Use a Mnemonic Device to Assess Difficult Airways

Airway management is a fundamental aspect of every level of care in the EMS profession. Before the airway can be managed, it must be assessed. Thus, first responders must be taught to properly assess patency and use simple maneuvers to open the airway; EMTs must know how to perform a more in-depth assessment and corrective interventions; and paramedics must be able to carry out all the basic procedures as well as more invasive techniques. All providers need to be able to predict the difficult airway because their management approach will require modifications from standard procedures.

Given the myriad factors that must be considered when assessing and managing the airway, it’s critical that each provider learn and retain theory and psychomotor skills from the onset of certification and throughout their entire career. As educators, we must maximize our efforts at teaching each airway assessment and intervention skill. It’s vital that we apply solid educational principles to reach the greatest number of learners, enhance learning for each student and facilitate long-term retention for all. This article presents information to help educators and training officers in the EMS profession apply a valid learning model to enhance classroom instruction of assessment of the difficult airway.

We all possess a learning style that can be identified through one or more tests, but many instructors simply don’t have the time to assess each student’s style. If these are the realities you face as an educator, you can rest easy knowing that applying some basic principles from the field of educational psychology can still have a profound effect on the learners you teach.

The VARK (Visual, Auditory, Reading/Writing, Kinesthetic) model is one of the simpler and fairly popular forms. It can be used to improve EMS instruction because it’s based on sound, educational psychology and is easy to employ in the classroom. The four types of learning are visual, auditory, reading/writing and kinesthetic.

Visual: Students with a visual learning style appreciate diagrams, illustrations, pictures and graphs.

Auditory: Students who primarily learn with this style will appreciate listening to lecture material, hearing podcasts and participating in group discussions.

Reading/Writing: Note, the student employing this style will enjoy reading information about a given subject. The VARK model separates out reading and writing, while the VAK model incorporates this aspect into the visual style.

Kinesthetic: Those who learn through this style appreciate hands-on application as well as simulation training.

Research has shown that we each use one or more of these areas as our primary means of learning, but a closer examination reveals that we learn through multiple modalities.

That’s why the learning styles are often referred to as “learning preferences.” Although one style is preferred, other types can still be used by the same person.

The educator can be more effective by knowing all four styles and using as many as possible when planning and teaching. In fact, it has been shown that failure to use multiple modes or mismatching teaching with learning styles can lead to poor results.

Patients who present with difficult airways create new challenges for the provider charged with assessment and management, and can create anxiety in even seasoned paramedics. But we can teach providers to predict the difficult airway by learning associated factors.

The mnemonic LEMON is one of the best tools for predicting problems, and tailoring this tool to all learning styles will improve their skill competency. The following examples illustrate how this mnemonic can assist you in airway management sessions.

Look externally: This factor involves a visual inspection of the patient_s airway. Remind your students to look for facial trauma, distorted anatomy, (such as large incisors or tongue) or facial hair. All of the external cues must be accounted for early.

Your lesson should include photos of patients who have facial trauma, large incisors, facial hair or a large tongue. Discuss how each factor creates difficulty with managing the patient.”ž=

Have the students read an article about the difficult airway before instruction occurs, and encourage note-taking during the lecture. With this combination of lecture, demonstration and reading assignments, you’ll hit three of the four learning styles. If you have airway manikins that mimic the difficult airway, your kinesthetic learner will appreciate those.

Evaluate the 3-3-2 rule: This aspect of airway education involves three measurements — the distance between the upper and lower incisors, the distance between the hyoid bone and the chin, and the distance from the thyroid cartilage to the floor of the mouth.

Each measurement is assessed using the provider’s fingers and can be done fairly quickly. At least three fingers should be able to fit between the patient’s upper and lower incisors. This doesn’t mean the caregiver must stick their hand in the patient’s mouth. The measurement can be done by holding the index, middle and ring fingers closely together, opening the patient’s mouth by gently pulling down the chin and determining if at least three fingers would fit.

Using the fingers held together, assess the distance from the hyoid bone to the chin (should be at least three fingers) and the distance from the thyroid cartilage to the floor of the mouth (at least two fingers). Any measurement that is less than 3-3-2 indicates potential difficulty with airway management.

Illustrations of the 3-3-2 assessment procedure and images of providers performing the procedure should be used in the class and lab. Discuss the different cases that would present with decreased measurements, such as a patient with micrognathia (small jaw). Talk about how the procedure is performed. Have your students form small groups to discuss images of patients presenting with anatomy that results in decreased measurement, and have one representative from each group share the information with the entire class. Students can also perform assessments on each other.

Mallampati:This assessment involves looking into the mouth to determine how much of the uvula, soft palate and pillars are visible. You can evaluate students using a scale from 1 – 4, but remeber the practical application for the EMS provider is to remember that less-visible anatomy is associated with greater difficulty in airway management.

The conscious patient is asked to open the mouth as wide as possible and to stick out the tongue. This can be particularly helpful for a patient with potential or known airway burns, because progression from a patent airway to full occlusion can happen quite quickly.

Photos and illustrations of the four Mallampati classifications are readily available. While presenting the lecture material, show different images and talk about how much anatomy is visible. Ask the class to comment on these images. Your students should read at least one article about Mallampati prior to or after class. Prepare cases with an easy and a difficult airway associated with this factor.

Obstruction: Students tend to be more aware of this factor because of basic CPR training; however, they may not be as aware of anatomical obstructions, such as the presence of an abscess or swelling from trauma. As with teaching the other factors, use illustrations and photos, lecture on the topic, and assign reading materials and at least one case presentation to reach all learning modalities.

Neck mobility: Patients who have experienced trauma that warrants full spinal motion restriction will present with airway management difficulties because proper positioning of the airway will be less than ideal. Patients who have kyphosis (abnormal curvature of the upper spine) present a challenge, as do those who have a halo device in place from recent spinal surgery.

Locate illustrations and photos of patients with full spinal motion restriction, kyphosis and/or a halo device in place. If an Internet connection is available in the classroom, images of each type are readily available online. Discuss how the problems associated with limited neck mobility differ from normal airway positioning. Reading material, such as a brief case involving one or more of the factors, should be assigned. Hands-on practice should include managing the airway of a fully immobilized patient.

The LEMON assessment can be readily incorporated into either the initial training or continuing education. Using all four aspects of VARK will help ensure all students are able to understand how LEMON is applied in the field setting. Each of the teaching examples presented can be used in any combination in the classroom and lab settings.


Airway management is a fundamental aspect of both initial training and ongoing skills maintenance. Adding instruction on the difficult airway will enhance the educational experience while better preparing students for real-life application of the skills.

But those important lessons are only meaningful when we ensure true learning and retention, which can be improved by targeting instruction to all four VARK learning styles. Using all parts of the model will also reinforce learning across the whole group because most learn with more than one modality. Simple adaptations to the classroom and lab will thus result in better learning and retention — and better care in the field. JEMS


  1. 1. Flemming ND, Mills C. Not another inventory, rather a catalyst for reflection. To Improve the Academy. 1992;11:137.
  2. 2. “VARK: A Guide to Learning Styles.” Pask G. Styles and strategies of learning. Br J Educ Pyschol. 1976;46:128—148.
  3. 3. Reed MJ, Dunn MJ, McKeown DW. Can an airway assessment score predict difficulty at intubation in the emergency department? Emerg Med J. 2005;22:99 015 015—102.


This article originally appeared in March 2010 JEMS as “LEMON-Aid: Using a mnemonic devices to assess difficult airways.”

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