Transpulmonary pressure
Encyclopedia
Transpulmonary pressure is a term used to describe the difference between the alveolar pressure and the intrapleural pressure in the lungs. During human ventilation, air flows because of pressure gradients.
Ptp = Palv - Pip. Where Ptp is transpulmonary pressure, Palv is alveolar pressure, and Pip is intrapleural pressure.
It is nothing but the elastic recoiling of the lungs.
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 pressure is always negative and relatively large, while alveolar pressure moves from slightly positive to slightly negative as a person breathes. For a given lung volume the transpulmonary pressure is equal and opposite to the elastic recoil pressure of the lung.
The transpulmonary pressure vs Volume curve of inhalation (usually plotted as Volume in function of Pressure) is different from that of exhalation, the difference being described as hysteresis. Lung volume at any given pressure during inhalation is less than the lung volume at any given pressure during exhalation.
.
Measurement of transpulmonary pressure assists in spirometry
in availing for calculation of static lung compliance.
Ptp = Palv - Pip. Where Ptp is transpulmonary pressure, Palv is alveolar pressure, and Pip is intrapleural pressure.
Physiology
Since atmospheric pressure is relatively constant, pressure in the lungs must be higher or lower than atmospheric pressure for air to flow between the atmosphere and the alveoli.It is nothing but the elastic recoiling of the lungs.
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
Pneumothorax
Pneumothorax is a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. It may occur spontaneously in people without chronic lung conditions as well as in those with lung disease , and many pneumothoraces occur after physical trauma to the chest, blast...
), the lungs collapse as a result of their inherent elastic recoil. Under physiological conditions the transpulmonary pressure is always positive; intrapleural pressure is always negative and relatively large, while alveolar pressure moves from slightly positive to slightly negative as a person breathes. For a given lung volume the transpulmonary pressure is equal and opposite to the elastic recoil pressure of the lung.
The transpulmonary pressure vs Volume curve of inhalation (usually plotted as Volume in function of Pressure) is different from that of exhalation, the difference being described as hysteresis. Lung volume at any given pressure during inhalation is less than the lung volume at any given pressure during exhalation.
Measurement
Transpulmonary pressure can be measured by placing pressure transducers. The alveolar pressure is estimated by measuring the pressure in the airways while holding one's breath. The intrapleural pressure is estimated by measuring the pressure inside a balloon placed in the esophagusEsophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...
.
Measurement of transpulmonary pressure assists in spirometry
Spirometry
Spirometry is the most common of the pulmonary function tests , measuring lung function, specifically the measurement of the amount and/or speed of air that can be inhaled and exhaled...
in availing for calculation of static lung compliance.