Chapter 7. Asthma and Chronic Obstructive Pulmonary Disease

Management of Acute Exacerbations

Pathophysiology

• Progressive shortness of breath (SOB) 2/2 ↓ expiratory airflow; associated with acute airway inflammation (progressive symptom onset; slow treatment response) &/or bronchospasm (abrupt rapid symptom onset; quick treatment response)
• Triggers: airway inflammation → respiratory infections (URI, bronchitis, sinusitis), allergens (pets, dust, pollen, etc.); bronchospasm → allergens, exercise, emotions; other → cold air, fog, tobacco, wood smoke, drugs (aspirin, NSAIDs)

Diagnosis & Evaluation

• Identify exacerbation: acute or subacute condition; progressively worsening SOB, cough, wheezing, &/or chest tightness; PEF <80% predicted/personal best

Treatment & Follow-Up

• Treatment goals: reverse airflow obstruction, correct hypoxemia, ↓ relapse/recurrent exacerbation

Pharmacological Treatment

• SABA: albuterol, levalbuterol; DOC in exacerbation; can use MDI or nebs (Chest 2002;121:1036); onset of action ∼5min; no clinical difference between onset of action & side effect profile between albuterol or levalbuterol (Ann Emerg Med 2005;46:29); monitor: ↓ K+, especially with continuous treatment
• Systemic corticosteroids: prednisone, methylprednisolone, prednisolone (Am J Med 2009;122:977); fast onset w/in hours; IV = PO; ↑ infection, hyperglycemia
• Anticholinergics: ipratropium bromide; given in combination with SABA during acute exacerbation; benefit only in initial ER management (Am J Med 1999;107:363; Chest 2002;121:1977); onset w/in 15min, peak effect 1–2h; may cause urinary retention
• Magnesium sulfate: for life-threatening exacerbations or those not responding to standard therapy (Ann Emerg Med 2000; 36:181; Chest 2002; 122:489); controversial in adults (Emerg Med J 2007;24:823); onset <20min
• Antibiotics: only if evidence of bacterial infection (Chest 2009;136:498)
• Criteria for discharge: PEF >70% → if rapid response to therapy, close observation for 30–60min; PEF 50–69% → evaluate on case-by-case basis
• Consider adding inhaled corticosteroid (ICS) to therapy, or ↑ ICS dose at discharge (Cochrane Database of Syst Rev 2000;CD002316)

Nonpharmacological Treatment

Oxygen to achieve SaO2 >90%, or >95% (pregnancy or concomitant heart disease); consider heliox for severe exacerbations after 1h of therapy (Anaesthesia 2007;62:34)

Chronic Asthma Management

Pathophysiology