# Difficult Airway Management

## Overview

This module describes how to manage a patient who is difficult to intubate or ventilate. Most of these cases may be recognised early by a pre-operative assessment, or during emergency assessment. The unanticipated difficult airway is rare, but may rapidly become urgent.

## Indications

1. Any patient who has failed initial attempts at intubation

## Contraindications

1. None

## Patient information and consent

Patients with an anticipated difficult airway should be informed of the additional risks they face and consent for potential additional procedures obtained. In patients with an unanticipated difficult airway, the procedure is emergent and consent is inferred, unless “Do Not Resuscitate” (DNR) orders, “Not For Max” orders, or living wills that specify that no resuscitation may be performed are present.

## Preparation

During the pre-operative assessment, evaluate risk factors generally, and using airway assessment tests.

### General Risk Factors

Suspect difficulty ventilating if:

1. Bearded
2. Obese
3. No teeth
4. Elderly
5. Snorer
6. Facial anatomical abnormalities

Suspect difficulty intubating if:

1. History of difficult intubation
2. Protruding upper incisors
3. Large tongue
4. Small mandible
5. Short neck
6. Obesity
7. Restricted neck motility
8. TMJ limitation
9. Stridor
10. Facial trauma or burns
11. Previous radiotherapy to head and neck

### Airway Assessment Tests

1. Mallampati Scale

The visibility of the patient’s uvula and palate is assessed while they are sitting with their head in neutral and the mouth open.

- Class I: the soft palate, uvula, and pillars are visible
- Class II: the soft palate and the uvula are visible
- Class III: only the soft palate and base of the uvula are visible
- Class IV: only the hard palate is visible

2. Mouth Opening

Ask the patient to insert three fingers vertically into the mouth to assess mouth opening. An inability to do so is a risk factor for a difficult airway.

3. Lower Jaw Motility

Ask the patient to protrude/shift forward their lower jaw. An inability to protrude the lower jaw beyond the upper jaw is a risk factor for a difficult airway.

4. Neck Motility

Ask the patient to flex and extend their neck. Reduced motility is a risk factor for a difficult airway.

5. Thyromental Distance

Measure the distance between the thyroid prominence (Adam’s apple) and the tip of the chin with the neck extended. A distance < 7 cm is a risk factor for a difficult airway.

If a difficult airway is suspected, an experienced practitioner should perform the intubation, video laryngoscopy should be made available, and preparations made for alternative measures, e.g. awake intubation should be considered. The patient should be evaluated for ease of emergency invasive airway access.

#### Equipment

A difficult airway trolley containing a variety of

supraglottic airway devices

supraglottic airway devices

1st Generation SAD: simple breathing tube, usually with some form of mask or opening at the larynx. Examples: the Classic LMA is most common.

2nd Generation SAD: includes provision for gastric drainage and improved protection against aspiration. Examples: Proseal LMA, LMA-Supreme, and i-gel are most common in South Africa.

(SAD)

## Site & Positioning

The patient should be in the “sniffing” position, with the ear aligned to the sternal notch. This may require building a ramp with pillows and blankets to raise the patient’s head.

## Procedure

Use medical asepsis with non-sterile gloves. Follow the DAS guidelines: call for help and proceed, starting with step 1.

## Troubleshooting

I am unsure about alternative methods of endotracheal intubation.

Alternative methods include video laryngoscopy, using different laryngoscope blades, intubating through a supraglottic airway, fibre optic intubation, using a stylet, and blind intubation.

## Risks

1. Hypoxic brain injury
2. Cardiac arrest ± death due to hypoxia
3. Damage to dentition
4. Airway injuries
5. Aspiration & resultant pneumonia

## References

1. American Society of Anesthesiologists. Practice guidelines for management of the difficult airway: An updated report. Anesthesiology. 2013; 118(2).
2. Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth. 2015;115(6):827-848. doi:10.1093/bja/aev371. Available at https://das.uk.com/guidelines/das_intubation_guidelines