What is the treatment for status asthmaticus?

Status Asthmaticus Treatment

Status asthmaticus requires immediate aggressive treatment with high-flow oxygen, nebulized beta-agonists, systemic corticosteroids, and ipratropium bromide as first-line therapy. 1

Definition and Assessment

Status asthmaticus is defined as severe asthma unresponsive to repeated courses of beta-agonist therapy, characterized by:

• Too breathless to complete sentences in one breath
• Respiratory rate >25 breaths/min
• Heart rate >110 beats/min
• Peak Expiratory Flow (PEF) <50% of predicted or best
• Silent chest, cyanosis, or feeble respiratory effort
• Exhaustion, confusion, or coma 1

First-Line Treatment

1. Oxygen Therapy:

   • Administer high-flow oxygen (40-60%) to maintain SaO₂ >92% via face mask 1

2. Beta-agonists:

   • Deliver salbutamol/albuterol 5 mg or terbutaline 10 mg via oxygen-driven nebulizer 2, 1
   • If nebulizer unavailable, use multiple actuations of MDI with spacer (10-20 puffs) 1
   • Repeat every 15-30 minutes based on response 2
   • Note: Albuterol has been shown to have more effect on bronchial smooth muscle relaxation than isoproterenol at comparable doses while producing fewer cardiovascular effects 3

3. Systemic Corticosteroids:

   • Administer immediately: prednisolone 30-60 mg orally or hydrocortisone 200 mg IV 2, 1
   • Dose: 1-2 mg/kg body weight daily (maximum 60 mg) for oral prednisolone 1

4. Ipratropium Bromide:

   • Add ipratropium 0.5 mg nebulized to treatment regimen 2, 1
   • Alternative: 100 μg nebulized (or 4-8 puffs via MDI with spacer) 1
   • Repeat every 6 hours 1

Monitoring and Response Assessment

• Measure Peak Expiratory Flow (PEF) 15-30 minutes after starting treatment and regularly thereafter 1
• Monitor oxygen saturation continuously, targeting SaO₂ >92% 1
• Obtain arterial blood gases in severe cases 1
• Assess for markers of severe attack:
  • Normal or high PaCO₂ in a breathless patient
  • Severe hypoxia (PaO₂ <8 kPa) despite oxygen therapy
  • Low pH 1

Second-Line Treatment (If No Improvement)

1. IV Medications:

   • Consider aminophylline (5 mg/kg over 20 minutes, followed by maintenance infusion of 1 mg/kg/h) 1
   • Alternative: IV salbutamol/terbutaline 1

2. Mechanical Ventilation:

   • Consider if pharmacological therapy fails to reverse severe airflow obstruction 4
   • Optimal ventilation should avoid excessive lung inflation by limiting minute ventilation and prolonging expiratory time, despite consequent hypercapnia 4
   • Avoid paralytic agents if possible due to risk of intensive care myopathy 4

Important Cautions

• Avoid sedation in status asthmaticus 1
• Monitor for deterioration requiring ICU transfer: worsening PEF, persistent hypoxia, exhaustion, confusion, or drowsiness 1
• Fatalities have been reported with excessive use of inhaled sympathomimetic drugs 3
• Paradoxical bronchospasm can occur with beta-agonists and can be life-threatening; discontinue immediately if it occurs 3
• Cardiac effects: Beta-agonists may have clinically significant cardiac effects in some patients 3

Discharge Criteria and Follow-up

• Do not discharge until:

  • Symptoms have stabilized
  • PEF >75% of predicted or best value
  • Diurnal variability <25%
  • No nocturnal symptoms 1

• Follow-up plan:

  • Prescribe prednisolone tablets (30 mg daily) for 1-3 weeks
  • Increase inhaled steroids dosage higher than before admission
  • Continue inhaled beta-agonists as needed
  • Arrange follow-up with primary care within 1 week 1

Pediatric Considerations

• For children weighing <15 kg who require <2.5 mg/dose, use albuterol inhalation solution 0.5% instead of 0.083% 3
• The usual dosage for children weighing at least 15 kg is 2.5 mg of albuterol administered three to four times daily by nebulization 3
• Initial treatment should include high-flow oxygen, inhaled short-acting beta-agonists, and systemic corticosteroids 1

Status asthmaticus is a medical emergency that requires prompt recognition and aggressive treatment to prevent respiratory failure and death. Early administration of systemic corticosteroids is crucial, as clinical benefits may not occur for 6-12 hours 5.