What are the next steps in managing severe asthma that is unresponsive to intravenous (IV) corticosteroids, inhaled corticosteroids, and bronchodilators?

Management of Severe Asthma Unresponsive to Standard Therapy

For patients with severe asthma unresponsive to IV corticosteroids, inhaled corticosteroids, and bronchodilators, the next step should be administration of IV magnesium sulfate, which has been shown to be more effective and safer than other rescue medications for refractory severe asthma. 1

Immediate Management Steps

• Administer IV magnesium sulfate as a single bolus dose, which reduces hospital admissions and improves pulmonary function in severe asthma exacerbations 2, 3
• Consider adding ipratropium bromide to the nebulized β2-agonist therapy to increase bronchodilation in severe exacerbations 4
• Continue high-flow oxygen therapy via face mask to maintain SaO₂ >90% (>95% in pregnant women and patients with heart disease) 4
• Increase the frequency of nebulized β-agonist treatments up to every 30 minutes if the patient is not improving 5

If No Improvement After IV Magnesium Sulfate

• Consider IV aminophylline (5 mg/kg over 20 minutes followed by maintenance infusion of 1 mg/kg/h); omit the loading dose if the patient is already receiving oral theophyllines 5
• Alternatively, consider IV terbutaline (250 μg over 10 minutes) 5
• Monitor for side effects: aminophylline may cause nausea and vomiting, while terbutaline may cause hypokalemia 1

Monitoring and Assessment

• Continuously monitor vital signs, oxygen saturation, and peak expiratory flow (PEF) 5
• Arrange for chest radiography to exclude pneumothorax, consolidation, or pulmonary edema 5
• Check plasma electrolytes, urea concentrations, and blood count 5
• Assess for signs of deterioration requiring intensive care: worsening PEF, persistent hypoxia despite oxygen therapy, exhaustion, feeble respirations, confusion, or drowsiness 5

Indications for ICU Transfer

• Transfer to intensive care unit accompanied by a doctor prepared to intubate if there is:
  • Deteriorating PEF or worsening exhaustion, feeble respirations, persistent hypoxia or hypercapnia 5
  • Coma or respiratory arrest, confusion, or drowsiness 5
  • Onset of exhaustion, feeble respiration, confusion, or drowsiness 5

Indications for Mechanical Ventilation

• Consider intermittent positive pressure ventilation for patients with:
  • Worsening hypoxia or hypercapnia despite maximal therapy 5
  • Drowsiness or unconsciousness 5
  • Respiratory arrest 5

Important Considerations

• Avoid sedation as it is contraindicated in severe asthma 5
• Antibiotics should only be given if bacterial infection is present 5
• Percussive physiotherapy is unnecessary in acute severe asthma 5
• The anti-inflammatory effects of corticosteroids may not be apparent for 6-12 hours after administration, making early and aggressive intervention critical 4

Discharge Planning

• Patients should not be discharged until symptoms have stabilized with PEF >75% of predicted value 5
• Ensure patients have been on discharge medication for at least 24 hours with inhaler technique checked and recorded 5
• Provide oral prednisone for 1-3 weeks after discharge 4
• Arrange follow-up with primary care within 1 week and respiratory specialist within 4 weeks 5

Caution

• The threshold for ICU admission should be lower in patients seen in the afternoon or evening, those with recent nocturnal symptoms, or those with previous severe attacks 5
• Magnesium sulfate appears to be most beneficial in patients with severe acute asthma and may not be as effective in milder cases 3