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How to Do Thoracentesis

By Noah Lechtzin, MD, MHS, Johns Hopkins University School of Medicine

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Patient Education

Thoracentesis is needle aspiration of fluid from a pleural effusion. It may be done for diagnosis or therapy.

Indications

  • Diagnostic thoracentesis: Indicated for almost all patients who have pleural fluid that is new or of uncertain etiology and is ≥ 10 mm in thickness on CT scan, ultrasonography, or lateral decubitus x-ray (see Figure: Diagnosis of pleural effusion)

  • Therapeutic thoracentesis: Indicated to relieve symptoms in patients with dyspnea caused by a large pleural effusion

Diagnostic thoracentesis is usually not needed when the etiology of the pleural fluid is apparent (eg, viral pleurisy, typical heart failure).

Selection of laboratory tests typically done on pleural fluid is discussed in pleural effusion.

If pleural fluid continues to reaccumulate after several therapeutic thoracenteses, pleurodesis (injection of an irritating substance into the pleural space) may help prevent recurrence. Pleurodesis is most commonly done to prevent reaccumulation of malignant effusions.

Contraindications

There are no absolute contraindications to thoracentesis.

Relative contraindications include

  • Bleeding disorder or anticoagulation

  • Uncertain fluid location

  • Minimal fluid volume

  • Altered chest wall anatomy

  • Pulmonary disease severe enough to make complications life threatening

  • Uncontrolled coughing

Complications

Major complications include

  • Pneumothorax

  • Bleeding (hemoptysis due to lung puncture)

  • Re-expansion pulmonary edema and/or hypotension ( 1)

  • Hemothorax due to damage to intercostal vessels

  • Puncture of the spleen or liver

  • Vasovagal syncope

Bloody fluid that does not clot in a collecting tube indicates that blood in the pleural space was not iatrogenic, because free blood in the pleural space rapidly defibrinates.

Equipment

  • Local anesthetic (eg, 10 mL of 1% lidocaine), 25-gauge and 20- to 22-gauge needles, and 10-mL syringe

  • Antiseptic solution with applicators, drapes, and gloves

  • Thoracentesis needle and plastic catheter

  • 3-way stopcock

  • 30- to 50-mL syringe

  • Wound dressing materials

  • Bedside table for patient to lean on

  • Appropriate containers (eg, red top and purple top tubes, blood culture bottles) for collection of fluid for laboratory tests

  • Evacuated containers (vacuum bottle) or collection bags for removal of larger volumes during therapeutic thoracentesis

  • Ultrasound machine (if the procedure is ultrasonically guided)

Additional considerations

  • Thoracentesis can be safely done at the patient’s bedside or in an outpatient setting.

  • Ample local anesthetic is necessary, but procedural sedation is not required in cooperative patients.

  • Thoracentesis needle should not be inserted through infected skin (eg, cellulitis or herpes zoster).

  • Positive pressure ventilation can increase the risk of complications.

  • If the patient is receiving anticoagulant drugs (eg, warfarin), consider giving fresh frozen plasma or another reversal agent prior to the procedure.

  • Bloody fluid that does not clot in a collecting tube indicates that blood in the pleural space was not iatrogenic, because free blood in the pleural space rapidly defibrinates.

  • Only unstable patients and patients at high risk of decompensation due to complications require monitoring (eg, pulse oximetry, ECG).

Positioning

  • Best done with the patient sitting upright and leaning slightly forward with arms supported.

  • Recumbent or supine thoracentesis (eg, in a ventilated patient) is possible but best done with ultrasound or CT guidance.

Relevant anatomy

  • The intercostal neurovascular bundle is located along the lower edge of each rib. Therefore, the needle must be placed over the upper edge of the rib to avoid damage to the neurovascular bundle.

  • The liver and spleen rise during exhalation and can go as high as the 5th intercostal space on the right (liver) and 9th intercostal space on the left (spleen)

Step-by-step description of procedure and key teaching points

  • Explain the procedure to the patient and obtain written informed consent.

  • Confirm the extent of the pleural effusion by chest percussion and consider an imaging study; bedside ultrasonography is very helpful when available ( 2). If the effusion is small or loculated, ultrasound should be used to identify the location of the fluid.

  • Select a needle insertion point in the mid-scapular line at the upper border of the rib one intercostal space below the top of the effusion.

  • Mark the insertion point and prepare the area with a skin cleansing agent such as chlorhexidine and apply a sterile drape while wearing sterile gloves.

  • Using a 25-gauge needle, place a wheal of local anesthetic over the insertion point. Switch to a larger (20- or 22-gauge) needle and inject anesthetic progressively deeper until reaching the parietal pleura, which should be infiltrated the most because it is very sensitive. Continue advancing the needle until pleural fluid is aspirated and note the depth of the needle at which this occurs.

  • Attach a large-bore (16- to 19-gauge) thoracentesis needle-catheter device to a 3-way stopcock, place a 30- to 50-mL syringe on one port of the stopcock and attach drainage tubing to the other port.

  • Insert the needle along the upper border of the rib while aspirating and advance it into the effusion.

  • When fluid or blood is aspirated, insert the catheter over the needle into the pleural space and withdraw the needle, leaving the catheter in the pleural space. While preparing to insert the catheter, cover the needle opening during inspiration to prevent entry of air into the pleural space.

  • Withdraw 30 mL of fluid into the syringe and place the fluid in appropriate tubes and bottles for testing.

  • If a larger amount of fluid is to be drained, turn the stopcock and allow fluid to drain into a collection bag or bottle. Alternatively, aspirate fluid using the syringe, taking care to periodically release pressure on the plunger.

  • If a large amount of fluid (eg, > 500 mL) is withdrawn, monitor patient symptoms and blood pressure and stop drainage if the patient develops chest pain, dyspnea, or hypotension. Some clinicians recommend withdrawing no more than 1.5 L in 24 h, although there is little evidence that the risk of re-expansion pulmonary edema is directly proportional to the volume of fluid removed. Thus it may be reasonable for experienced operators to completely drain effusions in one procedure in properly monitored patients.

  • Remove the catheter while patient is holding breath or expiring. Apply a sterile dressing to the insertion site.

Aftercare

  • Sometimes chest x-ray

  • Analgesia with oral NSAIDs or acetaminophen if needed

  • Advise patients to report any shortness of breath or chest pain; coughing is common after fluid removal and not a cause for concern.

It has been standard practice to obtain a chest x-ray after thoracentesis to rule out pneumothorax, document the extent of fluid removal, and view lung fields previously obscured by fluid, but evidence suggests that routine chest x-ray is not necessary in asymptomatic patients. A chest x-ray is needed for any of the following:

  • The patient is ventilated

  • Air was aspirated

  • The needle was passed more than once

  • Symptoms or signs of pneumothorax develop

Warnings and common errors

  • Be sure to adequately anesthetize the parietal pleura.

  • Be sure to insert the thoracentesis needle just above the upper edge of the rib and not below the rib, to avoid the intercostal blood vessels and nerves at the lower edge of each rib.

Tips and tricks

  • When marking the insertion point, use a skin marking pen or make an impression with a pen so that the skin cleansing prep will not remove the mark.

References

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Drugs Mentioned In This Article

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  • TYLENOL
  • COUMADIN
  • XYLOCAINE

* This is the Professional Version. *