Crossover comparison of airway sealing pressures of 1.5 and 2 size LMA-ProSeal™ and LMA-Classic™ in children, measured with the manometric stability test

Objectives: To compare airway sealing pressures, air leak, optimal positioning of the LMA-ProSeal™ and LMA-Classic™ in children. Methods: A crossover, randomized study was conducted in children aged 6 months-7 years weighing <20 kg scheduled for minor elective surgery under GA with sevoflurane. Either a 1.5 or 2-size LMA-ProSeal™ or LMA-Classic™ was inserted first. Optimal position of the devices was evaluated by fiberoptic bronchoscopy (FOB). Airway sealing pressures were determined under standardized conditions by the manometric stability test at the proximal end of the LMA device. Gas leak observed by auscultation over the neck and epigastrium was noted at these pressures. Results: Twenty-seven children of mean ages 29.48 ± 19.81 months and mean weight 11.23 ± 3.28 kg were included for evaluation. Airway sealing pressures were noted to be similar: 23.11 ± 8.28 cm H₂O with LMA-ProSeal™ and 23.26 ± 8.21 cm H ₂O with LMA-Classic™. At these sealing pressures, air leak in the neck was observed in 21/27 children with LMA-ProSeal™ compared with 24/27 with LMA-Classic™ (P = 0.467). Optimal device positioning as viewed by FOB was seen in 14/27(51.8%) children with LMA-ProSeal™ and 15/27(55.6%) with LMA-Classic™. Airway sealing pressures with suboptimal position of LMA-ProSeal™ was 22.23 ± 10.23 cm H₂O and with optimal position 23.93 ± 6.25 cm H₂O (P = 0.612). Conclusion: The LMA-ProSeal™ and LMA-Classic™ size 1.5 and 2 provide similar mean airway sealing pressures as assessed by the manometric stability test under standardized conditions, with similar air leak and optimal positioning.