Choosing the size of guedel airway is an important part of oropharyngeal intubation. There are two airway adjuncts types available in the market, oral airway sizes for adults & pediatric oral airway sizes. Colour and numeric coding make sizing guedel airway are very easy. You can measure from the tip of the patient's ear lobe to the tip of the patient's nose to find the correct sized airway. The maximum diameter of the airway that will fit should be used. To do this, choose a size close to the diameter of the patient's little finger.