Intrapleural Pressure

• Intrapleural Pressure

  • Intrapleural pressure (Pip)
  • Pressure within the pleural cavity
  • Also fluctuates within breathing phases
  • ALWAYS negative relative to intrapulmonary pressure (Ppul)
  • Approx 4mmHg less than Ppul
• Intrapleural Pressure:

  • becomes more negative during inspiration
  • becomes more positive during expiration

  
• Why is Intrapleural Pressure Negative?

  • Negative intrapleural pressure is created by 2 opposing forces
  • Tendency of the chest wall to expand
  • Tendency of the lungs to recoil
  • These 2 forces act to pull the visceral pleura away from the parietal pleura
  • Pleural fluid ensures the 2 layers remain locked together