One lung ventilation

Open pneumothorax

• Awake
• Paradoxical respirations and mediastinal shift as air enters the pleural cavity
• Anesthetized
• PP ventilation reverses the above 2 effects

Lateral decubitus

• Awake
• Ventilation is matched to perfusion because the lower hemidiaphragm is more efficient in contraction + lower lung is more compliant
• 
• Anesthetized
• VQ mismatch as the reduction in FRC moves lower lung lower down the compliance curve
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One-lung ventilation

• Intrapulmonary shunt is decreased by HPV
• HPV is inhibited by abnormal PA pressures, abnormal venous pO2, hypocapnia, PNA, drugs: vasodilators, beta blockers, PDE-I, CCB, volatiles
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