Higher airway seal does not imply adequate positioning of laryngeal mask airways in paediatric patients.

Background: It has been generally accepted that a higher airway seal pressure indicates adequate positioning of the laryngeal mask airway (LMA) in adult patients. The present study was undertaken to clarify whether a higher airway seal pressure correlates with an adequate positioning of the LMA in paediatric patients.

Methods: One hundred and eighty-one healthy children, aged 6-121 months, weighing 7.0-30.0 kg, managed with size 1.5-2.5 LMAs during elective surgery, were enrolled in this study. LMAs were inserted without using muscle relaxants, and patients breathed spontaneously during surgery. At the end of surgery, we documented oropharyngeal sealing pressure and fibreoptic aperture views of the LMA. We used a new fibreoptic score evaluating the anatomical relationship between LMA aperture and epiglottis: 1, the aperture view covered with anterior epiglottis completely, but the airway staying open; 2, anterior epiglottis seen for more than two-thirds of the aperture view in diameter; 3, anterior epiglottis seen for more than one-third, but less than two-thirds of the aperture view in diameter; and 4, anterior epiglottis seen for less than one-third of the aperture view in diameter.

Results: The oropharyngeal sealing pressures for each fibreoptic position, scores 1 to 4, were 17.0 +/- 6.4, 17.9 +/- 4.2, 20.1 +/- 7.3 and 17.1 +/- 6.1 cm H2O, respectively. There were no significant differences in sealing pressure between the four groups (P=NS).

Conclusions: A higher airway seal is believed to be one of the clinical signs correlating with the correct position of an LMA. We found no relationship between oropharyngeal sealing pressure and LMA cuff position in paediatric patients.