Chapter 44: Chronic Obstructive Pulmonary Disease

KEY CONCEPTS

• Chronic obstructive pulmonary disease (COPD) is a treatable and preventable disease characterized by progressive airflow limitation that is not fully reversible and is associated with an abnormal inflammatory response of the lungs to noxious particles or gases.

• Mortality from COPD has increased steadily over the past three decades; it currently is the fourth leading cause of death in the United States.

• The primary cause of COPD is cigarette smoking, implicated in 85% of diagnosed cases in the United States. Other risks include a genetic predisposition, environmental exposures (including occupational dusts and chemicals), and air pollution.

• In patients with COPD, staging of airflow limitation (GOLD 1-4) is classified by spirometry measurements, while disease severity (Category A-D) is classified using a combined assessment of symptom score, as measured by validated questionnaire, and risk for future exacerbations.

• Smoking cessation and avoidance of other known toxins are the only management strategies proven to slow the progression of COPD.

• Oxygen therapy has been shown to reduce mortality in selected patients with COPD. Oxygen therapy is indicated for patients with a resting PaO₂ of less than 55 mm Hg (7.3 kPa) or a PaO₂ of less than 60 mm Hg (8.0 kPa) and evidence of right-sided heart failure, polycythemia, or impaired neurologic function.

• Inhaled bronchodilators are the mainstay of drug therapy for COPD and are used to relieve patient symptoms, improve exercise tolerance and quality of life. Guidelines recommend short-acting bronchodilators as initial therapy for patients with occasional symptoms and for all patients as rescue therapy for the relief of symptoms.

• For patients experiencing persistent symptoms, either a long-acting β₂-agonist (LABA) or long-acting anticholinergic (LAMA) offers significant benefits and both are of comparable efficacy. If a patient has continued symptoms, combining long-acting bronchodilator agents (LABA plus LAMA) is recommended.

• For patients at high risk for future exacerbations, either a long-acting β₂-agonist (LABA) or long-acting anticholinergic (LAMA) are effective at reducing exacerbation frequency. Anticholinergic agents are more effective at reducing exacerbation frequency and should be considered first-line. If a patient has continued exacerbations or has more severe disease (Category D) combining long-acting bronchodilator agents (LABA plus LAMA) is recommended.

• The role of inhaled corticosteroid (ICS) therapy in COPD is controversial. Patients with frequent and severe exacerbations may benefit from ICS therapy, although the risk of pneumonia is increased.

• Acute exacerbations of COPD have a significant impact on disease progression and mortality. Treatment of acute exacerbations includes intensification of bronchodilator therapy and a short course of systemic corticosteroids.

• Antimicrobial therapy should generally be used during acute exacerbations of COPD if the patient exhibits at least two of the following: increased dyspnea, increased sputum volume, and increased sputum purulence. A C-reactive protein (CRP) test may be ...