Norm of Thoracentesis

Amount <20 mL Cells Few lymphocytes, few red blood cells
Color Clear    
Specific gravity <1.016 Lactate Equal to serum level
pH Equal to serum level dehydrogenase  
Protein <3 g/dL Glucose Equal to serum level
Fibrinogen None Amylase Equal to serum level


Usage of Thoracentesis

Therapeutic: Relieves dyspnea because of pleural effusion.
Diagnostic: Evaluates underlying cause of pleural effusion. Abnormal accumulation of fluid in the pleural space may be classified as either transudate or exudate.


Color Clear Cloudy, turbid
Specific gravity <1.016 >1.016
pH Equal to serum level <7.3
Protein <3 g/dL >3 g/dL
Fibrinogen None or may be present Present
Cells Few lymphocytes Many; may be a few red blood cells or purulent
Lactate Equal to serum level May be >lactate dehydrogenase, serum
Glucose Equal to serum level May be <serum
Amylase Equal to serum level May be >serum


Description of Thoracentesis

Thoracentesis is the removal of fluid or air from the pleural space by transthoracic aspiration. It is performed to determine the nature or cause of an effusion, to relieve dyspnea caused by an effusion, or to obtain fluid for testing.


Professional Considerations of Thoracentesis

Consent form IS required.

The risk of pneumothorax as a complication is small if the needle is withdrawn immediately. Also air embolism, bradycardia, hypertension, pulmonary edema.
Bleeding disorders or anticoagulated state, uncontrolled coughing.



  1. The procedure may be preceded by ultrasonography or chest radiography.
  2. Identify the upper border of the effusion by the loss of fremitus and the presence of flat percussion. The thoracentesis will be performed in the interspace below this level and 5–10 cm lateral to the spine.
  3. Obtain sterile gloves, injectable lidocaine, a thoracentesis tray, collection bottles with heparin, sterile 4- × 4-inch gauze pads, tape, a container of ice, and povidone-iodine solution.
  4. Obtain baseline vital signs.
  5. List any recent antibiotic therapy on the laboratory requisition.
  6. Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.



  1. The client is positioned sitting upright, often in the orthopneic position, with arms and head supported by a table at the bedside. Clients who cannot sit up are placed in the lateral decubitus position, lying on the side of the effusion, near the edge of the bed. This procedure can be performed on those who are ventilator dependent.
  2. The skin is cleansed with povidone-iodine solution.
  3. The underlying tissue at the previously identified effusion site is anesthetized.
  4. A 20-gauge or larger needle is placed immediately above the superior aspect of the lower rib and advanced until the parietal membrane is penetrated and no more than 1 L of fluid is aspirated.
  5. At least 50 mL of fluid is needed for diagnostic studies. Place syringe on ice for transport to the laboratory.


Postprocedure Care

  1. Apply a pressure dressing and assess the puncture site for bleeding and crepitus every 5 minutes × 6.
  2. Assess vital signs every 30 minutes × 4.
  3. A follow-up chest radiograph should be taken within several hours of the procedure, or immediately if respiratory distress is exhibited.


Client and Family Teaching

  1. Describe the procedure and the usual sensations the client may expect related to the test.
  2. Do not cough, breathe deeply, or move during the procedure.


Factors That Affect Results

  1. Complications that affect results include air embolism, hemothorax, pneumothorax, and pulmonary edema.
  2. Transudate in the pleural space may be caused by ascites, cirrhosis (hepatic), congestive heart failure, hypertension (pulmonary, systemic), nephritis, and nephrosis.
  3. Exudate in the pleural space may be caused by blocked lymphatic drainage, empyema, esophageal rupture, infarction (pulmonary), infection, neoplasm, pancreatitis, rheumatoid arthritis, systemic lupus erythematosus, thoracic duct disruption, accidental injury, and tuberculosis.
  4. Allowing fluid to stand for a prolonged period before processing may cause deterioration and artifacts.


Other Data

  1. If the thoracentesis is performed below the tenth intercostal space, care should be taken to avoid laceration of the spleen or liver or penetration of the diaphragm (ipsilateral shoulder pain is a sign of diaphragmatic penetration).
  2. Malignant cells cannot be recovered from all fluids for clients with malignancies.
  3. Increased amylase levels in the effusion are associated with pancreatitis, lung cancer, and esophageal perforation.
  4. The most common pathogens found in pleural effusions are Mycobacterium tuberculosis, Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae.