Oropharyngeal and nasopharyngeal airways

What they are (and why you use them)

• Oropharyngeal airway (OPA/Guedel): a curved plastic airway placed in the mouth to stop the tongue occluding the pharynx.
• Nasopharyngeal airway (NPA): a soft tube placed through the nostril into the nasopharynx to bypass upper airway obstruction and improve airflow.
• Both are airway adjuncts: they do not protect against aspiration and do not replace a definitive airway when needed.
• Main aims: improve bag-mask ventilation, reduce upper airway obstruction, and buy time while you optimise positioning and plan next steps.

When to use an OPA

• Unconscious or deeply sedated patient with airway obstruction (snoring, paradoxical chest/abdominal movement, poor air entry).
• During bag-mask ventilation to improve seal and reduce obstruction.
• After induction of anaesthesia (especially before LMA or intubation) if obstruction is present.
• Useful with jaw thrust/chin lift and head positioning (often works best in combination).

When to use an NPA

• Patient with partial airway obstruction who is not deeply unconscious (e.g., light sedation) where an OPA may trigger gagging.
• Trismus, clenched teeth, oral trauma, or limited mouth opening where OPA insertion is difficult.
• Adjunct during bag-mask ventilation when oral route is not possible or poorly tolerated.
• Can be used in some awake patients (e.g., to relieve obstruction) if tolerated and appropriate.

Contraindications / cautions

• OPA: avoid in conscious or semi-conscious patients with intact gag reflex (can cause vomiting/laryngospasm).
• NPA: avoid with suspected basal skull fracture or significant mid-face trauma (risk of intracranial placement).
• NPA: caution with anticoagulation/coagulopathy, known nasal pathology, recent nasal surgery, severe deviated septum, or recurrent epistaxis.
• Both: if airway obstruction persists despite adjuncts, reassess positioning, depth of anaesthesia, and consider supraglottic airway/intubation early.

Sizing (quick and safe)

• OPA size: measure from the corner of the mouth to the angle of the mandible (or tragus). Too small worsens obstruction; too large can cause trauma or laryngospasm.
• NPA diameter: choose a size that passes comfortably (commonly 6.0–7.0 mm internal diameter for many adults; smaller for petite adults, larger for big adults).
• NPA length: estimate from nostril to tragus/angle of jaw; aim for the tip to sit behind the tongue in the nasopharynx (not too short).
• If in doubt between two sizes: OPA often better slightly larger than too small; NPA often better slightly smaller if resistance/bleeding risk.

Insertion technique: OPA (Guedel)

• Preparation: suction ready, check for loose teeth/dentures, consider bite block if needed, ensure adequate depth of anaesthesia/unconsciousness.
• Open the mouth with scissor technique; insert with the curve facing up (towards the palate) until past the tongue, then rotate 180° so the curve follows the tongue.
• Alternative (often gentler): use a tongue depressor and insert in the correct orientation without rotating (reduces trauma).
• Stop when the flange rests on the lips/teeth; do not force it.
• Confirm effect: improved chest rise, easier bagging, reduced snoring/obstruction, better capnography if ventilating.

Insertion technique: NPA

• Preparation: choose the more patent nostril if possible; suction available; consider topical vasoconstrictor/local anaesthetic per local practice (especially if awake).
• Lubricate well (water-based gel). Insert along the floor of the nose (straight back, not upwards).
• Advance gently with a slight twisting motion; stop if significant resistance—do not force (try the other nostril or a smaller size).
• Correct position: flange at the nostril; patient may cough briefly; airflow and bagging should improve.
• If using with bag-mask ventilation: you can ventilate via the mouth while the NPA splints the airway; ensure a good mask seal.

How to know it’s working (and what to do if it isn’t)

• Signs of improvement: easier bagging, better chest rise, reduced airway noise, improved oxygen saturation, presence of capnography trace if ventilating.
• If still obstructed: optimise head position (sniffing/ramped), apply jaw thrust, check depth of anaesthesia, suction secretions, consider two-person mask technique.
• If OPA causes gagging/retching: remove it; consider NPA (if safe) or deepen anaesthesia if appropriate.
• If NPA bleeds: remove, apply pressure, suction, consider alternative airway strategy; avoid repeated traumatic attempts.

Common first-time scenarios

• Post-induction obstruction: start with jaw thrust + OPA; if difficult mask ventilation persists, call for help early and move to supraglottic airway.
• Sedation list (e.g., endoscopy): NPA can help if snoring/obstruction occurs and patient is not fully unconscious; use cautiously and monitor closely.
• Edentulous patient: mask seal may be difficult; OPA can help maintain patency; consider leaving dentures in if it improves seal (case-dependent).
• Copious secretions/vomitus: suction first; adjuncts help patency but do not prevent aspiration—consider definitive airway if ongoing risk.