What is the initial management for acute asthma exacerbation?

Initial Management of Acute Asthma Exacerbation

The initial management for acute asthma exacerbation should focus on high-flow oxygen administration, nebulized beta-agonists, and systemic corticosteroids to rapidly address the underlying bronchospasm and improve oxygenation. 1, 2

Assessment of Severity

• Recognize features of severe asthma exacerbation, including inability to complete sentences in one breath, respiratory rate >25 breaths/min, peak expiratory flow (PEF) <50% of predicted/best, and heart rate >110 beats/min 1
• Life-threatening features include PEF <33% of predicted/best, silent chest, cyanosis, feeble respiratory effort, bradycardia, hypotension, exhaustion, confusion, or coma 1
• Arterial blood gas markers of severe, life-threatening attack include normal/high PaCO₂ in a breathless patient, severe hypoxia (PaO₂ <8 kPa), and low pH 1

Immediate Management Algorithm

Step 1: Oxygen Therapy

• Administer oxygen through nasal cannulae or mask to maintain oxygen saturation (SaO₂) >90% (>95% in pregnant patients or those with heart disease) 1
• Monitor oxygen saturation continuously until a clear response to bronchodilator therapy has occurred 1

Step 2: Bronchodilator Therapy

• Administer albuterol via nebulizer (2.5-5 mg every 20 minutes for 3 doses, then 2.5-10 mg every 1-4 hours as needed) or metered-dose inhaler (MDI) with spacer (4-8 puffs every 20 minutes for up to 3 doses) 1, 3
• For children weighing at least 15 kg, use 2.5 mg of albuterol administered three to four times daily by nebulization 3
• For children weighing <15 kg, use albuterol inhalation solution 0.5% instead of 0.083% 3

Step 3: Systemic Corticosteroids

• Administer systemic corticosteroids early: oral prednisone 40-60 mg in single or divided doses 1
• Alternative: intravenous hydrocortisone 200 mg immediately 1
• Oral administration is as effective as intravenous administration and less invasive 1

Adjunctive Therapies

• Add ipratropium bromide to beta-agonist therapy for severe exacerbations: 0.5 mg every 20 minutes for 3 doses, then as needed 1
• Consider magnesium sulfate for patients with severe refractory asthma: 2 g IV administered over 20 minutes 1
• Antibiotics are not generally recommended unless there is strong evidence of bacterial infection (e.g., pneumonia or sinusitis) 1

Monitoring and Reassessment

• Reassess the patient 15-30 minutes after starting treatment 1
• Measure PEF or FEV₁ before and after treatments 1
• Monitor symptoms and vital signs 1
• Response to treatment is a better predictor of hospitalization need than initial severity 1

Criteria for Hospital Admission

• Any life-threatening features 1
• Any features of a severe attack that persist after initial treatment 1
• PEF 15-30 minutes after nebulization <33% of predicted or best value 1
• Lower threshold for admission is appropriate in patients seen in the afternoon/evening, with recent onset of nocturnal symptoms, previous severe attacks, poor assessment of severity, or concerning social circumstances 4

Common Pitfalls and Caveats

• The severity of an asthma attack is often underestimated by patients, relatives, and doctors due to failure to make objective measurements 1
• Do not administer sedatives of any kind to patients with acute asthma exacerbation 1
• Do not delay administration of systemic corticosteroids as clinical benefits may not occur for 6-12 hours 5
• Regular use of short-acting beta-agonists can lead to reduced effectiveness, highlighting the need for careful management 1
• For patients with severe refractory asthma, consider additional treatments such as intravenous magnesium, heliox, and other therapies before resorting to intubation 1

Signs of Impending Respiratory Failure

• Monitor for inability to speak, altered mental status, intercostal retraction, worsening fatigue, and PaCO2 ≥42 mm Hg 1
• Do not delay intubation once it is deemed necessary 1
• Factors associated with increased likelihood of intubation include exhaustion despite maximal therapy, deteriorating mental status, refractory hypoxemia, increasing hypercapnia, hemodynamic instability, and impending coma or apnea 6