One of the causes of an Upper Airway Obstruction includes a backwards displacement of the tongue in an unconscious person. One solution to this, is to insert an oropharyngeal airway (OPA).
When I insert an OP airway the patient must first be unconscious (this seems obvious), but it can also be used as a diagnostic measure, in which a patient who has a slightly decreased GCS will not actually tolerate an OP airway.
If the patient is unconscious, I generally have a few other things to consider (and inserting an OP airway needs to be done rapidly).
I measure the OP airway for a correct size, by measuring from the corner of the mouth to the ear lobe.
I then hold the flange (largest part of the OP airway, which will sit at the patient’s lips), and point the curve side down. As I insert the curved side down (so that it can get passed the tongue, I will rotate it 180 degrees .
While I do this, I’m looking for a gag reflex in the patient (and am quick to remove it if the patient starts to gag/ vomit).
I then ventilate the patient a few times and auscultate the patient’s lungs to make sure that it is doing the job that it’s supposed to and maintaining an open upper airway.