used the classical method to expose the glottis.The imporved method group used the improved method to expose the glottis.After induction of general anesthesia,respectively recorded Cormack and Lehane laryngoscope grade,laryngoscope exposure time,intubation time,the blood pressure(BP)and heart rate(HR)of 5min before induction?3min after induction and 1min? 2min and 5min after intubation were recorded,and immediate complications of tracheal intubation were observed and recorded.Results: A total of 240 patients were prospectively enrolled.There were no significant statistical differences in age,height,body weight,body mass index,interincisor distance?thyromental distance and chest-chin distance between group A1 and group B1,group A2 and group B2(P>0.05).There were no significant differences in systolic blood pressure,heart rate and immediate complications of intubation and Cormack and Lehane laryngoscope grade in group A1 and B1(P>0.05),but laryngoscope exposure time(12.61±3.48 vs 14.90±3.83,P < 0.05)and intubation time(45.96±9.66 vs 49.43±6.86,P < 0.05)in group B1 was shorter than in group A1,and all these differences were statistically significant.There were no significant differences in systolic blood pressure,heart rate,immediate complications of intubation and Cormack and Lehane laryngoscope grade in group A2 and group B2(P>0.05),but laryngoscope exposure time(14.03±8.20 vs 16.85±6.38,P<0.05)and intubation time(51.26±10.67 vs 56.71±10.93,P<0.05)in group B2 was shorter than these in group A2,and these differences were statistically significant.Conclusion: Compared with the classic method of exposing glottis,the improved method can reduce the time of exposing glottis and intubation time.The classic method should not be the only standard way of teaching,the improved method is not inferior tothe traditional classical method,but has more clinical advantages thus deserving popularization.