What are the management steps for acute asthma exacerbation?

Management of Acute Asthma Exacerbation

The management of acute asthma exacerbation requires immediate administration of oxygen, inhaled short-acting beta-agonists (SABAs), and systemic corticosteroids as the primary treatment, with severity assessment determining the intensity and frequency of interventions. 1

Initial Assessment and Classification

Features of Severe Asthma

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

Life-Threatening Features

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

Step-by-Step Management Algorithm

1. Oxygen Therapy

• Administer supplemental oxygen through nasal cannulae or mask
• Maintain SaO₂ >90% (>95% in pregnant women and patients with heart disease)
• Monitor oxygen saturation until clear response to bronchodilator therapy 1

2. Inhaled Short-Acting Beta-Agonists (SABAs)

• First-line treatment: High-dose inhaled beta-agonists
• Administer salbutamol 5 mg or terbutaline 10 mg via nebulizer with oxygen
• Alternative: Multiple actuations (4-12 puffs) of SABA via MDI with spacer device 1
• Initial strategy: 3 treatments every 20-30 minutes, then adjust frequency based on response
• For severe exacerbations (FEV₁ or PEF <40% predicted): Consider continuous nebulization 1

3. Systemic Corticosteroids

• Administer early to all patients with moderate-to-severe exacerbations
• Oral prednisolone 30-60 mg daily until lung function returns to previous best (usually 7 days, may need up to 21 days) 1
• IV hydrocortisone 200 mg is an alternative for patients who are seriously ill or vomiting 1
• Early administration may reduce hospitalization rates 1

4. Inhaled Ipratropium Bromide (Anticholinergic)

• Add to SABA therapy for severe exacerbations to increase bronchodilation
• Dosage: 0.5 mg nebulizer solution or 8 puffs via MDI in adults
• The combination of SABA and ipratropium has been shown to reduce hospitalizations, particularly in severe airflow obstruction 1, 2

5. Monitoring and Reassessment

• Measure PEF 15-30 minutes after starting treatment and thereafter according to response
• Repeat assessment after initial dose of bronchodilator for severe exacerbations
• All patients should be reassessed after 3 doses of bronchodilator (60-90 minutes after initiation) 1
• Response to treatment is a better predictor of need for hospitalization than initial severity 1

6. Additional Investigations (If Hospitalized)

• Arterial blood gas analysis for patients with severe exacerbations
• Chest radiography to exclude pneumothorax, consolidation, or pulmonary edema
• Plasma electrolytes, urea concentrations, and blood count 1

Management Based on Response

Improving Condition

• Continue oxygen therapy
• Continue systemic corticosteroids
• Give nebulized beta-agonist every 4 hours 1

Not Improving After 15-30 Minutes

• Give nebulized beta-agonists more frequently (up to every 15 minutes)
• Consider adding IV aminophylline (250 mg over 20 minutes) or IV salbutamol/terbutaline (250 μg over 10 minutes)
• Caution: Do not give bolus aminophylline to patients already taking oral theophyllines 1

Impending Respiratory Failure (Warning Signs)

• Inability to speak
• Altered mental status
• Intercostal retraction
• Worsening fatigue
• PaCO₂ ≥42 mm Hg 1

Common Pitfalls and Caveats

1. Underestimation of severity: The severity of asthma exacerbations is often underestimated by patients, relatives, and doctors due to failure to make objective measurements 1

2. Delayed corticosteroid administration: Systemic corticosteroids should be given early as clinical benefits may not occur for 6-12 hours 3

3. Inappropriate antibiotic use: Antibiotics are not generally recommended as viruses are a much more common cause of exacerbations. Reserve for cases with strong evidence of bacterial infection (pneumonia, sinusitis) 1

4. Paradoxical bronchospasm: In rare cases, SABAs can cause paradoxical bronchospasm. If this occurs, consider switching to anticholinergic agents 4

5. Sedation: Any sedation is contraindicated in acute asthma exacerbations 1

6. Excessive hydration: Aggressive hydration is not recommended for older children and adults but may be appropriate for some infants and young children 1

Criteria for Hospital Admission

• Any life-threatening features
• Any features of severe attack that persist after initial treatment
• PEF <33% of predicted or best value 15-30 minutes after nebulization
• Lower threshold for admission in patients:
  • Seen later in the day
  • With recent nocturnal symptoms
  • With previous severe attacks
  • With poor social support 1

By following this systematic approach to managing acute asthma exacerbations, clinicians can effectively reduce morbidity and mortality while optimizing patient outcomes.