What is the best treatment approach for a patient experiencing an asthma exacerbation?

Management of Asthma Exacerbation

Begin immediate treatment with high-dose inhaled albuterol (2.5-5 mg via nebulizer or 4-8 puffs via MDI with spacer every 20 minutes for 3 doses), supplemental oxygen to maintain SaO₂ >90%, and early systemic corticosteroids (prednisone 40-60 mg orally for adults) within the first 15-30 minutes of presentation. 1, 2

Initial Assessment and Oxygen Therapy

• Assess severity immediately using peak expiratory flow (PEF) or FEV₁, with severe exacerbation defined as PEF <40% predicted, inability to complete sentences, respiratory rate >25 breaths/min, and heart rate >110 beats/min 1, 2
• Administer high-flow oxygen (40-60%) via face mask or nasal cannula to maintain SaO₂ >90% (>95% in pregnant patients or those with cardiac disease) 3, 1, 4
• Continue oxygen saturation monitoring until clear response to bronchodilator therapy occurs 1, 4

Primary Bronchodilator Treatment

• Administer albuterol 2.5-5 mg via nebulizer or 4-8 puffs via MDI with spacer every 20 minutes for 3 doses as initial therapy 1, 4, 2
• For severe exacerbations (PEF or FEV₁ <40% predicted), consider continuous nebulization of albuterol rather than intermittent dosing, as this may be more effective 3, 4
• After initial 3 doses (60-90 minutes), adjust frequency based on patient response: most patients (60-70%) will respond sufficiently to be discharged after these initial treatments 3
• The usual maintenance dosing is 2.5 mg three to four times daily by nebulization, with flow rate regulated to deliver medication over 5-15 minutes 5

Systemic Corticosteroids

Administer systemic corticosteroids early to all patients with moderate-to-severe exacerbations and those not responding to initial albuterol therapy. 3, 1

• Give prednisone 40-60 mg orally in single or divided doses for adults (1-2 mg/kg/day, maximum 60 mg/day for children) 3, 1
• Oral prednisone has equivalent efficacy to intravenous methylprednisolone but is less invasive 3
• Continue for 5-10 days total; no taper needed for courses <10 days, especially if patient is concurrently taking inhaled corticosteroids 3, 2
• Early administration may reduce likelihood of hospitalization in moderate-to-severe exacerbations 3

Adjunctive Therapies for Severe Exacerbations

Ipratropium Bromide

• Add ipratropium bromide 0.5 mg via nebulizer or 8 puffs via MDI to albuterol for all moderate-to-severe exacerbations 1, 4, 2
• Administer every 20 minutes for 3 doses, then as needed 1, 4

Magnesium Sulfate

• Administer intravenous magnesium sulfate 2 g over 20 minutes for life-threatening features or severe exacerbations not responding after 1 hour of intensive treatment 1, 2
• Most effective when administered early in the treatment course 4
• For children, dose is 25-75 mg/kg (maximum 2 g) 3

Reassessment Protocol

• Reassess patient 15-30 minutes after starting treatment, measuring PEF or FEV₁ before and after treatments 1, 4
• Repeat PEF measurement after 3 doses of bronchodilator (60-90 minutes total) 2
• Response to treatment is a better predictor of hospitalization need than initial severity 4
• Monitor for signs of impending respiratory failure: inability to speak, altered mental status, intercostal retraction, worsening fatigue 4

Hospital Admission Criteria

• Admit for any life-threatening features or features of acute severe asthma present after initial treatment 1
• Lower threshold for admission with history of recent nocturnal symptoms, recent hospital admission, or previous severe attacks 1
• Patients presenting with apnea or coma should be intubated immediately 3
• Persistent or increasing hypercapnia, exhaustion, and depressed mental status strongly suggest need for ventilatory support 3

Discharge Criteria and Planning

• Discharge when PEF >75% of predicted or personal best, symptoms minimal or absent, patient stable for 30-60 minutes after last bronchodilator dose, and oxygen saturation stable on room air 2
• Continue oral corticosteroids for 5-10 days (no taper needed) 2
• Initiate or continue inhaled corticosteroids at discharge 2
• Provide written asthma action plan before discharge and arrange follow-up with primary care within 1 week 1, 2

Critical Pitfalls to Avoid

• Never delay transport or treatment while waiting for additional assessments - EMS providers should not delay patient transport while administering bronchodilator treatment, with maximum of 3 treatments during first hour, then 1 per hour during transport 1
• Avoid sedatives of any kind in patients with acute asthma exacerbation 4
• Do not use intravenous isoproterenol due to danger of myocardial toxicity 3
• Monitor for paradoxical bronchospasm with albuterol, which can be life-threatening and requires immediate discontinuation 5
• Be aware that large doses of albuterol may cause hypokalemia (20-25% decline in serum potassium), though usually asymptomatic and transient 5
• Use albuterol with extreme caution in patients on monoamine oxidase inhibitors or tricyclic antidepressants, as vascular effects may be potentiated 5