A prospective randomized study comparing the efficacy of the LMA ClassicTM, the AMBU Aura40 Laryngeal MaskTM and the I-GelTM using fibroptic bronchoscope in spontaneously breathing anesthetized patients.

ABSTRACT

Background: Supraglottic airway devices (SAD’s) have revolutionized airway management both inside and outside the operating room ever since the invention of the LMA Classic. Objectives: Objective of this study was to compare efficacy of LMA classic, Ambu Aura laryngeal mask and I-gel in terms of ease of insertion, fiberoptic bronchoscopic assessment of the glottic view, oropharyngeal leak pressure, intra and post-operative complications. Material and methods: Ninety patients of ASA Grade 1 or 2, aged 18–70 years, scheduled for elective short surgical procedures requiring general anesthesia were randomly divided in to three groups as LMA Classic, Ambu Aura40 laryngeal mask and I-gel group whose airway were secured with these devices. Anesthetic technique was standardized and maintained on spontaneous breathing. The number of attempts for the correct positioning (at least 6 square Etco2 traces on the capnograph and 4 ml/kg tidal volume) of the device were counted. Glottic view was noted by fiberoptic bronchoscope passed into the supralottic device and graded as 1 = Vocal Cords entirely visible, 2 = Vocal Cords or Arytenoids Cartilages partially visible, 3 = Epiglottis only visible, 4 = No laryngeal structures visible. Oropharyngeal leak pressure (OPLP) was measured. Intra and post-operative complications were looked for and recorded. Results: Ambu Aura40 could be positioned successfully in a single attempt in 90% of the patients (27 out of the 30), whereas it’s only 80% in both the LMA Classic and the I-gel groups without a statistical significance (P = 0.518). Successful positioning during the next or second attempt was more with I-gel compared to LMA classic (20.0% and 16.7% respectively). 63.3% of Ambu laryngeal mask group had a glottic view grade of 1 while only 46.7% and 13.3% of patients in the LMA classic and the I-gel group had a similar glottic view respectively which was statistically significant (P = 0.000). Significantly higher mean OPLP with I-gel 36.23 ± 3.00 and least with LMA classic 30.90 ± 2.15 (p=0.000). 3 patients (10%) in the LMA Classic group complained of sore throat in the postoperative period which was statistically significant (P = 0.045). Conclusion: Over all Ambu Aura40 laryngeal mask airway device is superior in comparison to the other devices with respect to parameters studied. I-gel due to high oropharyngeal pressure leak could be useful in positive pressure ventilation. The LMA Classic is associated with a minimal incidence of sore throat in our study.