How do you size a nasopharyngeal airway

Prospective Evaluation of the Routine Use of a Nasopharyngeal Airway (Wendl Tube) during Endoscopic Propofol-Based Sedation

“…The correctly placed NPA will lie over the epiglottis separating the soft palate from the posterior wall of the oropharynx. The ideal length of the NPA measured at nasal endoscopy correlates with the subject's height, which is independent of sex [22,23,24]. Despite the knowledge that NPAs are frequently misplaced, if the airway is too short it will fail to separate the soft palate from the pharynx, and if too long it can either pass into the larynx and aggravate cough and gag reflexes [7]; we had no problems with the position of the NPA with the standard size 7.…”

A review of emergency equipment carried and procedures performed by UK front line paramedics on paediatric patients

“…However the evidence for this complication is based upon a single case report 5 and has recently been contested on the grounds that the clinical indicators of a basal skull fracture can be difficult to interpret, especially outside of the well lit hospital environment and that teaching should focus on correct placement of the NPA (parallel to the nasal floor) and the advantages of this piece of equipment rather than the often quoted but once cited complication. 6 The value of prehospital intubation of children is dubious, with a large, well conducted study demonstrating no benefit over efficient bag valve mask ventilation. 7 Nevertheless, paramedics should be able to place an endotracheal tube in a child of any age, in case of a difficult airway or special circumstances making bag valve mask ventilation less desirable-such as very long transit times or when there is a high risk of aspiration such as drowning.…”

Part 8: Advanced Life Support

“…2 One study showed that the traditional methods of sizing a nasopharyngeal airway (measurement against the patient's little finger or anterior nares) do not correlate with the airway anatomy and are unreliable (LOE 5). 3 In 1 report, insertion of a nasopharyngeal airway caused some airway bleeding in 30% of cases (LOE 5). 4 Two case reports reported inadvertent intracranial placement of a nasopharyngeal airway in patients with basal skull fractures (LOE 5).…”