- Introduction to respiratory physiology:
- Understanding physiology is crucial for critical care practice.
- Respiratory support is a defining feature of intensive care.
- An understanding of respiratory mechanics and gas exchange is required.
- Respiratory mechanics involve flows, volumes, and pressures.
- Respiratory mechanics:
- Gas flows driven by differences in airway and alveolar pressures.
- Pressure dissipates against friction and is stored temporarily in tissues.
- Measurements include flows, volumes, and pressures.
- Regional mechanics are important for determining ventilation.
- Transpulmonary pressure:
- Chest volume depends on compliance and pressure difference.
- Transmural pressure for the lung is Paw - Ppl.
- Pleural pressure deflections drive tidal movement.
- Lung mechanical properties can be assessed during ventilation.
- Key differences between active and passive breathing:
- Differences in mechanical behaviors exist in acutely injured lungs.
- Active contraction affects local transmural pressures.
- Conditions like ARDS accentuate regional differences in mechanics.
- Pulmonary vascular filling and compliance are influenced by pleural pressure.