Pediatric Intubations

 

By: Peggy Tseng, MD

A 7 yo girl is brought in by ambulance with blunt head trauma. As per medics, girl was running on a slip-and-slide on concrete at the local park and fell backwards hitting her head. Witnesses heard a loud crack when she hit the ground, and the girl was unresponsive for about 5 minutes. When EMS arrived, the patient was GCS 1-1-5, and she was placed in full c spine precautions.

BP 111/73, HR 72, RR 20, 100% RA, GCS 4-2-5.

They are 8-10 minutes out.

You prepare the team for the blunt head trauma and altered mental status patient.

Patient arrives with team, and on primary exam unremarkable except for GCS of 2-4-5, and the patient keeps repeating, ‘’let me sleep!”

You order IV, O2, Monitor, POC glucose (80), and POC hemoglobin (

Your secondary exam does not reveal any other findings, and E-FAST is negative.

You call for CT head stat.

As the team is transitioning the patient to portable monitors and getting ready to go, the patient stops responding.

Repeat Vitals BP 136/101, HR 62, RR 12, 100% RA GCS 1-1-1

What do you do?

You’re afraid the patient is herniating from this:

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But in order to get to CT, you need to first protect the patient’s airway.

In this blog post, we will review key points about pediatric intubation. We will highlight anatomic differences between pediatric and adult airways, and we will review all our relevant formulas for airway management. And finally we’ll identify the pearls to approach the pediatric intubation.

Why do we care?

As emergency physicians, we are the masters of resuscitation and we start with the ABCs in critically ill patients. The airway of ABC is paramount especially in this pediatric trauma case. 95% of pediatric arrests are due to respiratory causes. And intubating a child or infant is scary.

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But it shouldn’t scare us.

Remember 4 points:

  1. Positioning is key
  2. Practice with the Miller
  3. Start slow and shallow
  4. Have a backup plan

First it all comes down to anatomy.

I find it most helpful to turn an anatomic drawing on the side so that I can visualize anatomy from an intubating perspective.

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The tongue is larger relative to the oral cavity in pediatric patients. This makes tongue control with laryngoscopy more challenging.

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The larynx is more anterior and superior in pediatric airways than compared to adults.

The epiglottis in a pediatric airway is longer and more difficult to control with indirect elevation of the vallecula.

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Infants have a large occiput so when laying on a flat surface they will naturally be in a slightly flexed position.

We can use our knowledge of anatomy to change the patient’s position to maximize our changes of visualizing the larynx. We want to bring the oral axis, pharyngeal axis, and laryngeal axis as much into line as possible.
Here is an example of an adult.

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With a child, sometimes the occiput already naturally places their anatomy in a more aligned position. Sometimes we have to bring the shoulders up into alignment.

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(thanks to Dr. Emily Rose and her baby!)

But be careful not to overextend. This is also a common mistake and can also close off your visualization.

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What size ET tube should we use in our 7 year old patient?

(Age/4) + 4

-0.5 for cuffed tube.

5.75, So we rounded to 5.5 cuffed tube for our 7 yo patient.

An easier way to estimate if you don’t like formulas:

Remember:

4.0 at 1 yo

5.0 at 5 yo

6.0 at 8-10 yo

 

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Or if you can’t remember any numbers –

Just physically compare the outside ET tube diameter with the patient’s pinky finger and use the closest fit.

How deep should the tube be inserted?

3x ETT size (uncuffed number)

= 17.25 in our patient, rounded to 17cm.

What size blade should we use in our patient?

Remember size 2 at 2 yo.

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Should you use a straight Miller blade or a curved Mac?

Ah, the age old question. We’re taught that Millers are better for babies right?

That may not be true…

An anesthesia study found that optimal views were found in infant patients equally well with Mac and Miller blades. The researchers could also obtain an optimal view of the vocal cords when using a straight blade either to lift the epiglottis directly or to elevate the vallecula (as if using a curved blade).

Another pediatric anesthesia study compared laryngoscopic views in small children and found Miller and Mac views to be equal in success. In fact, when one laryngoscopic view was restricted, switching to use the other blade would often obtain the ideal view. Again, the anesthesiologists found that using either blade with either direct elevation of the epiglottis or indirect on the vallecula was also successful.  You could use the Mac as a Miller and the Miller as a Mac.

Both studies found that Miller blades were just as good as Mac blades in small children and infants, and you could use the Miller blade as a Mac if needed.

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Never used a Miller blade?

Dr. Richard Levitan is an airway expert, and he has tons of videos online to help us visualize the cords.

Check out www.airwaycam.com

I found watching and re-watching the technique helps us to learn especially for novice intubators. Dr. Levitan has written a great deal describing pediatric intubation, and there are a few pearls about his technique.

Intubation is all about visualization of the airway anatomy and finding the epiglottis. So make sure you start slowly in the posterior oropharynx and visualize every part of the airway as you advance.

A common mistake is immediately inserting the blade too deep, and by then no maneuvering will bring the epiglottis into view. The pediatric patient’s larynx is much more superior and anterior than in an adult airway so you may be surprised how shallow you insert before you get a view.

When you see the epiglottis you can either place pressure on the vallecular to indirectly elevate the epiglottis as you would an adult airway with the Mac blade.   Keep in mind that the pediatric epiglottis tends to be longer, floppier and more difficult to elevate with just pressure on the vallecular. You may need to use the blade to directly elevate the epiglottis. This may be easier with a longer blade or a straight blade.

Dr. Levitan starts with a right sided approach to allow for proper tongue control. He does not use the Miller to sweep to the left like a Mac blade. This avoids impacting the central dentition and gives us more room to see the vocal cords and maneuver the endotracheal tube.

Here he shows a direct laryngoscopy with Miller blade

Intubation of an infant with large tonsils using a Miller blade:

 

When all else fails

Go back to the basics. We are all trained on how to provide good bag valve mask ventilation. Infants require a faster BVM rate than older children. An easy way to remember is infants 30 bpm, toddlers 20 bpm, and children 10 bpm.

A prehospital study found that there was no difference in survival between intubated pediatric patients versus pediatric patients who received bag valve mask ventilation.   There was also no significant difference in neurologic outcome.

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We can even use a laryngomask airway to ventilate as well.

What if we can’t intubate, and we can’t ventilate? We can always perform a surgical airway.

Under what age is surgical cricothyrotomy contraindicated?

Different experts have different age cutoffs but overall the consensus is that if the patient is under 8 years of age, the cricothyroid membrane is too small for the surgical airway.

The focus of our post today is on intubation, but a brief overview. In the same area between the thyroid cartilage and cricoid cartilage insert a needle with syringe at 45 degrees until you can aspirate air.

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To connect a 14 gauge catheter to our standard bag valve mask you need a 3.0 ETT connector:

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Or you can use a 3cc syringe connected to the 7.0 ETT connector.

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Back to our patient

You correctly sized the ETT, used a size 3 Mac blade, and successfully intubated her maintaining c spine precautions prior to CT.   She was taken emergently from the ED immediately for evacuation of her epidural bleed with neurosurgery. She was discharged on day 6 of her hospitalization.

Months later, she is doing well and back at school.

So in review:

Remember that positioning is key. Align the head and ensure the ear is level with the sternal notch. Remember that in infants with large heads this may mean you need to elevate the shoulders. Do not over extend the patient’s neck as too much can also occlude your view of the vocal cords. Practice when you can with the Miller or watch as many videos as you can. And then when it comes down to it, start with whichever blade you feel comfortable using. If you can’t get an optimal view with one, you need to know how to use the other.   Novice intubators often insert the laryngoscopy blade too quickly and too deep in a pediatric airway. Make sure you are visualizing every part of the posterior oropharynx so you don’t miss the epiglottis in the pediatric patient. It’s a lot more anterior and superior than we may be used to. And as always, have a back-up plan.

As emergency physicians we’re good at anticipating and preparing for the worst. So if you think a few steps ahead, nothing will surprise you and you’ll always be ready for whatever happens.

 

Resources:

www.airwaycam.com

http://epmonthly.com/article/demystifying-pediatric-laryngoscopy/

Mahadevan, S. V. and Garmel G. M. An Introduction to Clinical Emergency Medicine. Cambridge University Press. 2012.

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