13.13 Troubleshooting Guidelines

We are Looking for That Area Between the Oropharyngeal Junction and the Epligotti, Called the Oropharynx

A good example of this landmark would be represented on the below graphic as the second smaller hill next to the first large hill on the graph, between the two small triangles. Typically, this can be found in the first “hump” after the oral cavity – from the first “dip” to the second “dip”. In some graphs, that area may be harder to identify.
To locate the oropharynx on the Pharyngometry display screen, search about 10 cm “mouth-ward” of the glottis. This is the pharynx. The glottis is the dip located at around 20 cm, corresponding to the narrow area around the vocal cords. This landmark may then help us to locate the area we are interested in located just left of the pharynx.

Placement of the Mouthpiece and Ways to Troubleshoot

Be sure to use the ‘new’ mouthpieces only!
When testing, look for a sizeable oral cavity (but not much greater than 9 cm) and a dip almost to 0 on the nose-breath graph.
For the next three mouth-breaths, look for a sizeable oral cavity (often around 3 cm) and clear curves with a minimum GREATER than 0 at the oropharynx. This should be because the vellum will be open while mouth breathing, creating a larger area in the airway. All three curves should be clear and reproducible.

The Tongue is Misplaced

Tongue is most likely misplaced at the roof of the mouth.
Reposition the tongue; making sure that it is resting under the ledge of the mouthpiece. If this fails, try inserting the mouthpiece without the wave tube attached, and look, with a flashlight, to see if placement is correct.
For those individuals with “meaty tongues”, it may be possible that, even with correct placement of the mouthpiece, the graph will appear this way. In that case, note that in the comment section.

Oral Cavity Appears Artificially Large

Very large (off the chart on top) oral cavities are likely that the subject is not creating a good seal around the mouthpiece or not resting their teeth on the “bite blocks” of the mouthpiece because the oral cavity appears artificially large.
Instruct the subject to bite down, or to rest their teeth on the “bite blocks.”
Also, the clicking sound will seem louder to the tester as the lips are not confining the sound to the mouth.

Nose Breathing

Gary Glass approved of these techniques, and suggested the nose holding technique, as a final option when all others have failed.

One can tell the subject is nose-breathing because the dip after the oral cavity hits 0. That is appropriate for the nose-breath trial, but be sure that for the "mouth-breath” trial you attain proper data, with that same dip falling above zero.
If the subject has trouble breathing through the mouth only, instruct them to inhale slowly though their mouth, and throat. This may help.
You may also ask them to blow out slowly – as if they were blowing up a balloon.
As a last resort, you may have them hold their nose, so they will only breathe though their mouth.

Scattered Curves, Sailboats, or Flat Lines

If you find that you are obtaining “scattered” curves, “sailboats”, or flat lines, there are several things you may do.

Check the connection to the computer. See that the wave tube is securely fastened and in place at the port.
Have the participant wet their lips, and reposition the mouthpiece to avoid air leaks.
Remind participant to rest their teeth on the bite blocks, to avoid air leaks.

National Sleep Research Resource

Cleveland Family Study