Pleural pressure

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As pleural pressure (p Pleu , and intrapleural pressure , intrathoracic pressure ) refers to the differential pressure between the in Pleuraspalt prevailing pressure and the external pressure (atmospheric pressure or air pressure ). It depends on the elastic tension of the lungs and the expansion of the thoracic cavity and, if the actual pressure on the body surface to be added is assumed to be zero, it corresponds to the transthoracic pressure .

With normal breathing, the pleural pressure is always subatmospheric and takes values ​​between −0.8 kPa ( end-inspiratory ) and −0.5 kPa ( end-expiratory ). With forced expiration, ie "squeezing" with the help of the auxiliary expiratory muscles, the pleural pressure can increase, but it never becomes positive.

A direct measurement of the pleural pressure can be done via a pleural puncture , but it is risky and usually impractical (see also pneumothorax ). In medical use, the so-called “deep esophageal pressure ” is therefore preferably measured at the caudal end of the esophagus , since comparable pressure conditions exist at this location. To do this, the patient has to swallow a thin catheter , at the end of which there is a pressure sensor that the doctor places near the stomach entrance. In order to obtain the most accurate results possible, the measurement should be carried out with the chest upright.

literature

  • F. Lang, Ph. Lang: Basic Knowledge Physiology , Springer, Berlin 2008 (2nd edition), ISBN 978-3540714019 ( online ).
  • P. Lotz: Anatomy and Physiology of the Respiratory Tract. In: J. Kilian, H. Benzer, FW Ahnefeld (ed.): Basic principles of ventilation. Springer, Berlin a. a. 1991, ISBN 3-540-53078-9 , pp. 3-45; here: p. 7 f.
  • Thomas Pasch, S. Krayer, HR Brunner: Definition and measurands of acute respiratory insufficiency: ventilation, gas exchange, breathing mechanics. In: J. Kilian, H. Benzer, FW Ahnefeld (ed.): Basic principles of ventilation. Springer, Berlin a. a. 1991, ISBN 3-540-53078-9 , 2nd, unchanged edition, ibid 1994, ISBN 3-540-57904-4 , pp. 93-108; here: p. 102 f.