Airway Adjuncts: OPA and NPA Sizing and Insertion

Airway adjuncts are simple devices that help keep an airway open. The two basic ones are the oropharyngeal airway (OPA), a curved plastic airway placed through the mouth, and the nasopharyngeal airway (NPA), a soft tube placed through the nose. Both are basic airway management skills at every level of EMS. Both are easy to use badly: the wrong size, the wrong patient or the wrong technique can make an airway worse rather than better.

What an airway adjunct does, and does not do

In a patient with a decreased level of consciousness, the muscles of the jaw and tongue relax and the tongue falls back against the back of the throat. That is the most common cause of airway obstruction in an unresponsive patient, and the snoring sound it makes is often the first clue. An OPA or NPA holds the tongue and soft tissue away from the back of the throat so air can pass.

• An adjunct does not replace positioning. Open the airway first with a head-tilt chin-lift, or a jaw thrust where a spinal injury is suspected, and keep holding the position if the patient needs it. Many patients need both the adjunct and the manual maneuver.
• An adjunct does not protect the airway from aspiration. Vomit, blood and secretions can still reach the lungs past an OPA or NPA. Have suction ready.
• An adjunct does not breathe for the patient. If breathing is inadequate, the patient needs ventilation with a bag-valve mask, and the adjunct makes that ventilation easier.
• An OPA can stimulate gagging and vomiting in a patient with a gag reflex, which is why it is used only when there is none.

OPA vs NPA: which one, and when

There is no rule that a patient gets only one. A patient may tolerate an NPA, lose the gag reflex as their condition worsens and then tolerate an OPA, and some protocols allow two NPAs, one in each nostril. Reassess the patient, not the device.

OPA sizing: how to measure an OPA

An OPA is sized by holding it against the side of the patient's face, with the flange at the mouth, and checking where the tip lands. Several landmarks are commonly taught, and different texts and courses use different ones: from the corner of the mouth to the earlobe, from the center of the mouth (the front teeth) to the angle of the jaw, or, as AHA courses teach, from the corner of the mouth to the angle of the jaw. They usually give a similar size. Use the one your program teaches, and measure on the patient in front of you rather than choosing by age or body size.

1. Choose an airway that looks about right for the patient.
2. Hold it against the side of the face with the flange level with the lips and the curve following the jaw.
3. Check that the tip reaches the landmark your program uses, the earlobe or the angle of the jaw.
4. If it falls short or runs past, try the next size.

How to insert an OPA

Adults: the rotation technique

1. Confirm the patient is unresponsive with no gag reflex, and open the mouth with a crossed-finger technique or a jaw lift.
2. Insert the airway upside down, with the tip pointing toward the roof of the mouth, so it slides over the tongue instead of pushing it back.
3. Advance it until you feel resistance at the soft palate, about halfway in.
4. Rotate it 180 degrees as you continue to advance, so the curve follows the tongue down into the throat.
5. Seat it with the flange resting on the lips or teeth.
6. Some texts teach a variation in which the airway is inserted sideways and turned 90 degrees. Either way, the aim is to get past the tongue without pushing it backward.

Children: the tongue-depressor technique

In infants and children the rotation technique is generally not used, because turning the airway in a small mouth can injure the soft palate and the delicate tissue of the throat. Instead, use a tongue depressor to press the tongue down and forward, then insert the airway right side up, in the position it will finally sit, following the natural curve of the tongue. Some texts teach this technique for adults as well. Children's airways are smaller and easier to obstruct, so the sizing step matters even more.

After it is in

• If the patient gags, coughs or begins to wake up, remove the OPA. It means the gag reflex is present.
• To remove it, pull it out following its curve, toward the chin. It does not need to be rotated on the way out.
• Turn the patient to the side and suction if they vomit, within any spinal precautions your protocol calls for.

NPA sizing: length and diameter

An NPA is sized for both length and diameter. The length is most commonly measured from the tip of the patient's nose to the earlobe, and some texts measure to the angle of the jaw instead. For diameter, choose the largest airway that will pass into the nostril without force. A traditional rule says to match the diameter to the patient's little finger. It is still commonly taught, but the little finger is not a reliable guide to the size of the nostril, so look at the nostril itself.

How to insert an NPA

1. Check the nostrils for blockage, injury or bleeding. Most texts teach trying the right nostril first, often the larger, because a standard NPA's bevel then faces the septum; techniques for the left nostril differ between texts.
2. Lubricate the airway generously with a water-soluble lubricant. Never use a petroleum-based lubricant.
3. Insert it with the bevel toward the septum, the wall dividing the nostrils.
4. Advance it gently straight back along the floor of the nose, toward the back of the head, not upward toward the eyes.
5. If you meet resistance, rotate it gently back and forth while advancing. If it still will not pass, stop, take it out and try the other nostril. Never force it.
6. Seat it with the flange resting against the nostril, and check that air is moving through it.

The NPA and suspected basilar skull fracture

Many EMS curricula teach that an NPA should not be used, or should be used with great caution, in a patient with a suspected basilar skull fracture or significant midface trauma, because of the risk of the tube passing through a fracture into the skull. Signs that raise the suspicion include fluid draining from the nose or ears, bruising around both eyes and bruising behind the ears. The caution is widely taught, but it is debated: the reports of an NPA entering the skull are rare case reports, and some airway texts treat it as a relative caution in a patient who needs an airway and has no other option. In most EMT curricula and on certification exams it is taught as a contraindication. Your protocol decides which applies in your system. Where you do place one in a head-injured patient, the straight-back angle along the floor of the nose matters even more.

Signs the adjunct is the wrong size

The device is judged by the patient, not by how it looks. After placing any adjunct, check for chest rise, listen for breath sounds on both sides, listen for snoring or gurgling, and notice whether bag-valve-mask ventilation has become easier or harder. If the airway is worse, the size or the placement is wrong.

Reassessment, and when an adjunct is not enough

An adjunct is a starting point in airway management, not the end of it. Reassess the airway and breathing every time you move the patient and whenever anything changes.

• Gurgling means fluid in the airway: suction. Neither adjunct prevents vomiting, and an OPA in a patient who starts to gag can cause it.
• Snoring that returns means the tongue or soft tissue is obstructing again: reposition, recheck the adjunct's size and placement, and consider a second adjunct if your protocol allows.
• Inadequate breathing, whether too slow, too shallow or absent, needs ventilation with a bag-valve mask and oxygen. The adjunct and a good mask seal make ventilation possible; they do not replace it.
• A patient whose airway cannot be kept open, or protected, with positioning, suction and basic adjuncts may need an advanced airway: a supraglottic airway or intubation, according to your scope of practice and protocol. Call for help early if that is beyond your scope.
• A patient who regains a gag reflex or consciousness may no longer need, or tolerate, the device you placed. Remove an OPA and reassess.

Estimate how long an oxygen cylinder will last for ventilation

For paramedics whose protocols include RSI: work through the RSI preparation checklist

Airway adjuncts on the NREMT skills exam

The NREMT's psychomotor exam includes airway and ventilation skills in which an adjunct is sized and inserted as part of managing a patient who is not breathing adequately. This guide does not reproduce the skill sheets. Download the current ones from nremt.org and practice against the exact steps and critical criteria they list, since the Registry revises them. Our NREMT Skill Sheets guide explains how to study with them.

The short version

• An OPA or NPA keeps the tongue off the back of the throat. It does not replace positioning, does not protect against aspiration and does not breathe for the patient.
• OPA: only an unresponsive patient with no gag reflex. NPA: tolerated by a patient who still has a gag reflex.
• Measure an OPA from the corner of the mouth to the earlobe, the center of the mouth to the angle of the jaw, or, as AHA courses teach, the corner of the mouth to the angle of the jaw, as your program teaches; texts differ.
• Size an NPA from the tip of the nose to the earlobe, with the largest diameter that passes without force.
• Adult OPA: insert upside down and rotate. Child OPA: tongue depressor, inserted right side up. NPA: lubricate, bevel toward the septum, straight back, never forced.
• A suspected basilar skull fracture is a widely taught caution for the NPA; it is debated, and your protocol decides.
• Keep suction ready, reassess often, and move to bag-valve-mask ventilation or an advanced airway, within your scope and protocol, when an adjunct is not enough.