What is the recommended assessment and management of an acute asthma exacerbation?

Acute Asthma Exacerbation Management

Immediately administer three simultaneous therapies within the first 15–30 minutes: high-dose inhaled β₂-agonist (albuterol 5 mg nebulized or 4–8 puffs via MDI with spacer), systemic corticosteroids (prednisolone 40–60 mg orally or hydrocortisone 200 mg IV), and supplemental oxygen (40–60% via face mask targeting SaO₂ >90%). 1

Initial Severity Assessment (First 5–15 Minutes)

• Obtain objective measurements (PEF or FEV₁) before treatment—failure to do so is the most common preventable cause of asthma deaths. 1

• Severe exacerbation features 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, 2

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

• High-risk patients warrant heightened vigilance: prior intubation/ICU admission for asthma, ≥2 hospitalizations or ≥3 emergency department visits in the past year, use of >2 short-acting β₂-agonist canisters per month, recent hospitalization/ED visit within the past month, or poor perception of symptom severity. 3, 1

Immediate Treatment Protocol (First Hour)

Bronchodilator Therapy

• Administer albuterol 5 mg via oxygen-driven nebulizer every 20 minutes for three consecutive doses (or 4–8 puffs from MDI with spacer every 20 minutes). 1, 2

• For pediatric patients weighing <15 kg, use half the adult dose (≈2.5 mg albuterol). 1

• Add ipratropium bromide 0.5 mg to each nebulized treatment (or 8 puffs via MDI) for all moderate-to-severe exacerbations—this combination reduces the risk of hospitalization. 1, 4

Systemic Corticosteroids (Must Be Given Immediately)

• Adults: prednisolone 40–60 mg orally or IV hydrocortisone 200 mg. 1, 2

• Children: prednisolone 1–2 mg/kg (maximum 40–60 mg). 1

• Oral administration is as effective as IV and is strongly preferred when the patient can tolerate it. 1

• Do not postpone corticosteroid administration while "trying bronchodilators first"—clinical benefit requires a minimum of 6–12 hours, making early delivery critical. 1, 5

Oxygen Therapy

• Deliver 40–60% oxygen via face mask or nasal cannula to maintain SaO₂ >90% (target >95% in pregnant patients or those with cardiac disease). 1, 6

Reassessment After Initial Treatment (15–30 Minutes)

• Re-measure PEF/FEV₁ and reassess symptoms, vital signs, and oxygen saturation to guide next steps. 1

Good Response (PEF >75% Predicted)

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

Incomplete Response (PEF 50–75% Predicted)

• Continue nebulized β₂-agonist every 4–6 hours and maintain oral corticosteroids; consider hospital admission if severe features persist. 1

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

• Increase nebulized β₂-agonist frequency to every 15–30 minutes and continue ipratropium bromide 0.5 mg every 20 minutes for additional doses; arrange immediate hospital admission. 1

Adjunctive Therapies for Refractory Cases (After 1 Hour)

• Intravenous magnesium sulfate 2 g infused over 20 minutes for severe exacerbations with PEF <40% after initial treatment or any life-threatening feature. 1, 4, 7

• IV aminophylline 250 mg over 20 minutes may be used for life-threatening features, but never give a bolus aminophylline to patients already receiving oral theophylline due to toxicity risk. 1

• Continuous nebulized albuterol can be considered for markedly severe cases. 4

Hospital Admission Criteria

• Admit immediately for any life-threatening feature (PEF <33%, silent chest, altered mental status, PaCO₂ ≥42 mmHg) or for severe attack features persisting after initial therapy. 1

• Admit when PEF remains <50% predicted after 1–2 hours of intensive treatment. 1

• Lower the threshold for admission in the evening/overnight, with recent nocturnal symptoms, prior intubation, ≥2 hospitalizations or ≥3 ED visits in the past year, or poor social circumstances limiting reliable monitoring. 3, 1

ICU Transfer Criteria

• Transfer to intensive care when deteriorating PEF despite ongoing therapy, worsening or persistent hypoxia/hypercapnia, exhaustion, feeble respirations, altered mental status, coma, or respiratory arrest occurs. 1

• A physician prepared to intubate should be immediately available when any of these features are present. 1

Critical Pitfalls to Avoid

• Never administer sedatives of any kind—they are absolutely contraindicated and potentially fatal. 1

• Do not rely solely on subjective assessment—objective PEF/FEV₁ measurement is mandatory. 1, 2

• Do not delay corticosteroids while attempting bronchodilator therapy alone. 1

• Normal SpO₂ should not be assumed to exclude severe asthma, especially in patients on beta-blockers. 6

• Physicians' subjective assessments of airway obstruction are often inaccurate—always use objective measures. 5

Discharge Planning (After Stabilization)

• Discharge when PEF ≥70–75% of predicted or personal best, symptoms are minimal or absent, oxygen saturation is stable on room air, and the patient remains stable for 30–60 minutes after the last bronchodilator dose. 1, 7

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

• Initiate or continue inhaled corticosteroids—doubling the dose during an exacerbation does not improve outcomes and is ineffective. 1

• Verify and document correct inhaler technique before discharge. 1

• Provide a written asthma action plan with PEF zones and supply a peak flow meter if needed. 1, 7

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