Lab

Functional Residual Capacity

search

Functional Residual Capacity, FRC

  • Physiology
  1. Volume remaining in lungs at resting expiratory level
  2. Equivalent to alveolar volume (Va)
    1. Respiratory Bronchioles and alveolar ducts: 30-40%
    2. Alveoli: 60-70%
  3. Calculation: ERV + RV
  4. Normal adult: 1.8 to 3.4 Liters
  • Causes
  • Factors that increase FRC (Hyperinflation)
  1. Emphysema
  2. Aging
  3. Asthma
  4. Peribronchial fibrosis
  • Causes
  • Factors that decrease FRC
  1. Age
  2. Obesity
  3. Supine Posture
  4. Sedation