A randomized comparison of size selection strategies for I Gel with regard to patient weight and thyroid cartilage width measurement

This study evaluates three methods for selecting the appropriate size of the I-Gel airway device in anesthetized patients: manufacturer’s weight-based formula, external thyroid cartilage width measurement using vernier calipers, and ultrasound-guided internal thyroid cartilage width measurement. A total of 150 patients will be randomized into three groups (n=50 each). Anesthetists and outcome assessors will know group assignments, while participants and data analysts will remain blinded.All patients will receive standard anesthesia management, including IV midazolam, fentanyl, propofol, and atracurium. I-Gel placement will follow the assigned method. Oropharyngeal leakage pressure (OLP) will be measured to assess seal quality, and mechanical ventilation will be initiated in volume-controlled mode. Ultrasound will be used to evaluate I-Gel positioning, focusing on air leakage, epiglottis movement, and asymmetry at the thyroid cartilage and hyoid bone levels. Misplacement will be determined using ultrasound and clinical criteria such as abdominal distension, audible air leaks, or tidal volume loss exceeding 20%. Misplaced devices will be resized, and failed placements will result in tracheal intubation.

Postoperative care includes antiemetics, reversal of neuromuscular blockade, and monitoring in the recovery unit. Key outcomes measured include OLP, leak fraction, necessity for manipulation or failure, and presence of blood on the device.

Data will be analyzed using SPSS software. Continuous variables will be compared using ANOVA, while categorical variables will be analyzed with the chi-square test. Statistical significance is set at p < 0.05.

This study aims to determine whether thyroid cartilage-based sizing methods improve I-Gel placement success and reduce complications compared to the traditional weight-based formula, potentially improving airway management precision.