Airway Sizing and Placement Guide: Oral, Nasopharyngeal, and Endotracheal Tubes

Airway Selection and Verification

1. Sizing

• Oropharyngeal airway (OPA): Length = distance from corner of mouth to angle of mandible (or earlobe). Too short → ineffective; too long → laryngospasm/obstruction.
• Nasopharyngeal airway (NPA): Length = distance from nares to earlobe. Diameter = largest that passes easily (typically 6–8 mm adults). Lubricate well.
• Endotracheal tube (ETT): Adults: 7.0–8.0 mm ID (women/men). Pediatrics: uncuffed <8 yrs; cuffed ≥8 yrs. Formula: (age/4) + 4 (cuffed) or +3.5 (uncuffed). Confirm with Broselow tape or ultrasound.

2. Insertion

• OPA: Insert upside down, rotate 180° at soft palate (adults); right-side-up with tongue depressor (pediatrics).
• NPA: Bevel toward septum; gentle twisting.
• ETT: Direct/videolaryngoscopy; pass cuff 2–3 cm past cords.

3. Confirmation (Mandatory)

• End-tidal CO₂ (capnography) – gold standard.
• Bilateral breath sounds, chest rise, fogging in tube.
• Chest X-ray (ETT depth: tip 2–5 cm above carina).

4. Secure & Monitor

Tube holder/tape; continuous SpO₂, EtCO₂, hemodynamic monitoring. Reassess after any position change.