A nasopharyngeal airway (NPA), also known as a nasal trumpet, is a flexible tube designed to maintain an open airway. It is inserted through the nostril and extends into the posterior pharynx, bypassing upper airway obstructions like the tongue or soft palate, common in unconscious or semi-conscious individuals. This device is particularly useful when a patient has an intact gag reflex, making an oropharyngeal airway unsuitable, or when access to the mouth is limited. Its purpose is to ensure continuous airflow, facilitating ventilation and oxygen delivery. Proper measurement of the NPA is important for its safe and effective function.
Why Accurate Sizing Matters
Accurate sizing of a nasopharyngeal airway is important for its effectiveness and to prevent complications. An incorrectly sized NPA can lead to issues, compromising breathing. The correct length extends just beyond the base of the tongue without irritating deeper structures.
If a nasopharyngeal airway is too long, its tip can extend too far into the pharynx, stimulating the gag reflex, causing vomiting and aspiration risk. It might also enter the esophagus instead of the trachea, misdirecting airflow and failing to oxygenate. It could also injure pharyngeal or laryngeal tissues.
Conversely, if the NPA is too short, it will not extend past the base of the tongue and soft palate, failing to clear the airway obstruction. This renders the device ineffective, as breathing difficulties will persist. A short NPA may also dislodge or occlude easily, requiring frequent repositioning or replacement. Selecting the correct length ensures the airway remains open.
Measuring an NPA Airway
Measuring a nasopharyngeal airway involves identifying anatomical landmarks for correct length. The primary method is aligning the NPA against the patient’s face. This estimates the distance from the nostril to the pharynx.
Hold the NPA’s flared end, or flange, at the patient’s nostril. Extend the tube along the side of the face towards the earlobe. The tip should reach the tragus of the ear. This approximates the distance from the nasal opening to the epiglottis, ensuring the device sits above the vocal cords without stimulating the gag reflex.
After selecting a tube, visual confirmation assures proper sizing. Once the NPA is gently inserted, the flared end should rest against the nostril. If properly sized, the tip should be visible just behind the uvula in the posterior pharynx. This confirms the tube bypasses the tongue and soft palate, providing an open pathway for air.
Key Safety Considerations
NPA use involves safety considerations beyond accurate measurement. Certain conditions can make NPA insertion risky or contraindicated. For instance, facial trauma, especially involving the nose or mid-face, increases the risk of misplacement or injury.
A suspected or confirmed skull fracture is a contraindication. Inserting an NPA could inadvertently introduce the device into the brain cavity, causing neurological damage. Cerebrospinal fluid leakage from the nose or ears also indicates a skull fracture, making NPA use unsafe.
Before insertion, check the nostril for obstructions like polyps, deformities, or foreign bodies, which could hinder passage or cause trauma. Lubricate the NPA with water-soluble jelly for smooth insertion and to minimize mucosal injury and bleeding. Insert the tube gently; never force it, as this can cause nasal or pharyngeal damage.
After insertion, continuously monitor respiratory status to confirm effectiveness and detect complications. Observe for improved breathing sounds, chest rise and fall, and changes in oxygen saturation. Assess for irritation, bleeding, or dislodgement, ensuring the airway remains patent.