What is the continued dose protocol for a patient with an asthma exacerbation using a 90mcg (microgram) metered dose inhaler (MDI) with a spacer?

Albuterol MDI Dosing Protocol for Asthma Exacerbations

For an acute asthma exacerbation using a 90mcg albuterol MDI with spacer, administer 4-8 puffs every 20 minutes for 3 doses, then continue with 4-8 puffs every 1-4 hours as needed based on severity and response. 1, 2

Initial Treatment Phase (First Hour)

• Deliver 4-8 puffs rapidly in succession using the spacer device (total dose 360-720 mcg per treatment session) 2
• Repeat this complete treatment session every 20 minutes for a total of 3 doses 1, 2
• The 20-minute interval refers to time between complete treatment sessions, not between individual puffs—administer all 4-8 puffs within 1-2 minutes 2
• For children under 4 years, use a valved holding chamber with face mask 1

Maintenance Phase (After Initial 3 Doses)

• Continue with 4-8 puffs every 1-4 hours as needed based on clinical response 1, 2, 3
• Patients who show poor initial response (<15% improvement in FEV1 at 15 minutes) benefit most from continued 30-minute interval treatments 4
• Patients with good initial response (>15% improvement) can be safely treated at 60-minute intervals with equivalent outcomes 4

Critical Adjunctive Therapy

• Add systemic corticosteroids early (prednisone 40-60 mg daily for adults, or 1-2 mg/kg/day [maximum 60 mg/day] for children) for 3-10 days 1, 2
• Consider adding ipratropium bromide for moderate-to-severe exacerbations: 8 puffs every 20 minutes for adults (4-8 puffs for children) for up to 3 hours 1, 2
• The combination of ipratropium and albuterol significantly reduces hospitalization rates in severe exacerbations 2

Evidence Supporting MDI with Spacer

• MDI with spacer is as effective as nebulized therapy in mild-to-moderate exacerbations when proper technique is used 2, 5, 6
• Meta-analysis demonstrates MDI with spacer produces significantly greater reduction in pulmonary index scores and smaller increases in heart rate compared to nebulization 5
• Adult ED studies show MDI/spacer achieves greater peak flow improvement (126.8 vs 111.9 L/min), shorter ED time, and lower relapse rates compared to nebulization 6

Monitoring Requirements

• Watch for adverse effects including tachycardia, tremor, and hypokalemia, particularly with frequent dosing 2, 3
• Monitor for signs of impending respiratory failure: inability to speak, altered mental status, intercostal retractions, worsening fatigue 2
• Response to treatment is a better predictor of hospitalization need than initial severity 2

Common Pitfalls to Avoid

• Do not delay treatment by spacing individual puffs excessively—rapid sequential dosing (all 4-8 puffs within 1-2 minutes) is specifically designed to deliver maximal bronchodilator effect when airways are most constricted 2
• Do not continue ipratropium once patient is hospitalized, as additional benefit has not been demonstrated 1
• Ensure proper spacer technique with adequate seal and single actuation per inhalation 1, 2