An airway adjunct is a bridge, not a destination. It holds the tongue off the posterior pharynx so your bag-valve-mask actually moves air. It does not protect against aspiration. It does not replace a definitive airway. Size it wrong and you make the obstruction you were trying to fix. Here is the field method for both.
OPA vs NPA: pick by gag reflex
One decision drives the choice.
- OPA (oropharyngeal / Guedel airway): unconscious patients with no gag reflex only. Place one in a patient who still has a gag and you buy yourself vomiting or laryngospasm.
- NPA (nasopharyngeal airway): better tolerated when the gag is intact or the patient is only obtunded. It slides past the tongue without touching the back of the throat the way an OPA does.
Neither protects the airway. Both are holding actions while you set up for something more definitive.
OPA: sizing
Measure before you insert. The OPA is sized from the corner of the mouth to the angle of the mandible (the earlobe works as the same landmark on most patients). Too long and the tip can push the epiglottis down and obstruct. Too short and it leaves the tongue sitting against the posterior wall — you accomplished nothing.
OPA: insertion
Standard adult technique:
- Insert inverted — concave side toward the roof of the mouth, tip pointing up.
- Advance until it approaches the back of the hard palate.
- Rotate 180 degrees as it passes, so the curve follows the tongue down into place.
In pediatric patients, skip the rotation. Insert it right-side up with a tongue depressor to avoid tearing the soft palate. If the patient starts to gag or cough during placement, pull it — the gag came back, and the OPA is now the wrong tool.
NPA: sizing
Length first: measure from the tip of the nose to the tragus (or earlobe) of the ear. That distance sets how far the tube should sit. Diameter is roughly matched to the patient's nostril; the traditional "size it to the little finger" rule is a rough visual estimate, not a hard spec, so lead with the length measurement. Standard adult tubes run about 6.0 to 7.0 mm internal diameter, but always defer to your service or department protocol.
NPA: insertion
- Lubricate generously with a water-based lubricant.
- Insert with the bevel toward the nasal septum, typically the right nostril first.
- Advance straight back along the floor of the nasal passage — parallel to the palate, not angled up toward the top of the head. This is the most common rookie error: people aim up and hit turbinates.
- If you meet firm resistance, do not force it. Back out and try the other nostril.
Caution point: NPAs are traditionally avoided with suspected basilar skull fracture or significant midface trauma, given the theoretical risk of cranial misplacement. The evidence is debated and practice varies — know what your protocol says and follow it.
The common failure modes
- Guessing the size. Both adjuncts have a physical landmark. Use it every time. Eyeballing it is how you end up with an airway that obstructs.
- Wrong patient for an OPA. Intact gag plus a hard plastic airway equals aspiration risk. Reassess before you place.
- Angling the NPA upward. Straight back along the floor. Nosebleeds come from aiming high.
- Treating the adjunct as the fix. It keeps the tongue out of the way so your mask seal and rate do the work. Reassess chest rise and your capnography after placement, not just the fact that a tube is in.
An adjunct that is measured, matched to the patient, and seated correctly is invisible — it just works. That is the goal. Everything else is noise.
This is a study reference for RT students, not medical advice. Follow your program, service, and department protocols, and your medical director, over anything written here.
Built by an RT, for the people running the airway at 0300. If you want the field-manual aesthetic on your chest for the next code, the Night Ops respiratory therapist tee lives in the shirt collection. More reference drops in Field Notes.