The pressure is computed assuming an International standard sea-level pressure datum of 1013.25 hPa, and therefore is not necessarily the same as the aircraft's true altitude either above mean sea level or above ground level.he pressure is computed assuming an International standard sea-level pressure datum of 1013.25 hPa, and therefore is not necessarily the same as the aircraft's true altitude either above mean sea level or above ground level.
The term pleurisy (pleuritis) is inflammation or infection in the pleural space around the lungs. Pyothorax also known as empyema of the pleural cavity is the presence of pus in the pleural cavity between the layers of the pleural membrane Py/o-Pus.
Causes of Pleural Effusions. The pleura is a thin membrane that lines the surface of the lungs and the inside of the chest wall outside the lungs. In pleural effusions, fluid accumulates in the space between the layers of pleura.leural effusions often cause no symptoms. Symptoms are more likely when a pleural effusion is moderate or large-sized, or if inflammation is present. Symptoms of pleural effusions may include: 1  Shortness of breath. 2  Chest pain, especially on breathing in deeply (pleurisy, or pleuritic pain). 3  Fever.