Clinical Relevance

• Tidal volume:

  • Adequate tidal volume necessary to maintain oxygenation and co2 clearance
• Inspiratory reserve volume:

  • Required during cough & undertaking exercise
• Functional residual capacity:

  • Essential to maintain distal lung patency on expiration
  • Critical value called “closing volume” or “closing capacity"
• Residual volume:

  • Can increase in lung disease due to “air trapping”
  • When increased may alter respiratory mechanics
• Functional Residual Capacity:

  • Can reduce in many clinical situations
• Vital capacity:

  • Critical value ( 1 L ) used to identify if patient is able to maintain spontaneous ventilation