Management of Asthma Exacerbations
The cornerstone of asthma exacerbation management is the prompt administration of short-acting beta-2-agonists (SABAs), systemic corticosteroids for moderate to severe exacerbations, and oxygen supplementation for hypoxemia, with treatment intensity determined by exacerbation severity. 1
Assessment of Exacerbation Severity
Severity classification guides treatment intensity and monitoring frequency:
Mild Exacerbation
- Dyspnea only with activity
- PEF ≥70% of predicted/personal best
- Able to speak in complete sentences
- Respiratory rate normal
- No accessory muscle use
Moderate Exacerbation
- Dyspnea interfering with usual activities
- PEF 40-69% of predicted/personal best
- Speaking in phrases
- Increased respiratory rate (>20-25 breaths/min)
- Heart rate 100-120 beats/min
Severe Exacerbation
- Dyspnea at rest
- PEF <40% of predicted/personal best
- Speaking in words only
- Respiratory rate >25-30 breaths/min
- Heart rate >120 beats/min
- Use of accessory muscles
- Oxygen saturation <90% 2, 1
Life-threatening Features
- PEF <33% of predicted/personal best
- Silent chest
- Cyanosis
- Feeble respiratory effort
- Exhaustion, confusion, or coma
- Bradycardia or hypotension 1
Initial Management
Oxygen
- Administer to maintain oxygen saturation 94-98% 1
- Monitor continuously with pulse oximetry
Bronchodilators
SABA (e.g., albuterol/salbutamol):
- Mild exacerbation: 2-4 puffs via MDI with spacer every 20 minutes for first hour
- Moderate/severe exacerbation: 2.5 mg nebulized or 4-8 puffs via MDI with spacer every 20 minutes for first hour 2, 1, 3
- For children weighing <15 kg: Use 0.5% solution instead of 0.083% 3
- Consider continuous nebulization for severe exacerbations
Anticholinergics (e.g., ipratropium bromide):
- Add to SABA for severe exacerbations
- 0.5 mg nebulized or 4-8 puffs via MDI with spacer every 20 minutes for 1-2 hours 1
Corticosteroids
- Start immediately for moderate to severe exacerbations
- Oral prednisone/prednisolone: 40-60 mg daily for adults, 1-2 mg/kg/day for children
- IV methylprednisolone if unable to take oral medication
- Clinical benefits expected within 6-12 hours 2, 1
Adjunctive Therapies for Severe Exacerbations
Magnesium Sulfate
- Consider IV magnesium sulfate for severe exacerbations not responding to initial treatment
- Adults: 2 g IV over 20 minutes
- Children: 25-75 mg/kg (max 2 g) IV over 20 minutes 1
Intubation Considerations
- Intubate immediately for apnea or coma
- Consider for persistent/increasing hypercapnia, exhaustion, or depressed mental status
- Maintain intravascular volume during intubation to prevent hypotension
- Use "permissive hypercapnia" ventilation strategy to minimize barotrauma 2
Monitoring Response to Treatment
- Reassess after initial 3 doses of bronchodilator (60-90 minutes)
- Measure PEF or FEV1 15-30 minutes after each treatment
- Monitor oxygen saturation continuously
- Assess work of breathing, respiratory rate, heart rate 2, 1
Hospitalization Criteria
Admit patients with:
- No response or worsening after initial treatment
- PEF/FEV1 <40% of predicted after treatment
- Oxygen saturation <90% despite supplemental oxygen
- Signs of impending respiratory failure
- High-risk features (previous ICU admission, multiple ED visits/hospitalizations) 1
Discharge Criteria
Patients can be discharged when:
- FEV1 or PEF ≥70% of predicted/personal best
- Symptoms minimal or absent
- Stable on 30-60 minutes observation after last bronchodilator dose 2, 1
Discharge Management
- Prescribe systemic corticosteroids for 3-10 days
- Continue or initiate inhaled corticosteroid therapy
- Provide written asthma action plan
- Instruct on proper inhaler technique
- Arrange follow-up with primary care within 1 week and respiratory clinic within 4 weeks 2, 1, 4
Special Considerations
Infants and Young Children
- Assessment relies more on physical examination than objective measurements
- Warning signs: accessory muscle use, inspiratory/expiratory wheezing, paradoxical breathing, cyanosis, respiratory rate >60 breaths/min, SaO2 <90%
- Lack of response to SABA therapy indicates need for hospitalization 2
Prehospital Management
- EMS should administer oxygen and inhaled SABAs
- Treatment can be repeated during transport (max 3 treatments in first hour, then 1/hour)
- Do not delay transport to hospital 2
Common Pitfalls to Avoid
- Delaying corticosteroid administration in moderate-severe exacerbations
- Underestimating severity due to poor perception of symptoms by patient
- Discharging patients too early without adequate observation
- Failing to provide a written asthma action plan at discharge
- Not arranging appropriate follow-up
- Using sedatives, which should be strictly avoided 2, 1