Weight-based guide to choosing LMA size

Guide to choosing LMA size. Note that these are guidelines only, and clinical judgment may be needed. In general, the size-4 LMA will be suitable for most adult females, and the size-5 for adult males up to 100 kg. The new size-6 is intended for adult patients over 100 kg. The size-3 LMA is now considered to be a pediatric size. Be careful not to exceed the maximum cuff inflation volume; if more than this volume is necessary to maintain a seal, consider the use of a larger size, as a better seal may be obtained by using a larger size with less air. Using too small a mask and overinflating the cuff may result in a poor fit within the oropharyngeal space and may possibly injure the oropharyngeal mucosa. Many clinicians measure the cuff pressure to ensure that it never exceeds 60 cmH₂O (ie, 41 mmHg).