Chapter 13

Overview of COPD

  • Chronic Obstructive Pulmonary Disease (COPD): Preventable and treatable disease characterized by air flow limitation that is not fully reversible.

    • Air flow limitation is usually progressive.

    • Associated with an abnormal inflammatory response of the lungs to noxious particles or gases, primarily caused by cigarette smoking.

    • Affects the lungs and produces significant systemic consequences.

Types of COPD

Chronic Bronchitis

  • Definition: Chronic productive cough for 3 months in each of 2 successive years, excluding other causes of productive chronic cough.

  • Characteristics:

    • Permanent enlargement of air spaces distal to terminal bronchioles, accompanied by destruction of their walls and fibrosis.

Emphysema

  • Definition: Anatomic alterations of the lungs characterized by the permanent enlargement and destruction of air spaces distal to the terminal bronchioles.

  • Clinical Features:

    • Associated with destruction of the alveolar-capillary membrane and weakening of the distal airways.

    • Air trapping and hyperinflation may occur, especially in late stages.

Clinical Classification of COPD

  • Both chronic bronchitis and emphysema can be present; distinguishing their relative contributions may be challenging.

  • American Thoracic Society Definitions:

    • Chronic Bronchitis: Based on clinical manifestations.

    • Emphysema: Based on pathological changes.

Pathophysiology

Chronic Bronchitis

  • Pathologic Changes:

    • Chronic inflammation and thickening of peripheral airway walls.

    • Excessive mucus production leading to accumulation and possible airway plugging.

    • Smooth muscle constriction causing bronchospasms.

    • Air trapping and hyperinflation of alveoli may arise in later stages.

Emphysema

  • Key Changes:

    • Destruction of the alveolar walls leading to reduced surface area for gas exchange.

    • Weakening of the respiratory bronchioles exacerbating air trapping and hyperinflation.

Epidemiology

  • Prevalence: Estimated 10-15 million people in the U.S. have chronic bronchitis, emphysema, or a combination of both.

  • Underdiagnosis of COPD is common.

Risk Factors for COPD

Genetic

  • Alpha-1-antitrypsin deficiency.

Environmental

  • Tobacco smoke, occupational dusts, and chemicals.

  • Indoor and outdoor air pollution.

Other Influencing Factors

  • Age, gender, socioeconomic status, asthma, bronchial hyper-reactivity, and history of respiratory infections.

Diagnosis of COPD

Key Indicators (COPD in patients over age 40)

  • Symptoms:

    • Dyspnea (difficulty breathing).

    • Chronic cough.

    • Chronic sputum production.

    • History of exposure to risk factors.

    • Family history of COPD.

Pulmonary Function Tests (PFTs)

  • Essential for diagnosis, including:

    • Spirometry Tests:

      • FVC (Forced Vital Capacity).

      • FEV1 (Forced Expiratory Volume in 1 second).

      • FEV1/FVC ratio (indicator of obstruction).

Additional Screening Methods

  • BODE Index, chest radiograph, computed tomography (CT) of the chest, lung volumes and diffusing capacity, oximetry, and arterial blood gases analysis.

Clinical Manifestations in COPD

  • Resulting from excessive bronchial secretions, bronchospasms, and distal airway/alveolar weakening.

PFT Findings

  • Moderate to Severe Chronic Bronchitis/Emphysema:

    • Forced Expiration Findings:

      • Decreased FVC, FEV1, PEFR (Peak Expiratory Flow Rate), and MVV (Maximum Voluntary Ventilation).

      • FEV1/FVC ratio decreased.

    • Lung Volumes & Capacities:

      • FRC (Functional Residual Capacity) increased; TLC (Total Lung Capacity) normal or increased.

Chest Assessment Findings

  • Emphysema:

    • Decreased tactile fremitus, reduced chest expansion, hyper-resonance on percussion, and diminished breath sounds.

  • Chronic Bronchitis:

    • Normal findings compared to emphysema.

Arterial Blood Gas Analysis

  • Severe COPD:

    • Chronic ventilatory failure and hypoxemia may occur.

    • Compensated respiratory acidosis with elevated HCO3-.

    • Important findings for respiratory therapists include monitoring for acute ventilatory changes.

Laboratory Tests & Procedures

  • Common Findings:

    • Hematocrit/hemoglobin levels, electrolytes.

    • Sputum examinations (culture) can reveal typical pathogens.

    • Imaging may show characteristic changes (e.g., hyperinflated lungs, flattened diaphragm).

Management of COPD

Treatment Strategies

  • Medications:

    • Bronchodilators (SABA/LABA/LAMA).

    • Corticosteroids.

    • Antibiotics for bacterial infections.

  • Therapeutic Considerations:

    • Smoking cessation, pulmonary rehabilitation, patient education on management of triggers.

    • Nutritional considerations based on comorbidities (e.g., carbohydrates vs. protein intake).

    • Assess for supplemental oxygen therapy and vaccines.

Surgical Options for Advanced Cases

  • Lung volume reduction surgery, bullectomy, large airway stenting, lung transplant considerations.

Preventative Measures

  • Assess need for supplemental oxygen, ongoing smoking cessation programs, and vaccinations such as influenza and pneumococcal.

Acute COPD Interventions

  • Acute Management:

    • Administer SABA, oxygen therapy, and IV corticosteroids as necessary during exacerbations.

    • Continuous monitoring and adjustments based on arterial blood gas findings and patient response.