3.3.4 Pleural Effusions
Any abnormal fluid in the pleural cavity，the space between the visceral and the parietal pleurae，is called a pleural effusion.Normally，the pleural cavity contains only a small amount of lubricating fluid.However，some disorders may cause excessive fluid to collect in the pleural cavity.Common causes include tumor，infection，and inflammation.Depending on the substances involved，pleural effusions are described as empyema（pus），also termed pyothorax；hemothorax（blood）；or hydrothorax（fluid）.Although not considered as pleural effusion，air can enter the pleural space（pneumothorax），resulting in a partial or complete collapse of a lung.
Two initial techniques used to diagnose pleural effusion are auscultation and percussion.Auscultation is the listening of sounds made by organs of the body using a stethoscope.Percussion is the gentle tapping of the chest with the fingers and listening to the resultant sounds to determine the position，size，or consistency of the underlying structures.Chest X-ray or MRI can be used to confirm the diagnosis.Effusions are classified as transudates and exudates.A transudate is a noninflammatory fluid that resembles serum but with slightly less protein.It results from an imbalance in venous/arterial pressure or decrease of protein in blood.Both of these conditions allow serum to leak from the vascular system and collect in the pleural space.
Treatment is designed to prevent fluid collection from recurring in the pleural space and to relieve the discomfort and dyspnea experienced by the patient.Often，a surgical puncture of the chest using a hollow-bore needle（thoracentesis）is undertaken to remove excess fluid for diagnostic or therapeutic purposes（Fig.3-7）.Sometimes chest tubes are inserted to drain fluid or remove air in pneumothorax.
Fig.3-7 Thoracentesis
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Task 6 Select the best answer according to the text.
1.The function of lubricating fluid is to________.
A.decrease the blood pressure
B.increase the blood pressure
C.increase friction
D.reduce friction
2.Collection of blood in the pleural cavity is called________.
A.hemothorax
B.pleurisy
C.pneumothorax(https://www.daowen.com)
D.pyothorax
3.Pus and air in the pleural cavity are symptomatic of________.
A.hydropneumothorax
B.pyopneumothorax
C.pneumohemothorax
D.pyothorax
4.________is the gentle tapping of a part of the body with the fingers and listening to the resultant sounds for diagnostic purposes.
A.Inspection
B.Percussion
C.Auscultation
D.Palpation
5.A surgical puncture of the chest using a hollow-bore needle is named as________.
A.thoracoscopy
B.stethalgia
C.thoracentesis
D.thoracotomy