Assessment of Suitability of I-gel and Laryngeal Mask Airway-supreme for Controlled Ventilation in Anesthetized Paralyzed Patients: A Prospective Randomized Trial

Context: Laryngeal mask airway supreme (LMA-S) has an inflatable cuff while i-gel has a noninflatable cuff made of thermoplastic elastomer.

Aims: To study the efficacy of ventilation and the laryngeal seal pressures (LSPs) with either device. Our secondary objectives were to compare the ease of insertion, adequacy of positioning the device, hemodynamic response to device insertion, and any postoperative oropharyngeal morbidity.

Settings And Design: A prospective, randomized, single-blinded study at Teaching Medical School in South India.

Materials And Methods: Forty-two patients posted for surgery under general anesthesia were randomly divided into two groups - LMA-S and i-gel. After a standardized premedication and anesthesia induction sequence, the supra-glottic devices were introduced. Ease of insertion was assessed from the number of attempts taken to insert, insertion time, and any maneuvers required to insert the device. Position of the device was assessed by the ease of gastric catheter placement and the fibreoptic grading of laryngeal visualization. Efficacy of ventilation was determined from the LSP, peak inspiratory pressure (PIP), and end-tidal carbon dioxide (EtCO2)values. Any postoperative oropharyngeal morbidity was also recorded.

Statistical Analysis: Descriptive analysis was reported as a mean and standard deviation, median, and range of continuous variables. Demographics were analyzed using a unpaired t-test for parametric data and Chi-square test for nonparametric data. Respiratory and hemodynamic data was analyzed using one-way ANOVA to find statistical difference within and between the two groups.

Results: LMA-S was successfully inserted in 95% of patients and i-gel in 85.5% of patients. There was a significant difference (P = 0.021) in the LSPs between the two groups (18.15 cmH2O in LMA-S and 21.28 cmH2O in the i-gel group). There was no significant difference in the PIPs, leak fraction, and the EtCO2values.

Conclusion: Both devices are suitable for positive pressure ventilation (PPV) in anesthetized paralyzed patients. However, i-gel gives a better laryngeal seal when compared to LMA-S and may be chosen preferentially for PPV.