Effects of tracheal tube orientation on the success of intubation through an intubating laryngeal mask airway: study in Mallampati class 3 or 4 patients.

BACKGROUND We evaluated the effects of conventional tracheal tube orientation on success of intubation through an intubating laryngeal mask airway (ILMA) in Mallampati class 3 or 4 patients. METHODS Two hundred adults, ASA I-II, Mallampati class 3 or 4, undergoing elective surgery under general anaesthesia were enrolled. All the patients were randomly allocated to either normal or reverse group based on the orientation of the tracheal tube as it was initially inserted into the ILMA. Tracheal intubation was considered successful, if proper tracheal positioning was attained within three insertion attempts. chi(2) analysis was used to compare categorical variables. RESULTS Tracheal intubation through the ILMA was successful in 183 of 200 patients (91.5%): 157 (78.5%) on the first attempt. Seventeen (8.5%) were intubated using direct laryngoscopy. The first-attempt success rate was higher in the reverse than in the normal group (85.0% vs 72.0%, P=0.025), although the overall success rate was similar between the reverse and the normal groups (93.0% vs 90.0%). The incidence of sore throat was comparable in the normal group and the reverse group (22.0% vs 12.0%, NS). CONCLUSIONS Overall, tracheal intubation was successful in 91.5% of patients through an ILMA with a conventional tracheal tube in Mallampati class 3 or 4 patients. The first-attempt success rate was higher in the reverse group compared with the normal group, but the overall success rate was similar between the reverse and the normal groups.