What is the best course of treatment for a 14-year-old patient with an asthma exacerbation, presenting with tachycardia, hyperthermia, and hypoxemia?

Treatment of Asthma Exacerbation in a 14-Year-Old with Tachycardia, Hyperthermia, and Hypoxemia

Immediately administer high-flow oxygen (40-60%) via face mask, nebulized salbutamol 5 mg (or terbutaline 10 mg) via oxygen-driven nebulizer, and systemic corticosteroids (prednisolone 30-60 mg orally OR intravenous hydrocortisone 200 mg), then reassess in 15-30 minutes to determine if escalation to life-threatening protocol is needed. 1, 2

Initial Severity Assessment

The presenting features of tachycardia and hypoxemia indicate at minimum an acute severe asthma exacerbation. 1

Key severity markers to assess immediately:

• Ability to speak in complete sentences (inability = severe) 1
• Respiratory rate (>25 breaths/min = severe) 1, 2
• Heart rate (>110 beats/min = severe) 1, 2
• Peak expiratory flow (PEF) if obtainable (<50% predicted = severe; <33% = life-threatening) 1
• Oxygen saturation (maintain SpO2 >92%) 1, 3

Life-threatening features that would escalate treatment include: silent chest, cyanosis, feeble respiratory effort, bradycardia, hypotension, exhaustion, confusion, or coma. 1, 2

Immediate Treatment Protocol

First-Line Therapy (All Patients)

1. High-flow oxygen 40-60% via face mask to maintain SpO2 >92% 1, 2

   • Titrated oxygen is preferred over high-concentration oxygen to avoid hypercapnia (high-concentration oxygen increases PaCO2 ≥4 mmHg in 44% of severe asthma patients) 4
   • Target SpO2 93-95% to balance hypoxemia correction without inducing hypercarbia 4

2. Nebulized beta-agonist via oxygen-driven nebulizer 1, 2

   • Salbutamol 5 mg OR terbutaline 10 mg 1
   • For a 14-year-old, use full adult doses (not the reduced pediatric doses used in very young children) 1

3. Systemic corticosteroids 1, 2

   • Oral prednisolone 30-60 mg if patient can swallow 1
   • OR intravenous hydrocortisone 200 mg if vomiting or unable to take oral medication 1, 2
   • Corticosteroids are the only effective treatment for the inflammatory component and take 6-12 hours to manifest effects 2

If Life-Threatening Features Present

Add immediately:

• Ipratropium bromide 100 mcg nebulized (repeat every 6 hours) 1
• Intravenous aminophylline: 5 mg/kg loading dose over 20 minutes, followed by 1 mg/kg/hour maintenance infusion 1
  • Omit loading dose if patient already receiving oral theophyllines 1

Reassessment at 15-30 Minutes

Measure and record PEF and clinical response. 1, 2

If Patient is Improving:

• Continue high-flow oxygen 1
• Continue prednisolone 1-2 mg/kg daily (maximum 40 mg for pediatrics) 1
• Nebulized beta-agonist every 4 hours 1

If Patient is NOT Improving:

• Continue oxygen and steroids 1
• Increase nebulized beta-agonist frequency to every 30 minutes (up to every 15 minutes if needed) 1
• Add ipratropium to nebulizer if not already given, repeat 6-hourly 1
• Consider aminophylline or parenteral beta-agonist 1, 2

Ongoing Monitoring

• Chart PEF before and after each beta-agonist dose, minimum 4 times daily 1
• Continuous pulse oximetry to maintain SpO2 >92% 1
• Vital signs including heart rate, respiratory rate, blood pressure 1
• Clinical assessment for exhaustion, confusion, drowsiness, or deteriorating respiratory effort 1

Criteria for ICU Transfer

Transfer to intensive care unit accompanied by a doctor prepared to intubate if: 1, 2

• Deteriorating PEF or worsening exhaustion 1, 2
• Feeble respirations 1, 2
• Persistent hypoxia (PaO2 <8 kPa despite 60% oxygen) or hypercapnia (PaCO2 >6 kPa) 1, 2
• Confusion, drowsiness, coma, or respiratory arrest 1

Additional Investigations

Arrange urgently:

• Chest radiography to exclude pneumothorax, consolidation, or pulmonary oedema 1
• Arterial blood gas if life-threatening features present 1
• Plasma electrolytes and urea (beta-agonists can cause hypokalemia) 1, 5
• Electrocardiogram (tachycardia and hypoxemia can cause myocardial ischemia even with normal coronaries) 6

Critical Pitfalls to Avoid

• Never give sedation - it is absolutely contraindicated in acute asthma 1
• Do not delay systemic corticosteroids - underuse is a major factor in preventable asthma deaths 1
• Avoid antibiotics unless bacterial infection is documented 1
• Do not use percussive physiotherapy - it is unnecessary and potentially harmful 1
• Beware of hyperthermia - while mentioned in your case, this is unusual in uncomplicated asthma and should prompt consideration of infection or other complications requiring additional workup 1

Discharge Criteria

Patient should not be discharged until: 1

• On discharge medication for 24 hours with verified inhaler technique 1
• PEF >75% predicted or personal best 1
• PEF diurnal variability <25% 1
• No nocturnal symptoms 1

Discharge medications must include: 1

• Prednisolone tablets 30-40 mg daily for 1-3 weeks 1
• Inhaled corticosteroids at higher dose than pre-admission 1
• Inhaled beta-agonists as needed 1
• Peak flow meter with written self-management plan 1

Follow-up: GP within 1 week, respiratory clinic within 4 weeks 1