Anatomy
The classic laryngeal mask airway (cLMA) is a soft silicone mask attached to a silicone tube. It is designed to be placed with its tip at the top of the oesophagus (Fig 1). When this is achieved the cLMA orifice will lie over the glottis.
The cuff of the mask is inflatable via a pilot tube. When inflated, the cLMA cuff should encircle the glottis, producing a low pressure seal.
The cLMA is designed to be reused 40 times.
There are eight sizes ranging from neonatal (size 1) to large adult (size 6). The sizes are 1, 1.5, 2, 2.5, 3, 4, 5 and 6 (Table 1).
Fig 1 Features of cLMA
| cLMA Size | Patient Selection Guidelines | Maximum Cuff Inflation Volume (ml) |
|---|---|---|
|
1 |
Neonates/infants up to 5 kg | 4 |
|
1.5 |
Infants 5-10 kg | 7 |
|
2 |
Infants/children 10-20 kg | 10 |
|
2.5 |
Children 20-30 kg | 14 |
|
3 |
Children 30-50 kg | 20 |
|
4 |
Adults 50-70 kg | 30 |
|
5 |
Adults 70-100 kg | 40 |
|
6 |
Adults over 100 kg | 50 |
Table 1 cLMA sizing, patient selection and inflation volumes