“Pediatric Airway Assessment” by Tonya Miller for OPENPediatrics

“Pediatric Airway Assessment” by Tonya Miller for OPENPediatrics

January 7, 2020 0 By Bertrand Dibbert


Pediatric Airway Assessment, by Dr. Tonya
Miller. Hi there. I’m Tonya Miller, one of the anesthesiologists
here on staff at Children’s Hospital Boston, and I’m going to speak about airway management,
or approach to the airway management of pediatrics, which can sometimes be somewhat challenging. The goal of this talk is to give you an idea
of how to approach the airway of a patient from the perspective of an anesthesiologist. We’re going to go over assessment, and then
some special circumstances that you might want to keep in mind when you’re approaching
a pediatric airway. Airway Exam. For assessment of the patient, always look
to the ABCs: the airway, breathing, and circulation. 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 axes
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. Pediatric Considerations. So in terms of pediatric airway development,
the head and the occiput of their head has a different relationship to the rest of the
size of their body. This diagram shows a situation of a patient
laying supine in where you may or may not want to be bolstering a patient in order to
get an optimal visual alignment of the oral and then the laryngeal axes. You see, in the newborn or very young child,
it’s less likely that you’re going to want a pillow under the head because they already
have a large occiput and putting a pillow under their head would malalign these axes
of the oral pharynx and the larynx versus in a kid who is 10, 15, or an adult, where
you frequently will put a pillow behind the head to bolster in order to bring up their
oral access to meet their laryngeal access. Also, their tongue is very large compared
to an adult. So again, going to the box-to-tongue ratio,
they already start off with a larger tongue to the box of their mouth ratio than an adult. The larynx location tends to be more cephalad
and more anterior than in an adult. And therefore, the tracheal opening will be
more difficult to align when you are looking through the oral pharynx down towards the
tracheal axis because you will note it’s more anterior than you would expect. Again, this is why we don’t put a head pillow
underneath an infant automatically. The cricoid cartilage is a circumferential
ring, and in pediatrics, this becomes the smallest part or the narrowest part of the
pediatric airway. Versus in an adult, as the patient grows and
all their structures grow, actually, the inlet to the larynx is smaller than the cricoid
cartilage. Critical Update: Recent radiologic studies
have demonstrated that the subglottic region, not the cricoid, is the narrowest part of
the pediatric airway. However, there is concern that these findings
may be the result of artifact related to which phase of respiration was captured in the images. Autopsy specimen still confirm that the cricoid
outlet is the narrowest level of the pediatric airway. The epithelium of a pediatric airway is very
delicate, moreso than in the adult. And airway diameter being extra small in a
pediatric patient, the epithelium, if it gets irritated, inflamed, or incurs any sort of
swelling in the airway management process, more swelling in a small airway will lead
to a much greater effect on airway flow dynamics than would the same amount of airway swelling
in an airway that starts out at a much larger diameter to begin with. The epiglottis is something to make comment
on. The adult epiglottis tends to be longer, broader,
more easily manipulated with a laryngoscope blade than does a neonate glottis. Here are two pictures– one showing the adult
glottis, which is much larger, and one showing the neonate glottis, which you can tell is
very short and quite narrow– almost omega-shaped we would call it. This is much more difficult to put behind
a blade or to manipulate because it’s very stiff and will flop everywhere you don’t want
it to go. As far as the laryngeal opening, this picture
denotes that the laryngeal opening is more conical almost– like a funnel– where the
thyroid cartilage down to the cricoid cartilage narrows quite a bit. By the time children become adults, this becomes
much more cylindrical as opposed to a funnel shape. Again, just emphasizing that the cricoid ring
may be your smallest area in your pediatric patient’s airway. These two x-rays, if we compare them, the
one on the right is an adult airway. And you can see that the epiglottis and the
posterior laryngeal airway, the glottic area, and then the trachea all almost line up naturally
in a very vertical line. Compare that to the pediatric airway where
the epiglottis and the glottic opening is on an angle coming from the posterior pharynx
and then makes a turn as the trachea then dives back posteriorly from the glottic opening. Abnormal Anatomical Relationships. Continuing on as to some abnormal anatomical
relationships that you may encounter in a pediatric patient. You may, from a multitude of reasons, have
an abnormal situation of an otherwise normal bit of anatomy for the pediatric patient. For example, if they’ve had surgery or radiation
or some sort of disease process that lends to scarring, you may find that their face
looks very different, as this teen pictured here appears very different after he’s had
surgery and radiation for a cancer that was found in and around his neck. Or you may see a pediatric patient with a
very common disease process, such as a retropharyngeal abscess, in which there is some sort of inflammatory
mass that creates a distortion of normal airway anatomy. This is a CT scan showing such an abscess
and how its displaced the airway to be off center and a little bit smaller than otherwise
expected. There are other issues that you may have,
such as bone or spine issues. A patient with severe scoliosis or some sort
of disease process that lends their spine to have an abnormal curvature. Or if they have any kind of inflammation or
joint disease, they may have limited mobility of their neck, but also can lead to distortions
of anatomical relationships. Childhood obesity is another issue with airway
management in terms of getting a proper positioning for alignment of your axes. Here, we see a teenager who is quite obese. And in order to align all the different areas
or axes– the LA, being the Laryngeal Airway, the OA, being the Oral Airway, and the PA,
being the Pharyngeal Airway. In order to align these as closely as possible
to one another for the optimal airway intervention, you see here we have a big ramp made out of
blankets and pillows in order to get her in the proper position. Likewise, if you have some sort of trauma
coming in and, for example, a pneumothorax, as shown in this slide, you could have distortion
of the airway anatomy distal to the supraglottic structures that may make the placement of
a breathing tube more difficult. Other abnormal and anatomical relationships
can come in pediatrics from simply having congenital abnormalities. Here are a few different examples of this. The first is laryngomalacia, where the structures
of the larynx are extra floppy. It may be more difficult to get the breathing
tube into a patient who has laryngomalacia because the epiglottis may be even more compacted
on itself. It may be difficult to visualize the cords. And, also, your patient’s breathing status,
respiratory status, at the time of airway intervention may require some unique manipulations
or pharmacological choices in order to preserve the respiratory function as much as possible
while intubating these patients. A patient Pierre-Robin syndrome is another
classical example of an abnormal airway, where they have mandibular hypoplasia. They have a very short neck, and they have
a large tongue. Very difficult to intubate these patients
from the standpoint of alignment of all the axes and being able to see the glottis, which
is very anterior and very cephalad in these patients. Trisomy 21 children. This is a typical face of a child with Down
Syndrome. As you recall, the tongue is very, very large. They tend to have very short necks. They may have atlanto-axial instability of
their C1 spine. Thus, making it maybe more dangerous to manipulate
their head into an optimal position. And, then, the Kippel-Feil patient, who has
a very, very short neck and some bony abnormalities that inhibit the extension of the spine. Again, all these patients may require different
techniques in order to align their axes for visualization, or they may be impossible to
visualize and intubate directly, and may need to have other sorts of intubating techniques. And, lastly, as far as abnormalities of anatomical
relationship, if you have abnormal masses that just normally aren’t there. They’re not congenital, or they may be, but
they are acquired or otherwise. Whether it’s a mediastinal mass, a foreign
body in the airway, or vascular malformations that can grow over time. These can make your airway management very
difficult. Please help us improve the content by providing
us with some feedback. What did or didn’t you like about this video? Was the content too simple, just right, or
too difficult? Was the length too short, just right, or too
long? Any additional comments? You can either click the Start a New Discussion
button and type in feedback, or send us an email at [email protected] hildrens.harvard.edu. Note, feedback is not required to complete
this activity in the guided learning pathway.