What is the treatment for severe asthma?

Treatment of Severe Asthma

The treatment of severe asthma requires immediate administration of high-flow oxygen, inhaled short-acting beta-agonists (SABAs) such as nebulized salbutamol 5mg or terbutaline 10mg, and systemic corticosteroids (oral prednisolone 30-60mg or IV hydrocortisone 200mg). 1, 2

Initial Assessment and Management

Assessment of Severity

Recognize severe asthma by these features:

• Too breathless to complete sentences in one breath
• Respiratory rate >25 breaths/min
• Heart rate >110 beats/min
• PEF <50% of predicted or best 1, 2

Life-threatening features include:

• PEF <33% of predicted or best
• Silent chest, cyanosis, or feeble respiratory effort
• Exhaustion, confusion, or coma
• Bradycardia or hypotension 2, 1

First-Line Treatment

1. Oxygen therapy (40-60%) to maintain SaO₂ >90% (>95% in pregnant women and those with heart disease) 2, 1

2. Inhaled beta-agonists:

   • Nebulized salbutamol 5mg or terbutaline 10mg 2, 1
   • Can be given continuously in severe exacerbations 2
   • For adults, typically 2.5-5mg every 20 minutes for 3 doses, then 2.5-10mg every 1-4 hours as needed 2

3. Systemic corticosteroids:

   • Prednisolone 30-60mg orally or hydrocortisone 200mg IV 2, 1
   • Should be administered early as effects may not be apparent for 6-12 hours 2, 3

Subsequent Management

If Patient Is Improving

• Continue high-flow oxygen
• Continue prednisolone 30-60mg daily
• Continue nebulized beta-agonist every 1-4 hours as needed 2

If Patient Is Not Improving After 15-30 Minutes

1. Intensify bronchodilator therapy:

   • Give nebulized beta-agonist more frequently (up to every 30 minutes) 2
   • Add ipratropium bromide 0.5mg to nebulizer and repeat 6-hourly 2, 1

2. Consider additional therapies:

   • IV magnesium sulfate 2g over 20 minutes for patients with severe refractory asthma 2
   • Magnesium causes bronchial smooth muscle relaxation and improves pulmonary function 2

3. For life-threatening features:

   • Consider IV aminophylline or IV beta-agonists (terbutaline or salbutamol) 2
   • Note: IV beta-agonists have not consistently shown significant improvements in clinical outcomes 2

Monitoring Treatment Response

Repeat assessment should occur:

• After initial bronchodilator treatment for severe exacerbations
• After 3 doses of inhaled bronchodilator (60-90 minutes after initiation) for all patients 2

Assessment should include:

• Subjective response to treatment
• Physical findings
• PEF or FEV₁ measurements
• Oxygen saturation 2

Criteria for ICU Transfer

Consider transfer to ICU if:

• Deteriorating PEF despite treatment
• Persistent hypoxia (PaO₂ <8 kPa) despite oxygen therapy
• Hypercapnia (PaCO₂ >6 kPa)
• Exhaustion, confusion, drowsiness, or coma
• Respiratory arrest 2, 1

Discharge Criteria

Patients should only be discharged when:

• They've been on discharge medications for 24 hours
• Inhaler technique has been checked and recorded
• PEF >75% of predicted or best with diurnal variability <25%
• Treatment includes oral steroids and inhaled steroids in addition to bronchodilators
• Follow-up with primary care provider is arranged within 1 week 2

Common Pitfalls to Avoid

1. Underestimating severity: Always assess objectively with PEF measurements 1

2. Delaying corticosteroid administration: This worsens outcomes; administer early even if response is not immediately apparent 1

3. Inadequate monitoring: Continuous monitoring of respiratory rate, heart rate, and oxygen saturation is essential 1

4. Premature discharge: Ensure patients meet all discharge criteria before sending home 2

5. Relying solely on beta-agonists: While essential for immediate symptom relief, they do not address the underlying inflammation 4

Recent evidence suggests that fixed-dose combinations of beta-agonists with corticosteroids (such as albuterol-budesonide) may reduce the risk of severe exacerbations compared to beta-agonists alone 4, 5, though this approach is not yet incorporated into all guidelines for acute severe asthma management.