Studies on the Correct Length of Nasopharyngeal Airways in Adults: A Literature Review

The use of a nasopharyngeal airway (NPA) as an adjunct airway device can be critically important in emergency medicine. When placed correctly, the device can prevent upper airway obstruction. The goal of our review was to learn whether there is scientific evidence about the correct length and the insertion depth, and also possible facial landmarks, that can predict the appropriate length of the NPA. There has been no real consensus on how to measure the appropriate tube length for the NPA. Several studies have been able to demonstrate correlations between facial landmarks and body dimensions; however, we did not find any scientific evidence on this matter. The reviewed studies do not indicate evidence to support current recommended guidelines. This could potentially lead to both military and civilian emergency training programs not having the most accurate scientific information for training on anatomic structures and also not having a better overall understanding of intraoral dimensions. Emergency personnel should be taught validated scientific knowledge of NPAs so as to quickly determine the correct tube length and how to use anatomic correlations. This might require further studies on the correlations and perhaps radiographic measurements. A further approach includes adjusting the tube to its correct length according to the sufficient assessment and management of the airway problem.