learning intubation is like learning to dance. 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. To learn intubation, you not only need to know the physical steps, you need to understand why you’re doing those steps. This article will explain how to perform the steps of intubation, as well as the rationale behind them. Links to other articles on intubation technique appear both in the body of the text as well as repeated as a list at the end.
This article is adapted from my original article on this website, Intubation: Step By Step. The text and illustrations below are excerpted from my books Anyone Can Intubate: A Step By Step Guide and Pediatric Airway Management: A Step By Step Guide.
Learning Intubation Can Be Scary
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 40 years, I’ve intubated thousands of people in the U.S. and, as an international volunteer, eight countries.
As you gain experience, the fear of intubation will pass but you must always maintain a healthy respect!
Learning Intubation With A Curved Blade
Novice intubations often begin learning intubation with the curved Mac blade because this blade is more forgiving of imperfect placement and makes it easier to stabilize the head while lifting. Therefore this article will concentrate on the curved blade. See the links at the end for discussions on the Miller, or straight, blade.
Optimally Position The head and neck
We see in a straight line. We can’t see around corners. During direct laryngoscopy, you must be able to see down a straight path from the front teeth/gum line to the larynx. The Xray image shows the relationship of the laryngeal cartilages to the neck vertebrae in a neutral neck position. The neutral neck provides a right angle path to the larynx. Unless you manipulate angle of the head and neck you will not see the larynx during direct laryngoscopy.
To create this straight view to the larynx you must manipulate the 3 axes of the airway: the oral, pharyngeal, and laryngeal axes. As the illustration below shows, opening the mouth wide, lifting the head above the bed, and tilting the head backward —a position known as the sniffing position —straightens the airway path and allows you to see the larynx in most patients. As you might imagine, inability to tilt the head, or open the mouth would greatly interfere with your ability to perform direct laryngoscopy.
Intubation Alternates Hands
The act of intubation alternates hands. One hand positions the patient for the next action by the other hand. When learning intubation, this is initially awkward but with practice, coordinating the alternating hand movements becomes natural. Once the head is optimally positioned, tilt the head into extension with your right hand to bring all the axes into alignment. This provides you with as straight a path as possible to see the larynx and pass the tube.
Anchor it there momentarily using your left hand .
Anchoring the head frees your right hand. Open the mouth with your right hand by placing your thumb on the lower jaw and your middle finger on the upper jaw. The position is similar to snapping your fingers. By using a pushing rather than a spreading motion, you can open the mouth wider and more forcefully. Make sure that you place your fingers as far to the right side of the mouth as you can in order to keep your fingers out of the way of the blade. Your right hand now does double duty. It holds the mouth open as wide as possible. Pulling toward you also places the head in extension.
Your right hand opening the mouth now also holds the head in extension.
Pick Up The Blade
You can now use your left hand to pick up the blade. Hold it with the blade away from you. Because my hands are small, I place my hand lower down on the handle. By positioning the heel of my hand on the junction between blade and handle, I can fine tune the angle of the blade. You will need to see what feels correct for you.
Notice how easily you can change the angle of the blade by tilting your wrist. You must control this motion very carefully to avoid tooth damage. A small amount of rotation lets you precisely position the tip of the blade in the vallecula (curved) or lifting the epiglottis (straight). Too much rotation will break teeth.
Inserting The Blade: Protect Those Lips and Teeth
Insertion of the blade should be delicate and deliberate. Hold the handle in your left hand, blade down, pointing away from you. Grasp it firmly but don’t clench your fist because this decreases control and causes early fatigue.
With the mouth open, insert the blade, slightly to the right of the tongue. Don’t hit the teeth as you insert. If necessary, you can tilt the top of the handle slightly to insert the blade into the mouth, then rotate the blade back, scooping it around the right side of the tongue as you do so.
Avoid catching the lips between the blade and the teeth. I use my right index finger to sweep the lips out of the way of the blade as I insert it. You may need to angle a curved blade slightly to pass the teeth and then return the blade to a more neutral position once it has entered the mouth.
Look For The Tip Of The Epiglottis Before The Final Lift
Slowly advance the blade with your left hand until you see the tip of the epiglottis, a very important landmark. Simultaneously sweep the tongue to the left as you advance. The epiglottis is the same color as the mucosa of the tongue. Once you see the epiglottis you can start to transfer the weight of the patient’s head onto the blade as you lift. Leave your blade toward the left side of the mouth with the tongue pushed out of the way.
As you start to lift the tongue, the tip of the epiglottis will move, separate from the tongue, and become more visible.
You can usually identify the epiglottis with minimal upward pressure on the tongue and you shouldn’t aim to fully control the tongue until you actually have identified the tip of the epiglottis. Waiting until you have the epiglottis in sight allows you to tweak the position of the blade with small, precise movements. Once you see the epiglottis, then sweep the tongue left and lift upward and away.
How You Lift Matters
Good intubation technique depends on optimal mechanical advantage. Lift upward with the left arm held fairly rigid. Keep you elbows in. Lift on a line connecting the patient’s head with the intersection of the opposite ceiling and the wall . It won’t be straight, but keeping your arm straighter and fairly rigid it gives you the strength of your shoulders to lift the head. It prevents you from using the teeth as a fulcrum — dangerous for the teeth. And it allows you to use binocular vision for depth perception.
The typical beginners often use bad intubation technique. They mistakenly hunch close to the patient, bend the elbow completely, and place the right eye practically in the patient’s mouth. They then can’t understand why he or she has no leverage or control.
Seeing The Larynx
The tip of the curved Macintosh (Mac) blade fits into the vallecula, the dip between the tongue and the epiglottis. Unlike a straight blade, the blade tip does not directly lift the epiglottis. By pressing on the vallecula, the curved blade lifts the epiglottis passively by pulling the tissue folds attached at its base and anchored to the hyoid bone. It acts like a pulley system lifting a trap door. When the intubator lifts the head upward, the blade displaces the tongue forward into the hypoglossal space.
As you lift, the epiglottis will separate from the tongue and you will see it hanging over the larynx. Placement of the tip of the blade is critical. As you gently wiggle the MAC blade tip up and down (being careful of the teeth) and change pressure in the vallecula you will see the epiglottis raise and lower like a trap door. When you lift the jaw upward you will have an unobstructed view of the glottic opening. If you place the blade in the center of the tongue, it will mound up blocking your view. You must sweep the tongue to the left or you will see nothing.
Ask For Cricoid Pressure If You Can’t See The Larynx
Cricoid pressure is one of the most valuable intubation techniques to help you during intubation. We often use it to improve visualization of the so-called anterior airway, where the view of the larynx is hidden behind the back of the tongue. Often used during difficult intubation, cricoid pressure can also help with the routine intubation if the patient’s positioning is not optimal or if the blade you have chosen is not providing the best view.
Cricoid pressure can also be used to protect against aspiration, as this action pinches off the upper esophageal sphincter in patient’s with full stomachs or a history of gastric reflux.
To apply cricoid pressure, place your assistant places their thumb on one side of the cricoid ring and their index or ring finger on the other. Pushing down firmly to force the cricoid also forces the vocal cords downward and often into the field of view.
Pass The Tube
The head is now suspended from the blade held in your left hand, freeing your right hand to place the tube. Use a 6.5-8.5 for a woman and a 7.5-9.0 for a man. The larger the tube, the less resistance to breathing there will be. Hold the preselected tube in your right hand like a pencil, curve forward.
Pass the tube into the larynx through the cords in one smooth motion. If the patient is breathing, time the forward thrust for inspiration when the cords are fully open. During expiration, the tube may bounce off the closing cords into the esophagus.
Pass the tube to the right of the blade, past the right side of the tongue. You can understand why the blade should optimally be as far to the left side of the mouth as possible.
Watch The Tube Enter The Trachea
Try to watch the tube pass through the cords into the trachea. Although there may be a blind spot impairing your view at the moment of intubation, you can often see the arytenoid cartilages behind the tube after proper placement. Don’t relax and pull the blade out without trying to be sure of success with your own eyes. Get into the habit of seeing the tube between the cords and you will be less likely to intubate the esophagus. Stop advancing the tube when you see the cuff completely pass the cords,usually 21-22 cm at the front teeth in an adult. Carefully hold the tube where it exits the right side of the mouth and remove the blade with your left hand.
Remove The Stylet
If you’ve used a stylet, remove it before you fully advance the tube down the trachea. Make sure you have a strong grip on the tube where it exits the mouth because the force needed to remove the stylet will sometimes threaten to pull the tube out with it.
To inflate the cuff, slowly inject air through the pilot tube until the pilot balloon just starts to get tense. Don’t overfill. You don’t want the pilot balloon to feel hard when you squeeze it or it may apply excessive pressure to the tracheal mucosa. Later, after verifying tracheal placement you can go back to check the minimal sealing pressure of the cuff. To check minimal seal, suction the airway free of secretions. Apply constant airway pressure of about 20 mmHg. Remove some air until you hear a leak and then refill the cuff until the tracheal leak just disappears. Excessive cuff inflation can damage mucosa by impairing its blood supply.
Always Verify Tube Placement, Assume Nothing!
Before doing anything else, be sure that the tube is in the trachea. Listen for the presence and equality of breath sounds over both lung fields and for the absence of gurgling sounds over the stomach. Never assume that the tube is in the trachea until you have checked it yourself.
Ventilation Is More Important Than Intubation
In the event you can’t intubate easily, stop after 30 – 60 seconds. Ventilate the patient briefly before your next attempt in order to maintain oxygenation. As long as you can ventilate the patient you have time. Time to alter your technique, change the position of the head, or use a different type of laryngoscope blade. Keep your suction handy and use it. Don’t be afraid to ask for help.
Although intubation technique requires practice to master, if you understand how the steps fit together to bring the larynx into view, and are gentle and purposeful in your actions, you too will soon be safely performing this life saving skill.