Objective: To measure an appropriately sized nasopharyngeal airway, it is taught that the size is related to the patients little finger or nostril (anterior nares). This study has been designed to identify whether these comparisons are valid.
Method: Direct comparison of the dimensions of ten subjects' little fingers and anterior nares with the internal anatomy of their nose as visualised on coronal MRI scans.
Results: Neither method correlated statistically with the nasal anatomy of that subject.
Conclusions: The methods used traditionally to size a nasopharyngeal airway do not correlate with the airway anatomy and are unreliable. It is more appropriate to size the airway dependent upon the patient's size, sex and race.