Airway

Question 1

Describe the gross anatomy of the upper airway.

Answer 1

The upper airway consists of the oral cavity, nose, and pharynx. The pharynx itself is sub-divided into the nasopharynx, oropharynx, and laryngopharynx. NB/ the lower respiratory system refers to everything below the vocal cords (tracheobronchial tree).

Question 2

What are the functions of the upper airway?

Answer 2

Conduct, humidify and warm air. Prevent foreign materials from entering the lower airway. Contribute to speech, swallowing and smell.

Question 3

What are the signs of airway obstruction (partial and complete)?

Answer 3

LOOK/LISTEN/FEEL!

LOOK:

• Are they conscious?
• See-saw movements/paradoxical breathing
• Accessory muscles?
• Central cyanosis

LISTEN:

Partial = coughing, gagging, stridor, dysphonia, noisy
Complete = drooling, gagging, aphonia, silent

FEEL:

• Air movements at mouth?
  > Yes = partial
  > No = complete

Question 4

List the causes of airway obstruction.

Answer 4

• CNS depression (GCS <8)
• Foreign body
• PNS disorder (recurrent laryngeal n. palsy/hypocalcaemia)
• Neuromuscular disorder (laryngospasm/myasthaenia gravis)
• Infection (epiglottis/bacterial tracheitis)
• Haemorrhage
• Laryngeal oedema (anaphylaxis/hereditary angiodaema)
• Trauma
• Burns
• Neoplasm (upper airway malignancy/polyp)

Question 5

What is the easiest way to determine an airway is patent?

Answer 5

The patient is speaking to you.

Question 6

How does the airway “collapse” in an unconscious patient?

Answer 6

Patients who are sedated, anaesthetised or unconscious, the commonest cause is the loss of airway muscle tone. The usual site of obstruction is the soft palate > epiglottis > tongue.

Question 7

How do you approach an obstructed airway?

Answer 7

ABCDE –> A = Head tilt, chin lift OR jaw thrust (cannot perform head tilt chin lift in C-spine injury/rheumatoid arthritis as risk of atlanto-axial subluxation.

Question 8

Explain the benefit of basic airway manouevres (head-tilt chin lift/jaw thrust).

Answer 8

Tenses the muscles at the floor of the mouth causing the hyoid and larynx to be lifted away from the posterior pharyngeal wall.

Question 9

What is the commonmost cause of airway obstruction?

Answer 9

Loss of airway muscle tone.

Question 10

What is the indication for a guedel/oropharyngeal airway?

Answer 10

UNCONSCIOUS patient with obstructed airway (prevents tongue from obstructing airway).

Question 11

What is the contraindication for a guedel/oropharyngeal airway?

Answer 11

Stimulates a powerful gag reflex in conscious or partially conscious patients (if you try to insert one and a patient gags - remove the airway adjunct and replace with a nasopharyngeal airway).

Question 12

How is a guedel/oropharyngeal airway inserted?

Answer 12

Insert the airway upside down until contact is made with the soft palate - then rotate 180 degrees.

Question 13

How do you size a guedel/oropharyngeal airway?

Answer 13

HARD TO HARD –> Place the guedel airway from the lateral incisor to the angle of the mandible.

Question 14

What is the advantage of a nasopharyngeal airway?

Answer 14

Prevents the stimulation of a gag reflex and therefore is indicated in the use in patients with in-tact airways (partially conscious patients).

Question 15

How do you size a nasopharyngeal airway?

Answer 15

SOFT TO SOFT –> Measure from the nostrils to the tragus of the ear.

Question 16

What are the contraindications of a nasopharngeal airway?

Answer 16

• Active nose bleeds.
• Nasal polyps.
• Known or suspected basal skull fracture.

Question 17

What is an iGel?

Answer 17

iGels are the newest generation of laryngeal mask airways - a supraglottic airway. They do not need to be inflated like previous models.

Question 18

What are the main benefits of laryngeal mask airways (LMAs)/iGels?

Answer 18

These airways free the hands of the clinician and produce less gastric distension.

Question 19

What are the contraindications of LMAs/iGels?

Answer 19

• Non-fasted patients (risk of aspiration)
• Morbidly obese/pregnancy (risk of aspiration due to increase in intra-abdominal pressure)
• Obstructive or abnormal orophaynx.

Question 20

How are LMAs sized?

Answer 20

LMAs are sized based on the weight of the patient. The size/weight in kg’s will be on the LMA (good tip for OSCEs).

Question 21

How can you tell a patient is ventilating after LMA/iGel insertion?

Answer 21

Look at capnograph for end-tidal CO2 trace. No trace means the LMA is not placed correctly.

Question 22

What are the disadvantages of an LMA over endotracheal tube?

Answer 22

• Aspiration more likely (NOT a protected airway as supraglottic)
• Air leak more likely
• Cause of laryngospasm (emergency)

Question 23

Why are endotracheal tubes considered the only “protected” or “secure” airway?

Answer 23

Endotracheal tubes transverse through the vocal cords to sit a few centimetres above the bronchial carina - a cuff is then inflated and thereby the lungs are protected from gastric contents aspiration/other secretions.

Question 24

What are the advantages of an endotracheal airway?

Answer 24

• Only protected airway
• Access to tracheo-bronchial tree for suctioning of secretions
• Does not cause gastric distension

Question 25

What are the complications associated with endotracheal tubes?

Answer 25

• Oesophageal intubation - FATAL - will have no capnograph trace
• Endobronchial intubation (insertion into main bronchi - only one lung inflated)
• Herniation (inflated cuff occludes opening)
• Impaction
• Stretching of tracheal wall (from over-inflation - leads to tissue necrosis)

Question 26

What is a tracheostomy?

Answer 26

The creation of a stoma in the trachea (trache-ostomy).

Question 27

What are the functions of a tracheostomy?

Answer 27

• Bypass an airway obstruction
• Removal of airway secretions
• Ventilation in patients with neuromuscular disease
• Facilitate the weaning off ventilator support (in ICU)

Question 28

Distinguish between the two “types” of neck-breathers.

Answer 28

• Post-laryngectomy patients (also known as obligate neck breathers). CANNOT supply O2 via nose/mouth as no larynx. Will have RED sign above bed.
• Tracheostomy patients (larynx in tact - so can supply O2 through nose/mouth). Will have GREEN sign above bed.

Question 29

What MUST you consider in post-laryngectomy patients in airway emergencies?

Answer 29

These patients have NO patent upper airway. They have an END STOMA. You cannot provide supplemental oxygen via nose/mouth. If in doubt supply oxygen to nose/mouth and tracheostomy.

Question 30

Where should you refer to in airway emergencies in post-laryngectomy and tracheostomy patients?

Answer 30

Refer to the emergency management of post-laryngectomy patients algorithm (RED) and emergency tracheostomy management - patent upper airway (GREEN).

Question 31

What are the two methods of tracheostomy insertion>

Answer 31

1. Percutaneous dilatation (most common)

2. Surgical

Question 32

List the THREE tracheostomy tube lumens.

Answer 32

1. Single/dual cannula
2. Cuffed/uncuffed
3. Speaking valves

Question 33

How do you manage an obstructed tracheostomy?

Answer 33

• LOOK, LISTEN, FEEL (as with all airway emergencies) is tracheostomy still patent?
• ask to cough - if can then airway is patent - apply O2 to tracheostomy until anaesthetist comes
• if NOT patent then remove any speaking valves and inner tube
• try to pass a soft suction catheter through as this will determine patency
• if cannot pass through - then deflate cuff if there is one and assess airway at mouth and nose
• if ventilation taking place here now cuff removed - add supplemental O2
• if not ventilation then remove tracheostomy tube - ventilate patient with LMA/iGEL and ambu bag (covering stoma) until anaesthetics arrive

Question 34

What must you NOT do in the case of bleeding at a tracheostomy site?

Answer 34

Do NOT remove the tracheostomy or deflate the cuff - this may be providing a tamponade that is containing the bleeding.