What is the treatment approach for asthma exacerbation and subsequent maintenance therapy?

Asthma Exacerbation Treatment and Maintenance Therapy

For asthma exacerbation treatment, administer oxygen to maintain SaO₂ >90%, provide inhaled short-acting beta-agonists (SABA) every 20 minutes for 3 doses, and give systemic corticosteroids early in the treatment course, followed by appropriate maintenance therapy based on asthma severity. 1, 2

Initial Management of Asthma Exacerbation

Assessment of Severity

• Classify exacerbation severity based on symptoms, signs, and lung function (PEF or FEV1) 1:
  • Mild: Dyspnea only with activity, PEF ≥70% predicted
  • Moderate: Dyspnea interferes with usual activity, PEF 40-69% predicted
  • Severe: Dyspnea at rest, PEF <40% predicted
  • Life-threatening: Too dyspneic to speak, perspiring, PEF <25% predicted

Primary Treatment Components

• Administer oxygen through nasal cannulae or mask to maintain SaO₂ >90% (>95% in pregnant patients or those with heart disease) 2
• Provide inhaled albuterol (SABA) via nebulizer or metered-dose inhaler (MDI) with spacer 1:
  • Nebulizer: 2.5-5 mg every 20 minutes for 3 doses, then 2.5-10 mg every 1-4 hours as needed
  • MDI: 4-12 puffs every 20 minutes for up to 3 doses, then as needed
• Administer systemic corticosteroids early 1, 2:
  • Adults: Oral prednisone 40-60 mg in single or divided doses
  • Children: 1-2 mg/kg/day (maximum 60 mg/day)

Adjunctive Therapies

• Add ipratropium bromide to SABA therapy for moderate to severe exacerbations 1, 2:
  • 0.5 mg via nebulizer or 8 puffs via MDI every 20 minutes for 3 doses, then as needed
• Consider intravenous magnesium sulfate (2g IV over 20 minutes) for patients with severe refractory asthma 2

Monitoring and Reassessment

• Measure PEF or FEV1 before and after treatments 1
• Monitor oxygen saturation continuously until clear response to bronchodilator therapy 2
• Reassess the patient 15-30 minutes after starting treatment 2
• Response to treatment is a better predictor of hospitalization need than initial severity 1, 2

Maintenance Therapy After Exacerbation

Discharge Planning

• Provide an ED asthma discharge plan 1
• Review inhaler technique whenever possible 1
• Consider initiating inhaled corticosteroids (ICS) 1, 2
• Arrange follow-up asthma care within 1-4 weeks 1
• Encourage patient contact with provider during first 3-5 days after discharge 1

Maintenance Therapy Options

• For mild persistent asthma (Step 2), two equally preferred options 1, 3:
  • Daily low-dose ICS with SABA as needed
  • As-needed concomitant ICS and SABA
• For moderate persistent asthma (Steps 3-4), ICS/formoterol as both maintenance and reliever therapy is preferred for patients ≥5 years old 1
• For severe persistent asthma (Step 5), consider adding long-acting muscarinic antagonists (LAMAs) to ICS/LABA for patients ≥5 years old 1

Adjusting Maintenance Therapy

• If asthma is well controlled for at least 3 months, consider stepping down therapy 1
• Reduce ICS dose by 25-50% every 3 months to identify minimum therapy required 1
• If not well controlled, step up 1 step; if very poorly controlled, step up 2 steps 1
• Short courses of oral systemic corticosteroids may be needed for patients experiencing frequent interruptions of sleep or normal daily activities 1, 4

Common Pitfalls and Caveats

• Do not delay administration of systemic corticosteroids in moderate to severe exacerbations 1, 5
• Avoid treatments not recommended in emergency care: methylxanthines, antibiotics (except for comorbid conditions), aggressive hydration, chest physical therapy, mucolytics, or sedation 1
• Be aware that the severity of an asthma exacerbation is often underestimated 2
• Recognize that even short courses of systemic corticosteroids can have adverse effects including bone density loss, hypertension, and gastrointestinal issues 4
• Remember that budesonide inhalation suspension is indicated for maintenance treatment of asthma but NOT for relief of acute bronchospasm 6

Special Considerations for Children

• For children 0-4 years with recurrent wheezing, consider a short course of ICS (in addition to SABA) at the onset of respiratory illness 1
• Dosing for children should be adjusted based on age and weight 1, 2
• Blood gas estimations are rarely helpful in deciding initial management for children 2

By following this structured approach to asthma exacerbation management and subsequent maintenance therapy, clinicians can effectively control symptoms, reduce the risk of future exacerbations, and improve patient outcomes.