II. Definitions
- Emphysema
- Subtype of Chronic Obstructive Pulmonary Disease
- "Lung Dry Rot"
- Alveolar distention
- Destruction of alveolar septae
III. Pathophysiology
- High Alveolar Dead Space
- Wasted ventilation to diseased alveoli that have poor gas exchange
- Progressively more limited Ventilatory response to pCO2 (as Emphysema progresses)
- Increased airway resistance requires increased work of breathing
- Increased work of breathing generates higher CO2 that is poorly excreted in severe COPD
- Increased airway resistance causes hyperinflation due to air trapping
- Overall weakness, Asthenia and wasting results in further muscle Fatigue and decreased work of breathing
IV. Type
- Panacinar
- Affects both central and peripheral portions acinus
- Centriacinar
- Affects primarily Bronchioles and alveolar ducts
- Minimal involvement of peripheral acini
VI. Signs
- "Pink Puffer"
- Thin, dyspneic patient with mild Hypoxia
- Increased respiratory drive to maintain a normal pCO2
- Contrast with "Blue Bloater" of Chronic Bronchitis
- Tachypnea
- Prolonged expiration
- Hyperresonant chest
- Diminished breath sounds
VII. Labs
-
Arterial Blood Gas (ABG)
- Slightly decreased arterial pO2
- Slightly decreased arterial pCO2
- Pulmonary Function Tests
VIII. Staging
- See COPD Staging
IX. Imaging: Chest XRay
- Hyperinflated lungs
X. Management
- SEE COPD Management
-
Lung reduction surgery
- Removal of most severely damaged lung (n=20)
- Increased mean lung elastic recoil by 27%
- Increased FEV1
- Increased FVC
- Reduced FRC and RV
- Improved walking capacity
- References
XI. Complications
- Cor Pulmonale
- Hypercapnic Respiratory Failure
XII. References
- Wilson (1991) Harrison IM, McGraw-Hill, p.1074-82
- Martinez (1998) Postgrad Med 103(4):112-25 [PubMed]