Lung Physiology 5: Respiratory failure

Question 1

What would be an abnormal PaO2 that would indicate respiratory failure?

Answer 1

<8KPa and <60mmHg

Question 2

What would be an abnormal PaCO2 that would indicate respiratory failure?

Answer 2

> 6.5KPa and >49mmHg

Question 3

What is an indication of Type I respiratory failure?

Answer 3

• Low PaO2 (hypoxia)
  due to ventilation/perfusion mismatch (V/Q)

Question 4

What is an indication of Type II respiratory failure?

Answer 4

• Low PaO2 (hypoxia)
• High PaCO2 (hypercapnia)
  resulting in hyperventilation (possibly due to COPD)

Question 5

What causes type I respiratory failuer?

Answer 5

Infection: Pneumonia, Bronchiectasis
Congenital: heart disease
Airway: COPD, asthma
Pulmonary embolism/ fibrosis

Question 6

What is respiratory failure?

Answer 6

Signified by low PaO2
- Inability to maintain normal blood gases

Question 7

How do we treat type I respiratory failure?

Answer 7

Airway patency (help to breathe)
Oxygen delivery
Many differing systems
Increasing FiO2

Question 8

What causes Type II respiratory failure?

Answer 8

• COPD, asthma
• Drugs
• Metabolic (poisoning, overdose)

Question 9

What are some clinical features of hypoxia?

Answer 9

Central Cyanosis (bluish discolouration)
Irritability
Reduced intellectual function
Reduced consciousness
Convulsions
Coma
Death

Question 10

What are some clinical features of Hypercapnia?

Answer 10

Irritability
Headache
Papilloedema (optic disc swelling_
Warm skin
Bounding pulse
Confusion
Somnolence (drowsiness)
Coma

Question 11

How do we treat type II respiratory failure?

Answer 11

Airway patency
Oxygen delivery (may be more difficult as COPD patients rely on hypoxia to stimulate respiration)
Assisted ventilation (invasive and non-invasive) When still inadequate PaO2 after increasing FiO2