What is the management for acute exacerbation of bronchial asthma?

Management of Acute Asthma Exacerbation

Immediately administer high-flow oxygen to maintain SaO₂ >90% (>95% in pregnant patients or those with heart disease), nebulized albuterol 2.5-5 mg every 20 minutes for 3 doses, and oral prednisolone 40-60 mg or IV hydrocortisone 200 mg within the first hour of presentation. 1, 2

Initial Assessment and Severity Classification

Assess severity immediately using objective measurements, as failure to do so is a common cause of preventable asthma deaths 3:

Severe Exacerbation Features:

• Cannot complete sentences in one breath 3, 1
• Respiratory rate >25 breaths/min 3, 1
• Heart rate >110 beats/min 3, 1
• Peak expiratory flow (PEF) <50% of predicted or personal best 3, 1

Life-Threatening Features (requiring immediate ICU consideration):

• PEF <33% of predicted or personal best 3, 1
• Silent chest, cyanosis, or feeble respiratory effort 3, 1
• Altered mental status, confusion, drowsiness, or coma 3, 1
• Normal or elevated PaCO₂ (>42 mmHg) in a breathless patient 1, 2
• Severe hypoxia (PaO₂ <8 kPa or 60 mmHg) 3

Immediate Treatment Protocol (First Hour)

Oxygen Therapy

Administer high-flow oxygen at 40-60% immediately via face mask or nasal cannula to maintain SaO₂ >90% (>95% in pregnant patients or those with cardiac disease) 3, 1. CO₂ retention is not aggravated by oxygen therapy in asthma, so do not withhold oxygen 3.

Bronchodilator Therapy

Administer albuterol 2.5-5 mg via nebulizer or 4-8 puffs via MDI with spacer every 20 minutes for 3 doses 1, 2, 4. Both delivery methods are equally effective when properly administered 1, 5. For severe exacerbations with FEV₁ or PEF <40% predicted, consider continuous nebulization 6, 2.

Systemic Corticosteroids

Administer prednisolone 30-60 mg orally or hydrocortisone 200 mg IV immediately 3, 1. Early administration within the first hour significantly reduces hospitalization rates, particularly in severe exacerbations 1, 7. Oral administration is as effective as IV and less invasive 1, 2.

Adjunctive Ipratropium Bromide

Add ipratropium bromide 0.5 mg to nebulizer or 8 puffs via MDI every 20 minutes for 3 doses for all moderate-to-severe exacerbations 1, 2, 8. This combination reduces hospitalizations by 49% compared to albuterol alone, particularly in patients with FEV₁ ≤30% predicted 8.

Reassessment at 15-30 Minutes

Measure PEF or FEV₁, assess symptoms, vital signs, and oxygen saturation 3, 1, 2. Response to treatment is a better predictor of hospitalization need than initial severity 1, 2.

If Patient is Improving:

• Continue oxygen 40-60% 3
• Continue prednisolone 30-60 mg daily or IV hydrocortisone 200 mg every 6 hours 3
• Reduce nebulized albuterol to every 4-6 hours 3, 6
• Continue monitoring PEF before and after each treatment 3

If Patient is NOT Improving After 15-30 Minutes:

• Continue oxygen and steroids 3
• Increase nebulized albuterol frequency to every 15-30 minutes 3
• Continue ipratropium 0.5 mg every 6 hours until improvement starts 3
• Consider continuous albuterol nebulization for severe cases 6, 2

Severe Refractory Exacerbations

For life-threatening features or severe exacerbations not responding after 1 hour of intensive treatment, administer IV magnesium sulfate 2 g over 20 minutes 1, 2, 7. This significantly increases lung function and decreases hospitalization necessity, particularly in children and patients with severe obstruction 7.

Do NOT administer:

• Sedatives of any kind 3, 1
• Methylxanthines (theophylline) due to increased side effects without superior efficacy 1
• Antibiotics unless strong evidence of bacterial infection (pneumonia, sinusitis) 1, 2
• Aggressive hydration in older children and adults 1

Monitoring Parameters

• Repeat PEF measurement 15-30 minutes after starting treatment 3, 1
• Continuous pulse oximetry until clear response to bronchodilator therapy 1, 6
• Repeat arterial blood gas within 2 hours if initial PaO₂ <8 kPa (60 mmHg), initial PaCO₂ was normal or raised, or patient deteriorates 3
• Chart PEF before and after each bronchodilator treatment 3

ICU Transfer Criteria

Transfer to ICU accompanied by a physician prepared to intubate if: 3

• Deteriorating PEF despite treatment
• Worsening or persistent hypoxia or hypercapnia
• Exhaustion, feeble respirations, or poor respiratory effort
• Confusion, drowsiness, coma, or respiratory arrest

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

Hospital Admission Criteria

Admit if: 3, 1

• Any life-threatening features present
• Features of acute severe asthma persist after initial treatment
• PEF <33% predicted after treatment

Lower threshold for admission if: 3

• Attack occurs in afternoon or evening
• Recent nocturnal symptoms or hospital admission
• Previous severe attacks
• Poor social circumstances or inability to assess own condition

Discharge Criteria

Patients may be discharged when: 3, 1, 2

• PEF >75% of predicted or personal best 3, 1
• PEF diurnal variability <25% 3
• Symptoms minimal or absent 1
• Stable for 30-60 minutes after last bronchodilator dose 1
• Oxygen saturation stable on room air 1

At discharge, ensure: 3, 1

• Patient on discharge medication for 24 hours with documented inhaler technique 3
• Oral corticosteroids prescribed for 5-10 days (no taper needed for courses <10 days) 1, 2
• Inhaled corticosteroids initiated or continued 3, 1
• Written asthma action plan provided 1
• Peak flow meter provided if appropriate 3
• GP follow-up arranged within 1 week 3
• Respiratory clinic follow-up within 4 weeks 3

Pediatric Considerations

For children, use weight-based dosing: 3, 2

• Prednisolone 1-2 mg/kg/day (maximum 40-60 mg) 3
• Albuterol 5 mg via nebulizer (half doses in very young children) 3
• Ipratropium 100-250 mcg nebulized every 6 hours 3
• If life-threatening features present, give IV aminophylline 5 mg/kg over 20 minutes followed by 1 mg/kg/h maintenance infusion (omit loading dose if already receiving oral theophyllines) 3

Blood gas estimations are rarely helpful in deciding initial management in children 3.

Common Pitfalls to Avoid

• Underestimating severity by failing to obtain objective measurements (PEF or FEV₁) is a leading cause of preventable asthma deaths 3, 1
• Delaying or underusing corticosteroids significantly increases hospitalization risk 3, 7
• Using regular scheduled albuterol instead of as-needed dosing after initial stabilization increases total drug exposure without improving outcomes 9
• Administering sedatives can precipitate respiratory failure 3, 1
• Failing to arrange adequate follow-up within 1 week increases relapse risk 3