Clinical Application Of Truview～(TM) EVO₂ Optic Laryngoscope In Endotracheal Intubation

Aim: To evaluate Truview^TM EVO₂ optic laryngoscope in elective surgical patients requiring tracheal intubation by comparing with Macintosh direct laryngoscope and assess its clinical application in patients with unexpected difficult intubation.Methods:Part 1: Two hundred patients, ASAⅠ～Ⅱscheduled for elective surgery under general anaesthesia requiring orotracheal intubation were selected in the period from Feb 2006 to Apr 2006. Information was collected identifying the patient demographics (age, sex, height and weight) and airway assessment features ( Mallampati oropharyngeal grade, thyromenta distance and mouth opening), excluding the patients with possible difficult airway such as Mallampati oropharyngeal gradeâ…£. After induction, the patient was given a Cormack-Lehane grade of laryngeal view by the anaesthetist using a Macintosh size 3 blade or Truview^TM EVO₂ laryngoscopes in random order. After given the Cormack-Lehane grade of laryngeal view using the second laryngoscope, the patient was intubated using the later type of laryngoscope. The Cormack-Lehane grade was evaluated by the same anaesthetist. Parameters were recorded, including age, sex, height, weight, thyromenta distance, mouth opening, Mallampati oropharyngeal grade and Cormack-Lehane grade of laryngeal view .Part 2: Twenty patients, ASAⅠ～Ⅱscheduled for elective surgery under general anaesthesia requiring orotracheal intubation with unexpected difficult intubation were selected . All patients have no obvious preanesthesia difficult airway with normal mouth opening. After induction, intubation was atemptted by using a Macintosh size 3 blade . All patients met the criteria of difficult intubation. Then, Truview^TM EVO₂ laryngoscope was used to expose the epiglotis and atempt to intubate the patient. The Cormack-Lehane grade was evaluated by the same anesthetist. Parameters were recorded, including age, sex, height, weight, thyromenta distance, mouth opening, Mallampati oropharyngeal grade and Cormack-Lehane grade of laryngeal view .Results:Part 1: There were 200 patients including 107 males and 93 females, age range 52±13 years, height 164.8±11.3 cm, weight 64.0±11.5 kg, thyromenta distance 6.9±1.1cm , mouth opening 3.7±0.5cm. Using Spearman Test, there was a significant relationship (P<0.001) between Mallampati oropharyngeal grade and the Cormack-Lehane grade of laryngeal view with two types of laryngoscope. Cormack-Lehane grade of two laryngoscopes was tested using Wilcoxon test: Truview^TM EVO₂ optic laryngoscope achieved better laryngeal view than Macintosh direct laryngoscope did and in the patients who had factors indicating difficult airway Truview^TM EVO₂ optic laryngoscope also achieved better laryngeal view than Macintosh direct laryngoscope did. There were 4 patients who needed a second attempt to be intubated using Truview^TM EVO₂ opticlaryngoscope.Part 2: In nineteen of twenty patients, Truview^TM EVO₂ optic laryngoscope achieved better laryngeal view than Macintosh direct laryngoscope did and there was only one patient who get the same Cormack-Lehane grade of laryngeal view with two laryngoscopes, gradeâ…¢. The Cormack- Lehane grade of laryngeal view with Macintosh direct laryngoscope was 18 gradeâ…¢and 2 gradeâ…£, but laryngeal view with Truview^TM EVO₂ optic laryngoscope was 8 gradeâ… ,11 gradeâ…¡and 1 gradeâ…¢. Nineteen patients were intubated successfully by one atemptation and only one patient was intubated by a second atemptation with Truview^TM EVO₂ optic laryngoscope.There was no considerable injuries recorded in all patients.Conclusion: In most patients, Truview^TM EVO₂ laryngoscope yielded comparable or superior laryngeal view compared with Macintosh laryngoscope. The new type of laryngoscope has potential advantage over direct laryngoscope, and may be good alternative for managing the difficult intubation.