A Nasopharyngeal Airway (NPA), often nicknamed a nasal trumpet, is a soft, flexible tube inserted through the nose to the back of the throat. Its primary function is to maintain an open and clear passage for breathing by bypassing upper airway obstructions. This temporary device is used in emergency situations when a patient cannot maintain an airway independently. The NPA works by holding the tongue and soft palate away from the posterior pharynx wall, preventing collapse and blocked airflow in individuals with an altered level of consciousness.
Clinical Situations Requiring Airway Support
The selection of a Nasopharyngeal Airway is largely determined by a patient’s level of responsiveness and the presence of specific reflexes. It is particularly indicated for individuals who are semi-conscious or have a decreased level of awareness but still retain an intact gag reflex. In such cases, an oropharyngeal airway (OPA), which is inserted through the mouth, would likely trigger gagging, vomiting, and potentially aspiration, complicating the airway issue further. The NPA is generally better tolerated because it runs through the nasal passage, causing less stimulation of the gag reflex.
This device is also the preferred choice when mouth access is restricted or impossible due to conditions like trismus (jaw spasm) or severe trauma to the mouth and jaw. The nasal route provides an alternative means of establishing an open airway, ensuring ventilation and oxygenation. Patients exhibiting noisy or obstructed breathing, often caused by the tongue falling back, are candidates for NPA insertion to restore a clear path for air movement. The NPA is a temporary adjunct used until the patient can breathe independently or until a more secure airway, like an endotracheal tube, can be placed.
Situations Where Use Is Prohibited
While the NPA is a life-saving device, its use is strictly prohibited in certain patient populations due to complication risks. The most significant contraindication is the presence or suspicion of a basal skull fracture. Inserting the tube through a fractured skull base, particularly through the cribriform plate, risks misdirecting the tube into the cranial cavity and damaging brain structures.
Clinical signs suggesting a basal skull fracture include bruising around the eyes (“raccoon eyes”) or bruising behind the ear (“Battle’s sign”). Leakage of cerebrospinal fluid from the nose or ears is another strong indicator. Significant mid-face or nasal trauma, especially complex fractures, also warrants complete avoidance of the NPA. Forcing the tube past a nasal fracture can increase bleeding, compromise the airway, or further disrupt the skull base integrity.
Ensuring Proper Fit and Function
Effective function of the Nasopharyngeal Airway depends on selecting the correct size, involving both the length and the diameter of the tube. An improperly sized NPA can fail to clear the airway or cause further harm. The proper length is estimated by measuring the distance from the patient’s nostril to the tragus of the ear or the angle of the jaw.
If the tube is too short, the tip will not extend far enough into the pharynx to lift the tongue and soft palate, allowing the obstruction to persist. If the NPA is too long, the tip can enter the esophagus, potentially leading to gastric distension during rescue breathing. An excessively long tube can also stimulate the gag reflex, negating the advantage over the OPA. To ensure smooth insertion, the outside of the tube must be coated with a water-soluble lubricant. Lubrication minimizes friction against the nasal mucosa, reducing the risk of epistaxis (nosebleeds).