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October 14, 2007
9:00 AM - 11:00 AM
Room Hall D, Area D,
Evaluation of Truview evo2 Laryngoscope in Anticipated Difficult Intubation Cases
Abhishek Gupta, M.B.B.S., Ishwar Singh, M.D.
Anaesthesia and Intensive Care, Jaipur Golden Hospital, New Delhi, Delhi, India
Introduction: Today many airway management devices are there for Difficult Airway, but they are not free from limitations.Truview evo2 (TE) is a modified laryngoscope that incorporates an innovative prism and lens assembly attached to a special angulated blade with provision for O2 insufflation.TE has been found to offer a better laryngeal view.We aimed to compare TE with Macintosh blade (MB)laryngoscope in anticipated difficult intubaion cases in terms of improvement of glottic view (Cormack and Lehane grading CL) and success rate and ease of intubation.

Methods:Following approval by Board of Studies and Ethical Committee of Hospital, 50 ASA I&II patients of either sex[age range 20-60 yrs] undergoing general anaesthesia needing endotracheal intubation for elective surgery[non-malignant, non head and neck surgery] were included and evaluated for difficult intubation parameters[Mallampatti grading, Thyromental distance and Atlanto-Occipital Joint extension].Cases with a difficulty score of 2-5 were included for the study. Following a uniform premedication, standard induction and relaxation technique,CL grading with MB was done.Grade 2,3,4 were further evaluated with TE and corresponding CL view noted. Intubation time with TE was noted from the time of introduction of laryngoscope into the mouth till it was taken out. Alternate methods of intubation were adopted for cases requiring more than one minute for endotracheal intubation. Paired 't' test and Wilcoxon Rank test were used for statistical analysis.p<0.05 was taken as significant.All intubations were carried out by an experienced anaesthesiologist with more than 30 years of experience.

Results and Conclusion:There was well distribution of cases among all age groups. Body weight distribution was clustered for either sex. For each CL grading by MB, there was an improvement in the CL grade by TE. TE had improved the glottic view to grade I in 39/50(78%) cases. 46/50(92%) cases had shown improvement in glottic view. 23/50(46%) cases had shown improvement by 2 grades and 20/50(40%)cases had shown improvement by 1 grade. Subsequent analysis of cases not showing any improvement in CL grades, had revealed a short thyromental distance. p<0.01 showed a very high significance.

Average time taken,31.6 secs, for the negotiation of endotracheal tube seemed apparently longer, but considering the difficulty involved in these cases, the time taken was well acceptable.In CL grade I&II, 94%(37/50) and 75%(6/8) cases were intubated without much difference in the mean intubation time. We had achieved successful intubation in 44/50(88%) cases within the stipulated time frame of one minute. Prolonged intubation time was attributed to relative inexperience with the device.

References:1)Lieberman N, et al. Abstr. ASA; 2003;A-565

2)Gaitini LA, et al. Abstr.ESA; 2003:A-163.[table1][table2]

Anesthesiology 2007; 107: A584
Corresponding TE grading for each CL grade by MB
MB gradeNo. of casesTE grade
Total5039 (78%)8 (16%)3 (6%)
TE has improved the glottic view to grade I in 78% cases
Time taken for negotiation of endotracheal tube by TE
TE gradeTotal no. of casesNo. of cases intubated in 1 minute%Mean intubation time with S.D.
In grade I&II, 94% & 75% cases were intubated without much difference in mean intubation time