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How To Do Thoracentesis


Rebecca Dezube

, MD, MHS, Johns Hopkins University

Reviewed/Revised Jul 2022 | Modified Sep 2022
Topic Resources

Thoracentesis may be done for diagnosis and/or therapy.

Indications for Thoracentesis

Diagnostic thoracentesis

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

Therapeutic thoracentesis

  • To relieve symptoms in patients with dyspnea caused by a large pleural effusion

If pleural fluid continues to reaccumulate after several therapeutic thoracenteses, pleurodesis (injection of an irritating substance into the pleural space, which causes obliteration of the space) may help prevent recurrence. Alternatively, placement of an indwelling pleural catheter can allow drainage of pleural fluid by patients at home. Pleurodesis and placement of an indwelling pleural catheter are most commonly done to manage malignant effusions.

Contraindications to Thoracentesis

Absolute contraindications

  • None

Relative contraindications

  • Bleeding disorder or anticoagulation

  • Altered chest wall anatomy

  • Cellulitis or herpes zoster at the site of thoracentesis puncture

  • Pulmonary disease severe enough to make complications life threatening

  • Uncontrolled coughing or an uncooperative patient

Complications of Thoracentesis

Equipment for Thoracentesis

  • 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 for collection of fluid for laboratory tests

  • Collection bags for removal of larger volumes during therapeutic thoracentesis

  • Ultrasound machine

Additional Considerations for Thoracentesis

  • 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.

  • Hemorrhagic complications are infrequent after ultrasound-guided thoracentesis in patients with abnormal preprocedural coagulation parameters (2 References Thoracentesis is needle aspiration of fluid from a pleural effusion. Thoracentesis may be done for diagnosis and/or therapy. Diagnostic thoracentesis Indicated for almost all patients who have... read more References ).

  • 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, electrocardiography [ECG]).

Relevant Anatomy for Thoracentesis

  • 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).

Positioning for Thoracentesis

  • 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 using ultrasonography or CT to guide procedure.

Step-by-Step Description of Thoracentesis

  • Confirm the extent of the pleural effusion by chest percussion and consider an imaging study; bedside ultrasonography is recommended both to reduce the risk of pneumothorax and to increase the success of the procedure (3 References Thoracentesis is needle aspiration of fluid from a pleural effusion. Thoracentesis may be done for diagnosis and/or therapy. Diagnostic thoracentesis Indicated for almost all patients who have... read more References ).

  • 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. Coughing is normal and represents lung re-expansion. Some clinicians recommend withdrawing no more than 1.5 L in 24 hours, although there is little evidence that the risk of re-expansion pulmonary edema is directly proportional to the volume of fluid removed (1 References Thoracentesis is needle aspiration of fluid from a pleural effusion. Thoracentesis may be done for diagnosis and/or therapy. Diagnostic thoracentesis Indicated for almost all patients who have... read more References ). Animal data suggest that rapidly draining long-standing effusions may lead to re-expansion pulmonary edema by decreasing surfactant. 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.

Thoracentesis Using Ultrasonographic Guidance

Aftercare for Thoracentesis

  • Sometimes imaging (usually chest x-ray or ultrasonography) to exclude pneumothorax

  • Analgesia with oral nonsteroidal anti-inflammatory drugs (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. Pneumothorax can also be excluded by the presence of lung sliding on multiple interspaces on ultrasonography, but ultrasonography is also not necessary routinely (4 References Thoracentesis is needle aspiration of fluid from a pleural effusion. Thoracentesis may be done for diagnosis and/or therapy. Diagnostic thoracentesis Indicated for almost all patients who have... read more References ). Post-procedural chest imaging 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 for Thoracentesis

  • 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 for Thoracentesis

  • 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.


Drugs Mentioned In This Article

Drug Name Select Trade
7T Lido, Akten , ALOCANE, ANASTIA, AneCream, Anestacon, Aspercreme with Lidocaine, AsperFlex, Astero , BenGay, Blue Tube, Blue-Emu, CidalEaze, DermacinRx Lidocan III, DermacinRx Lidogel, DermacinRx Lidorex, DERMALID, Dologesic, Ela-Max, GEN7T, Glydo, Gold Bond, LidaFlex, LidaMantle, Lido King Maximum Strength, Lidocan, Lidocare, Lidoderm, LidoDose, LidoDose Pediatric, Lidofore, LidoHeal-90, LIDO-K , LidoLite, Lidomar , Lidomark, LidoPure, LidoReal-30, LidoRx, Lidosense 4 , Lidosense 5, Lidosol, Lidosol-50, LIDO-SORB, Lidotral, Lidovix L, LIDOZION, Lidozo, LMX 4, LMX 4 with Tegaderm, LMX 5, LTA, Lubricaine For Her, Lydexa, Moxicaine, Numbonex, ReadySharp Lidocaine, RectaSmoothe, RectiCare, Salonpas Lidocaine, Senatec, Solarcaine, SUN BURNT PLUS, Tranzarel, Xyliderm, Xylocaine, Xylocaine Dental, Xylocaine in Dextrose, Xylocaine MPF, Xylocaine Topical, Xylocaine Topical Jelly, Xylocaine Topical Solution, Xylocaine Viscous, Zilactin-L, Zingo, Zionodi, ZTlido
Coumadin, Jantoven
Betasept, Chlorostat, DYNA-HEX, Hibiclens, Oro Clense , Peridex, Periogard, PerioRx , Perisol
7T Gummy ES, Acephen, Aceta, Actamin, Adult Pain Relief, Anacin Aspirin Free, Aphen, Apra, Children's Acetaminophen, Children's Pain & Fever , Children's Pain Relief, Comtrex Sore Throat Relief, ED-APAP, ElixSure Fever/Pain, Feverall, Genapap, Genebs, Goody's Back & Body Pain, Infantaire, Infants' Acetaminophen, LIQUID PAIN RELIEF, Little Fevers, Little Remedies Infant Fever + Pain Reliever, Mapap, Mapap Arthritis Pain, Mapap Infants, Mapap Junior, M-PAP, Nortemp, Ofirmev, Pain & Fever , Pain and Fever , PAIN RELIEF , PAIN RELIEF Extra Strength, Panadol, PediaCare Children's Fever Reducer/Pain Reliever, PediaCare Children's Smooth Metls Fever Reducer/Pain Reliever, PediaCare Infant's Fever Reducer/Pain Reliever, Pediaphen, PHARBETOL, Plus PHARMA, Q-Pap, Q-Pap Extra Strength, Silapap, Triaminic Fever Reducer and Pain Reliever, Triaminic Infant Fever Reducer and Pain Reliever, Tylenol, Tylenol 8 Hour, Tylenol 8 Hour Arthritis Pain, Tylenol 8 Hour Muscle Aches & Pain, Tylenol Arthritis Pain, Tylenol Children's, Tylenol Children's Pain+Fever, Tylenol CrushableTablet, Tylenol Extra Strength, Tylenol Infants', Tylenol Infants Pain + Fever, Tylenol Junior Strength, Tylenol Pain + Fever, Tylenol Regular Strength, Tylenol Sore Throat, XS No Aspirin, XS Pain Reliever
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