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If 'transpulmonary pressure' = 0 (alveolar pressure = intrapleural pressure), such as when the lungs are removed from the chest cavity or air enters the intrapleural space (a pneumothorax), the lungs collapse as a result of their inherent elastic recoil. Under physiological conditions the transpulmonary pressure is always positive; intrapleural ...
Dynamic compression of the airways results when intrapleural pressure equals or exceeds alveolar pressure, which causes dynamic collapsing of the lung airways. It is termed dynamic given the transpulmonary pressure (alveolar pressure − intrapleural pressure) varies based on factors including lung volume, compliance, resistance, existing pathologies, etc. [1]
At rest, there is a negative intrapleural pressure. This provides a transpulmonary pressure, causing the lungs to expand. If humans didn't maintain a slightly negative pressure even when exhaling, their lungs would collapse on themselves because all the air would rush towards the area of lower pressure. Intra-pleural pressure is sub-atmospheric.
Once air enters the pleural cavity, the intrapleural pressure increases, resulting in the difference between the intrapulmonary pressure and the intrapleural pressure (defined as the transpulmonary pressure) to equal zero, which cause the lungs to deflate in contrast to a normal transpulmonary pressure of ~4 mm Hg. [28]
Static lung compliance is the change in volume for any given applied pressure. [1] Dynamic lung compliance is the compliance of the lung at any given time during actual movement of air. Low compliance indicates a stiff lung (one with high elastic recoil ) and can be thought of as a thick balloon – this is the case often seen in fibrosis .
Dynamic airway compression occurs when intrapleural pressure equals or exceeds alveolar pressure, which causes dynamic collapsing of the lung airways. It is termed dynamic given the transpulmonary pressure (alveolar pressure − intrapleural pressure) varies based on factors including lung volume, compliance, resistance, existing pathologies, etc. [6] It occurs during forced expiration when ...
West's Respiratory Physiology states that transpulmonary pressure is "the difference in pressure between the inside and the out- side of the lung (alveoli)" or "is numerically equal to the pressure around the lung when the alveolar pressure is atmospheric" whereas transmural pressure (as relates to the lung) is "The pressure difference between ...
Image illustrating transpulmonary, intrapleural and intra-alveolar pressure. Alveolar pressure (P alv) is the pressure of air inside the lung alveoli.When the glottis is opened and no air is flowing into or out of the lungs, alveolar pressure is equal to the atmospheric pressure, that is, zero cmH 2 O.