***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Video-laryngoscopes are marketed for intubation in difficult airway management . They provide a better view of the larynx and may facilitate tracheal intubation , but there is no adequately powered study comparing different types of video-laryngoscopes in a difficult airway scenario or in a simulated difficult airway situation . Methods / Design The objective of this trial is to evaluate and to compare the clinical performance of three video-laryngoscopes with a guiding channel for intubation ( Airtraq ™ , A. P. Advance ™ , King Vision ™ ) and three video-laryngoscopes without an integrated tracheal tube guidance ( C-MAC ™ , GlideScope ™ , McGrath ™ ) in a simulated difficult airway situation in surgical patients . The working hypothesis is that each video-laryngoscope provides at least a 90 % first intubation success rate ( lower limit of the 95 % confidence interval > 0.9 ) . It is a prospect i ve , patient-blinded , multicenter , r and omized controlled trial in 720 patients who are scheduled for elective surgery under general anesthesia , requiring tracheal intubation at one of the three participating hospitals . A difficult airway will be created using an extrication collar and taping the patients ’ head on the operating table to substantially reduce mouth opening and to minimize neck movement . Tracheal intubation will be performed with the help of one of the six devices according to r and omization . Insertion success , time necessary for intubation , Cormack-Lehane grade and percentage of glottic opening ( POGO ) score at laryngoscopy , optimization maneuvers required to aid tracheal intubation , adverse events and technical problems will be recorded . Primary outcome is intubation success at first attempt . Discussion We will simulate the difficult airway and evaluate different video-laryngoscopes in this highly realistic and clinical ly challenging scenario , independently from manufacturers of the devices . Because of the sufficiently powered multicenter design this study will deliver important and cutting-edge results that will help clinicians decide which device to use for intubation of the expected and unexpected difficult airway . Trial registration BACKGROUND The GlideScope intubating device has been reported to provide a comparable or superior laryngoscopic view compared with direct laryngoscopy in adults . This study compared the use of the GlideScope with direct laryngoscopy for the laryngoscopic view and intubation time in children . METHODS The laryngoscopic view in 203 children was scored using both the Macintosh laryngoscope and the GlideScope using Cormack and Lehane ( C&L ) grade s. After scoring each laryngoscopic view with and without BURP , the patients were r and omly allocated to two groups . The trachea was intubated using direct laryngoscopy ( Group DL , n=100 ) or the GlideScope ( Group GS , n=103 ) . We compared C&L grade s for the two views in the same patient , and also the time to intubate for each group . RESULTS The GlideScope improved the view without BURP in the patients with C&L grade 2 ( 16/26 , P<0.01 ) and with C&L grade s 3 and 4 ( 7/11 , P<0.05 ) . The view with BURP was also improved by the GlideScope in C&L grade 2 ( 4/9 , P<0.05 ) and with C&L grade s 3 and 4 ( 4/5 , P=0.059 ) . The mean time for tracheal intubation was 36.0 ( 17.9 ) s in the GS group and 23.8 ( 13.9 ) s in the DL group ( P<0.001 ) . CONCLUSIONS In children , the GlideScope provided a laryngoscopic view equal to or better than that of direct laryngoscopy but required a longer time for intubation Purpose : Airtraq ™ is an optical laryngoscope that allows viewing of the vocal cords without a direct line of sight . The main objective of this prospect i ve , r and omized , controlled trial was to evaluate Airtraq intubation characteristics , mainly intubation time and cardiovascular changes in the pediatric patients . Methods : Fifty children of American Society of Anesthesiologists class I , 2 - 10 years of age were divided into 2 groups using sealed envelope technique . Children were premedicated with midazolam .  Anesthesia was induced with sevoflurane , fentanyl , and atracurium . Patients were r and omly allocated to be intubated with either Airtraq ( Airtraq group ) or Macintosh laryngoscope ( Macintosh group ) . Intubation time , number of intubation attempts , optimization maneuvers , and ease of intubation were recorded . Hemodynamic variables were recorded before and after anesthetic induction , 1 , 3 , and 5 min after tracheal intubation . Results : The mean age of children was 6.1 years . Compared with Macintosh group , the use of Airtraq was associated with shorter intubation time ( 51.6±26.7 s vs 22.8±6.1 s , respectively , P=0.001 ) , less median number of intubation attempts 2 ( 1 - 2 ) versus 1 ( 1 - 1 ) , P=0.001 ) , more ease of intubation [ 2 ( 1 - 3 ) versus 1 ( 1 - 1 ) , P=0.001 ] and less increase in the heart rate 5 min after intubation ( P=0.007 ) . No optimization maneuvers required for Airtraq laryngoscope ( P=0.001 ) . Conclusion : Airtraq decreases intubation time , number of attempts , and optimization maneuvers , less heart rate changes during intubation compared with Macintosh laryngoscope AIM To compare time to intubation , time to optimal laryngoscopy , best laryngeal view , and success rate of intubation with  pediatric Bullard laryngoscope and short-h and led Macintosh laryngoscope in children being intubated with neck stabilization . BACKGROUND Securing airway of a patient with restricted cervical spine movement has been a challenge faced by anaesthesiologists around the world . Macintosh laryngoscope with manual inline stabilization is most commonly used . Bullard laryngoscope is also useful in this situation as minimal neck movement occurs with its use . METHODS Forty patients , ASA I or II , aged 2 - 10 years , were enrolled in this prospect i ve , controlled , and r and omized study . Patients were r and omly allocated to one of two groups : Group MB ( first laryngoscopy using short-h and led Macintosh laryngoscope followed by pediatric Bullard laryngoscope ) and Group BM ( first laryngoscopy using pediatric Bullard laryngoscope followed by short-h and led Macintosh laryngoscope ) with manual inline stabilization after induction of anesthesia and paralysis . Trachea was intubated orally using the second equipment . RESULTS Laryngeal view when obtained was always Grade 1 with Bullard laryngoscope ( 38/38 ) when compared to Macintosh laryngoscope [ Grade 1 ( 10/40 ) ] . The mean time to laryngoscopy ( and intubation ) was shorter with Macintosh laryngoscope [ 15.53 s ( 38.15 s ) ] than Bullard laryngoscope [ 35.21 s ( 75.71 s ) ] , respectively . Success rate of intubation was higher with Macintosh laryngoscope ( 100 % ) when compared to Bullard laryngoscope ( 70 % ) . CONCLUSIONS Laryngoscopy and intubation is faster using a short-h and led Macintosh laryngoscope with a higher success rate compared to pediatric Bullard laryngoscope in pediatric patients when manual inline stabilization is applied Background Tracheal intubation with Macintosh laryngoscope is taught to medical students as it is a lifesaving procedure . However , it is a difficult technique to learn and the consequences of intubation failure are potentially serious . The Airtraq optical laryngoscope is a relatively novel intubation device , which allows visualization of the glottic plane without alignment of the oral , pharyngeal , and tracheal axes , possessing advantages over Macintosh for novice personnel . We introduced a teaching mode featured with a progressive evaluation scheme for preparation and performance of tracheal intubation with medical students in this prospect i ve r and omized crossover trial who had no prior airway management experience to find the superior one . Methods Twenty-six medical students of the 8-year programme in the 6th year participated in this trial , when they did their one-week rotation in the department of anaesthesiology . Each of the students intubated 6 patients , who were scheduled for surgeries under general anaesthesia , each laryngoscope for 3 patients respectively . One hundred and forty-nine consecutive patients scheduled for surgical procedures requiring tracheal intubation were enrolled . Patients were r and omly allocated to undergo tracheal intubation using Macintosh ( n = 75 ) or Airtraq ( n = 74 ) laryngoscope . The progressive evaluation scheme was applied to each intubation attempt . Results Intubation success rate was significantly higher in Airtraq group than Macintosh group ( 87.8 % vs. 66.7 % , P < 0.05 ) . Duration of glottis exposure was significantly shorter in Airtraq group compared to Macintosh group ( 50 ± 19 s vs. 81 ± 27 s , P < 0.001 ) . A grade I Cormack and Lehane glottic view was obtained in 94.6 % of patients in the Airtraq group versus 32 % of patients in the Macintosh group ( P < 0.001 ) . Duration of intubation in Airtraq group was significantly shorter ( 68 ± 21 s vs. 96 ± 22 s , P < 0.05 ) compared to Macintosh group . Conclusions Airtraq laryngoscope is easier to master for novice personnel with a higher intubation success rate and shorter intubation duration compared with the Macintosh laryngoscope . Trial registration Trial registration number is ChiCTR-TRC-13003987 , approval date Dec 12 , 2013 Background and Aims : C-MAC ® video laryngoscope ( VL ) with Macintosh blade has been found to improve Cormack-Lehane ( C-L ) laryngoscopic view as well as intubating conditions for orotracheal intubation . However , studies done on the performance of C-MAC ® VL for nasotracheal intubation ( NTI ) are very few in number . Hence , we compared laryngoscopy and intubating conditions between Macintosh direct laryngoscope and C-MAC ® VL for NTI . Methods : Sixty American Society of Anesthesiologists Physical Status I , II patients , aged 8 - 18 years , posted for tonsillectomy surgeries under general anaesthesia with NTI were r and omised , into two groups . Patients in group 1 were intubated using Macintosh direct laryngoscope and group 2 with C-MAC ® VL . C-L grading , time required for intubation , need for additional manoeuvres and haemodynamic changes during and after intubation were compared between the groups . Results : C-L grade 1 views were obtained in 26 and 29 patients in group 1 and group 2 , respectively ( 86.7 % vs. 96.7 % ) . Remaining patients were having C-L grade 2 ( 13.3 % vs. 3.3 % ) . Duration of intubation was less than a minute in group 2 ( 93.3 % ) . Need for additional manoeuvres ( M1-M5 ) were more in group 1 ( 97 % vs. 77 % ) . M1 ( external manipulation ) was needed more in group 2 compared to group 1 ( 53.3 % vs. 30 % ) . Magill′s forceps alone ( M4 ) and M4 with additional external manipulation ( M5 ) were needed more in group 1 compared to group 2 ( 60 % vs. 16 % ) . Conclusion : The overall performance of C-MAC ® VL was better when compared to conventional direct Macintosh laryngoscope during NTI in terms of glottis visualisation , intubation time and need for additional manoeuvres BACKGROUND The Berci-Kaplan video laryngoscope was developed to improve the visualization of the glottis and ease tracheal intubation . Whether this technique is also effective in patients with an expected difficult intubation is unclear . We have prospect ively evaluated the conditions and success rate of tracheal intubation in patients with a Mallampati score of III or IV . METHODS Two hundred patients , undergoing general anaesthesia , were r and omized to be intubated using direct laryngoscopy ( n=100 ) or video laryngoscopy ( n=100 ) . Visualization of the vocal cords , success rate , time for intubation , and the need for additional manoeuvres ( laryngeal manipulations , head positioning , and Eschmann stylet ) were evaluated . RESULTS Video laryngoscopy produced better results for the visualization of the glottis using Cormack and Lehane criteria ( P<0.001 ) , success rate ( n=92 vs 99 , P=0.017 ) , and the time for intubation [ 60 ( 77 ) vs 40 ( 31 ) s , P=0.0173 ] . In addition , the number of optimizing manoeuvres was also significantly decreased [ 1.2 ( 1 
    Output:
    
Use of indirect laryngoscopy , or videolaryngoscopy , might lead to improved vocal cord view , but marked heterogeneity between studies made it difficult for review authors to reach conclusions on this outcome