Acute Asthma

Asthma is a common chronic respiratory condition which affects up to 20% of children and 10% of adults. It is characterised by episodic, reversible, variable symptoms including:

  • Wheezing
  • Breathlessness
  • Chest tightness
  • Cough

Acute asthma is likely to present with all or most of these symptoms, often deteriorating over the preceding days. On some occasions, it may present as a very rapid deterioration. Acute asthma is characterised by:

  • Reversible airway narrowing (bronchospasm)
  • Excess mucus secretion and plugging of the airways

Acute asthma patients are at risk of developing complications such as hypoxia, dehydration, cardiac arrhythmias and are at increased risk of developing a spontaneous pneumothorax.

The British Thoracic Society asthma guidelines classify asthma exacerbations into 3 main categories: moderate, acute severe or life-threatening asthma with different clinical features:

Signs of moderate asthma exacerbation:

  • Normal speech
  • Peak expiratory flow rate (PEFR) > 50% predicted best
  • No features of severe asthma

Signs of acute severe asthma – any 1 of:

  • Cannot complete full sentences
  • Pulse >110 / min
  • Respiratory Rate >25 / min
  • PEFR 33-50% predicted best

Signs of life-threatening asthma – any 1 of:

  • Feeble respiratory effort
  • ‘Silent chest’
  • Cyanosis
  • Oxygen saturations <92%
  • PEFR <33%
  • Exhaustion, confusion, altered consciousness

Assessing an acute asthma exacerbation

The method should be the same for any acutely unwell or injured patient: safe approach, AB(& O2)CDE.


- Consider supplemental oxygen. Can they complete a sentence?


- Check RR - Chest expansion & percussion - Auscultate – listen for wheeze and equal air entry


- Check pulse (rate and volume)



Exposure & Environment

- Are you in a safe and suitable place?

- Does the patient have their own inhaler?

Managing acute severe asthma and life-threatening asthma


Any life-threatening features – refer to hospital

Sit the patient up

  • Oxygen - 10-15 L/min via a non-rebreathe mask
  • Encourage use of player’s own inhaler
  • Nebulisers - Salbutamol 5 mg (Ventolin®) & Ipatropium 500 mcgs (Atrovent®)
  • Steroids - Prednisolone 40-50mg PO* If necessary, repeat salbutamol nebuliser with partial or no clinical improvement – so called ‘back-to-back’ nebs. This can prove a highly effective treatment. The nebuliser should be driven with oxygen.

* Steroids will take approximately 2-4 hours to have an effect. There is no evidence to suggest that IV hydrocortisone is any more efficacious than oral prednisolone.

If in any doubt, refer to ED.