Status Asthmaticus

Inhaled Bronchodilators

INTERMITTENT ALBUTEROL

• Mechanism: Beta agonist (B1 and B2)
• B2 activity = airway smooth muscle relaxation
• Available as inhaler or nebulization for intermittent treatments
• Adverse Effects: Tachycardia (B1 activity), Hypertension (B1 activity), Low potassium (intracellular shifts), nausea
• Levalbuterol = no additional benefit, more expensive

CONTINUOUS ALBUTEROL

• Can be escalated to a continuous nebulization 
• Typical starting dose of 10 mg/hour, with some centers escalating to doses up to 30 mg/hour

Inhaled Anticholinergics

IPRATROPIUM

• Bronchodilation by smooth muscle relaxation
• Can have drying effects for excess mucus
• Adverse effects commonly associated with anticholinergics are minimal due to low systemic absorption with inhaled therapy
• Reduces hospitalization for patients with status asthmaticus
• No evidence for benefit once hospitalized, however is commonly utilized clinically

Corticosteroids

METHYLPREDNISOLONE

• Mechanism: reduced inflammatory mediators and cytokines, therefore reducing airway edema
• Systemic therapy preferred. Routinely started on IV therapy due to increased work of breathing.
• Early administration = better outcomes
• Dosing
  • Methylprednisolone: Prednisolone: Prednisone = 1:1:1
  • Some centers utilize an optional loading dose of 1-2 mg/kg
  • Usual starting dose is 0.5 mg/kg (max 60 mg) Q6H, varies by severity and provider preference 
• Adverse effects: may have hyperglycemia, hypertension, etc.
  • Dose dependent
• Consider steroid taper for patients receiving high dose steroids for 7+ days

DEXAMETHASONE

• Some centers utilize as an alternative to methylprednisolone
• Dosing is typically one dose of 0.6 mg/kg (max 16 mg) IV, which can be repeated Q24H as required

Magnesium

MAGNESIUM SULFATE

• Decreases cholinergic stimulation and histamine release, which inhibits smooth muscle contractions
• Administered as an Intravenous Bolus 
  • Usual dose = 50 mg/kg IV (max 2g) over 20-30 minutes
  • Administered faster than boluses for electrolyte repletion
  • Monitor for hypotension, fluid bolus if needed
  • Can repeat for a second dose 
• Toxicity rare: Respiratory depression, arrythmias, weakness
• Evidence for reducing hospitalization

Advanced Therapies

TERBUTALINE

• Causes bronchodilation by relaxing smooth muscle, similar to albuterol
• Continuous intravenous infusion (loading doses may be utilized) or subcutaneous injection
• Utility in refractory exacerbations
• Some centers utilize a loading dose
• Adverse effects: hypotension, hyperglycemia, hypokalemia, arrhythmias
• Can utilize fluid boluses to prevent tachycardia 
• Evidence limited and controversial

THEOPHYLLINE AND AMINOPHYLLINE

• Commonly administered as a continuous intravenous infusion, loading dose may be utilized
• Theophylline levels commonly monitored
• Infusion rates can be adjusted to target levels