Comparison of Digital and Bougie-aided Technique for Proseal Laryngeal Mask Airway Insertion in Mastoid Surgery: A Randomised Clinical Study

Abstract

Introduction: While placing the Proseal-laryngeal Mask Airway (PLMA) using the digital technique, there may be failed insertion or inadequate ventilation. Therefore, a placement technique using the Gum Elastic Bougie (GEB)-aided placement was employed. Aim: To compare the clinical efficacy of Proseal Laryngeal Mask Airway (PLMA) insertion by two different techniques viz. Digital and Gum elastic bougie-aided, in mastoid surgery in adult patients done under General Anaesthesia. Materials and Methods: In this randomised clinical study conducted at the Department of Anaesthesiology, R.G. Kar Medical College, Kolkata, West Bengal, India from November 2016 to December 2022. A total of 88 patients of American Society of Anaesthesiologists (ASA) class I and II of either sex undergoing mastoid surgery using the PLMA as an airway management device were allocated to Digital (Group D) and gum elastic Bougie (Group B) techniques. Parameters studied included the percentage of successful insertion of PLMA on the first attempt, number of attempts required and time taken for successful insertion of PLMA and postoperative complications if any. The t-test was used to compare the groups regarding PLMA insertion time, while categorical data such as airway trauma was compared using Chi- square test or Fischer’s-exact test (whichever applicable). Results: In the present study 88 patients were included, with 44 patients in each of the two groups. The difference in Mallampati scoring of both groups was statistically insignificant. In the present study 68.18% patients in Gum elastic bougie group and 70.45% patients in Digital group were of ASA Grade I, showing no statistical significance between these two groups regarding ASA status. In Group B (GEB), PLMA was successfully inserted in 95.45% of cases on the first attempt, and in group D (digital) the corresponding figure was 77.27% and 22.72% of cases required a 2nd attempt, this difference was statistically significant (p-value<0.001). The difference of PLMA insertion mean time was statistically significant between the two groups (24.33±3.209 seconds in gum elastic bougie group whereas in digital group it was 13.42±3.228 seconds) (p-value <0.001). Conclusion: The GEB-aided Proseal-LMA insertion is more successful in the first attempt than in the digital technique. Although GEB-aided insertions of PLMA took longer, they helped achieve higher oropharyngeal leak pressure. With peak airway pressures less than 20 cm of H2O there was no audible leak from the drain tube and there were fewer failed insertions.