Evaluation of the Effect of Tracheal Tube Orientation on Success of Intubation through Intubating Laryngeal Mask Airway.

INTRODUCTION: Polyvinyl Chloride Endotracheal Tube (PVC ETT) can be used as an alternative to Fastrach Silicone Wire-Reinforced Tube (FTST) for intubation through Intubating Laryngeal Mask Airway (ILMA) as the latter is expensive and has low volume high pressure cuff.

AIM: To evaluate the effects of orientation of PVC ETT (normal curve and reverse curve) on the success of intubation through ILMA, haemodynamic response and postoperative sore throat.

MATERIALS AND METHODS: Sixty healthy adult patients of ASA physical status I & II scheduled for elective surgery under general anaesthesia requiring endotracheal intubation were randomly divided into two groups. In Normal (N) group (n=30), the tracheal tube was inserted with its natural curve following the 90° curvature of ILMA. In Reverse (R) group (n=30), the tracheal tube was inserted with its natural curve directed opposite to the curvature of ILMA. The time taken to intubate, number of attempts, and maneuvers required for successful endotracheal intubation along with haemodynamics and oxygen saturation were noted. Postoperative sore throat was evaluated using a Verbal Analogue Scale (VAS) (0-10). Qualitative data was analysed by Chi-Square test and Fisher's exact test. Quantitative data was analysed by unpaired t-test and Mann-Whitney test.

RESULTS: Placement of ILMA was successful in all patients. Total Intubation Time (mean±SD) in Group N was 12.53±1.78 seconds and in Group R was 11.97±1.33 seconds (p>0.05). Tracheal intubation through ILMA was successful in all patients. First attempt success rate in R Group (26 patients, 86.7%) was higher than N Group (22 patients, 73.3%) (p>0.05). Four patients (13.3%) in R Group and 8 patients (26.7%) in N Group required 2nd step of Chandy's maneuver during second attempt for successful intubation. Incidence of sore throat 6 hours postoperatively was statistically significant (median value 2.00 in N Group vs. 0.00 in R Group) between two groups.

CONCLUSION: PVC ETT with reverse orientation increases first attempt success rate of intubation through ILMA with less immediate postoperative laryngeal morbidity.