pulmonary disease

Question 1

what is COPD?

Answer 1

disease of the large and small airways and the lung parenchyma that is characterised by airflow obstruction

damage to the alveoli which causes a limitation in getting air out

Question 2

what are the risk factors for pulmonary disease?

Answer 2

environmental factors: smoking, dust, chemical vapours, and fumes

occupational exposure

indoor/outdoor airpollution

allergens

infections

age

genetics

gender

Question 3

what are the general consequences of pulmonary disease?

Answer 3

exercise intolerance is a main factor in limiting participation in ADLs

primary limitation is reduction in oxygen consumption which limits this participation

anxiety and poor motivation are also linked to exercise intolerance

Question 4

what are the primary symptoms of pulmonary disease?

Answer 4

SOB and fatigue which may result from ventilatory constraints, pulmonary gas exchange abnormalities, peripheral muscle dysfunction, cardiac dysfunction

Question 5

what are the ventilatory limitations on exercise response

Answer 5

• FEV1 is less than 80% of predicted
  
  • Tendency toward air trapping and lung hyperinflation
    ○ Residual volume (RV) above normal (less lung elastic recoil opposing chest wall expansion); inspiratory capacity (IC) is typiaclly reduced
    ○ Described as an “inability to get air in” or :air hunger”
    Lung operating volume shifts higher on the lungs pressure-volume curve

Question 6

what are the peripheral muscle dysfunction on exercise response

Answer 6

• Mostly attributed to deconditioning
  
  • Muscular weakness:
    ○ Quadriceps strength may be 20-30% lower in COPD patients
    ○ Dysfunction greater in lower limbs
  • Diminished capillarisation, mitochondrial derangement, and diminished levels of aerobic enzymes are all observed in the peripheral muscles of patients with COPD
    Cause not known? systemic inflammation, oxidative stress

Question 7

what are the effects of respiratory muscle fatigue on exercise response

Answer 7

• Flattened diaphragm: less force-generating potential (reduced length-tension relationship)
  ○ Diaphragm muscle adapts and shortens the optimal length of the muscles fibers through sarcomere deletion
  ○ Muscle fiber type shift: type II (glycolytic muscle fibers, high force fast twitch fibers that fatigue quicker)
  
  • Inspiratory neural rive of the diaphragm relative to the maximum as measured by electromyography
    ○ Because of issues getting gas out and gas exchange system impaired, increased inspiratory neural drive to try and breath harder
    ○ Results in respiratory muscle fatigue which also leads to fatigue
    Overall: reduced performance (fatigue quicker)

Question 8

what are the key observations in COPD

Answer 8

• Increase in ventilation (higher than normal) at lower workloads
  
  • Reduction in performance, peak VO2 will be lower than what is predicted
  • Muscle weakness
    Terminate exercise earlier because of high levels of SOB