Optimal flexible laryngeal mask airway size in children weighing 10 to 20 kg.

This prospective, randomised study was conducted to assess the effect of flexible laryngeal mask airway (FLMA) size on oropharyngeal leak pressure (OLP) in children at the recommended intracuff pressure. A total of 120 children undergoing elective ophthalmic surgery were randomly assigned to the size 2 FLMA group or size 2.5 FLMA group. The primary measurement was OLP at an intracuff pressure of 40 cmH2 O. Secondary outcomes included the incidence of OLP <10 cmH2 O, insufficient ventilation, gastric insufflation, insertion time, successful first-attempt insertion rate, fibreoptic view grade and pharyngolaryngeal adverse events. The median OLP was comparable for the size 2 and size 2.5 FLMA (18 cmH2 O versus 18 cmH2 O, P =0.38). However, the size 2 FLMA group had a higher incidence of OLP <10 cmH2 O and insufficient ventilation (13.3% versus 0, P =0.006). In subgroup analyses based on weight, the size 2.5 FLMA had a lower occurrence of OLP <10 cmH2 O and insufficient ventilation (27% versus 0, P =0.0046) in children 16-20 kg. We conclude that at a 40 cmH2 O intracuff pressure, the OLP with the size 2 and size 2.5 FLMA was similar in children weighing 10-15.9 kg. However, in children weighing 16-20 kg, size 2 devices had a higher incidence of low OLP and insufficient ventilation, so a 2.5 FLMA may be preferable in this subgroup.