What is the recommended immediate treatment for an acute asthma exacerbation?

Immediate Treatment for Acute Asthma Exacerbation

Administer high-dose inhaled short-acting β₂-agonist (albuterol 2.5–5 mg via nebulizer or 4–8 puffs via MDI with spacer every 20 minutes for three doses), systemic corticosteroids (prednisone 40–60 mg orally or IV hydrocortisone 200 mg), and supplemental oxygen to maintain SpO₂ >90% (>95% in pregnancy or cardiac disease) within the first 15–30 minutes. 1

Initial Assessment & Severity Recognition (First 5–15 Minutes)

• Measure peak expiratory flow (PEF) or FEV₁ before treatment to objectively gauge severity—subjective assessment alone frequently underestimates dangerous exacerbations. 1

• Severe exacerbation indicators include inability to speak full sentences in one breath, respiratory rate >25 breaths/min, heart rate >110 beats/min, and PEF <50% of predicted or personal best. 1

• Life-threatening features requiring immediate ICU consideration: PEF <33% predicted, silent chest, cyanosis or feeble respiratory effort, altered mental status (confusion, drowsiness, exhaustion), bradycardia or hypotension, and normal or elevated PaCO₂ ≥42 mmHg in a breathless patient. 1

First-Line Pharmacologic Therapy (First Hour)

Bronchodilator Administration

• Albuterol 2.5–5 mg via oxygen-driven nebulizer OR 4–8 puffs via MDI with spacer every 20 minutes for three doses (at 0,20,40 minutes). 1, 2

• MDI with spacer is equally effective to nebulization when properly administered and may result in lower admission rates with fewer cardiovascular side effects. 1, 3

• For children weighing <15 kg, use half-dose (2.5 mg nebulized or 2–4 puffs MDI). 1

Systemic Corticosteroids (Critical—Do Not Delay)

• Give systemic corticosteroids immediately upon recognition—do not delay while "trying bronchodilators first," as clinical benefits require 6–12 hours minimum to manifest. 1

• Oral prednisone 40–60 mg for adults (single or divided dose) OR prednisolone 1–2 mg/kg (maximum 60 mg) for children. 1

• Oral administration is as effective as intravenous and is strongly preferred unless the patient is vomiting or critically ill. 1

• IV hydrocortisone 200 mg if unable to tolerate oral intake. 1

Oxygen Therapy

• Administer supplemental oxygen via nasal cannula or face mask to maintain SpO₂ >90% (target >95% in pregnant patients or those with cardiac disease). 1

Reassessment Protocol (15–30 Minutes After First Dose)

• Repeat PEF measurement 15–30 minutes after the first bronchodilator dose to guide subsequent management—response to treatment is a better predictor of hospitalization need than initial severity. 1

Good Response (PEF >75% Predicted)

• Continue usual maintenance therapy with modest step-up, monitor PEF trends, and arrange follow-up within 48 hours. 1

Incomplete Response (PEF 50–75% Predicted)

• Continue albuterol every 4–6 hours, maintain oral corticosteroids for 5–10 days (no taper needed for courses <10 days), and consider hospital admission if severe features persist. 1

Poor Response (PEF <50% Predicted or Persistent Severe Features)

• Increase albuterol frequency to every 15–30 minutes OR consider continuous nebulization (10–15 mg/hour for adults). 1

• Add ipratropium bromide 0.5 mg to nebulizer every 20 minutes for three doses, then every 4–6 hours—the combination reduces hospitalizations, particularly in severe airflow obstruction. 1

• Arrange immediate hospital admission. 1

Escalation for Severe/Refractory Cases (After 1 Hour of Intensive Therapy)

• Intravenous magnesium sulfate 2 g over 20 minutes for adults (25–75 mg/kg up to 2 g for children) for life-threatening features or severe exacerbations not responding after 1 hour. 1

• Consider IV aminophylline 250 mg over 20 minutes for refractory severe asthma, but never give a bolus to patients already on oral theophylline due to toxicity risk. 1

• Continuous pulse oximetry aiming for SaO₂ >92% and repeat PEF measurements before and after each bronchodilator dose. 1

Hospital Admission Criteria

• Immediate admission required for any life-threatening feature (PEF <33%, silent chest, altered mental status, respiratory acidosis). 1

• Admit if severe attack features persist after initial treatment or PEF remains <50% after 1–2 hours of intensive therapy. 1

• Lower threshold for admission if presentation occurs in afternoon/evening, recent nocturnal symptoms, previous severe attacks requiring intubation/ICU, ≥2 hospitalizations or ≥3 ED visits in past year, or poor social circumstances. 1

ICU Transfer Criteria

• Deteriorating PEF despite therapy, worsening or persistent hypoxia/hypercapnia, exhaustion or altered consciousness, inability to speak, worsening fatigue, and PaCO₂ ≥42 mmHg. 1

• Do not delay intubation once deemed necessary—it should be performed semi-electively before respiratory arrest occurs. 1

Critical Pitfalls to Avoid

• Never administer sedatives of any kind—they are absolutely contraindicated in acute asthma and can be fatal. 1

• Do not delay corticosteroids while "trying bronchodilators first"—both must be given immediately. 1

• Always obtain objective PEF or FEV₁ measurement—failure to do so is the most common preventable cause of asthma-related death. 1

• Never give aminophylline bolus to patients already on oral theophylline. 1

• Avoid antibiotics unless strong evidence of bacterial infection (e.g., pneumonia, sinusitis)—viral infections are the most common trigger. 1

• Avoid aggressive hydration in older children and adults, methylxanthines, chest physiotherapy, and mucolytics. 1

Discharge Criteria & Planning

• PEF ≥70% of predicted or personal best, minimal or absent symptoms, stable oxygen saturation on room air, and clinical stability for 30–60 minutes after last bronchodilator dose. 1

• Continue oral corticosteroids for 5–10 days (no taper needed for courses <10 days). 1

• Initiate or continue inhaled corticosteroids immediately. 1

• Verify correct inhaler technique and provide written asthma action plan with PEF zones. 1

• Arrange primary care follow-up within 1 week and respiratory specialist follow-up within 4 weeks. 1