What is the initial management for an inpatient with severe bronchial asthma exacerbation?

Inpatient Management of Severe Bronchial Asthma Exacerbation

Immediately administer high-dose inhaled beta-agonists (salbutamol 5 mg or terbutaline 10 mg via oxygen-driven nebulizer), systemic corticosteroids (prednisolone 30-60 mg orally or hydrocortisone 200 mg IV), and supplemental oxygen to maintain SaO₂ >90% (>95% in pregnant patients or those with heart disease) as the cornerstone of initial management. 1, 2

Immediate Assessment and Recognition of Severity

Upon hospital arrival, rapidly identify severity markers to guide treatment intensity:

Severe Asthma Features:

• Inability to complete sentences in one breath 1
• Respiratory rate >25 breaths/min 1
• Heart rate >110 beats/min 1
• Peak expiratory flow (PEF) <50% of predicted or personal best 1

Life-Threatening Features (requiring ICU consideration):

• PEF <33% of predicted or personal best 1
• Silent chest, cyanosis, or feeble respiratory effort 1
• Bradycardia or hypotension 1
• Exhaustion, confusion, or coma 1
• Normal or elevated PaCO₂ (≥42 mmHg) in a breathless patient 1, 2
• Severe hypoxia (PaO₂ <8 kPa) despite oxygen therapy 1

Critical Pitfall: The severity of asthma attacks is frequently underestimated by patients, families, and clinicians due to failure to obtain objective measurements—always measure PEF and obtain arterial blood gases in hospitalized patients. 1, 2

Initial Treatment Protocol (First Hour)

Primary Bronchodilator Therapy:

• Administer salbutamol 5 mg or terbutaline 10 mg via oxygen-driven nebulizer every 20 minutes for 3 doses 1, 2
• Alternative: 4-12 puffs of metered-dose inhaler with spacer every 20 minutes for 3 doses if nebulizer unavailable 1, 2
• For severe/refractory cases, consider continuous nebulization rather than intermittent dosing 2, 3

Systemic Corticosteroids (administer immediately, not after "trying bronchodilators first"):

• Prednisolone 30-60 mg orally (preferred route) 1, 2
• OR hydrocortisone 200 mg IV if unable to take oral medication 1, 2
• Oral administration is as effective as IV and less invasive 2

Oxygen Therapy:

• Administer 40-60% oxygen via mask or nasal cannula 1, 2
• Target SaO₂ >90% (>95% in pregnant patients or those with cardiac disease) 2
• Use oxygen to drive nebulizers 1

Additional Therapies for Severe Exacerbations

If Life-Threatening Features Present:

Add Ipratropium Bromide:

• 0.5 mg via nebulizer mixed with beta-agonist every 20 minutes for 3 doses, then as needed 1, 2
• This combination reduces hospitalizations, particularly in patients with severe airflow obstruction 2

Consider IV Magnesium Sulfate:

• 2 g IV over 20 minutes for adults 2, 3
• Indicated for severe exacerbations with PEF <40% after initial treatment or life-threatening features 2, 3
• Significantly improves lung function and decreases hospitalization necessity 2

Parenteral Beta-Agonists (if inadequate response):

• Aminophylline 250 mg IV over 20 minutes 1
• OR salbutamol/terbutaline 250 mcg IV over 10 minutes 1
• Critical Warning: Do NOT give bolus aminophylline to patients already taking oral theophyllines 1, 2

Monitoring Protocol

Reassess at 15-30 Minutes After Initial Treatment:

• Measure PEF or FEV₁ 2
• Assess symptoms, vital signs, and oxygen saturation 2
• Evaluate speech ability, respiratory effort, and mental status 1

Ongoing Monitoring:

• Continuous oxygen saturation monitoring 2
• Serial PEF measurements after each treatment 2
• Arterial blood gases in all hospitalized patients with severe asthma 1
• Monitor for hypokalemia with repeated beta-agonist dosing (typically asymptomatic 20-25% decline) 4

Further Investigations

Obtain chest radiograph to exclude:

• Pneumothorax 1, 3
• Consolidation/pneumonia 1, 3
• Pulmonary edema 1, 3

Laboratory studies:

• Plasma electrolytes and urea concentrations 1
• Complete blood count 1
• Electrocardiography in older patients 1

Treatment Response Categories and Next Steps

Good Response (PEF ≥70% predicted, minimal symptoms):

• Continue nebulized beta-agonist every 4-6 hours 1
• Continue prednisolone 30-60 mg daily or IV hydrocortisone 200 mg every 6 hours 1
• Observe for 30-60 minutes after last bronchodilator dose before considering discharge 2

Incomplete Response (PEF 40-69% predicted, persistent symptoms):

• Continue intensive treatment 2
• Admit to hospital ward 2
• Continue frequent nebulized bronchodilators 1
• Continue systemic corticosteroids 1

Poor Response (PEF <40% predicted after 1-2 hours):

• Admit to hospital, consider ICU admission 2
• Escalate to continuous nebulization 3
• Ensure magnesium sulfate has been administered 3
• Consider parenteral beta-agonists 3

ICU Admission Criteria

Transfer to ICU if:

• PEF <33% predicted after treatment 2
• Silent chest with minimal air movement 2
• Altered mental status, drowsiness, or confusion 2, 3
• Minimal relief from frequent short-acting beta-agonists 2
• PaCO₂ ≥42 mmHg (indicates impending respiratory failure) 2
• Worsening fatigue or inability to speak 2

Critical Pitfalls to Avoid

Never administer sedatives of any kind to patients with acute asthma 1, 2

Avoid methylxanthines (theophylline) due to increased side effects without superior efficacy 2

Do not delay corticosteroid administration—give immediately, not after "trying bronchodilators first" 2

Do not underestimate afternoon/evening presentations—these warrant lower threshold for admission 1

Avoid aggressive hydration in older children and adults (may be appropriate for infants/young children only) 2

Do not delay intubation once deemed necessary—perform semi-electively before respiratory arrest 2

Ongoing Hospital Management

Continue Treatment:

• Nebulized salbutamol 5 mg or terbutaline 10 mg every 4-6 hours (or more frequently if needed) 1
• Prednisolone 30-60 mg daily or hydrocortisone 200 mg IV every 6 hours 1
• Oxygen to maintain SaO₂ >90% 1
• Initiate or continue inhaled corticosteroids during hospitalization 2

Duration of Systemic Corticosteroids:

• 5-10 days for outpatient "burst" therapy 2
• No taper necessary for courses <10 days 2

Discharge Criteria

Patient may be discharged when:

• PEF ≥70% of predicted or personal best 2
• Symptoms minimal or absent 2
• Oxygen saturation stable on room air 2
• Patient stable for 30-60 minutes after last bronchodilator dose 2

At Discharge:

• Continue oral corticosteroids for 5-10 days (no taper needed) 2
• Initiate or increase inhaled corticosteroids 2
• Verify inhaler technique 2
• Provide written asthma action plan 2
• Arrange follow-up within 1 week with primary care 2
• Arrange specialist follow-up within 4 weeks 2