Treatment of Acute Asthma Exacerbation
Immediately administer oxygen to maintain saturation >90% (>95% in pregnant patients or those with heart disease), give albuterol 2.5-5 mg via nebulizer or 4-8 puffs via MDI with spacer every 20 minutes for 3 doses, and start oral prednisone 40-60 mg (or 1-2 mg/kg/day for children, maximum 60 mg/day) within the first hour of presentation. 1, 2, 3
Initial Assessment and Severity Classification
Assess severity immediately using objective measures, not just patient perception, as severity is frequently underestimated: 2, 3
- Mild exacerbation: Dyspnea only with activity, PEF ≥70% predicted, normal speech 1, 2
- Moderate exacerbation: Dyspnea interfering with usual activity, PEF 40-69% predicted, speaks in phrases 1, 2
- Severe exacerbation: Dyspnea at rest, PEF <40% predicted, respiratory rate >25/min, heart rate >110/min, inability to complete sentences, speaks only in words 1, 2, 3
- Life-threatening features: PEF <33% predicted, silent chest, cyanosis, altered mental status, feeble respiratory effort, bradycardia, hypotension, exhaustion, confusion, PaCO₂ ≥42 mmHg 2, 3
Primary Treatment Protocol
Oxygen Therapy
Administer oxygen immediately via nasal cannula or mask to maintain SaO₂ >90% (>95% in pregnant patients or those with heart disease), and monitor continuously until clear response to bronchodilator therapy occurs. 1, 2, 3
Bronchodilator Therapy
Albuterol is the first-line treatment for all asthma exacerbations. 1, 2, 3 Administer via:
- Nebulizer: 2.5-5 mg every 20 minutes for 3 doses, then 2.5-10 mg every 1-4 hours as needed 1, 2, 3
- MDI with spacer: 4-8 puffs every 20 minutes for 3 doses, then as needed (equally effective as nebulizer when properly administered) 1, 3, 4
- For severe exacerbations (PEF <40%): Consider continuous nebulization of albuterol 1, 3
Systemic Corticosteroids
Administer systemic corticosteroids within the first hour of presentation—this is critical and should not be delayed while "trying bronchodilators first." 1, 2, 3 Oral administration is as effective as intravenous and less invasive: 2, 3
- Adults: Prednisone 40-60 mg orally in single or divided doses 1, 2, 3
- Children: 1-2 mg/kg/day orally (maximum 60 mg/day) 1, 2, 3
- If unable to take oral: IV hydrocortisone 200 mg 3
- Duration: 5-10 days for outpatient "burst" therapy; no taper needed for courses <10 days 2, 3
Adjunctive Therapies for Moderate-to-Severe Exacerbations
Ipratropium Bromide
Add ipratropium bromide to albuterol for all moderate-to-severe exacerbations, as this combination reduces hospitalizations, particularly in patients with severe airflow obstruction: 1, 2, 3
- Nebulizer: 0.5 mg every 20 minutes for 3 doses, then as needed 1, 2, 3
- MDI: 8 puffs every 20 minutes for 3 doses, then as needed 1, 2, 3
Magnesium Sulfate
For severe exacerbations (PEF <40%) not responding to initial therapy or life-threatening features, administer IV magnesium sulfate early in the treatment course: 1, 2, 3
This significantly increases lung function and decreases hospitalization necessity. 3, 4
Reassessment Protocol
Reassess the patient 15-30 minutes after starting treatment, measuring PEF or FEV₁ before and after treatments, and assessing symptoms and vital signs. 1, 2, 3 Response to treatment is a better predictor of hospitalization need than initial severity. 1, 3
Response Categories After 1 Hour of Treatment:
- Good response (PEF ≥70% predicted, minimal symptoms): Continue albuterol every 3-4 hours, continue oral corticosteroids, observe for 30-60 minutes after last bronchodilator dose before discharge 3
- Incomplete response (PEF 40-69% predicted, persistent symptoms): Continue intensive treatment, admit to hospital ward 3
- Poor response (PEF <40% predicted): Admit to hospital, consider ICU if life-threatening features present 3
Critical Pitfalls to Avoid
- Never delay corticosteroid administration while "trying bronchodilators first"—give them immediately 3
- Never administer sedatives of any kind to patients with acute asthma 1, 3
- Avoid aminophylline/theophylline due to increased side effects without superior efficacy compared to standard therapy 3, 5
- Do not routinely prescribe antibiotics unless strong evidence of bacterial infection (pneumonia, sinusitis) exists 2, 3
- Avoid aggressive hydration in older children and adults 3
- Do not delay intubation once deemed necessary—perform semi-electively before respiratory arrest 3
Warning Signs of Impending Respiratory Failure
Monitor for these signs requiring immediate ICU consideration: 1, 3
- Inability to speak or altered mental status
- Drowsiness, confusion, or exhaustion
- Silent chest (absence of wheezing despite severe distress)
- Intercostal retraction with worsening fatigue
- PaCO₂ ≥42 mmHg (normal or elevated CO₂ in a breathless asthmatic is ominous)
- Bradycardia or hypotension
Hospital Admission Criteria
- Any life-threatening features present
- Features of severe attack persisting after initial treatment
- PEF <40% predicted after 1-2 hours of treatment
- Presentation in afternoon/evening with recent nocturnal symptoms
- Previous severe attacks or poor assessment of severity
Discharge Planning
- PEF ≥70% of predicted or personal best
- Symptoms minimal or absent
- Oxygen saturation stable on room air
- Patient stable for 30-60 minutes after last bronchodilator dose
- Continue oral corticosteroids for 5-10 days (no taper needed)
- Initiate or continue inhaled corticosteroids
- Provide written asthma action plan
- Verify proper inhaler technique
- Arrange follow-up within 1 week with primary care, within 4 weeks with specialist 3
- Consider IM depot corticosteroid injection for patients at high risk of non-adherence 3
Special Considerations
Regular use of short-acting beta-agonists (≥4 times daily) reduces their duration of action, indicating need to step up daily long-term control therapy. 6, 3 If using more than one canister per month, increase daily maintenance therapy. 6