What is the management approach for a patient with a severe exacerbation of bronchial asthma?

Management of Severe Asthma Exacerbation

For severe asthma exacerbation, immediately administer high-flow oxygen to maintain SaO₂ >90% (>95% in pregnancy/heart disease), nebulized albuterol 2.5-5 mg every 20 minutes for 3 doses, systemic corticosteroids (prednisone 40-60 mg orally or hydrocortisone 200 mg IV), and add ipratropium bromide 0.5 mg to reduce hospitalizations. 1, 2, 3

Initial Assessment and Recognition of Severity

Severe exacerbation is defined by specific clinical criteria that must be rapidly identified:

• Respiratory distress markers: inability to complete sentences in one breath, respiratory rate >25 breaths/min in adults (>60 breaths/min in infants), heart rate >110 beats/min in adults (>140 beats/min in children), use of accessory muscles, and intercostal retractions 4, 1, 3

• Objective measurements: peak expiratory flow (PEF) or FEV₁ <40% of predicted or personal best 1, 2, 3

• Life-threatening features requiring immediate ICU consideration: PEF <33% predicted, silent chest, cyanosis, altered mental status/confusion, feeble respiratory effort, bradycardia, hypotension, exhaustion, coma, or PaCO₂ ≥42 mmHg 4, 1, 3

Immediate Treatment Algorithm (First 60 Minutes)

Step 1: Oxygen Therapy (Initiate Immediately)

• Administer high-flow oxygen via face mask or nasal cannulae to maintain SaO₂ >90% (>95% in pregnant patients or those with heart disease) 4, 1, 2
• Monitor oxygen saturation continuously until clear response to bronchodilator therapy occurs 1, 2

Step 2: Bronchodilator Therapy (Within First 5 Minutes)

• Albuterol (first-line): 2.5-5 mg via oxygen-driven nebulizer OR 4-8 puffs via MDI with spacer, repeated every 20 minutes for 3 doses (total of 3 treatments in first hour) 4, 1, 2, 5
• For severe exacerbations with FEV₁/PEF <40%, consider continuous nebulization at 10-15 mg/hour rather than intermittent dosing 4, 2
• MDI with spacer is equally effective as nebulizer when properly administered with appropriate coaching 4, 6

Step 3: Systemic Corticosteroids (Within First 15-30 Minutes)

• Oral route preferred: Prednisone 40-60 mg in single or divided doses for adults; 1-2 mg/kg/day (maximum 60 mg/day) for children 1, 2, 3
• IV alternative if unable to take oral: Hydrocortisone 200 mg IV, then 200 mg every 6 hours 4, 1
• Early administration (within first hour) significantly reduces hospitalization rates 1, 6

Step 4: Add Ipratropium Bromide (For All Severe Exacerbations)

• Dosing: 0.5 mg via nebulizer OR 8 puffs via MDI every 20 minutes for 3 doses, then as needed 1, 2, 3
• Can be mixed with albuterol in the same nebulizer 4
• Combination therapy reduces hospitalizations, particularly in patients with severe airflow obstruction 1, 3

Reassessment Protocol (After 60-90 Minutes)

• Measure PEF or FEV₁, assess symptoms, vital signs, and oxygen saturation 4, 1, 2
• Response to treatment is a better predictor of hospitalization need than initial severity 4, 1, 2

Good response (discharge candidate):

• PEF ≥70% predicted/personal best, minimal symptoms, SaO₂ stable on room air, patient stable for 30-60 minutes after last bronchodilator 1, 3

Incomplete response (hospital ward admission):

• PEF 40-69% predicted with persistent symptoms despite treatment 1

Poor response (ICU consideration):

• PEF <40% predicted, life-threatening features present, or signs of impending respiratory failure 1, 3

Adjunctive Therapies for Severe/Refractory Cases

Intravenous Magnesium Sulfate

• Indication: Life-threatening exacerbations OR severe exacerbations remaining after 1 hour of intensive conventional treatment with FEV₁/PEF <40% 4, 1, 3
• Dosing: 2 g IV over 20 minutes for adults; 25-75 mg/kg (maximum 2 g) over 20 minutes for children 1, 3
• Significantly increases lung function and decreases hospitalization necessity 1, 6
• Most effective when administered early in treatment course 2

Critical Pitfalls to Avoid

• Never delay corticosteroid administration while "trying bronchodilators first"—they must be given immediately 1
• Never administer sedatives of any kind to patients with acute asthma exacerbation 4, 1, 2
• Do not delay intubation once deemed necessary—it should be performed semi-electively before respiratory arrest occurs 4, 1
• Avoid bolus aminophylline in patients already taking oral theophyllines; methylxanthines are not recommended due to increased side effects without superior efficacy 4, 1
• Do not use aggressive hydration in older children and adults (may be appropriate for infants/young children with dehydration) 4, 1
• Avoid chest physiotherapy, mucolytics, and antibiotics unless strong evidence of bacterial infection (pneumonia/sinusitis) exists 4, 1
• Underestimating severity is common—patients, families, and clinicians frequently fail to recognize dangerous exacerbations due to inadequate objective measurements 1

Recognition of Impending Respiratory Failure

Monitor continuously for warning signs requiring immediate ICU transfer and intubation preparation:

• Inability to speak, drowsiness, confusion, altered mental status 4, 1, 3
• Worsening fatigue, intercostal retraction, feeble respiratory effort 4, 1
• Silent chest (absence of wheezing despite severe distress) 4, 1
• PaCO₂ ≥42 mmHg (normal or elevated CO₂ in breathless patient indicates ventilatory failure) 4, 1
• Bradycardia or hypotension (ominous signs indicating impending respiratory arrest) 1

Note: Tachycardia >110 beats/min indicates severe exacerbation, but beta-agonist therapy will further increase heart rate—this is expected and not a contraindication to treatment 1

Hospital Admission Criteria

Immediate hospital admission required for:

• Any life-threatening features present 1, 3
• Features of severe attack persisting after initial treatment 4, 1
• PEF <50% predicted after 1-2 hours of treatment 1

Lower threshold for admission in:

• Patients presenting afternoon/evening 4, 1
• Recent nocturnal symptoms or recent hospital admission 4, 1
• Previous severe attacks requiring intubation 1
• Poor adherence, psychiatric illness, or concerning social circumstances 4, 1

Ongoing Hospital Management

• Continue oxygen to maintain SaO₂ >90% 1, 3
• Nebulized albuterol every 1-4 hours as needed (or continuous if severe) 4, 1
• Continue systemic corticosteroids: prednisone 30-60 mg daily OR IV hydrocortisone 200 mg every 6 hours 4, 1
• Continue or initiate inhaled corticosteroids during hospitalization 1
• Monitor PEF/FEV₁ and vital signs regularly 1, 3

Discharge Planning

Discharge criteria:

• PEF ≥70% predicted or personal best 1, 3
• Symptoms minimal or absent, oxygen saturation stable on room air 1, 3
• Patient stable for 30-60 minutes after last bronchodilator dose 1, 3

At discharge, ensure:

• Continue oral corticosteroids for 5-10 days (no taper needed for courses <10 days) 1, 2, 3
• Initiate or continue inhaled corticosteroids 1, 3
• Provide written asthma action plan 1, 3
• Verify correct inhaler technique 1
• Arrange follow-up within 1 week with primary care and within 4 weeks with specialist 1
• Consider IM depot corticosteroid injection for patients at high risk of non-adherence 1