A nasopharyngeal airway, an NPA, is a flexible tube designed for insertion into a patient’s nostril. Its primary function is to create and maintain an open air passage between the nostril and the back of the throat. It is used in unconscious patients or individuals experiencing an obstructed upper airway, helping to ensure continuous breathing. Proper technique is essential for its safe and effective use in emergency and clinical settings.
Why Proper Sizing Matters
The length of a nasopharyngeal airway is a critical factor influencing both its effectiveness and patient safety. Correct sizing ensures the tube extends just enough to bypass any obstruction in the upper airway without causing harm. Healthcare professionals typically determine the appropriate length by measuring from the patient’s nostril to the tragus of the ear, or sometimes to the angle of the jaw. This measurement provides a guideline for selecting a device that will adequately reach the pharynx.
If an NPA is too short, it may not extend far enough to relieve an airway obstruction, rendering it ineffective. Conversely, a nasopharyngeal airway that is excessively long poses a distinct set of problems. An overly long tube can extend beyond the intended pharyngeal space, potentially irritating or injuring delicate tissues.
Direct Local Complications
A concern with an overly long nasopharyngeal airway is the potential for direct physical trauma and subsequent bleeding. The tip of a tube extending too far can abrade or lacerate the sensitive mucous membranes lining the nasal passages, nasopharynx, or pharynx. Such injuries commonly result in nosebleeds (epistaxis), which can range from minor oozing to more significant hemorrhage.
An NPA that is too long frequently stimulates the gag reflex due to its excessive reach into the posterior pharynx. This irritation can induce discomfort, coughing, or even vomiting. Vomiting presents a serious aspiration risk, where stomach contents enter the lungs, potentially leading to severe respiratory complications like aspiration pneumonia.
Incorrect placement or coiling within the airway is another issue with an overly long device. Instead of maintaining a clear passage, the excessive length can cause the tube to bend or coil within the pharynx. This misplacement renders the device ineffective and can increase the risk of aspiration.
Systemic Risks and Consequences
Beyond local irritation, an overly long nasopharyngeal airway can trigger broader physiological responses, including vagal stimulation. The vagus nerve, which influences heart rate and blood pressure, has branches in the pharynx. If the tip of the NPA irritates these branches, it can provoke a vagal response, potentially leading to bradycardia (slowed heart rate) or hypotension (low blood pressure). This can be dangerous for patients with pre-existing cardiac conditions.
While intended to open the airway, an excessively long NPA can paradoxically cause or worsen airway obstruction. If the tube’s tip pushes against structures in the pharynx or if it coils incorrectly, it can physically block the air passage. This unintended obstruction can compromise a patient’s breathing, making the device counterproductive and potentially life-threatening.
The increased risk of aspiration carries systemic consequences. If vomiting occurs and stomach contents are aspirated into the lungs, it can lead to aspiration pneumonitis or bacterial pneumonia, causing severe inflammation and infection. Such pulmonary complications can prolong hospital stays, increase morbidity, and in severe cases, be fatal.
An ill-fitting, overly long NPA can cause significant patient discomfort and intolerance. The constant irritation in the pharynx can lead to pain, agitation, and resistance to care. This discomfort can make patient management challenging and may lead to agitation or attempts to dislodge the device.