Assessing the Pediatric Airway Prior to Intubation by Dr. Tonya Miller.
As far as the specific airway exam, you're assessing the ability to intubate.
Alignment of the oral axis and the tracheal
axis is one thing that you need to keep in mind.
Are you going to be able to align these axises
in this patient or not, or how difficult will be?
Are you going to have any visualization obstacles, such as do they have limited mouth opening?
What is their tongue to box ratio, and we'll go over that in a minute, and how much range
of motion do they have with their neck?
As far as mouth opening, we frequently will talk about classification of an airway
with the Mallampati Classification.
When a patient fully opens their mouth, if you can see the uvula, and space, and the
tongue, and the posterior pharynx behind it, that's a class one.
And in this picture, you'll see that there are four classifications all the way to a
class four, which would be where you can only see, really,
the hard palate when they open their mouth.
As far as anterior mandibular space is concerned, frequently you're taught to measure the thyromental
distance from underneath the chin with your fingers.
This works fine in adults because you can standardize saying three finger breadths,
but in small patients, everybody has different finger sizes,
and so this becomes much less useful.
However, as you get accustomed to looking at the children and their faces and their
neck structures, you can see if they have an adequate
amount of anterior mandibular space.
And what that is, is how much space they have to house the tongue that is inside.
The tongue size is also something that you'll want to look at.
Do they have an extremely large tongue?
Is it protuberant out of their mouth?
Do they not have space inside their mouth to house that tongue?
This is what I'm talking about when I talk to a tongue to box ratio.
If you think of the tongue as a structure that's normally contained inside of a box,
does that box have any more space inside of it
than just the area that is needed for the tongue to take up?
Or, is the tongue so large that it is taking up the entire space inside the box of the
mouth, and even protruding out?
Most patients are somewhere in between the two.
As far as oropharyngeal shape, you'll look at the palate, the tonsils, and think about
the choanae of the nose, because infants, as you know, are obligate nasal breathers.
So becoming difficult to mask ventilate if you can't get an airway in through the mouth
and have to rely on the nose, and yet, if they have choanal atresia or some other issues
with formation of the nose, that might be also a very difficult situation to even ventilate.
So to give you an example of the pharyngeal shape, this picture shows a patient that has
a cleft lip and palate.
You see that the palate actually is open on the inside, and these palates typically have
a smaller lateral to lateral side distance, but they're very open so the shape of the
box in which the tongue is housed is going to be completely different.
When it comes to intubating these patients, you may find that your laryngoscope may get
caught up inside the cleft that is there, as opposed to being able to intubate normally
through a patient who has an intact palate.
When we talk of range of motion of the neck, we're talking about head extension and head
flexion, but we're also talking about how much the mandible is mobile.
The TMJ joint, is it able to be subluxed?
Can you pull it forward?
Can you open your mouth all the way, completely?
Or do you have limitation for some reason, whether you have joint disease, some sort
of trauma, or some other sort of dysplasia, or extra small mandibular bone size issue.
The neck itself-- is it long enough to be able to extend and flex, or is it very short,
is it contractured, does the patient have a syndrome
that their neck is not a normal size for them?
Lastly, in assessing the alignment and visualization in preparation for instrumenting the airway,
you want to look at the neck structure and the neck structures inside, such as the thyroid.
Does the patient have a big thyroid?
Are there any other masses that would alter the normal anatomy that you would expect when
you're going to be encountering the larynx and the sublaryngeal area.