Oropharyngeal  airway

• Curved plastic tubes, flattened in cross-section and flanged at the oral end. They lie over the tongue, preventing it from falling back into the pharynx.

• Available in a variety of sizes suitable for all patients, from neonates to large adults. The commonest sizes are 2–4, for small to large adults, respectively.

• An estimate of the size required is given by comparing the airway length with the vertical distance between the patient’s incisor teeth and the angle of the jaw.

• Initially inserted ‘upside down’ as far as the back of the hard palate (Fig. a), rotated 180° (Fig. b) and fully inserted until the flange lies in front of the teeth, or gums in an edentulous patient (Fig.c,d).

Nasopharyngeal  airway

Round, malleable plastic tubes, bevelled at the pharyngeal end and flanged at the nasal end.

• Sized on their internal diameter in millimetres, length increasing with diameter. The common sizes in adults are 6–8 mm, for small to large adults, respectively.

• A guide to the correct size is made by comparing the diameter to the external nares.

• Prior to insertion, the patency of the nostril (usually the right) should be checked and the airway lubricated.

• The airway is inserted along the floor of the nose, with the bevel facing medially to avoid catching the turbinates.

• A safety pin may be inserted through the flange to prevent inhalation of the airway.

• If obstruction is encountered, force should not be used as severe bleeding may be provoked. Instead, the other nostril can be tried.