Thoracentesis and Pleural Effusions - - Clinical Departments

Thoracentesis and Pleural 

Effusions 

Fletcher T. Penney, MD, FHM 

Medical University of South Carolina 

Department of Medicine 

June 6, 2013 / Hospital Medicine Curriculum 

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Outline 

Introduction 

Indications for Thoracentesis 

Contraindications for Thoracentesis 

How to Perform a Thoracentesis 

How to Analyze Pleural Fluid 

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Learning Objectives 

• To understand which patients should undergo 

thoracentesis 

• To understand contraindications to thoracentesis 

• To understand potential complications of 

thoracentesis 

• To understand how to interpret the results of pleural 

fluid studies 

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Key Messages 

• Dullness to percussion, and the absence of of 

reduced tactile fremitus are the two most useful 

physical exam maneuvers to diagnose or exclude 

pleural effusions. 

• Patients with bilateral pleural effusions, who are 

afebrile and likely have CHF usually do not need a 

thoracentesis. 

• Use ultrasound. 

• Patients with a high probability of a transudative 

effusion only need protein and LDH checked. 

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Outline 

Introduction 





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Does My Patient Have a Pleural Effusion? 

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A systematic review of the accuracy of the physical exam 

in the diagnosis of pleural effusion by Wong et al. 

evaluated 

• percussion 

• auscultatory percussion 

• breath sounds 

• chest expansion 

• tactile vocal fremitus 

• vocal resonance 

• crackles 

• pleural friction rub 

Wong (2009) 

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• Dullness to percussion was the most accurate for 

making the diagnosis (LR+ 8.7) 

• Absence of reduced tactile vocal fremitus made 

effusion less likely (LR- 0.21) 

So, in patients with a low pre-test probability, the absence 

of reduced tactile fremitus may effectively rule out effusion 

without requiring a radiograph. 

Of note, when testing for fremitus having your patient say 

“boy” or “toy” is more accurate than “ninety-nine”. 

Wong (2009) 

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Who Needs a Thoracentesis? 

• Patients with a pleural effusion. . . 

• . . . that is large enough to tap. . . 

• . . . without a known cause. . . 

• . . . and the effusion is at least 10mm thick by 

imaging. 

OR 

• Effusion of known etiology that has re-accumulated in 

order to remove fluid to improve symptoms. 

Light (2002) 

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Who Doesn’t Need a Thoracentesis? 

It is likely appropriate to defer thoracentesis in a patient 

with: 

• Bilateral pleural effusions. . . 

• . . . with a history and exam suggesting CHF. . . 

• . . . without a fever. . . 

• . . . when the effusions resolve within three days. 

Light (2002) 

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Outline 

Introduction 





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Who Shouldn’t Undergo a Thoracentesis? 

• Elevated INR? 

• Thrombocytopenia? 

• Cellulitis overlying the target site? 

• Patients on mechanical ventilation? 

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Elevated INR and Thrombocytopenia 

In a review of 1076 thoracenteses performed by trained 

providers, using ultrasound guidance, there was no 

difference in bleeding complications between patients with 

INR 1.5 (n = 267), INR > 2.0 (n = 

139), INR > 2.5 (n = 59), or INR > 3.0 (n = 32) . 

Similarly, no difference was noted in patients with 

platelets 150k). 

Patel and Joshi (2011) 

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Consensus guidelines (2009 and 2012) from the 

Cardiovascular and Interventional Radiological Society of 

Europe classify thoracentesis as a low risk procedure for 

bleeding, and they recommend: 

• Check INR in patients on warfarin or with 

known/suspected liver disease 

• Check aPTT in patients on heparin 

• Do not routinely check platelets or hematocrit 

• Do not withhold aspirin/hold clopidogrel for five days 

(2012 guidelines) 

• Hold LMWH one dose before procedure 

Malloy et al. (2009) 

Patel et al. (2012) 

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However, these guidelines did still recommend transfusing 

to a platelet count > 50,000 and giving FFP to INR < 2.0. 

Other authors have suggested this is not necessary. 

Malloy et al. (2009) 

Patel et al. (2012) 

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Cellulitis 

If there is an infection of the skin and/or soft tissue 

overlying the target site, you should choose a different 

site. 

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Mechanical Ventilation 

Traditional teaching was that thoracenteses should not be 

performed in patients who are on mechanical ventilation. 

However a study looking at 232 ultrasound guided 

thoracenteses performed on these patients with chest 

radiograph follow-up found that only 3 (1.3%) suffered a 

pneumothorax, and therefore received chest tubes. 

By comparison, average rates of pneumothorax have 

been reported from 6–18% without ultrasound and 1–5% 

with ultrasound, suggesting the procedure is relatively 

safe in this population. 

Daniels and Ryu (2011) 

Mayo et al. (2004) 

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Outline 

Introduction 





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The MUSC Library provides access to Procedures 

Consult, which includes information about: 

• Necessary equipment 

• Anatomical landmarks and considerations 

• Video demonstration of procedural technique 

• Procedure checklist 

http://www.library.musc.edu/page.php?id=1061 

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Figure : Procedures Consult web site 

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Key points: 

• Use ultrasound guidance 

• Do not withdraw more than 1000–1500 mL 

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Post-Procedure Complications 

Important complications: 

• Pneumothorax 

• Bleeding 

• Reexpansion Pulmonary Edema (REPE) 

Rates of complications correlate with: 

• practitioner inexperience 

• failure to use ultrasonography 

• aspiration of large (> 1 L) fluid volume 

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Pneumothorax 

Can occur from: 

• Puncture of the visceral pleura with air leak 

• Improper use of the stop-cock allowing influx of air 

• Drastic lowering of the intrapleural pressure 

• Shear trauma of the pleura 


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Pneumothorax 

Estimated rates range from 6–18% without ultrasound, 

and 1–5% with ultrasound 

Best practices can reduce rates of complication at an 

institution by: 

• Standardizing the procedures performed 

• Mandatory training 

• Limiting procedure to those who perform it regularly 

• Using real-time ultrasound 


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Pneumothorax 

Ultrasonography (90.9% sensitivity, 98.2% specificity) has 

been found to be better for the detection of 

pneumothoraces than chest radiography (50.2% 

sensitivity, 99.4% specificity) according to a 

meta-analysis. 

Additionally, the use of ultrasonography during the 

procedure has been shown to reduce the risk of a 

pneumothorax. 

Alrajhi et al. (2012) 

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When to Check a Chest Radiograph? 

A chest radiograph is not mandatory after thoracentesis, 

however one should be obtained if air is aspirated into the 

syringe during the procedure, or there is loss of tactile 

fremitus over the upper part of the chest on the side of the 

procedure. Alternatively, ultrasound can be used to 

diagnose a pneumothorax. 

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Bleeding 

As discussed previously, the risk of major bleeding from a 

thoracentesis is low, and the use of ultrasonography 

during the procedure can help minimize the risk of 

bleeding complications. 

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Reexpansion Pulmonary Edema (REPE) 

REPE can occur when a lung is reexpanded after multiple 

initial insults — pneumothorax, pleural effusion, or severe 

atelectasis. 

The mortality, pathophysiology, and risk factors of REPE 

are not clearly understood. In the setting of thoracentesis, 

it has been associated with removal of more than 1 to 1.5 

L of fluid. 

Sherman (2003) 

Feller-Kopman (2012) 

Maldonado and Mullon (2012) 

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Reexpansion Pulmonary Edema (REPE) 

It has also been suggested that measuring pressure 

(manometry) during thoracentesis can allow the 

practitioner to stop removing fluid when the pressure is 

below – 20 cm H2O, though this is somewhat 

controversial and unproven. 

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Outline 

Introduction 





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Transudate or Exudate? 

The first step is to differentiate transudate from exudate. If 

your suspicion for a transudate is high, checking protein 

and LDH are all that are initially required. 

A transudative effusion is caused by unbalanced 

hydrostatic forces (high pressure), effectively “pushing” 

the fluid into the pleural space. 

An exudative effusion is caused by increased capillary 

permeability or lymphatic obstruction. 

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Light’s Criteria 

Any of the following suggest that the fluid is an exudate: 

• Ratio of pleural-fluid protein to serum protein > 0.5 

• Ratio of pleural-fluid LDH to serum LDH > 0.6 

• Pleural-fluid LDH > 2/3 the upper limit of normal for 

serum 

Light’s Criteria (when combined) are 98% sensitive for an 

exudate, and 83% specific. If the clinical scenario strongly 

suggests transudate, but Light’s Criteria are positive, one 

can check the difference between the serum albumin and 

the pleural albumin (analogous to a SAAG). A gradient of 

more than 1.2 g/dL suggests that the fluid is actually a 

transudate. 

Light (2002) 

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Transudate 

If the fluid is consistent with a transudate, no further 

testing is generally necessary (and may in fact be 

misleading.) The most common etiologies for a 

transudate include: 

• Congestive heart failure 

• Cirrhosis 

• Nephrotic syndrome 

• Urinothorax 

• Myxedema 

• CSF leak to the pleura 

Light (2006) 

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Exudate 

Exudative effusions can be caused by a variety of 

etiologies, and further testing is usually necessary to 

distinguish among them. 

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Cell Count and Differential 

Bloody appearing fluid should prompt a hematocrit: 

• < 1% of peripheral hematocrit — nonsignificant 

• 1–20% of peripheral hematocrit — cancer, PE, 

trauma 

• > 50% of peripheral hematocrit — hemothorax 

Light (2002) 

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pH 

A pH in the pleural-fluid less than 7.20 suggests the need 

for drainage of the fluid (empyema), usually with a chest 

tube. It has a been suggested that a pH in this range 

correlates with a life expectancy of around 30 days. 

Light (2002) 

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Gram Stain and Culture 

Cultures show a higher yield if the bottles are inoculated 

at the bedside. 

Cultures for TB are rarely positive. High lymphocyte 

counts should prompt consideration of TB in the 

differential and an Adenosine deaminase or 

gamma-interferon may be helpful. ADA < 40 IU/L or 

gamma-interferon < 140 pg/mL make TB unlikely. 

Light (2002) 

Light (2006) 

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Glucose 

Low glucose ( < 60 mg/dL) suggests a complicated 

parapneumonic or malignant effusion. Other potential 

causes include: 

• hemothorax 

• tuberculosis 

• rheumatoid arthritis 

• Churg-Strauss 

• paraonimiasis 

• lupus pleuritis 

Light (2002) 

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LDH 

In addition to distinguishing between transudative and 

exudative effusions, LDH can be useful as a marker of 

inflammation. Trending pleural fluid LDH levels can be 

useful for tracking resolution of the underlying process, as 

the LDH should normalize as the underlying pathology 

resolves. 

Light (2002) 

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Other Tests 

• Cytology and flow cytometry — may be useful for 

diagnosing malignancy. Measuring tumor markers in 

the pleural fluid has not been proven reliable. 

• Amylase — pancreatic disease or esophageal rupture 

Light (2002) 

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Bibliography I 

Alrajhi, K, Woo, MY, and Vaillancourt, C. Test 

characteristics of ultrasonography for the detection of 

pneumothorax: a systematic review and meta-analysis. 

Chest, 141(3):703–708, March 2012. 

Daniels, CE and Ryu, JH. Improving the safety of 

thoracentesis. Current opinion in pulmonary medicine, 

17(4):232–236, July 2011. 

Feller-Kopman, D. Point: should pleural manometry be 

performed routinely during thoracentesis? Yes. Chest, 

141(4):844–845, April 2012. 

Light, RW. Clinical practice. Pleural effusion. The New 

England journal of medicine, 346(25):1971–1977, June 

2002. 

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Bibliography II 

Light, RW. The undiagnosed pleural effusion. Clinics in 

chest medicine, 27(2):309–319, June 2006. 

Maldonado, F and Mullon, JJ. Counterpoint: should 

pleural manometry be performed routinely during 

thoracentesis? No. Chest, 141(4):846–8– discussion 

848–9, April 2012. 

Malloy, PC, Grassi, CJ, Kundu, S, Gervais, DA, Miller, DL, 

Osnis, RB, Postoak, DW, Rajan, DK, Sacks, D, 

Schwartzberg, MS, Zuckerman, DA, and Cardella, JF. 

Consensus Guidelines for Periprocedural Management 

of Coagulation Status and Hemostasis Risk in 

Percutaneous Image-guided Interventions. JVIR, 20(S): 

S240–S249, July 2009. 

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Bibliography III 

Mayo, PH, Goltz, HR, Tafreshi, M, and Doelken, P. Safety 

of ultrasound-guided thoracentesis in patients receiving 

mechanical ventilation. Chest, 125(3):1059–1062, 

March 2004. 

Patel, IJ, Davidson, JC, Nikolic, B, Salazar, GM, 

Schwartzberg, MS, Walker, TG, and Saad, WA. 

Consensus Guidelines for Periprocedural Management 

of Coagulation Status and Hemostasis Risk in 

Percutaneous Image-guided Interventions. JVIR, 23(6): 

727–736, June 2012. 

Patel, MD and Joshi, SD. Abnormal preprocedural 

international normalized ratio and platelet counts are 

not associated with increased bleeding complications 

after ultrasound-guided thoracentesis. American 

Journal of Roentgenology, 197(1):W164–8, July 2011. 

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Bibliography IV 

Sherman, SC. Reexpansion pulmonary edema: a case 

report and review of the current literature. J Emerg 

Med, 24(1):23–27, January 2003. 

Wong, CL. Does This Patient Have a Pleural Effusion? 

JAMA : the journal of the American Medical 

Association, 301(3):309, January 2009. 

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Thoracentesis and Pleural Effusions - - Clinical Departments

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