What is the treatment for acute asthma exacerbation?

Treatment of Acute Asthma Exacerbation

Immediately administer oxygen to maintain SaO₂ >90% (>95% in pregnant patients or those with heart disease), nebulized albuterol 2.5-5 mg or 4-8 puffs via MDI with spacer every 20 minutes for 3 doses, and oral prednisone 40-60 mg (or IV hydrocortisone 200 mg if unable to take oral) 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 underestimation is a critical and common pitfall 1:

Severe exacerbation features:

• Inability to complete sentences in one breath 1
• Respiratory rate >25 breaths/min 1
• Heart rate >110 beats/min 1
• Peak expiratory flow (PEF) <50% predicted or personal best 1

Life-threatening features requiring immediate ICU consideration:

• PEF <33% predicted 1
• Silent chest, cyanosis, feeble respiratory effort 1
• Altered mental status, confusion, drowsiness 1
• Normal or elevated PaCO₂ (≥42 mmHg) in a breathless patient 1
• Bradycardia, hypotension, exhaustion 1

Primary Treatment Algorithm

First 15-30 Minutes 1, 2, 3

Oxygen therapy:

• Administer via nasal cannula or mask to maintain SaO₂ >90% (>95% in pregnancy or heart disease) 1, 2, 3
• Monitor continuously until clear response to bronchodilators 2

Bronchodilator therapy (first-line):

• Albuterol 2.5-5 mg via nebulizer OR 4-8 puffs via MDI with spacer 1, 2, 3
• Repeat every 20 minutes for 3 doses in the first hour 1, 2
• MDI with spacer is equally effective as nebulizer when properly administered 2, 4

Systemic corticosteroids (must give early, do not delay):

• Oral prednisone 40-60 mg for adults 1, 2, 3
• Children: 1-2 mg/kg/day (maximum 60 mg/day) 1, 2
• IV hydrocortisone 200 mg if unable to take oral 5, 1
• Oral route is as effective as IV and preferred 1, 2

Reassessment at 15-30 Minutes 1, 2, 3

Measure PEF or FEV₁ and assess symptoms and vital signs 1, 2:

Good response (PEF ≥70% predicted):

• Continue albuterol every 3-4 hours as needed 1
• Continue oral corticosteroids for 5-10 days (no taper needed for courses <10 days) 1, 2
• Consider discharge if stable for 30-60 minutes after last bronchodilator 3

Incomplete response (PEF 40-69% predicted):

• Continue intensive treatment 1
• Add ipratropium bromide 0.5 mg via nebulizer or 8 puffs via MDI every 20 minutes for 3 doses 1, 2, 3
• Arrange hospital admission 1

Poor response (PEF <40% predicted or life-threatening features):

• Admit to hospital, consider ICU 1, 3
• Add ipratropium bromide immediately 1, 2
• Consider IV magnesium sulfate 2 g over 20 minutes 1, 2, 3
• Consider continuous nebulized albuterol for severe cases 2, 3

Adjunctive Therapies for Severe/Refractory Cases

Ipratropium bromide (add for all moderate-to-severe exacerbations):

• 0.5 mg via nebulizer or 8 puffs via MDI every 20 minutes for 3 doses, then as needed 1, 2, 3
• Reduces hospitalizations, particularly in severe airflow obstruction 1, 4

IV magnesium sulfate (for severe refractory asthma):

• 2 g IV over 20 minutes for adults 1, 2, 3
• 25-75 mg/kg (maximum 2 g) for children 3
• Most effective when administered early in severe exacerbations 2, 4
• Significantly increases lung function and decreases hospitalization necessity 4, 6

Continuous albuterol nebulization:

• Consider for severe exacerbations (FEV₁ or PEF <40%) not responding to intermittent dosing 2, 3

Critical Pitfalls to Avoid

Never administer sedatives of any kind to patients with acute asthma 1, 2 - this is a potentially fatal error.

Do not delay corticosteroids while "trying bronchodilators first" 1 - they must be given immediately in moderate-to-severe exacerbations.

Avoid methylxanthines (theophylline/aminophylline) due to erratic pharmacokinetics, significant side effects, and lack of evidence of benefit over standard therapy 5, 1, 6 - the FDA label confirms controlled trials show conflicting results with most studies showing no benefit and increased adverse effects 7.

Do not give bolus aminophylline to patients already taking oral theophyllines 1.

Do not underestimate severity - patients, families, and clinicians frequently fail to recognize dangerous exacerbations due to inadequate objective measurements 1.

Hospital Admission Criteria 1, 3

Immediate admission required for:

• Any life-threatening features present 1, 3
• Features of severe asthma persisting after initial treatment 1
• PEF <33% predicted after treatment 5, 1

Lower threshold for admission if:

• Presentation in afternoon or evening 5, 1
• Recent nocturnal symptoms or hospital admission 5, 1
• Previous severe attacks 5, 1
• Poor social circumstances or inability to assess own condition 5, 1

Discharge Criteria 1, 3

Patients may be discharged when:

• PEF ≥70% of predicted or personal best 1, 3
• Symptoms minimal or absent 1, 3
• Oxygen saturation stable on room air 3
• Stable for 30-60 minutes after last bronchodilator dose 1, 3

At discharge, ensure:

• Oral corticosteroids prescribed for 5-10 days (no taper needed) 1, 2
• Inhaled corticosteroids initiated or continued 1, 3
• Written asthma action plan provided 3
• Inhaler technique verified 5, 3
• Follow-up arranged within 1 week 5, 3

Therapies NOT Recommended

Heliox: Meta-analysis does not support use as initial treatment 5, 6.

Leukotriene antagonists: Effectiveness during acute exacerbations unproven 5.

Antibiotics: Not recommended unless strong evidence of bacterial infection (pneumonia, sinusitis) 1, 3.

Aggressive hydration: Not recommended for older children and adults 1.

Subcutaneous epinephrine or terbutaline: No evidence of advantage over inhaled beta-agonists 5.