COPD

Question 1

COPD: How is it characterised?

Answer 1

• COPD is characterised as persistent airflow limitation

- It has a spectrum of diseases ranging from bronchitis to emphysema

Question 2

What is classified as chronic bronchitis?

Answer 2

• a disease of the airways

- a chronic cough with sputum production persisting for 3 months of 2 consecutive years

Question 3

Pathophysiology of chronic bronchitis?

Answer 3

-inflammatory cell infiltration of bronchial mucosa leading to: mucosal oedema, increased mucus secretions, mucus plugging, inflammation and fibrosis

Question 4

How does gas trapping occur in chronic bronchitis?

Answer 4

mucus plugs create a one-way valve allowing air into the alveoli however not out

Question 5

How does a V/Q mismatch occur in chronic bronchitis?

Answer 5

• airway obstruction due to mucus/inflammation causes decreased ventilations => lung tissue hypoxia => constriction of pulmonary blood vessels => decreased perfusion
• low V/Q due to decreased ventilation means hypoxaemia is the primary problem

Question 6

How is emphysema caused?

Answer 6

Exposure to irritating particles such as smoking, pollution, occupational irritants

Question 7

Pathophysiology of emphysema?

Answer 7

-Inflammation and proteolytic processes cause the destruction of connective tissue in terminal respiratory units and alveolar capillary beds

Question 8

How does the pathophysiology of emphysema effect V/Q ratio?

Answer 8

• enlarged airspaces create increased deadspace, which decreases alveolar ventilation
• destruction of capillaries leads to decreased perfusion

Question 9

How does emphysema cause increased work of breathing and dyspnoea?

Answer 9

Loss of elastic connective tissue leads to decreased recoil of the lungs and therefore WOB and dyspnoea

Question 10

How do COPD patients obtain their barrel-chested appearance?

Answer 10

Due to the long lung fields, caused by gas trapping, leading to hyperinflation and increased functional residual capacity

Question 11

Management of an acute exacerbation of COPD?

Answer 11

• correct hyperaemia: oxygen administration, titrated to Sp02 of 88-92%, ventilation if required
• bronchodilators: salbutamol, ipratropium to reverse bronchoconstriction
• corticosteriods: reduce airway inflammation

Question 12

Signs of CO2 retention?

Answer 12

• worsening conscious state
• tachycardia
• warm periphery and bounding pulse

Question 13

Things to remember when ventilating a COPD patient:

Answer 13

• allow for a long expiratory phase, use Sp02 as guidance

- be aware of hypotension due to hyperinflation, tension pneumothorax