Comparison of retrograde transillumination and conventional technique for flexible videoscopy by novice anaesthesia residents: A randomised controlled trial

Background and Aims:Retrograde transillumination technique has been found helpful for performing direct and video laryngoscopy by better identification of glottis. The usefulness of this technique during flexible videoscopy by novices has not been evaluated. So, we aimed to compare the retrograde transillumination and conventional technique of flexible videoscopy by novices. The primary outcomes were the time required to visualise the glottis from the point of insertion of the scope into the nostril (T1) and the time needed to see tracheal rings after glottis visualisation (T2). The secondary outcomes were incidence of desaturation with peripheral oxygen saturation (SpO(2)) < 92% and the ease of performance of flexible videoscopy using retrograde transillumination. Methods:A total of 92 surgical patients who are undergoing general anaesthesia with normal airway parameters were randomised into two groups, Group C (Conventional flexible videoscopy- Ambu (R) aScope (TM) 3 Broncho Slim) and Group R (Flexible videoscopy aided by retrograde transillumination through the cricothyroid space using an OTICA LED vein finder). Results:The time to visualise glottis from scope insertion into the nose (T1) (median [interquartile range]) in group C and group R was (19.23 [13.6-30.5] versus 22.50 [17.8-25.5] seconds; P value = 0.417) and time to visualise the tracheal rings (T2) was (13.07 [9.1-20.00] versus 12.13 [9.0-19.1] seconds; P value = 0.714) were comparable in both the groups. 61% of residents found the retrograde transillumination to be very helpful. No incidence of desaturation was noted in either group. Conclusion:Retrograde transillumination-aided flexible videoscopy does not shorten the time but facilitates glottis and tracheal rings visualisation among novice anaesthesia residents.