Lab

Lung Volume

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Lung Volume, Inspiratory Reserve Volume, Tidal Volume, Inspiratory Capacity, Expiratory Reserve Volume, Residual Volume, Total Lung Capacity

  • See Also
  1. Pulmonary Function Test
  2. Diffusing Capacity
  3. Inhalation Challenge Test
  4. Exercise Spirometry
  5. Functional Residual Capacity
  6. Vital Capacity
  7. Peak Expiratory Flow Rate (PEFR)
  8. Spirometry Lower Limit of Normal (PFT LLN)
  9. Obstructive Lung Disease
  10. Restrictive Lung Disease
  • Interpretation
  • Inspiratory Volumes
  1. Inspiratory Reserve Volume (IRV)
    1. Maximal inspired volume from end-tidal inspiration
  2. Tidal Volume (Vt)
    1. Volume inspired and expired with each normal breath
    2. Minimum volume: 3 ml/kg
    3. Typical ventilator Tidal Volume settings: 6-8 ml/kg
    4. Normal volume: 6-7 ml/kg
  3. Inspiratory Capacity (IC)
    1. Maximal volume inspired from resting expiratory level
    2. Calculation: IRV + Vt
  • Interpretation
  • Expiratory Volumes
  1. Expiratory Reserve Volume (ERV)
    1. Maximal expired volume from end-tidal inspiration
    2. Normal: 25% of Vital Capacity
  2. Residual Volume (RV)
    1. Volume remaining in lungs after maximal expiration
    2. Normal adult: 1.0 to 2.4 Liters
  3. Functional Residual Capacity (FRC)
    1. Volume remaining in lungs at resting expiratory level
  • Interpretation
  • Overall Lung Volumes
  1. Vital Capacity (VC)
    1. Maximal volume expelled after maximal inspiration
  2. Total Lung Capacity (TLC)
    1. Volume in lungs at end of maximal inspiration
    2. Calculation: VC + RV
    3. Normal adult: 4-6 Liters
  • References
  1. Rollings (1984) Facts and Formulas, McNaughton & Gunn
  2. Marini (1987) Respiratory Medicine, Williams & Wilkins