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

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.

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.

The mean antral CSA (cm²) 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 H₂O) 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.

Both LMA Protector and i-gel functioned comparably in terms of gastric insufflation.