COPD

Emphysema

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Emphysema, Pink Puffer

  • Definitions
  1. Emphysema
    1. Subtype of Chronic Obstructive Pulmonary Disease
    2. "Lung Dry Rot"
      1. Alveolar distention
      2. Destruction of alveolar septae
  • Pathophysiology
  1. High Alveolar Dead Space
    1. Wasted ventilation to diseased alveoli that have poor gas exchange
  2. Progressively more limited Ventilatory response to pCO2 (as Emphysema progresses)
    1. Increased airway resistance requires increased work of breathing
    2. Increased work of breathing generates higher CO2 that is poorly excreted in severe COPD
    3. Increased airway resistance causes hyperinflation due to air trapping
      1. Hyperinflation results in diaphragm flattening, shorter muscle fibers that are inefficient
      2. Shorter muscles are unable to generate adequate negative pressure to increase air flow past obstruction
    4. Overall weakness, Asthenia and wasting results in further muscle Fatigue and decreased work of breathing
  • Type
  1. Panacinar
    1. Affects both central and peripheral portions acinus
  2. Centriacinar
    1. Affects primarily Bronchioles and alveolar ducts
    2. Minimal involvement of peripheral acini
  • Symptoms
  1. Scant Sputum production
  2. Exertional Dyspnea
  • Signs
  1. "Pink Puffer"
    1. Thin, dyspneic patient with mild Hypoxia
    2. Increased respiratory drive to maintain a normal pCO2
      1. Contrast with "Blue Bloater" of Chronic Bronchitis
  2. Tachypnea
  3. Prolonged expiration
  4. Hyperresonant chest
  5. Diminished breath sounds
  • Labs
  1. Arterial Blood Gas (ABG)
    1. Slightly decreased arterial pO2
    2. Slightly decreased arterial pCO2
  2. Pulmonary Function Tests
    1. FEV1 reduced
    2. Diffusion capacity (DLCO) reduced
  • Staging
  1. Hyperinflated lungs
  • Management
  1. SEE COPD Management
  2. Lung reduction surgery
    1. Removal of most severely damaged lung (n=20)
    2. Increased mean lung elastic recoil by 27%
    3. Increased FEV1
    4. Increased FVC
    5. Reduced FRC and RV
    6. Improved walking capacity
  3. References
    1. Sciurba (1996) N Engl J Med, 334:1095-9 [PubMed]
  • Complications
  • References
  1. Wilson (1991) Harrison IM, McGraw-Hill, p.1074-82
  2. Martinez (1998) Postgrad Med 103(4):112-25 [PubMed]