Video of procedure

Takes about 3 minutes



Screening for Thoracentesis

  1. History of bleeding disorders or use of anticoagulants
  2. Chest x-ray : Make sure that the fluid is not loculated. This will have a bearing on the Thoracentesis site.
  3. Platelet count and PT should be reviewed in patients in whom you have reason to believe they could be abnormal. It is not necessary to perform them routinely in other clinical situations.


Selection of Site

The posterior approach is superior.

  1. The posterior gutter is deep and is the dependent site where the fluid tends to accumulate in the erect position.
  2. The interspaces are wider in the back as compared to the front.
  3. The neurovascular bundle is closer to the inferior margin of the rib posteriorly. Thus, there is a safer space to enter the chest.

It is scary to see the needle enter the chest. Hence, the anterior approach is not preferred.

If we select the axillary approach, it is inconvenient to position the patient's arm for the duration of the procedure. The arm will be in the way.





Steps of the procedure


Wing the Scapula

Prepare the Site




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The possible complications of Thoracentesis are as follows:

  1. Pneumothorax: There are two types of pneumothoraxes which can follow a Thoracentesis.

    The first one is secondary to the introduction of air from the outside. This is benign and does not give rise to any symptoms. It should be left alone.

    The second type of Pneumothorax occurs due to an accidental puncture of the lung. If the patient is asymptomatic, keep him under observation and follow the patient's progress with a serial chest x-ray. Usually, the puncture in the lung seals and air will be absorbed spontaneously. If the patient is symptomatic, chest tube drainage may be necessary.

  2. Hemothorax: Bleeding is a possibility during a Thoracentesis. Fortunately, this is rare. Injury to an intercostal artery is fortunately rare since physicians seem to be aware of their location and avoid it during Thoracentesis.
  3. Vaso-Vagal Syncope
  4. Empyema Empyema is a dreaded complication.  Follow strict surgical aseptic techniques to avoid it.
  5. Laceration of the Liver or Spleen
  6. Tumor Seeding Implantation of tumor cells through a Thoracentesis needle track is an infrequent complication. This occurs with a high degree of frequency in patients with Mesothelioma and may pose problems. However, with other tumors, it is of little significance.
  7. Pain  Pain during the procedure is due to poor technique in the use of a local anesthetic. Occasionally you may encounter a patient who is so high strung that even touching him may cause pain! Try premedication and reassurance if this should be the case. Mild pain is to be anticipated for 24 hours after the procedure. If the patient complains of shoulder pain during the procedure, it indicates that the needle is piercing the diaphragmatic pleura. The site of the tap is too low.
  8. Extravasation of Fluid
    Subcutaneous Seroma: If the fluid is under tension, extravasation can occur along the needle track to the subcutaneous tissue. In some patients, this is massive, disfiguring chest and abdominal wall. Anticipate this complication in massive effusions, particularly when the fluid spurts out or fills the syringe forcefully during the Thoracentesis. You may want to release the pressure by evacuating some fluid and following it up with a firm pressure bandage. Should this occur, reassure the patient. Usually, it gets reabsorbed in a matter of days.

    Seneff, et al, carried out a prospective evaluation of the spectrum and frequency of complications associated with Thoracentesis. I highly recommend your attention to this article. The following tables are taken from this reference.

Major Complications
Pneumothorax 11%
Splenic laceration 0.8%
Hemothorax 0.8%
Minor Complications
Pain 22%
Cough 11%
Dry tap 13%
Subcutaneous hamatoma 2%
Subcutaneous seroma 0.8%
The reported complications are in a center with trainees! Please be aware that a Thoracentesis does carry the risk of frequent morbidity. Take every precaution to minimize its occurrence. It is very safe and pain free in the hands of an expert.





Post Thoracentesis Management

Write a procedure note. Be sure to describe the gross appearance of the fluid.

Next you need to consider post procedure orders. The rationale for post procedure orders are as follows:

Most physicians consider ordering a Hb and Hct, Chest x-ray, Vital signs and bed rest.

Following the removal of 50 cc's of fluid for diagnostic purposes, very little changes occur in the patient's chest x-ray. The underlying lung can be visualized only if we deliberately evacuated the pleural space.

I do not order any tests routinely following uncomplicated Thoracentesis. I closely monitor the patient's vital signs, CBC and chest x-ray only if one or more of the following is presented:




Distribution of specimen

Anticipate all of the required tests and obtain the appropriate tubes before the actual procedure. Set up priorities for specimen collection, if something untoward should happen and you are unable to obtain sufficient amount of fluid, send it for the most important test first.

Studies will be dictated by the clinical diagnosis of the etiology of the effusion. Please review the lesson on pleural effusion for assistance.





Special Circumstances

Contraindications: none absolute, relative risk > benefit, bleeding diathesis, small effusion, mechanical ventilation, anticoagulation  One must consider the following special circumstances:

  1. Loculated Effusion:
    The primary concern in loculated effusions is the selection of the Thoracentesis site. The choice of methods available for site selection are:

    Unless there is Empyema necessitates, it is not a good idea to rely on a physical examination to select the site of loculation. You will end up puncturing multiple sites. This is of great pain to the patient. CT is a cumbersome and elaborate test. Ultrasound localization is ideal for this purpose. It may be done at the bedside. The needle can be placed through the probe and evacuation can also be ensured in the same sitting.

  2. Patient on a Ventilator:
    There are two considerations for a Thoracentesis when the patient is on a ventilator:
    1. Risk of Collapsing a Lung:
      The fear is whether positive pressure breathing will increase the risk of a puncture to the lung! My advise is:
      • Do not tap small effusions.
      • Leave it to an experienced physician.
      • Postpone the procedure if the indication is not that urgent.
      • Get a post-tap chest film routinely.
    2. Seating and Positioning:
      You will normally be able to position the patient by the side edge of the bed. You can have the patient rest on an adjustable table. This position will permit you to proceed with the Thoracentesis in the usual fashion.

      If you are unable to seat the patient due to hemodynamic status, mental status or because of tubes and indwelling lines, the Thoracentesis has to be done in the supine position. Turn the patient on his side and bring his back to the edge of the bed. You will be able to accomplish the Thoracentesis in this position.

      Be aware that the dependent diaphragm moves up. Let me show you a lateral decubitus chest x-ray to demonstrate the upward movement of the dependent diaphragm.

      Select the 5th or 6th interspace to avoid possible injury to the diaphragm. The selected site should be close to the surface of the bed.

    3. Patient with a Coagulation Defect:
      Postpone the Thoracentesis until the coagulation defect can be corrected. If the defect cannot be corrected, avoid proceeding with the Thoracentesis. In my opinion, suspected Empyema will be the only acceptable indication for an emergency Thoracentesis. Leave it to an experienced physician to perform this procedure. Use a size 21 or 22 needle. Proceed to attempt with a single stick. Do not give any local anesthetic. Enter the pleural space with one stroke. Do not try multiple attempts. Closely monitor for a Hemothorax by HGB, vital signs and a chest x-ray.






Alternate Techniques

There are alternate devices available for Thoracentesis:

The primary reason for these alternate devices is to circumvent the risk of a lung puncture by a sharp needle. This occurs during the evacuation process as the lung expands and meets the needle.

This should not occur with a diagnostic Thoracentesis where only 50 ml of fluid is removed. If the effusion is small, one should certainly use one of these catheter devices for Thoracentesis. Of course, one should always use a catheter device to evacuate the fluid for a therapeutic Thoracentesis.





Utility of test results:







Selected Exudates (There are many other causes besides these )





Diagnostic yield
Last Updated: Jan 10, 2006
Created: May 28, 1996