Comparative evaluation of two techniques of LMA CTrach™ insertion on manoeuvres required to obtain optimal laryngeal view

Background: LMA CTrach™ is a laryngeal mask airway (LMA™) device used for tracheal intubation under vision. A new technique of LMA CTrach™ insertion was evaluated with respect to number of manoeuvres of airway required to obtain grade 1 or 2 view of glottis when compared to standard recommended insertion technique. Methods: One hundred and ten patients were randomized to either standard technique group (LMA CTrach™ inserted according to manufacturer's recommendations) or modified technique group (LMA CTrach™ inserted with the viewer assembled and visualizing the process of insertion). The number of manoeuvres used before successful intubation were compared. Manoeuvres used to get adequate ventilation/good glottic view were the up-down manoeuvre, partial withdrawal, distal maneuver, Chandy manoeuvre and suctioning. Total number of manoeuvres and ease of LMA CTrach™ insertion were recorded. Results: Patient characteristics were comparable. Among 50 patients in each group 37 patients required 43 manipulations in modified technique group compared to 41 patients who required 65 manipulations in standard technique group before getting a good glottic view (P=0.013). The number of maneuvers required for successful insertion was significantly higher in the standard technique group compared to modified technique group. Modified insertion technique was significantly difficult (23/50 patients) compared to standard technique (6/50 patients); P<0.001. Time required to obtain the best possible glottic view and the incidence of sore throat was significantly lower with modified technique (P<0.001 and 0.046 respectively). Conclusion: Number of manoeuvres for getting good glottic view was significantly less with the modified technique of inserting LMA CTrach™. However, this technique was perceived to be more difficult.