Spirometry

• Spirometry:

  • Allows measurement of certain lung volumes
  • Has both diagnostic and monitoring functions
  • Interested in
  • forced vital capacity (FVC)
  • FEV1 & FEV1% derived from the FVC
• Forced Vital Capacity:

  • The maximal volume of air that can be forcefully exhaled following a full inspiration
  • Total amount of exchangeable air in the lungs
• Forced Expiratory Volume1

  • The volume of air that can be forcibly expelled from a maximal inspiration in the first second

  
• Restrictive conditions:

  • Difficulty taking a deep breath IN
  • Problem with the lung parenchyma or respiratory pump
  • Can you name some restrictive conditions? - pulmonary fibrosis as the lungs shrink
  • FVC will be lower than normal
  • No problem with emptying the lungs
  • FEV1/FVC% will be higher than normal (more than 80%)

  
• • What should FEV1 /FVC% be? - it should be 80%
  • decrease in FEV1/FVC% with what type of lung disease? - obstructive lung diseases (asthma, chronic bronchitis, emphysema)