1、ContentsAnatomy and Mechanism of pleural fluidsturnoverEtiology and pathogenesis of pleural effusionsClinical manifestationsRadiographic ExaminationApproach to the patient with pleural effusionsManagement of patient with pleural effusions1Dr. Canmao xieThe pleural space is not really a space but rat
2、her a potential space between the lung and chest wall. It is a crucial feature of the breathing apparatus since pleurae serves as a coupling system between the lung and chest wall.Introduction2Dr. Canmao xieIntroductionThere is normally a very thin layer of fluid (from 2 to 10 m thick) between the t
3、wo pleural surfaces, the parietal pleura and visceral pleura. The pleural space and the fluid within it are not under static conditions. During each respiratory cycle the pleural pressures and the geometry of the pleural space fluctuate widely. Fluid enters and leaves the pleural space constantly .
4、3Dr. Canmao xieAnatomy of the Pleural SpaceThe serous membrane covering the lung parenchyma is called the visceral pleura. The remainder of the lining of the pleural cavity is designated the parietal pleura. The parietal pleura receives its blood supply from the systemic capillaries. The visceral pl
5、eura is supplied predominantly by branches of the bronchial artery in humans.Dr. Canmao xie 4SC: Systemic capillaries PC: Pulmonary capillaries The lymphatic vessels in the parietal pleura are in direct communication with the pleural space by means of stomas. These stomas are the only route through
6、which cells and large particles can leave the pleural space.Although there are abundant lymphatics in the visceral pleura, these lymphatics do not appear to participate in the removal of particulate matter from the pleural space. Dr. Canmao xie 5SC: Systemic capillaries PC: Pulmonary capillaries Ana
7、tomy of the Pleural SpaceFigure 1. Anatomy of the pleural spaceSC: Systemic capillaries PC: Pulmonary capillaries 6Dr. Canmao xiestomasstomaselectronic microscopyFigure 2. pleural fluids turnoverPF enter the pleural space through parietal & visceral pleurae,And leave pleural space through lymphatics
8、 in parietal pleuraDr. Canmao xieThe passage of protein-free liquid across the pleural membranes is dependent on the hydrostatic and oncotic pressures across them. When the capillaries in the parietal pleura are considered, it can be seen that the net hydrostatic pressure favoring the movement of fl
9、uid from these capillaries to the pleural space is the systemic capillary pressure (30cm H2O) minus the negative pleural pressure (-5cm H2O) or 35cm H2O. Opposing this is the oncotic pressure in the blood (34cm H2O) minus the oncotic pressure in the pleural fluid (5 cm H2O), or 29cm H2O. The resulti
10、ng net pressure differences of 6 cm H2O (35-29) favors movement of fluid from the parietal pleura into the pleural space. Mechanism of pleural fluids turnover8Dr. Canmao xieFigure. Diagrammatic representation of the pressures involved in the formation and absorption of pleural fluid.Parietal Pleura
11、VisceralPleura Space PleuraHydrostatic Pressure+30 - 5 + 2435 296 0Net29 29+ 34 + 5 +34Oncotic Pressure9Dr. Canmao xieMechanism of pleural fluids turnoverThe net rate of pleural fluid formation in animals with thick pleura is approximately 0.01 ml/kg/hr or 15 ml per 24 hr. Normally, the pleural space is maintained nearly fluid free because the filtered fluid is removed from the pleural space by the pleural lymphatics, which can remove over 0.20 ml/kg/hr . 10Dr. Canmao xie
