Evaluation of Safety and Efficacy of AMBU® AuraOnce™ Laryngeal Mask Airway in Supine and Trendelenburg Position in Patients undergoing Perianal Surgeries: A Prospective Observational Study

Introduction: Oropharyngeal Leak Pressure (OLP) is a crucial marker for assessing the safety and efficacy of airway devices. Positional changes during surgeries may influence airway dynamics and require objective assessment. Aim: To compare the changes in OLP using the AMBU® AuraOnce™ Laryngeal Mask Airway (LMA) in patients undergoing perianal surgeries in supine and Trendelenburg positions. Materials and Methods: This prospective observational study was conducted among 35 adult patients undergoing elective perianal surgeries between March 2023 and February 2024, Department of Anaesthesiology, Indraprastha Apollo Hospital, New Delhi, India. The OLP, intracuff pressure, ETCO2 , heart rate, mean arterial pressure, and SpO2 were measured during surgeries under general anaesthesia with AMBU® AuraOnce™ LMA, which required both supine and Trendelenburg positions. Data were analysed using a paired t-test for continuous variables and Chisquare for categorical variables, with p-value <0.05 considered statistically significant. Results: The mean age and Body Mass Index (BMI) were 47.14±12.87 years and 27.37±4.5 kg/m2 . A total of 21 male and 14 female patients were assessed. The mean OLPs of patients in the supine and Trendelenburg positions after LMA insertion were 20.17±1.32 cmH2 O and 20.40±1.12 cmH2 O, respectively; however, the mean OLP difference in both positions was not statistically significant (p-value >0.05). The mean arterial pressure, End-Tidal Carbon Dioxide (ETCO2 ), and Peripheral oxygen saturation (SpO2 ) in supine and Trendelenburg positions were 87.7±16.36 mmHg and 90.23±7.28 mmHg, 31.66±3.18 mmHg and 31.63±3.45 mmHg, 99.6±0.60% and 98.97±0.70%, respectively. Conclusion: The AMBU® AuraOnce™ LMA can maintain a stable OLP, ventilation parameters, and haemodynamic profile, when the patient requires a change in position from supine to Trendelenburg position during perianal surgeries.