Difficult Airway Management

Context

CAVEAT: While the theory contained in this session provides useful knowledge about airway management, putting this knowledge into practice requires extensive supervised practical experience. Such experience can be reinforced and developed by courses such as the UK TEAM course upon which this session draws extensively.

Airway management in an elective situation is usually straightforward. Any difficulties in airway maintenance and ventilation prior to endotracheal intubation are usually dealt with by simple repositioning manoeuvres and the use of adjuncts. [1] Laryngoscopy usually provides a clear view of the cords and intubation itself is easy.

In the time critical environment of the emergency department, the scenario is complicated by

• Limited scope for prior assessment
• The often poor physiological reserve of the patient
• The potential for a range of pathologies which may still be rapidly evolving

The failure rate for rapid sequence intubation in the emergency department is about 1%, with a cricothyroidotomy rate varying from 0.5% (medical patients) to 2.3% (trauma). [1]

Awareness of indicators of difficulty and techniques to deal with problems can reduce the complication rate. [2]

Definition

For the purposes of this session the following definitions are used:

Difficult airway is being used to describe:

• Problems with bag-valve mask ventilation (BVM) despite repositioning and use of adjuncts, as covered in the session Basic Airway Management in the Adult
• Difficulties in intubation when attempted by a competent airway practitioner

Failed intubation is the inability to successfully place an endotracheal tube after three attempts by a competent airway practitioner. [3]

Can’t intubate, can’t oxygenate (CICO) is when a failed intubation is compounded by an inability to maintain adequate oxygen saturation with BVM.

An individual’s airway may be rendered ‘difficult’ by:

Poor Preparation:

• Inadequate positioning
• Poor availability of equipment
• Lack of suitable personnel
• Inadequate training

Normal anatomical and physiological variation:

• Facial hair
• Shape of jaw
• Abnormal teeth or lack of teeth
• Limited mouth opening
• Size of tongue
• Length and mobility of neck
• Position of larynx
• Pregnancy

Pathological anatomical variation:

• Soft tissue swelling as a result of burns, allergy/angio-oedema, infection and haematoma
• Maxillofacial trauma
• Cervical spine deformity or immobility, for example ankylosing spondylitis
• Obesity
• Abdominal distension
• Craniofacial syndromes for e.g. Down syndrome, Pierre robin syndrome, etc. [4]

Neck immobilisation

• Neck immobilisation: as in trauma, where you are unable to position the patient with head extended and neck flexed. This makes visualisation of the vocal cords harder. [5]
• Foreign body obstruction

An airway may be rendered difficult by a host of factors both pathological and anatomical.

Potential Hazards

In the emergency situation there may be very little time for a considered clinical assessment but even the briefest of glances may be sufficient to alert the wary practitioner to potential hazards.

An obese, bearded, immobilised trauma patient with facial injuries may challenge an expert.

Six features have been identified as likely to cause difficulty with BVM ventilation in elective patients [6,7]:

• Presence of a beard
• Lack of teeth
• Age>55
• BMI>30
• History of snoring
• Inability to protrude the mandible so that the lower incisors are anterior to the upper incisors

Elective patients who prove both difficult to ventilate and difficult to intubate have been noted to have the last three from the above list plus a history of sleep apnoea and/or a particularly thick or obese neck. [6]

Airway Assessment – The US Approach

The potential hazards identified on the previous page, and others, have been incorporated into two mnemonics from the American Emergency Airway Management course.

MOANS acts as an aide-memoire for indicators of difficult BVM:

• M: Mask seal – for example a beard or blood
• O: Obesity and obstruction
• A: Age
• N: No teeth
• S: Stiff lungs

LEMON highlights patients who may be difficult to intubate:

• L: Look: a rapid ‘gut-feeling’ assessment
• E: Evaluate the 3-3-2 rule
• M: Mallampati score see note below
• O: Obesity/obstruction (stridor in particular is worrying)
• N: Neck mobility

Image courtesy of LITFL [8]

Note: Mallampati score is assessed, conventionally, by asking a seated patient to open their mouth as far as they can. This can be approximated in the supine patient using a tongue depressor or laryngoscope blade if necessary. If only the base of the uvula, or less, can be visualised, intubation may be more challenging. It is difficult to assess in the immobilised or obtunded patient. [9]

Difficult LMA = RODS [4]

• Restricted mouth opening
• Obstruction
• Distorted airway
• Stiff lungs or c-spine

Difficult surgical airway = SHORT [4]

• Surgery
• Hematoma
• Obesity
• Radiation distortion or other deformity
• Tumor

Refresh your airway anatomy, watch this video.

Airway Assessment – The UK Approach

The UK TEAM course uses HAVNOT to cover both areas [10]:

• H: History – including previous airway problems
• A: Anatomy – anatomical features that may cause difficulty
• V: Visual clues – such as obesity and the presence of a beard
• N: Neck mobility and accessibility (including immobilisation)
• O: Opening of the mouth
• T: Trauma

However, none of these predictors is particularly sensitive and predictive tests are of limited value when the thing they are trying to predict is very rare. [11]

The presence of indicators of possible difficulty does not mean an airway will be difficult; more importantly, their absence does not mean it will be easy.

It is also vital to remember that pathology compromising the airway might progress rapidly. The ‘difficulty’ of an airway is not a static concept.

Learning bite

Don’t be falsely reassured just because things look straightforward.

Airway Compromisation

Pathological processes, which can compromise an airway might develop rapidly.

Example 1

Upper airway burns: a mildly hoarse voice may quickly progress to airway obstruction and the need for an emergency surgical airway.

Example 2

Penetrating injuries to the neck: can cause a rapidly expanding haematoma which may compress the airway.

Learning bite

Do not miss out on the opportunity to intervene early before the airway becomes critical.

The time critical nature of emergency airway scenarios mandates that the team be very familiar with their environment and roles.

A difficult airway trolley should be present with the equipment necessary to follow locally agreed guidelines. This will include alternative airway devices and equipment for establishing a surgical airway.

It’s so important to have an easy access to your airway equipment immediately when needed and the best way for this is to be kept in an airway trolley.

A variety of new devices for airway management have been developed in recent years including

• Fibreoptic stylets
• Video laryngoscopes
• Optically enhanced laryngoscopes

Video laryngoscopes vs DIRECT?

The advent of video laryngoscopy has led to some experts stating that it should be considered ‘standard of care’ (a loaded term) or at least best practice. this had led to vigorous and sometimes heated debate, especially in the emergency medicine community. [12]

“All departments should have access to video laryngoscopy equipment” — Scott Weingart. [13]

Learning Bite

If a difficult airway is anticipated, the most experienced practitioner available must be present.

Introduction

Other aspects of preparation for intubation are detailed in the session on Rapid Sequence Inductions in the ED and will not be covered here.

Learning Bite

Difficulty with an airway must be recognised early.

It is vital that the practitioner recognises when he or she is having problems and adopts an appropriate management strategy immediately. The temptation to struggle on without calling for assistance must be resisted.

The Difficult Airway Society (DAS) has published multiple guidelines related to key issues in airway management, which are recognised and widely used both in the UK and many other countries. [14]

DAS recommends having a checklist with Plan ABCD when attempting tracheal intubation of critically ill adults. [14]

Learning Bite

All airway practitioners must have a simple algorithm for the management of the difficult airway and ”can’t intubate/can’t oxygenate (CICO)” situations.

The Algorithm

Algorithm from Difficult Airway Society (DAS). Guidelines for the management of tracheal intubation in critically ill adults, 2017.15

Algorithm from Difficult Airway Society (DAS). Guidelines for the management of tracheal intubation in critically ill adults, 2017.15

Algorithm from Difficult Airway Society (DAS). Guidelines for the management of tracheal intubation in critically ill adults, 2017.15

1. Brown CA, III, Sakles JC, Mick NW, et al. The Walls Manual Of Emergency Airway Management, 6e. Lippincott Williams & Wilkins, a Wolters Kluwer business; 2023. Accessed October 29, 2025.
2. Mort TC. The incidence and risk factors for cardiac arrest during emergency tracheal intubation: a justification for incorporating the ASA Guidelines in the remote location. J Clin Anesth. 2004 Nov;16(7):508-16.
3. Nee PA, Benger J, Walls RM. Airway management. Emerg Med J. 2008 Feb;25(2):98-102.
4. Nickson C. Airway Assessment. Life in the Fast Lane, 2024.
5. Ollerton JE, Parr MJ, et al. Potential cervical spine injury and difficult airway management for emergency intubation of trauma adults in the emergency department–a systematic review. Emerg Med J. 2006 Jan;23(1):3-11.
6. Kheterpal S, Han R, et al. Incidence and predictors of difficult and impossible mask ventilation. Anesthesiology. 2006 Nov;105(5):885-91.
7. Langeron O, Masso E, et al. Prediction of difficult mask ventilation. Anesthesiology. 2000 May;92(5):1229-36.
8. Moseley C, Cadogan M, Mallampati Score. Life in the Fast Lane, 2022.
9. Levitan RM, Everett WW, Ochroch EA. Limitations of difficult airway prediction in patients intubated in the emergency department. Ann Emerg Med. 2004 Oct;44(4):307-13.
10. Burtenshaw A, Benger J, Nolan J, editors. Emergency Airway Management. 2nd ed. Cambridge: Cambridge University Press; 2015. ISBN: 9781107707542
11. Yentis SM. Predicting trouble in airway management. Anesthesiology. 2006 Nov;105(5):871-2.
12. Nickson C. Direct versus Video Laryngoscopy. Life in the Fast Lane, 2024.
13. Weingart S. EMCrit 94 – Debate: Has Video Laryngoscopy Killed the Direct Laryngoscope? Podcast. EMCrit. March 3, 2013.
14. Higgs A, McGrath BA, et al. Guidelines for the management of tracheal intubation in critically ill adults. Br J Anaesth [Internet]. 2018 Feb;120(2):323–52 [cited 2025 Oct 29].
15. Algorithm from Difficult Airway Society (DAS). Guidelines for the management of tracheal intubation in critically ill adults, 2017. [cited 2025 Oct 29].