Normal; physiology

• The most important concept to understand is that blood oxygenation is dependent on 3 factors:
  • Diffusion barrier (alveolar membrane) — can the molecule pass through?
    • Reduced in fibrosis, pulmonary edema
  • Surface area — higher surface area = more gas exchange
  • Gradient
• Work of Breathing (Respiratory Muscles)
• Airway resistance of the lower respiratory tract
• Blood Flow & the Bronchial Circuit
• Ventilation and Perfusion ★
• Physiologic responses to high altitude
• Pleural fluid

Abnormal; pathology

• Alveolar Hypoventilation
• Ventilation/Perfusion Mismatch
• Hypoxic Vasoconstriction
• Hyperventilation
• Tidal Volume & Physiologic Dead Space
• Diffusion Impairment
• Changes in Lung Compliance