The Surgical Airway

1%

"In the National Emergency Airway Registry (NEAR II) study, less than 1% of more than 7,700 ED intubations involved cricothyrotomy." -Manual of Emergency Airway Management, 3rd Edition


To apply that statistic to prehospital care, assuming the average paramedic in the area performed 6 live intubations a year (the minimum required for certification), over a career of 30 years that paramedic will have performed 180 intubations throughout their career. According to these numbers, that paramedic will on average perform less than 1.8 cricothyrotomies. This skill is the epitome of low-frequency, high risk. 


Because of the low frequency of surgical airways, there is not much data to study. It has been said that the most difficult part of this procedure, is making the decision to do it. 


How are we, as providers, prepared for this truly once-in-a-career type call? Here are few of my thoughts on the matter. I'd love to hear yours.

Training

"This potential hesitancy is readily overcome by technical proficiency." -Manual of Emergency Airway Management, 3rd Edition

It is recommended that providers practice this skill one to two times each year using manikins or animal tracheas, or whatever is available. It has also been studied that those who practiced this procedure repeatedly in one session improved each time, performing the cricothyrotomy on a manikin in 40 seconds or less after their fifth attempt. 

Anticipate Difficult Airways

Early in my career, I had a patient with high velocity penetrating trauma to the left chest resulting in multiple wounds. I anticipated that this patient had a very high likelihood of deteriorating and in preparation for that, I was preparing for invasive airway management. Fortunately for me, a more seasoned colleague cautioned me- recognizing that this patient also had great potential to be a very difficult intubation. We determined the benefit of intubation in a more controlled environment, with more advanced equipment (and frankly more experienced providers) at a hospital 10 minutes away would outweigh the risks of allowing this patient to continue to self-ventilate and potentially worsen. We provided advanced notice to the hospital of our situation, and upon arrival to the ED, anesthesia was already there with all of their bells and whistles. After multiple attempts, the patient was finally intubated. My lesson learned from this call was to be better at anticipating a difficult airway, rather than rushing to intubate. 


I currently use gut-feeling to determine that level of difficulty, but there are some tools that may help make a more specific assessment and I am practicing being in the habit of using them to assess each patient I see (MOANS, LEMON, RODS, SHORT). 

The Decision

Having a solid airway algorithm helps in making the decision to move to the surgical airway. Studies have shown that for the typical laryngoscopist, if successful intubation hasn't been achieved in 3 attempts, it is unlikely that intubation will be successful. If a patient is unable to be intubated or oxygenated, the next step in the algorithm must be invoked. 

What do you use as your airway algorithm? 

In addition to the algorithm, there are rare instances where cricothyrotomy may be the primary means of airway management. These include foreign body in the proximal trachea, airway disruption or midface trauma such that intubation or extraglottic device wouldn't be expected to work, epiglottitis, angioedema, anaphylaxis, penetrating trauma to Zone 2 of the neck (jaw to clavicle). 

The Double Set

The prime example of the double set up is the patient who cannot be intubated after the 3rd attempt and cannot be oxygenated with the bag-mask. The double set involves one provider attempting to place an extraglottic device, while another prepares for cricothyrotomy. 

Percutaneous Transtracheal Jet Ventilation

Recently, my fire district has started carrying commercial kits for transtracheal jet ventilation (TTJV). So here's a little information I found that applied to this set up. The full details of these notes can be found in Chapter 16. 

TTJV is the surgical airway of choice for children younger than 10-12 years old, however it can be used for adults as well. In either case it is a temporary measure to buy time until a better airway can be placed. It is helpful to have a patent upper airway to allow for exhalation as obstruction may cause air stacking and result in barotrauma. A nasopharyngeal or oropharyngeal airway may assist in allowing for exhalation. 

The procedure begins with identifying landmarks and immobilizing the larynx. The syringe attached to the transtracheal catheter can be partially filled with fluid to watch for bubbles- lidocaine may be a good choice as it can be sprayed in the airway once placement is confirmed to numb the structures and suppress coughing. After advancing the catheter, placement should be confirmed again and jet ventilation performed. The catheter should be held in place by hand until a better airway is placed. 

Gas flow through a 14 gauge needle at 50 psi is 1,600 mL/second and elastic recoil accounts for exhalation. So for the average adult, an I:E ratio of 1:3 is recommended, or 1 second ventilation, 3 seconds exhalation. Pressure should be titrated down to the lowest pressure needed to deliver tidal volume (usually around 30 psi). Pressures for small adults and children should be less than 20-30 psi and for patients less than 5 years old, a bag should be connected (using an ETT adapter from a 3.0 ID ETT) to deliver ventilations at a lower pressure. 

In this temporizing measure, PaCO2 will increase by 2-4 mmHg/minute.

Complications include subcutaneous emphysema, barotrauma, catheter kinking, obstruction from blood or mucus, and esophageal puncture. 

Pediatric Chest Pain

This is an EKG of a 15 year old female athlete who complained of chest pain which resolved upon medic unit arrival. What do you make of this?

Here's a closer look at some of the lateral leads... 

Looking only at this EKG, here's what I see from the top down: 

• HR 57 - Bradycardia
• PR 128 ms - Sinus Bradycardia
• QRS 76 ms - No bundle branch block
• QTc 406 ms - Within the normal range of 280-430 ms. Also, going by the general rule of the QT being half the R-R, the QT also appears normal in range.
• QRS Axis 98 degrees - Right axis deviation (a normal variant in pediatrics) confirmed by the negative complex in lead I, and positive complex in both II and III.

I See All Leads

• Inferior: ST elevation in II and aVF
• Septal: T wave inversion
• Anterior: ST elevation
• Lateral: ST elevation

So, what about this ST elevation? Are we looking at acute infarction?

One thing that may help is to ask, is the ST elevation (STE) concave or convex. Concave STE, sometimes referred to as "Smiley Face" STE and can be more likely associated with more benign causes of STE.

Non-concave STE is often more likely to be malicious and more serious, indicating acute infarction.

Now this is not a 100% sensitive test. An MI can certainly present with concave STE- especially early on in it's development. But it all becomes part of the picture in accordance with reciprocal changes and the overall patient presentation.

Let's talk about STEMI imitators...

I know of 6 main STEMI imitators
(please add to the list if you know more).

1. Ventricular Rhythms
2. Paced Rhythms
3. Left Bundle Branch Block
4. Pericarditis
5. Left Ventricular Hypertrophy
6. Early Repolarization

Ventricular Rhythms, Paced Rhythms and Left Bundle Branch Blocks

All these can fall under the Ventricular Rhythm category. These are fairly simple to identify given the wide QRS complex associated with them and since we're all fairly familiar with these, I'll move on down the list.

Pericarditis

Typically noted with diffuse ST elevation accompanied by PR depression.

LVH


Can be identified by adding the QRS height of V1 or V2 to the depth of V5 or V6. Greater than 35 mm indicates the presence of LVH.

Early Repolarization

Common in young athletes, early repolarization has long been considered innocent. This "fish hook" appearance is common with Early Repol. and is usually most pronounced in the anterior leads. Recent studies are showing that repolarization abnormalities like this can be associated with sudden cardiac arrest or recurrent VF.

To me, this EKG most resembles the pattern found with early repolarization. With the concave appearance of the STE, no reciprocal changes, I would lean toward the likelyhood that this STE is due to early repol and not acute ischemia. That being said, this EKG is only a small piece of the puzzle and should be considered among all the other findings of an assessment and history.

I'll try to update this post when I find out the outcome of this call. Until then, what are your thoughts on the matter?

Good to Great

What methods have you found, not only to stay sharp, but to continually improve, grow and challenge yourself as a prehospital provider?

Airway Chapters 1 & 2

Here are a couple thoughts out of a book I'm reading currently, The Manual of Emergency Airway Management:

"The gag reflex is of no clinical value when assessing the need for intubation."

-Ron M. Walls

In school I was taught the gag reflex was a way of measuring if an obtunded patient could maintain and protect their own airway. I have heard some conflicting information on that in the past few years, but Dr. Walls lays it out there pretty clearly and examines multiple studies that have shown that there is no correlation between the gag reflex and the proper functioning of someone's airway protective mechanisms. He further mentions the logical conclusion that testing the gag reflex may cause vomiting which only makes the situation worse. Walls suggests that perhaps a better sign is noting if there are any secretions in the mouth or airway that the patient has not swallowed.

What are you using to determine a patient's ability to protect their own airway? How can we translate this information into the prehospital setting?

The Obtunded Patient: Pretreat vs. No Pretreatment

Thinking specifically in obtunded overdose patients. Some of the medics I work with have brought up good questions about the use of our typical pretreatment medications (usually Etomidate and Succinylcholine) asking the question of whether they're necessary or not. I'm open to suggestions, and my thought is 1. If I was being intubated, I'd rather be over-sedated than under-sedated and 2. I choose to use paralytics to give myself the best chance of success during the intubation. Wall reviews a few studies on deeply sedated patients and withholding neuromuscular blockers during RSI in these patients. Each study had similar results, and in one study as many as 70% of these patients "demonstrated unacceptable intubating conditions with vocal cords either adducted or closing, excessive patient movement, or sustained coughing." What are your thoughts?

Intro

Friends and Colleagues,

Thanks for visiting this blog. It has long been a dream of mine to provide excellence in my patient care as a paramedic. There are two components of this achieving this dream- education and experience. I feel grateful to have some great examples of this in many of you that I have trained with and/or have the honor of working with. My intent in this blog is to create a space where I can hear your thoughts, suggestions and ideas on things we learn and experience in performing our duty on the street. I look forward to hearing your responses.

Matthew