Thoracentesis Technique

Updated: Apr 24, 2017
  • Author: Mark E Brauner, DO; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Technique

Approach Considerations

Proper personnel resources should be ensured, appropriate equipment collected, and diagnostic laboratory studies preordered, as necessary.

The clinician should become comfortable with the equipment available at the facility. If necessary, an unused kit or one from an aborted procedure may be opened to permit evaluation of the components. The clinician should likewise become comfortable with the ultrasound machine and learn how to adjust key functions such as depth and overall gain.

Anxiolysis should be considered and good local analgesia provided. Thoracentesis can be fraught with patient anxiety, and pain is the most common complication. If mild sedation is being considered, intravenous (IV) medications should be administered to the patient in advance.

The patient should be positioned appropriately. Thoracentesis can be performed with the patient sitting upright and leaning over a Mayo stand or with the patient supine (via an axillary approach).

Next:

Thoracentesis (Thoracocentesis)

Thoracentesis is performed as follows. [11]

Bedside ultrasonography

After the patient has been positioned, ultrasonography is performed to confirm the pleural effusion, assess its size, look for loculations, and determine the optimal puncture site. Either a curvilinear transducer (2-5 MHz) or a high-frequency linear transducer (7.5-1 MHz) may be used (see the image below). The diaphragm is brightly echogenic and should be clearly identified. Its exact location throughout the respiratory cycle should be determined. It is important to select a rib interspace into which the diaphragm does not rise up at end-exhalation.

Ultrasound image using curvilinear probe. Image sh Ultrasound image using curvilinear probe. Image shows chest wall and large volume of pleural fluid.

Motion-mode (M-mode) ultrasonography can also be used to determine the depth of the lung and the amount of fluid between the chest wall and the visceral pleura (see the image below). Freely floating lung can be seen as wavelike undulations on the M-mode tracing.

Ultrasound image in M-mode showing sinusoidal wave Ultrasound image in M-mode showing sinusoidal wave pattern. This is created by the lung moving within the large pleural effusion during respiration. The depth of the lung and the amount of fluid between the parietal pleura (adherent to the chest wall) and visceral pleura (adherent to lung tissue) are easily measured with ultrasonography.

Bedside ultrasonography is a useful guide for thoracentesis: It can determine the optimal puncture site, improve the administration of local anesthetics, and, most important, minimize the complications of the procedure. [2]

The optimal puncture site may be determined by searching for the largest pocket of fluid superficial to the lung and by identifying the respiratory path of the diaphragm (see the video below). Traditionally, this is between the seventh and ninth rib spaces and between the posterior axillary line and the midline. Bedside ultrasonography can confirm the optimal puncture site, which is then marked.

Video clip of ultrasound using the linear probe. Image demonstrates 2 ribs with their associated acoustic shadows, rib interspace, pleural fluid, and the presence of the diaphragm rising up into this rib interspace.

Preparation of puncture site

Standard aseptic technique is used for the remaining steps of the procedure. Sterile probe covers are available and should be used if thoracentesis is performed under real-time ultrasonographic guidance.

A wide area is cleaned with an antiseptic bacteriostatic solution. [12] Chlorhexidine solution is preferred for preparing the skin (see the image below); it dries faster and is far more effective than povidone-iodine solution.

Application of chlorhexidine solution. Application of chlorhexidine solution.

A sterile drape is placed over the puncture site (see the first image below), and sterile towels are used to establish a large sterile field within which to work (see the second image below).

Sterile drape with fenestration and adhesive strip Sterile drape with fenestration and adhesive strip placed over puncture site, with sterile towels draping a large work area.
Sterile towels on the bed, creating a large steril Sterile towels on the bed, creating a large sterile work space.

If the patient has loose skin or significant subcutaneous tissue, the puncture site can be optimized by using 3-inch tape to pull the skin or subcutaneous tissue out of the way before marking the spot and cleaning the puncture site.

The skin, subcutaneous tissue, rib periosteum, intercostal muscles, and parietal pleura should be well infiltrated with anesthetic (lidocaine 1-2%) (see the image below). Infiltration can also be guided by real-time ultrasonography using a high-frequency linear transducer (7.5-10 MHz).

Administering anesthesia to the skin, subcutaneous Administering anesthesia to the skin, subcutaneous tissue, rib periosteum, intercostal muscle, and parietal pleura.

Insertion of device or catheter and drainage of effusion

If a commercially available device or a large intravenous catheter is being used, the skin should be nicked with a No. 11 scalpel blade to reduce drag as the catheter is advanced through the skin (see the image below).

Nicking the skin with scalpel to reduce skin drag Nicking the skin with scalpel to reduce skin drag as the catheter is advanced through the skin.

With aspiration initiated, the device is advanced over the superior aspect of the rib until pleural fluid is obtained (see the image below). The neurovascular bundle is located at the inferior border of the rib and should be avoided.

Advancing the device over the superior aspect of t Advancing the device over the superior aspect of the rib.

Most commercial devices have a marker at 5 cm (see the image below). At this depth, the hemithorax is usually entered, and the needle need not need be advanced any further.

The 5-cm mark is at the level of the skin. The 5-cm mark is at the level of the skin.

The catheter is then fed over the needle introducer (see the first image below). In most cases, it can be fed all the way to the hub (see the second image below).

Feeding the catheter over the needle introducer. Feeding the catheter over the needle introducer.
The catheter is fed all the way to the hub. The catheter is fed all the way to the hub.

With either a syringe pump or a vacuum bottle, the pleural effusion is drained until the desired volume has been removed for symptomatic relief or diagnostic analysis (see the image below).

Use the manual syringe pump method or a vacuum bot Use the manual syringe pump method or a vacuum bottle. The syringe pump method (shown here) is more labor intensive and can cause thumb neurapraxia in the operator.

Completion of procedure

The catheter or needle is carefully removed, and the wound is dressed. If there is any doubt, pleural fluid should be sent for diagnostic analysis (see below); in practice, diagnostic analysis is almost always necessary. The patient is repositioned as appropriate for his or her comfort and respiratory status.

Finally, a procedure note is written, commenting specifically on the descriptive characteristics of the pleural fluid.

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