Learning Intubation: Head Position Effects Laryngeal View

When first learning intubation,  a beginner often concentrates on memorizing the key laryngeal anatomy. This is important of course. If you can’t recognize the vocal cords, you will not be able to successfully intubate. However, even more important to learning intubation is understanding how the larynx relates to the other structures in the head and neck. In order to intubate you must manipulate those other structures to bring the larynx into view.

A prior post, When Learning Intubation Is Hard, described in detail some of the most common barriers to learning to intubate. Here I will concentrate on helping you see how head position effects your ability to see the larynx.

Larynx Location In The Neck

To feel your own larynx, place your hand on the front of your neck, with thumb and forefinger on either side of the firm, roughly cylindrical shape in the midline.

Illustration showing Relationships thyroid and cricoid cartilage to cricothyroid membrane

Relationships thyroid and cricoid cartilage to cricothyroid membrane

The adult larynx lies opposite the 5th, 6th cervical vertebrae, as opposed to the infant larynx that lies opposite the 2nd, 3rd and 4th. The fact that the infant larynx is higher in the neck leads to greater risk of airway obstruction and a need to slightly alter technique during pediatric intubation. A link to how to intubate the pediatric patient is located at the end of this article. Here we will concentrate on the adult.

The larynx is located in front of the esophagus in the neck. The opening to the larynx, called the glottis, and the opening to the esophagus are immediately adjacent to each other. Misidentification of the esophagus as the glottic can lead to esophageal intubation.

Illustration showing how easy it is to insert a laryngoscope blade too deeply and hide the larynx during intubation of an infant or small child

It’s very easy  to insert the laryngoscope blade too deep, as in the right picture. If too deep you will not see recognizable anatomy because you are looking down the esophagus and hiding the larynx.

 

Photo of view during laryngoscopy, on the left the esophagus is seen "tented" to appear like the larynx, on the right the larynx.

If you insert your blade too deep you will hide the larynx underneath. This action also tents the esophagus and can made it mimic the glottic opening if you are not careful.

How The Larynx Relates To Other Structures

Look at this lateral Xray  of a head in neutral position. The outline of the epiglottis, the hyoid bone, the thyroid cartilage and the cricoid cartilage are easily identified. Notice the relationship of the larynx to the esophagus. The larynx lies in front of the esophagus but the opening to the larynx (the glottis) and the esophagus are right next to each other. Accidental esophageal intubation is a risk with every intubation.

Lateral view Xray showing the distinct outlines of the parts of the larynx and their relationship to the jaw, tongue and cervical spine.

Lateral view Xray showing the distinct outlines of the parts of the larynx and their relationship to the jaw, tongue and cervical spine.

Now imagine yourself intubating this patient. what would you have to do to bring the larynx into view? How deep would you have to insert a Macintosh blade to  place the tip in the vallecula? How deep would you need to insert a Miller blade to lift the epiglottis?

Here is a CT scan of another adult patient. Notice that in this second patient the larynx is located higher in the neck.

Normal CT side view showing relationship of laryngeal structures to external anatomy

Normal CT side view showing relationship of laryngeal structures to external anatomy

Whereas the epiglottis in the first patient is low behind the tongue, this patient’s epiglottis is higher. The depth of insertion and the strategy to lift the epiglottis will change from patient to patient. Straight blades often work better in patients with a larynx higher in he neck and this may be one of those patients.

How Does Neck Position Affect The Larynx During Intubation

Let’s look at a lateral Xray of our first patient, but now with his head tilted all the way back in full extension. Patients with respiratory distress, will often tilt their heads back. You can see that this position more fully opens the airway and decreases resistance to breathing.

lateral Xray of the neck in full extension showing how the relationship of the larynx changes with respect to the rest of the neck structures. Extension without placing the patient in the sniffing position will hide the larynx behind the tongue, or a so-called anterior larynx.

Lateral Xray of the neck in full extension showing how the relationship of the larynx changes with respect to the rest of the neck structures. Extension without placing the patient in the sniffing position will hide the larynx behind the tongue, or a so-called anterior larynx.

During intubation, we need to tilt the head back to bring the axis of the oral and pharyngeal axes into alignment. But if the patient is not in a good sniffing position,  with the head moved slightly forward  in addition to being tilted, the larynx may remain hidden behind the tongue during laryngoscopy.

Let me rotate this image to show you what I mean.

Lateral neck Xray showing how extreme head extension, without the sniffing position, can make visualization of the larynx difficult.

Lateral neck Xray showing how extreme head extension, without the sniffing position, can make visualization of the larynx difficult.

You can now see how anterior that larynx would look during laryngoscopy. Pushing down on the cricoid cartilage might help rescue a difficult intubation in a situation like this, but optimal head and neck positioning from the beginning would work better.

When getting ready to intubate, always glance at the side of your patient and assess whether the head and neck are in an optimal position before you start. If it’s not optimal, try to fix it. That several seconds can save you, and your patient, potential trauma.

Head Position Also Affects Laryngeal Opening

As long as we are looking at X-rays, let’s look at our first patient with his head flexed fully forward. When the head is flexed forward, the structures in the posterior pharynx and the tongue tend to obstruct the airway. You can test this by flexing your head forward as far onto your chest as you can. It becomes much harder to take a breath.

lateral Xray showing that With the head flexed fully forward onto the chest, the airway is almost fully obstructed. Visualization of the larynx wold be impossible.

With the head flexed fully forward onto the chest, the airway is almost fully obstructed. Visualization of the larynx would be impossible.

While no one would position a patient’s head this way for intubation, it’s common for novices to place too many pillows under the head trying to obtain a good sniffing position. If the head is too high, the patient, and the intubator, will not be able to tilt the head back.  In other words, our novice intubator, trying to maximize sniffing position, sabotages himself. Again, prior to intubation take a look to the side of your patient. Try to tilt the head back (or have the patient tilt their head back).

When learning to intubate, learn the anatomical relationships, not just laryngeal anatomy.  A good intubator understands that knowledge of how those structures move in relationship to each other gives you the power to manipulate that anatomy to give you the best possible view during intubation.

Please share with your fellow students. I’ve included a list with links below to previous posts on learning intubation to help you perfect your skills. Feel free to ask questions. Let me know if there are any topics that you would find helpful.

May The Force Be with You

Christine Whitten MD, author
Anyone Can Intubate, A Step By Step Guide
and
Pediatric Airway Management, A Step By Step guide

LINKS TO PRIOR DISCUSSIONS WITH MORE DETAILS OF HOW TO INTUBATE:

 

Button to see inside or buy the book Pediatric Airway Management: A Step-by-Step Guide by Christine Whitten  Button link to see inside or buy the book Anyone Can Intubate, A Step By Step Guide to Intubation and Airway Management, 5th edition on amazon

Please click on the covers to preview my books at amazon.com

GlideScope Technique For Intubation In Small Mouths

The GlideScope Video Laryngoscope (GVL) is an extremely useful tool for managing challenging intubations, but it can be more difficult to use if your patient has a small mouth and a high arched, narrow palate. The problem: once the GlideScope is in place in a small mouth, maneuvering the endotracheal tube around it and into the posterior pharynx can be challenging. If you can pass the endotracheal tube (ETT) at all, the cuff tends to scrape against the teeth, risking rupture. However, there is a modified GlideScope technique you can use in those situations. Continue reading

Difficult Intubation In A Newborn

Difficult neonatal intubation can occur unexpectedly. We’re ready to perform neonatal resuscitation in the delivery room. We may be less ready to have to deal with a difficult neonatal airway at the same time. Recently I, and my colleagues, had to manage an unanticipated difficult neonatal intubation in labor and delivery.

The Case

The baby was born extremely edematous, and in respiratory distress. Although it was easy to ventilate the baby using the NeoPuff, airway swelling prevented the neonatologist  from identifying the epiglottis and vocal cords. The anatomy was too distorted. Following protocol when faced with a difficult intubation, the neonatologist called a “Code White”, an overhead page that in my hospital summons help from anesthesia, nursing, respiratory care and pharmacy to assist with either a emergency pediatric cardiac arrest or emergency intubation.

As a responding anesthesiologist, I too was unable to see landmarks during laryngoscopy. Continue reading

Announcing My New Book: Pediatric Airway Management: A Step-by-Step Guide

At long last, after two years of writing (and rewriting),  illustrating, and  filming  on-line videos, I’m excited to announce the publication of my new book Pediatric Airway Management: A Step-by-Step Guide, by Christine E. Whitten MD.

Anyone who rarely cares for children tends to be anxious when faced with a small child’s airway. This is true even if they are comfortable with adult airway management.

My goal for this book is to demystify basic pediatric airway management. I want to give you the skills you need to recognize when a child is in trouble and act quickly to safeguard that child, including helping them breathe if necessary. Continue reading

Intubation During Cardiac Resuscitation

Intubation during cardiac resuscitation is often challenging because of the circumstances surrounding the intubation. Excitement and apprehension accompany this life saving effort. If you don’t intubate often, you’re likely to be nervous. Even experienced intubators get excited in emergency situations, but we control our excitement and let the adrenaline work for us, rather than against us.

Step one, therefore, is to remain in control of your own sense of alarm. The leaders, which includes the person in control of the airway, must stay calm. If you appear panicked, the rest of your team will follow your lead.

Step two is to quickly assess the situation. Is the patient being ventilated? Ventilation takes priority over intubation. Is there suction available? Without suction you many not be able to see the glottis, and you won’t be able to manage emesis. What help do you have? The intubator almost always needs some assistance in having someone hand equipment, or assist with cricoid pressure, among other tasks. As I tell my students, intubation is a team sport.

Finally you need to assess what position the patient is in, and how can you optimize that position. The patient is often in a less than optimal position while chest compressions are in progress. You usually find the patient in one of two awkward positions: on the ground or in a bed. This article discusses techniques to better manage intubation during cardiac resuscitation, especially with the patient in an awkward position. Illustrations are copyright from Anyone Can Intubate, 5th Edition.  Continue reading

When Learning Intubation Is Hard

Learning to intubate is easier for some people than for others. Sometimes, no matter how knowledgeable you are about the theory of the intubation technique, the novice can still struggle to bring it all together to pass the endotracheal tube. The anatomy can be confusing. Understanding how to place the laryngoscope blade and manipulate that anatomy can be challenging. And all the while you must be ever vigilant to protect those precious front teeth, avoid hypertension and tachycardia, and breathe for the patient at regular intervals.

I believe there are 4 chief barriers that inhibit learning how to intubate:

  1. Failure to visualize how the outside anatomy links with the inside anatomy makes it hard to predict how deeply to insert the blade.
  2. A mistaken belief that placing the laryngoscope blade itself is all that is needed to align the axes of the airway and reveal the larynx.
  3. Failure to grasp the dynamic nature of the larynx, and the need to actively manipulate it during intubation.
  4. A lack of understanding that intubation is not a sequence of isolated steps, but is instead a complex dance of interacting steps, each setting the stage for the next.

This discussion is going to assume some knowledge of the basic intubation technique. If you’d like to review those basics you can find links for multiple prior in depth discussions at the end of this article. (Illustrations and animation from Anyone Can Intubate, 5th edition, C Whitten MD.) Continue reading

Airway Emergency: Start With The Basics of Airway Management

We have just finished another round of Critical Event Training for my hospital’s Anesthesia and OR staff. One of the scenarios we ran was how to manage a failed airway emergency: the dreaded “can’t intubate-can’t ventilate” airway emergency scenario.

As an instructor, it’s important for me to set the stage realistically. The more real the scenario, the more the providers will learn and be able to apply the information should they ever find themselves in a comparable situation. I must observe as the trainees respond to the emergency, and then help the trainees self-analyze what went well — or not so well — during the scenario. Of course, discussion of how things went during a training scenario always leads to sharing of examples from past real life scenarios. And after 37 years of practice I’ve had a lot of sharable experiences.

One past case we discussed is particularly appropriate for those students around the country who are just beginning to learn airway management because the solution rested in basic airway management techniques. This case, involving an intubation in an ICU patient that turned into a “can’t intubate/can’t ventilate” emergency demonstrates how returning to the basics of airway management can sometimes be the way to save your patient from harm. All illustrations from Anyone Can Intubate 5th Edition. Continue reading

Hair Style Can Impact Intubation

Healing Little Heroes director dressed as Darth Vader at Ronald McDonald House, San Diego

Our Healing Little HeroesFoundation  founder dressed as Darth Vader at Ronald McDonald House, San Diego

Last weekend I spent time with the charity group Healing Little Heroes at the San Diego Rady’s Children’s Hospital, and Ronald McDonald House. The mission of Healing Little Heroes Foundation is to help pediatric patients in hospitals and outpatient settings to heal emotionally and mentally by appearing as Superheroes. My good friend, and general surgeon, Justin Wu, dressed below as Darth Vader, set up the Foundation.

On this day we arrived in full Star Wars costumes to entertain the kids and their families. I’m dressed as Queen Amidala. Which brings me to the topic of today’s conversation. Can hairstyle impact your intubation or even your anesthetic management? The answer is yes. There is no question that if Queen Amidala needed emergency intubation, that her hairstyle would get in the way. Continue reading

Intubation With Airway Bleeding and Massive Emesis

During intubation, any liquid in the mouth that obscures the view of larynx not only hinders visualization, it risks aspiration. We’re used to being able to rapidly suction the mouth clear or secretions, blood, or vomit and then have a clear view of the larynx. But sometimes, either because of continued profuse airway bleeding or massive emesis, fluid continues to accumulate while we’re watching. How can you manage this situation and successfully intubate? Here I describe two cases, one involving blood and the other massive emesis, that required intubation through a large puddle of fluid. I offer tips and tricks to assist you in your future emergency management. Continue reading

Intubation With A Curved Blade

Direct laryngoscopy depends on being able to bring the 3 axes of the airway into alignment to see the larynx. Curved blades are commonly used, especially by beginners because they are more forgiving of less than optimal placement and provide more room to pass the tube. However, it’s important to use them correctly. This article will discuss intubation technique using a curved blade. Straight and curved blades use different techniques for bringing the larynx into view. For a discussion of how to use a straight blade click here. Continue reading

Intubation: Step By Step

Learning intubation technique can be challenging. Fall is the time of year when new students commonly begin to learn how to intubate. My first intubation was one of the first times I literally held someone’s life in my hands. I was nervous. The anesthesiologist teaching me tried to not look too anxious as I awkwardly grabbed my laryngoscope blade, fumbled while opening the patient’s mouth, and cautiously maneuvered the endotracheal tube into the trachea. It felt like time stopped until the tube was in place, after which the three of us (me, my teacher and my patient) all took a deep breath. Since then, over the last almost 37 years, I’ve intubated thousands of people in the U.S. and, as an international volunteer, eight countries.

So I thought it would be helpful at this time of year to discuss a step-by-step approach to intubation with the commonly used curved blade. Intubation, like a dance, is composed of steps that flow naturally from one to the next. The trick to a smooth intubation is to allow each step to blend seamlessly into the next. The text and illustrations below are excerpted from my book Anyone Can Intubate, as well as from my upcoming book on pediatric intubation, which I’m busy writing. Continue reading

Tips To Teaching Intubation

To teach intubation skills on living patients, even those that have practiced on a manikin, can be challenging. With fall comes the new crop of trainees eager to learn how to intubate. There will also be a new group of instructors teaching their first students to intubate. It’s important to anticipate the common errors so we can safeguard our patients. Here I describe the all of the barriers, physical as well as psychological, that interfere with your student’s learning of the intubation technique. I offer tips on how to help your student conquer those barriers, while keeping your patient safe. Continue reading

Anticipated Difficult Intubation: Should I Intubate The Patient Awake?

When I was training, awake intubation for anticipated difficult airway was routine. Blind nasal intubation and fiberoptic intubation were common events. The advent of video laryngospcopy  has made the need for awake intubation much less common. Instruments like the Glidescope and the McGrath video laryngoscope have revolutionized intubation, and made the difficult intubation scenario fortunately much more uncommon.

However, awake intubation with the patient breathing spontaneously is still sometimes optimal for patient safety.  Awake intubation can be performed using standard laryngoscopy techniques, but it is more commonly done using specialty intubation techniques such as blind nasal or fiberoptic intubation.

Many providers are uncomfortable with performing awake intubations and leave it as a last resort. There are a variety of reasons for this discomfort, including lack of experience and/or the fear that the patient will remember the intubation and think poorly of their care. However, awake intubation can be a safe and comfortable strategy in many clinical situations and all providers should develop expertise with one or more techniques of choice — before an emergency forces them to use one.

This article will discuss how to decide when to do an awake intubation. Future articles will discuss how to do them. Continue reading

Avoiding Difficult Intubation Of The Easy Airway

It’s extremely easy to make any otherwise routine intubation difficult just by failing to properly position the patient or to use optimal technique. We’ve all done it. Let’s see how to avoid this pitfall. (All illustrations by Christine Whitten MD, Anyone Can Intubate). Continue reading

Intubating An Infant or Toddler

This article discussion some of the key anatomy, physiology, and technical points to intubating an infant or small child safely. I’ve been hard at work on writing and illustrating my upcoming book on pediatric airway management so I thought I would spend some time talking about care of our littlest patients.

Providers who infrequently care for children less than two years of age are often rightfully anxious when faced with a sick child, especially if airway management is required. This is especially true if the child is less than one. Healthy respect is certainly indicated because airway complications are one of the leading causes of pediatric cardiac arrest.

Children are not small adults. From infants to toddlers to teenagers, the anatomy and physiology of the child is continuously morphing until finally reaching the adult form and function. We all know this instinctively. When we look at a child we can often tell how old he or she is simply by looking at head size, characteristics of the face, length of neck, shape of the body, and how long the arms and legs are related to the trunk. It should not be surprising that the inside of the child is changing as well.

Photo placing oral airway in preparation to mask ventilating an infant

Even placing an oral airway and using a mask in an infant can seem more challenging because of the size and fragility of the patient.

Infants and young children are small. The head of a newborn infant can fit on the palm of my hand. The palm of a premature infant’s hand may be the same size as my thumbnail. It’s challenging to open the airway of such a small infant when adult fingers dwarf the size of the baby’s mouth and all of the instruments are smaller. And babies are fragile, with little reserve.

Like adults, children can be small or tall, lean or overweight. But unlike adults, their airway anatomy is changing shape and structural relationships as they grow. A particular 2 year old may be as tall as a particular 6 year old, or as heavy as a particular 8 year old, but all have very different airways.

Intubating an infant or small child is more of a challenge than an older child or adult both because of their anatomical differences as well as their physiologic predisposition for hypoxia. One can certainly argue that faced with elective care, that only experienced providers should manage the airways of infants and children less than two. However, medical care is not always elective.

Faced with a sick child, especially in more urgent settings, anyone who can ventilate and intubate an adult can also ventilate or intubate an infant or toddler safely —if they take the differences in anatomy and physiology into account, and are gentle and methodical in their approach. Illustrations and photos from Anyone Can Intubate: a Step by Step Guide, and Pediatric Airway Management: a Step by Step Guide. Continue reading

Positioning The Head For Intubation

Positioning the head and neck for intubation in the sniffing position can make intubation easy, or extremely hard. Many years ago our operating room administration decided that the bath towels we were using to position the head for intubation were a potential danger for shedding lint. So one night, in their infinite wisdom, the towels were all summarily confiscated and when we arrived the next morning there wasn’t a single towel to be found, ever again. It may be an exaggeration to say that chaos ensued, but it felt like that.

The reason this event is so memorable is that for the next several days our anesthesia providers had trouble intubating. We likened it to an expert golfer who, when suddenly faced with a new set of golf clubs of slightly different weight and length, suddenly has to relearn the game. It made us realize that how we position the head in the sniffing position often sets us up for either an easy or for a more difficult intubation if you don’t realize what’s happening during the positioning. Continue reading

To Extubate, Or Not to Extubate, That Is The Question

Assessing extubation criteria, and then deciding when to extubate a patient safely can sometimes be a difficult decision.

Extubation Criteria

We all know the common extubation criteria:

  • recovery of airway reflexes and response to command;
  • inspiratory capacity of at least 15 ml/kg;
  • no hypoxia, hypercarbia, or major acid/base imbalance;
  • no cardiopulmonary instability;
  • signs of intact muscle power;
  • absence of retraction during spontaneous respiration;
  • absence of a distended stomach.

In other words, you want your patient to be stable, able to breathe without help, and able to protect the airway.

However, sometimes the decision is not so easy. Here I describe a case of a patient who met some but not all of the criteria for extubation. The reason turned out to be due to a rare complication: plugging of the endotracheal tube. However, getting to that solution required working through the extubation algorithm.  Continue reading

Awake Intubation With The GlideScope

Awake intubation with the GlideScope can be an especially helpful technique when intubation of a difficult airway under direct vision is optimal. One of the most challenging scenarios to face is a tumor in the airway. Working closely with your surgeon is important. In this particular case, we actually had a video available of what this 8 mm airway polyp looked like popping in and out of a laryngeal opening of about the same size with each breath like a potential cork. According to the surgeon our patient had come to the clinic because she had been experiencing some increased shortness of breath. Having the video was a rare advantage. Follow this link to youtube video showing pedunculated vocal cord polyp obstructing the glottic opening. Here are some stills from that video.

Photo of pedunculated laryngeal polyp in lowest position below vocal cords at end of inhalation

Photo of pedunculated laryngeal polyp in lowest position below vocal cords at end of inhalation

Continue reading

Use Of A Nasal Airway To Assist Ventilation During Fiberoptic Intubation

Attaching a nasal airway to a breathing circuit as a tool to assist or control ventilation is a very helpful trick to have in challenging airway management situations.

Illustration of An alternate means of ventilation — insert an endotracheal tube connector into a nasal airway as in a. Place the nasal airway, close the opposite nostril and mouth. Ventilate as in b.

An alternate means of ventilation — insert an endotracheal tube connector into a nasal airway as in a. Place the nasal airway, close the opposite nostril and mouth. Ventilate as in b.

The Case

Many years ago I was taking care of a 40 y.o. man had Ludwig’s Angina, a serious, potentially life-threatening cellulitis infection of the tissues of the floor of the mouth, often occurring in an adult with a dental infection. Continue reading

Tongue Necrosis From Endotracheal Tube Compression

Image

Tongue necrosis is fortunately an extremely rare complication of endotracheal intubation, but the injury can be devastating. It’s important to recognize the patients at risk and to take precautions when securing an endotracheal tube to decrease the risk of injury.

Case Description

I saw this injury myself many years ago. I was called to the ICU to evaluate a patient for postoperative tongue pain. The patient was an otherwise healthy 41 year old who had undergone cervical spine decompression for tumor two days before. The patient had been in the prone, head flexed position in tongs during a surgery that had lasted about 7 hours. About 2 liters of crystalloid had been given and blood loss was less than 200 ml. Surgery had been successful and the patient had been extubated at the end of the case neurologically intact.

When the patient started talking to me, speech was terribly slurred. Almost the entire right side of the tongue was a pale brown and gray color, firm, and markedly edematous with an ulceration. Tongue necrosis was diagnosed. I don’t have a picture for this patient, but this photo, taken from an excellent review of tongue necrosis, is similar.

Photo of tongue necrosis from Laryngoscope. 2010 July; 120(7): 1345–1349.

Photo of tongue necrosis from Laryngoscope. 2010 July; 120(7): 1345–1349.

During the case, since neurostimulation was to be used to monitor spinal cord function, two fairly large, soft bite blocks made of rolled gauze had been placed to prevent the patient from chewing the tongue or mouth when stimulated. At the end of the case, the anesthesia team noted that the tongue looked a little swollen and that the tube had left an imprint over the back of the tongue. Continue reading