What is the management plan for a patient presenting with acute asthma?

Management of Acute Asthma

Immediately administer high-flow oxygen (40-60%) to maintain SaO₂ >92%, nebulized salbutamol 5 mg (or terbutaline 10 mg) via oxygen-driven nebulizer, and systemic corticosteroids (prednisolone 30-60 mg orally or hydrocortisone 200 mg IV) within the first few minutes of presentation. 1

Initial Severity Assessment

Rapidly categorize severity using objective criteria to guide treatment intensity:

Severe Asthma Features:

• Unable to complete sentences in one breath 2, 1
• Respiratory rate >25 breaths/min 2, 1
• Heart rate >110 beats/min 2, 1
• Peak expiratory flow (PEF) <50% of predicted or personal best 2, 1

Life-Threatening Features (requiring immediate ICU consideration):

• PEF <33% of predicted or best 2, 1
• Silent chest on auscultation, cyanosis, or weak respiratory effort 2, 1
• Bradycardia, hypotension, or altered mental status 2, 1
• Exhaustion, confusion, or coma 2
• PaCO₂ ≥42 mmHg or severe hypoxia (PaO₂ <60 mmHg despite oxygen) 2, 1

Critical Pitfall: Patients with severe or life-threatening attacks may not appear distressed initially—the presence of any single life-threatening feature should trigger maximum intensity treatment. 2

Immediate First-Line Treatment (First 5 Minutes)

Administer all three components simultaneously:

1. Oxygen Therapy:

• High-flow oxygen 40-60% via face mask 2, 1
• Target SaO₂ >92% (>95% in pregnant patients or those with cardiac disease) 1
• Important: CO₂ retention is NOT aggravated by oxygen therapy in asthma 2

2. Nebulized Beta-Agonist:

• Salbutamol 5 mg OR terbutaline 10 mg via oxygen-driven nebulizer 2, 1, 3
• Deliver over 5-15 minutes 3
• For children: same dose if weight ≥15 kg; half dose if <15 kg 2

3. Systemic Corticosteroids:

• Prednisolone 30-60 mg orally (adults) 2, 1
• OR hydrocortisone 200 mg IV if unable to take oral medication 2, 1
• For children: prednisolone 1-2 mg/kg (maximum 40 mg) 2, 1
• Critical: Administer immediately—clinical benefits require 6-12 hours to manifest 4

4. Additional Treatment for Life-Threatening Features:

• Add ipratropium 0.5 mg to the nebulized beta-agonist 2, 1
• Give IV aminophylline 250 mg over 20 minutes OR salbutamol/terbutaline 250 µg IV over 10 minutes 2
• Caution: Do NOT give bolus aminophylline to patients already taking oral theophyllines 2
• Obtain chest radiograph to exclude pneumothorax 2

Reassessment at 15-30 Minutes

Measure PEF and reassess clinical status after initial treatment 1:

If Patient is Improving:

• Continue 40-60% oxygen 2
• Continue prednisolone 30-60 mg daily or IV hydrocortisone 200 mg every 6 hours 2
• Nebulized beta-agonist every 4 hours 2

If Patient is NOT Improving:

• Continue oxygen and steroids 2
• Increase nebulized beta-agonist frequency to every 15-30 minutes 2
• Add ipratropium 0.5 mg to nebulizer if not already given, repeat every 6 hours 2
• Consider IV magnesium sulfate 2 g over 20 minutes for severe exacerbations not responding after 1 hour 1, 5

If Patient is Still NOT Improving:

• Aminophylline infusion: 750 mg/24 hours (small patient) to 1500 mg/24 hours (large patient) 2
• Monitor blood concentrations if continued >24 hours 2
• Salbutamol or terbutaline infusion as alternative to aminophylline 2

Critical Pitfalls to Avoid

Never administer sedatives of any kind during an acute asthma exacerbation—this can precipitate respiratory failure and increases mortality risk. 2, 1, 3

Do not underestimate severity based on initial presentation—patients can deteriorate rapidly and may not exhibit distress despite severe obstruction. 2, 1

Do not delay corticosteroids—waiting for response to bronchodilators before giving steroids is a common error that worsens outcomes. 1, 4

Monitoring During Treatment

Continuous monitoring includes:

• Pulse oximetry to maintain SaO₂ >92% 1
• PEF measurement before and after each nebulization 1
• Respiratory rate and heart rate every 15-30 minutes initially 1
• Arterial blood gas if PEF <25% predicted, severe distress, or suspected hypoventilation 1

Criteria for Hospital Admission

Admit to hospital if:

• Any life-threatening features present 2
• Features of severe asthma persist after initial treatment, especially PEF <33% 2
• PEF remains <50-75% after treatment 2
• Recent nocturnal symptoms or previous severe attacks 1

ICU Transfer Criteria

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

• Deteriorating PEF despite maximal therapy 2
• Worsening or persistent hypoxia or rising PaCO₂ 2
• Exhaustion, feeble respirations, confusion, or drowsiness 2, 1
• Inability to speak or worsening mental status 1

Intubation Consideration: When intubation becomes necessary, it should not be attempted until the most expert available physician (ideally an anesthetist) is present. 1

Discharge Criteria

Patients may be discharged when:

• Stable on discharge medication for 24 hours 2
• PEF >75% of predicted or best 2
• PEF diurnal variability <25% 2
• Inhaler technique checked and recorded 2

At discharge, ensure patient has:

• Own PEF meter and written self-management plan 2
• GP follow-up arranged within 1 week 2
• Respiratory clinic follow-up within 4 weeks 2
• Step-up in maintenance therapy considered 5