Comparison of gastric insufflation between LMA Protector and i-gel using ultrasound in adult patients – A randomized controlled trial

Abstract Background and Aims: Second-generation supraglottic airway devices (SADs) have the risk of gastric insufflation and aspiration with positive pressure ventilation. Gastric ultrasound is an emerging point-of-care tool used to assess gastric volume and evaluate perioperative aspiration risk. Hence, we planned this study to compare gastric insufflation using ultrasound between the LMA Protector and i-gel. The primary outcome was to compare the antral cross-sectional area (CSA) between the two SADs. Secondary outcomes included comparison of oropharyngeal leak pressure, peak airway pressure, and postoperative complications. Material and Methods: After institutional ethics committee approval and trial registration, 92 patients aged 18–60 years with American Society of Anesthesiologists physical status I/II/III were recruited. Patients were randomly allocated to groups I (i-gel) and P (LMA Protector). Antral CSA and gastric volume were evaluated before induction, after facemask ventilation (FMV), and before removal of SAD. Categorical variables were analyzed using Chi-square or Fisher’s exact test. Quantitative variables (CSA, gastric volume) were analyzed using independent samples t -test. Results: The mean antral CSA (cm 2 ) and hence gastric volume increased significantly from before induction (2.56; 2.17) to after FMV (2.82; 2.57) and at the end of surgery (3.45; 3.19) in both groups I and P, respectively. However, the difference in CSA and gastric volume between the two groups at any time point was not statistically significant, indicating a comparable increase with both devices ( P = 0.147; 0.356; 322). Oropharyngeal leak pressure (cm H 2 O) was significantly higher in group P (32.43) than in I (35.98) ( P = 0.008). Peak airway pressure and postoperative complications were similar between the groups. Conclusion: Both LMA Protector and i-gel functioned comparably in terms of gastric insufflation.