COPD Definition etc

• Definition of COPD:

  • A disease state characterised by airflow obstruction resulting from chronic bronchitis or emphysema
  • Airflow obstruction is progressive
  • Airflow obstruction is only partially reversible and does not change markedly over several months
• • patients who have COPD are said to have:
  • chronic bronchitis
  • emphysema
  • and sometimes asthma - patients with chronic asthma with no longer fully reversible airflow obstruction

  
• Epidemiology of COPD:

  • An estimated 3 million people are affected by COPD in the UK
  • About 900,000 have been diagnosed with COPD
  • An estimated 2 million people have COPD which remains undiagnosed
  • Approx 25,000 deaths each year in UK
• • Chronic bronchitis is a disease of your airways
  • Emphysema is a disease of your alveoli
• Differences in COPD diseases:

  A) reversibility

  B) sputum

  C) alveolar

  
• IMPORTANT!

  Chronic bronchitis and emphysema may well co-exist
• Polycythaemia:

  • Body’s response to chronic hypoxia
  • Increase in the total volume of red blood cells
  • Increases blood viscosity
  • Plethoric appearance (rosy face)
• Pulmonary Function Tests findings:

  • Static lung volumes are high (due gas trapping)
  • high residual volume
  • high total lung capacity
  • high functional residual capacity
  • Transfer factor / diffusing capacity (how easily oxygen can cross the alveolar membrane) is reduced
• Normal vs Obstructed lung volumes

  
• Pulmonary Function Tests results:

  • Obstructive pattern - difficulty breathing out due to narrowed airways
  • Restricted airflow due to high airway resistance
  • Difficulty emptying lungs
  • COPD measured/diagnosed using spirometry - results will show reduced FEV1 and FEV/FVC ratio
• Categorisation of COPD:

  • Mild COPD (FEV1 60 - 80% predicted)
  • Moderate COPD (FEV1 40 - 59% predicted)
  • Severe COPD (FEV1 < 40% predicted)
• FEV1:

  • forced expiratory volume in the first second, so is how much air you can blow out in the first second
  • normal values base on height, gender and age