2- acute asthma exacerbation

• Causes/triggers of acute asthma exacerbation


  • Environmental exposure to allergens
  • Viral infections (RSV, parainfluenza virus, rhinovirus)
  • Occupational sensitizers; irritant dusts/vapors/flames
  • Cold air; emotion
  • Drugs (NSAIDs, BBs)
• Investigations for acute asthma exacerbation

  • Chest x-ray to exclude pneumothorax, pneumonia, or other causes of dyspnea
  • Continuous pulse oximetry to monitor oxygen saturation
  • ABG to assess severity
  • PEFR for monitoring & to assess severity
  • Electrolytes: look for hypokalemia (may result from salbutamol or steroids)
• Acute severe asthma attack

  • Inability to complete a sentence in one breath
  • Respiratory rate of ≥25 breaths/min
  • Tachycardia (≥110)
  • PEFR 33–50% of predicted normal or best
• Life-threatening asthma attack


  • Silent chest, cyanosis or weak respiratory effort
  • Exhaustion or altered level of consciousness
  • Bradycardia, hypotension or arrhythmia
  • PEFR of <33% of predicted normal or best (<150 L in adults) or SpO2 of <92%
  • PaCO2 of > 6 kPa
  • Severe hypoxemia: PaO2 <8 kPa despite treatment with oxygen
  • Low or falling arterial pH
• Acute attack management


  1. Oxygen (40-60%)

  2. Nebulized SABA (salbutamol or albuterol). Repeated every 4 hours.

  3. Nebulized ipratropium bromide (antimuscarinics)

  4. IV hydrocortisone 200mg + oral prednisolone 40–60mg orally for at least 5 days.

  5. If there is no improvement à IV magnesium sulphate given at 1.2–2g over 20min.

  6. If the patient is not responding to all the previous management à shift to the ICU, intubate, and give mechanical ventilation.

  7. Long-acting bronchodilators are contraindicated in the acute setting
• Bad prognostic indicators: cyanosis, silent lung, increased CO2