THE DIFFICULT INTUBATION

DEFINITION

Attempted end tracheal incubation under direct vision with standard equipment that is not achieved after two attempts.

CAUSES

Inadequate preparation / technique - most common cause of a difficult end tracheal incubation

Anatomical

• Neck : short "bull" neck
• congenital abnormalities
• Mandible : small, large
• Teeth : abnormal dentition, especially "buck teeth"
• Larynx : anterior caudal larynx
• Other : excessive facial hair                            pregnancy (advanced)

Pathological

• Trauma - to the face or neck (blunt, penetrating, burns)
• Connective tissue disease affecting the mobility of the neck or mandible
• Goiter or other mass in the neck
• Obesity
• Airway obstruction (foreign body, epiglottis)

ASSESSMENT

History of previous problems with airway procedures, connective tissue disease etc

Physical assessment

• ability to visualize the soft palate, and in particular the uvula
• ability to extend the head
• recessed chin
• significant upper airway bleeding
• airway burns or anatomical disruption due to trauma, mass etc.

PREPARATION AND PREVENTION

     Preparation has three components :

1. The Equipment

2. The Patient

3. The Staff

MANAGEMENT

     Where difficult incubation is predicted

• Call a doctor experienced in airway management before commencement (if time allows)
• Before commencing, assess whether the patient's airway and breathing can be maintained using the bag valve mask.
• Plan to attempt colonoscopy under sedation only ie avoid using intramuscular blockers if possible.
• Have the difficult airway tray handy

     Where difficult incubation occurs

     1. Stop-Re oxygenate-Rethink

• Remove ETT
• Attempt to re-ventilate /re-oxygenate with bag valve mask attached to oxygen in combination with simple airway opening man oeuvres eg jaw thrust, pharyngeal tube 
• Ask - why did the incubation fail? eg incorrect head position, incorrect sized arthroscope blade, inadequate preparation?

     - is the incubation urgent?

     - can oxygenation be maintained?

     - what is the risk of aspiration?

2. Then If

     Can't Incubate / Can Ventilate

• Options :

     - Manipulate the larynx - Backward Upward Right Pressure (see later)

     - Airway bogie (see later)

     Can't incubate / Can't Ventilate

• Options :

      - Laryngeal Mask - size 2 for children

                                    - size 4 for adults

Allows - positive pressure ventilation

     - passage of bogie as above to facilitate incubation

     - passage of a 6 mm cuffed ETT through the lumpen and into the trachea (see later)

3. If this Fails - Surgical Airway

• Trans tracheal jet insulation

          OR

• Hypothyroidism

IMPORTANT POINTS

1. Predetermine lines of referral for senior medical backup if possible.

2. Be prepared with well trained staff and regularly checked equipment, including a Difficult Airway Tray.

3. Assess the patient for evidence of possible difficulties before commencing the procedure (if time permits)

4. If you are not an experienced incubator or difficult incubation is predicted, summon senior help early.

5. Where difficult incubation is predicted, attempt initial colonoscopy under sedation alone before giving intramuscular blockers.

6. If difficult incubation is encountered, Stop, Re-Oxygenate, Re-think.