• Sasha

What's the difference between NPA and OPA ?

Updated: Nov 9, 2021

Introduced in 1958 by Hans Karl Wendl, a nasopharyngeal airway is a type of airway adjunct. It is a flexible rubber tube designed to go through the nose and end at the tongue base to help keep the airway open.



It is also known as a nose hose or nasal trumpet due to its flared end.Airway management is necessary because in unconsciousness, a patient’s jaw usually relaxes, and the tongue could slide back and block the airway because of this.

To prevent tongue covering epiglottis in the patient with reduced Glasgow Coma Scale, an NPA is usually applied. NPAs are measured with the French catheter scale, but they are given in millimeters in terms of size quotation.


The usual sizes of the NPA include 6.5mm/28FR, 7.0mm/30FR, 7.5mm/32FR, 8.0mm/34FR, and 8.5mm/36FR. According to Portex sizing, an average height female will require a 6 NPA size, while an average height male will require a 7 NPA size.



When an artificial form of maintaining the airway is necessary, and tracheal intubation is inadvisable, impossible, or outside the practitioner's scope of practice, the NPA is used. The NPA is used by emergency care professionals like paramedics and EMTs. They are mostly used with patients that are conscious and who would have a gag reflex if an oropharyngeal airway is used.

They are not suggested for use if the patient has severe facial trauma. This is because the anatomy of their face (especially relating to the nasal passageways) may have been altered. Then, inserting an NPA may result in the patient getting additional harm.


To choose the correct size of NPA to use on a patient, the device should be measured on the patient, and it should be able to extend from the nostril of the patient to the angle of the jaw or the earlobe. To insert the NPA

  • Use a water-soluble jelly to lubricate the nasopharyngeal airway so that it can easily enter.

  • Then insert it into the patient’s nostril, preferably via the right one, vertically with slight twisting along the floor of the nose.

  • Insert the device until the flared end is resting against the nose, and while inserting, aim it towards the back of the opposite eyeball.

  • Then confirm if the airway is now opened or still obstructed.




Oropharyngeal Airway (OPA)

Just like the nasopharyngeal airway, the oropharyngeal airway is also a type of airway adjunct. A rigid plastic tube sits along the top of the patient’s mouth and ends at the tongue base to help keep or open the airway.



It prevents the covering of the epiglottis by the tongue in a patient with a reduced Glasgow Coma Scale. If the tongue covers the epiglottis, the patient could find it hard to breathe. Arthur Guedel designed this airway adjunct, and it is also known as the Guedel pattern airway or oral airway.

Ranging from infant to adult, they come in different sizes. They are used by certified first responders, paramedics, emergency medical technicians, and other health professionals for post-anesthetic short-term airway management and in a pre-hospital emergency or when manual methods are not good enough to keep the airway open.

They are also used when tracheal intubation is not advisable, available or if the duration of the problem is short-term. It is advisable to use the OPA only in unconscious people because it would likely result in a gag reflex if the patient is semi-conscious or conscious. This could lead to the patient vomiting and probably blocking the airway.

To get the correct OPA size to use on a patient, measure it from the first incisors to the angle of the jaw. To insert it into the patient’s mouth.

  • Make sure that there are no foreign bodies in the patient’s mouth.

  • Then lubricate the oropharyngeal airway.

  • Insert the OPA into the patient’s mouth, and once it has made contact with the hard-soft palate junction, rotate the device 180 d

  • egrees and continue insertion. This is to enable easy insertion and assurance that the tongue is secured.

  • Then confirm if the airway is now opened or still obstructed.

There is an alternative method of insertion, and this is the method that is recommended for using OPA in children and infants.

  • Use a tongue depressor to hold the tongue forward.

  • Then insert the airway right side up.

Remove the device by pulling on it without rotating it, or substitute it for an advanced airway once the patient regains swallow reflex and can protect their airway. If the patient gags during the process of insertion, stop the insertion and try a nasopharyngeal airway. The OPA has to be correctly sized and inserted to maximize efficiency and to minimize the possibility of complications like oral trauma.

Usage of an OPA does not prevent liquids such as saliva, food, blood, cerebrospinal fluid from closing or obstructing the glottis. It also does not eliminate the need for ongoing airway assessment or recovery position. It, however, can facilitate ventilation during CPR.


Some of the major risks associated with using an OPA includes

  • Vomiting if there is a gag reflex.

  • It can close the glottis, thus closing the airway if it is too big.

  • Bleeding in the airway can be caused by improper sizing.


Conclusion

Both the nasopharyngeal airway and the oropharyngeal airway perform the same function, but they have specific situations in which one will be preferred over the other one. They both can be used with a bag-mask or oxygen mask over the top if it is needed.

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