Respiratory failure

Question 1

When does respiratory failure occur?

Answer 1

When gas exchange is inadequate resulting in hypoxia

Question 2

Type I respiratory failure
1) What is type I respiratory failure
2) What is the main cause of type I respiratory failure?
3) What is a low VQ mismatch?
4) Name a cause of a low VQ mismatch
5) What is a high VQ mismatch?
6) Name a cause of a high VQ mismatch

Answer 2

1) PaO2 <8 kPa; PaCO2 Normal
2) VQ mismatch
3) Areas that have poor ventilation with oxygen but are well perfused by blood
4) Asthma, congestive cardiac failure, mucous plug, emphysema
5) Areas of the lung with adequate ventilation but are lacking blood perfusion
6) PE

Question 3

Type II respiratory failure
1) What is type II respiratory failure?
2) What causes type II respiratory failure?
3) Name a pulmonary disease that can cause type II respiratory failure
4) Name a reduced respiratory drive cause of type II respiratory failure
5) Name a neuromuscular disease that can cause type II respiratory failure
6) Name a thoracic wall disease that can cause type II respiratory failure

Answer 3

1) PaO2 < 8 kPa; PaCO2> 6 kPa
2) Alveolar hypoventilation - lungs fail to effectively oxygenate and blow off CO2
3) Asthma, COPD, pneumonia, pulmonary fibrosis, obstructive sleep apnoea
4) Trauma, CNS tumour, sedatives
5) Cervical cord lesions, diaphragmatic paralysis, poliomyelitis, myasthenia gravis, Guillain-Barre syndrome
6) Flail chest, kyphoscoliosis

Question 4

Name a sign/symptom of hypoxia

Answer 4

• Dyspnoea
• Restlessness and agitation
• Confusion
• Central cyanosis

Question 5

Name a sign/symptom of hypercapnia

Answer 5

• Headache
• Peripheral vasodilation
• Tachycardia
• Confusion/drowsiness
• Tremor/flap
• papilloedema