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.
Airway
- Consider supplemental oxygen. Can they complete a sentence?
Breathing
- Check RR - Chest expansion & percussion - Auscultate – listen for wheeze, and equal air entry
Circulation
- Check pulse (rate and volume)
Disability
- AVPU
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
CALL FOR HELP early
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.