Thoracentesis

Diagnostic: Acquisition of pleural fluid for analysis

Therapeutic: Relief of respiratory distress caused by pleural fluid

CONTRAINDICATIONS

Absolute

Traumatic hemo- or pneumothorax (tube thoracostomy is more appropriate)

Relative

Platelet count <50,000

Prothrombin time (PT)/partial thromboplastin time (PTT) >2 × normal

Cutaneous infection (e.g., herpes zoster)

Mechanical ventilation (small pneumothorax can become a tension)

Uncooperative or agitated patient

Effusion contralateral to a prior pneumonectomy side

RISKS

Generally an elective procedure. Informed consent is required.

Injury to lung (tube thoracostomy may be required if a pneumothorax develops)

Infection (sterile technique will be utilized)

Injury to liver or spleen

Pain (local anesthesia will be given)

Local bleeding

LANDMARKS

Posterior approach is most common

Identify the midscapular line and mark the site one to two rib spaces below the superior portion of the effusion

Intercostal neurovascular bundle runs along the inferior portion of the rib. The needle should be inserted superiorly (FIGURE 8.1).

Hemidiaphragm changes level with respiration. A thoracentesis should not be performed below the eighth intercostal space, given the risk for splenic or hepatic injury.

TECHNIQUE

General Basic Steps

Preparation

Identify site

Sterilize

Analgesia

Needle insertion

Aspiration

Preparation

Place the patient on oxygen

Place the patient in upright (most common), lateral decubitus, or supine position

Arrange materials on a sterile towel (FIGURE 8.2)

FIGURE 8.1 Relations of structures within an intercostal space (A). Intercostal vessels and nerves are shown in (B). Collateral vessels are shown. A, artery; V, vein; N, nerve.

FIGURE 8.2 Landmarks for the posterior approach.

Identify the Thoracentesis Site

Dullness to percussion, decreased breath sounds, and decreased tactile fremitus can be used to identify the superior margin of the effusion

Ultrasound is more accurate than physical examination for identifying effusions

Mark needle insertion site one to two rib spaces below the superior margin of the effusion

Sterilize

Sterilize a wide area surrounding the insertion site

Drape the area with sterile towels

Observe sterile technique for the remainder of the procedure

Analgesia

Use lidocaine with epinephrine (1% lidocaine is 10 mg/mL of solution). Usually 5 to 10 mL is required.

Inject the subcutaneous tissue with a small-bore (25-gauge) needle and raise a wheal at the superior margin of the selected rib in the midscapular or posterior axillary line

Alternating between aspiration and injection, advance to the superior portion of the posterior rib and anesthetize the periosteum

Gently advance the needle over the superior portion of the rib while infiltrating with lidocaine

Slowly advance the needle while aspirating, until pleural fluid is aspirated. Withdraw the needle 1 to 2 mm and inject 2 to 4 mL of lidocaine to anesthetize the parietal pleura. Though the visceral pleura are not innervated with pain fibers, the parietal pleura are quite sensitive.

Mark the depth of the chest wall by grasping the needle at the level of the skin with either your thumb and index finger or a Kelly clamp and withdraw the needle

Needle Insertion

Make a stab incision parallel to the rib at the marked site for easier insertion of the thoracentesis needle

Attach a 60-mL syringe to the catheter-clad needle. Insert the thoracentesis needle, with the bevel inferiorly, through the skin over the selected rib.

Advance the needle over the superior portion of the posterior rib, aspirating until pleural fluid is encountered

As the catheter enters the pleural space, angle the needle caudally and push the catheter off the needle into the pleural space

Occlude the lumen of the catheter (FIGURE 8.3)

Drain Pleural Fluid

Attach the three-way stopcock to the catheter hub. Set the stopcock valve to occlude the catheter port.

Attach the 60-mL syringe to one port of the three-way stopcock

Turn the stopcock valve to connect the syringe with the catheter and withdraw fluid from the pleural space. Turn the stopcock to connect the syringe to the intravenous tubing and empty the syringe into the collection bag or bottle. Continue this procedure until no further fluid drainage is desired.