Airway Obstruction

Question 1

When does the URT end and the LRT begin?

Answer 1

Vocal cords

Question 2

Movement of the vocal cords during phonation?

Answer 2

Adduct

Question 3

Movement of the vocal cords during respiration?

Answer 3

Abduct (action of posterior cricoarytenoid muscles)

Question 4

Features in the neonate that alter the airway?

Answer 4

Neonates are OBLIGATE NASAL BREATHERS

Relatively large tongue

Narrow subglottis (3.5mm at the cricoid)

Question 5

Structure of the larynx in neonates?

Answer 5

Small, soft larynx that is in a higher position

They have weak neck muscles and floppy head

Question 6

Describe Poiseuille’s equation

Answer 6

Blowing air through a tube with a decreasing diameter results in the resistance to flow increasing to the 3rd power of the radius

Thus, a slight reduction in diameter massively increases resistance

Question 7

Describe the Bernoulli principle/Venturi effect

Answer 7

………..

Question 8

Causes of airway obstruction?

Answer 8

Inflammatory/infective/allergy

Foreign body inhalation

Physical compression/invasion of the airway

Neoplastic causes, e.g: malignant pathology

Trauma (may be iatrogenic)

Burn

Congenital airway pathology

Question 9

Signs and symptoms of airway obstructor?

Answer 9

• SoB on exertion OR at rest (stertor/stridor); coughing/choking
• Inability to complete a sentence (good marker of severity)
• Sternal/subcostal recession
• Tracheal tug
• Dusky skin colour of skin
• Dysphagia, dysphonia
• Pyrexia and cyanosis

Question 10

What is stridor?

Answer 10

High-pitched harsh noise due to turbulent airflow caused by airway obstruction; typically inspiratory

Question 11

What is stertor?

Answer 11

Low-pitched sonorous sound arising from the nasopharyngeal airway, e.g: during a cold

Question 12

Consequences of enlarged tonsils and adenoids?

Answer 12

Obstructive sleep apnoea

Question 13

Management of airway in acute epiglottitis?

Answer 13

Require intubation

Question 14

Consequences of inhaling a peanut (foreign body)?

Answer 14

Airway obstruction

NOTE: peanuts are toxic and cause swelling

Question 15

CXR appearance of foreign body inhalation into the left main bronchus?

Answer 15

Shows mediastinal shift

Question 16

What is recurrent respiratory papillomatosis?

Answer 16

HPV causees papillomas to develop over time

Question 17

Treatment of recurrent respiratory papillomatosis?

Answer 17

Intubation + surgery + anti-virals

Question 18

What is sub-glottic stenosis?

Answer 18

Narrowing of the subglottis (just below the vocal cords); can be:
• Congenital
• Idiopathic (unknown cause)
• Acquired (majority are post-intubation)

Question 19

How can burns cause airway obstruction?

Answer 19

Assoc. swelling

Question 20

How to assess a patient with potential airway obstruction?

Answer 20

Appearance (anxious-looking, sternal recession, etc)

Work of breathing

Skin circulation

Question 21

Pathway of deterioration following airway obstruction?

Answer 21

1. Respiratory distress
2. Respiratory failure
3. Respiratory arrest
4. Cardiac arrest

Respiratory, cardiac and neurological failure are all linked

Question 22

Describe cardiorespiratory drive

Answer 22

If one fails, the other will as well

Question 23

Mx of airway obstruction?

Answer 23

ABC

Administer:
• Oxygen
• Heliox (79% helium + 21% oxygen; makes air thinner and easier to inhale)
• Steroids
• Adrenaline 

Secure the airway with:
• Endotracheal tube (intubation)
• Tracheostomy (avoid as there is an assoc. morbidity and mortality)

Treat the underlying pathology

Question 24

Methods of Ix of the airway?

Answer 24

Rigid endoscopy and/or flexible endoscopy; this is best done without the ET tube in place, if possible

Options include:
• Direct laryngoscopy or microlaryngoscopy
• Exam with Hopkins rod
• Laryngotracheobronchoscopy

Question 25

Types of general anaesthesia?

Answer 25

Anaesthetic gas (Sevoflurane)

IV anaesthesia (Propofol, Remifentanyl)

Question 26

Pharmacotherapy for airway obstruction?

Answer 26

Heliox

Nebulised budesonide

Dexamethasone

Nebulised adrenaline