Oropharyngeal Airway (OPA) Overview
The oropharyngeal airway is a rigid, curved device inserted into the mouth to prevent the tongue from obstructing the airway. It is used only in unconscious patients with no gag reflex. The OPA holds the tongue forward and provides a channel for air to pass through to the glottis. It is one of the most common basic airway adjuncts used by EMTs and is considered a temporary measure while preparing for definitive airway management or during bag-valve-mask ventilation.
OPA Sizing
Proper sizing is critical. An OPA that is too small will push the tongue posteriorly and worsen the obstruction. An OPA that is too large can obstruct the airway or cause trauma. To size an OPA, measure from the corner of the mouth to the earlobe, or from the center of the mouth to the angle of the jaw. The flange should rest against the lips when properly seated. OPAs are available in sizes ranging from infant (size 0, approximately 40 mm) to large adult (size 6, approximately 110 mm).
OPA Insertion Technique
In adults, insert the OPA with the tip pointing toward the roof of the mouth (upside down). Advance it along the hard palate until you feel resistance, then rotate it 180 degrees so the tip points toward the pharynx, and slide it into final position. In children and infants, insert the OPA right-side up using a tongue depressor to hold the tongue down to avoid damaging the soft palate. Never force the OPA into position. If the patient gags at any point during insertion, remove the device immediately, as this indicates the patient has a gag reflex and the OPA is contraindicated.
OPA Indications and Contraindications
Indications include unconscious patients with no gag reflex who need airway maintenance, patients being ventilated with a BVM who require tongue displacement, and unresponsive patients with sonorous (snoring) airway sounds. Contraindications include any patient with an intact gag reflex, conscious or semi-conscious patients, patients with oral trauma or active bleeding in the mouth, and patients with known or suspected ingestion of caustic substances.
Nasopharyngeal Airway (NPA) Overview
The nasopharyngeal airway is a soft, flexible rubber or silicone tube inserted through the nostril into the posterior pharynx. Unlike the OPA, the NPA can be used in patients with an intact gag reflex, making it the preferred adjunct for patients with altered mental status who are not completely unconscious. The NPA is better tolerated and less likely to induce vomiting than an OPA.
NPA Sizing
To size an NPA, measure from the tip of the nose to the earlobe. The diameter of the NPA should approximate the diameter of the patient's little finger or the internal diameter of the nostril. NPAs are sized by internal diameter in millimeters, typically ranging from 6 mm (small adult) to 9 mm (large adult). Using an NPA that is too long can stimulate the gag reflex, cause laryngospasm, or enter the esophagus. Using one that is too short will not adequately displace the tongue.
NPA Insertion Technique
Lubricate the NPA with a water-soluble lubricant. Insert it into the right nostril with the bevel facing the nasal septum. Advance the NPA along the floor of the nasal cavity, not upward, using gentle pressure and a slight rotating motion. If resistance is encountered, do not force it. Try the other nostril instead. The NPA is properly positioned when the flange rests against the nostril and the tip sits in the posterior pharynx behind the tongue.
NPA Indications and Contraindications
Indications include patients with altered mental status who have an intact gag reflex, patients with trismus (clenched jaw) who cannot receive an OPA, patients with oral trauma or wired jaws, and as an adjunct during BVM ventilation. Contraindications include suspected basilar skull fracture (look for Battle sign, raccoon eyes, CSF leakage from ears or nose), severe facial or nasal trauma, and history of nasal surgery or obstruction. While the contraindication for basilar skull fracture is debated in current literature, it remains a standard teaching point for the NREMT exam.