Asthma

Question 1

What is asthma?

Answer 1

• Chronic inflammatory disorder of the airways.
• Associated with acute exacerbations in response to a known or unknown trigger
• May be a history
• Displays diurnal variation
• Reversibility of airway obstruction
• FEV1/FVC <65%
• FEV1 <70% predicted
• FEV1 >12% increase in response to bronchodilators

Question 2

What is the pathophysiology of asthma?

Answer 2

• Chronic inflammatory airways disease with:
• smooth muscle hypertrophy
• goblet cell hyperplasia.

These changes lead to:

• airway reactivity (bronchospasm) and
• mucosal and submucosal oedema (mucus plugging)

Question 3

How can you assess the severity of acute asthma?

Answer 3

1. Vital signs:
   - HR
   - RR
   - saturations
   - BP
2. Clinical findings:
   - Wheeze or silent chest
   - cyanosis
   - use of accessory muscles
3. Bedside tests:
   - PEFR
   - ABG
   - ECG

Question 4

What are the features of acute severe asthma?

Answer 4

• PEFR 33-50%
• unable to complete sentences
• RR>25
• HR >110

Question 5

What are the features of life-threatening asthma?

Answer 5

Clinical features:

• Silent chest
• poor respiratory effort
• cyanosis
• hypotension
• arrhythmias
• impaired consciousness
• exhaustion

Vital signs:
- Sats <92%

Bedside tests:

• normal pCO2
• PO2 <8
• PEFR <33%

Question 6

What are the features of near-fatal asthma?

Answer 6

Raised pCO2

Requiring mechanical ventilation