Is levosalbutamol (albuterol) MDI 8 puffs every 20 minutes for three doses, then 8 puffs every hour, a suitable initial treatment for acute severe asthma exacerbations in adults?

Management of Acute Severe Asthma Exacerbations with Levosalbutamol MDI

Levosalbutamol MDI at 8 puffs every 20 minutes for three doses, followed by 8 puffs hourly, is an appropriate treatment regimen for acute severe asthma exacerbations in adults, particularly when administered through a spacer device. 1

Assessment of Asthma Severity

Before initiating treatment, assess the severity of the asthma exacerbation:

• Severe asthma features (requiring immediate treatment):

  • Too breathless to complete sentences in one breath 1
  • Respiratory rate >25 breaths/min 1
  • Peak Expiratory Flow (PEF) <50% of predicted normal or best 1
  • Heart rate >110 beats/min 1

• Life-threatening features (requiring more aggressive intervention):

  • PEF <33% of predicted normal or best 1
  • Silent chest, cyanosis, or feeble respiratory effort 1
  • Bradycardia or hypotension 1
  • Exhaustion, confusion, or coma 1

Treatment Protocol for Acute Severe Asthma

Initial Management

1. High-dose β2-agonist administration:

   • Levosalbutamol (albuterol) MDI: 8 puffs every 20 minutes for 3 doses via spacer device 1
   • This approach is equivalent to nebulized therapy when administered with proper technique and coaching 1
   • For severe exacerbations, MDI with spacer has been shown to be as effective as nebulized therapy 1

2. Systemic corticosteroids:

   • Administer prednisolone 30-60 mg orally or hydrocortisone 200 mg IV immediately 1
   • Continue high-dose steroids: prednisolone 40-80 mg daily until PEF reaches 70% of predicted or personal best 1

3. Oxygen therapy:

   • Maintain oxygen saturation >90% (>95% in pregnant women and patients with heart disease) 1
   • Monitor oxygen saturation until clear response to bronchodilator therapy 1

Subsequent Management

• If improving after initial treatment:

  • Continue levosalbutamol MDI at 8 puffs hourly 1
  • Continue oxygen therapy as needed 1
  • Continue systemic corticosteroids 1

• If not improving after 15-30 minutes:

  • Add ipratropium bromide (0.5 mg nebulized or 8 puffs via MDI) to the β2-agonist 1
  • Consider IV aminophylline (250 mg over 20 minutes) or IV salbutamol/terbutaline (250 μg over 10 minutes) 1
  • Consider hospital admission 1

Advantages of Levosalbutamol (R-albuterol)

• Levosalbutamol contains only the therapeutically active R-isomer responsible for bronchodilation 2, 3
• Recent studies suggest levosalbutamol may be more effective than racemic salbutamol in improving:
  • Respiratory rate 4
  • Oxygen saturation 4
  • Peak expiratory flow rate 4
  • Overall asthma score 4
• Levosalbutamol causes less tachycardia compared to racemic salbutamol 4, 3

Monitoring Response to Treatment

• Measure and record PEF 15-30 minutes after starting treatment and thereafter according to response 1
• Monitor heart rate, respiratory rate, and oxygen saturation 1
• The early response (within 30 minutes) to treatment is an important predictor of outcome 5

Criteria for Hospital Admission

Consider hospital admission if:

• Any life-threatening features are present 1
• Features of severe asthma persist after initial treatment 1
• PEF remains <33% of predicted or best value after treatment 1
• Patient has had previous severe attacks, especially with rapid onset 1

Common Pitfalls to Avoid

• Underestimation of severity: The severity of acute asthma is often underestimated due to failure to make objective measurements 1
• Inadequate dosing: About 30% of patients may require higher cumulative doses (≥3.6 mg) of β2-agonist to reach discharge threshold 5
• Delayed corticosteroid administration: Early administration of corticosteroids is crucial to reduce the likelihood of hospitalization 1
• Inappropriate sedation: Any sedation is contraindicated in acute asthma 1
• Overreliance on a single parameter: Use multiple parameters (symptoms, vital signs, PEF) to assess severity and response 1

Remember that approximately 70% of patients will respond sufficiently to initial doses of β2-agonist therapy, but 30% may show poor response and require more aggressive intervention 5.