View source for Thoracentesis

{{short description|Removal of fluids/air from the pleural cavity of the lungs}}
{{Infobox medical intervention
| Name       = Thoracentesis
| Image      = Left-sided Pleural Effusion.jpg
| Caption    = [[Chest X-ray]] showing a left-sided [[pleural effusion]] (right side of image). This can be treated with thoracentesis.
| ICD10      = 
| ICD9       = {{ICD9proc|34.91}}
| MedlinePlus = 003420
| OtherCodes = '''[http://www.nhsia.nhs.uk/clinicalcoding/pages/opcs_4.asp OPCS-4.2]'''T12.3
}}

'''Thoracentesis''' {{IPAc-en|ˌ|θ|ɔː|r|ə|s|ᵻ|n|ˈ|t|iː|s|ᵻ|s}}, also known as '''thoracocentesis''' ({{ety|el|''θώραξ'' (thōrax, <small>[[Genitive case|GEN]]</small> thōrakos)|chest, [[thorax]]||''κέντησις'' (kentēsis)|pricking, puncture}}), '''pleural tap''', '''needle thoracostomy''', or '''needle decompression''' (often used term), is an invasive medical procedure to remove [[pleural effusion|fluid]] or [[pneumothorax|air]] from the [[pleural cavity|pleural space]] for diagnostic or therapeutic purposes. A [[cannula]], or hollow needle, is carefully introduced into the thorax, generally after administration of [[local anesthesia]]. The procedure was first performed by [[Morrill Wyman]] in 1850 and then described by [[Henry Ingersoll Bowditch]] in 1852.<ref name=AMB>{{Cite AMB1920|wstitle=Wyman, Morrill}}</ref>

The recommended location varies depending upon the source. Some sources recommend the [[midaxillary line]], in the eighth, ninth, or tenth [[intercostal space]].<ref>{{cite web |url=http://www.med.umn.edu/anatomy/6150/CD/Lecture%20Handouts%20HTML/2004%2010%20thoracic%20wall%20and%20lungs.htm |title=Human Gross Anatomy |access-date=2007-10-22 |archive-url = https://web.archive.org/web/20080214132857/http://www.med.umn.edu/anatomy/6150/CD/Lecture%20Handouts%20HTML/2004%2010%20thoracic%20wall%20and%20lungs.htm <!-- Bot retrieved archive --> |archive-date = 2008-02-14}}</ref> Whenever possible, the procedure should be performed under ultrasound guidance, which has shown to reduce complications.<ref name=":0">{{cite journal |last1=Gordon |first1=Craig E. |last2=Feller-Kopman |first2=D |last3=Balk |first3=EM |last4=Smetana |first4=GW |title=Pneumothorax Following Thoracentesis |journal=Archives of Internal Medicine |date=22 February 2010 |volume=170 |issue=4 |pages=332–9 |doi=10.1001/archinternmed.2009.548 |pmid=20177035 |doi-access=free }}</ref><ref name=":1">{{cite journal |last1=Feller-Kopman |first1=David |title=Therapeutic thoracentesis: the role of ultrasound and pleural manometry |journal=Current Opinion in Pulmonary Medicine |date=July 2007 |volume=13 |issue=4 |pages=312–318 |doi=10.1097/MCP.0b013e3281214492 |pmid=17534178 |s2cid=21367134 }}</ref><ref name=":2">{{cite journal |last1=Daniels |first1=Craig E |last2=Ryu |first2=Jay H |title=Improving the safety of thoracentesis |journal=Current Opinion in Pulmonary Medicine |date=July 2011 |volume=17 |issue=4 |pages=232–236 |doi=10.1097/MCP.0b013e328345160b |pmid=21346571 |s2cid=25046432 }}</ref>

[[Pneumothorax#Tension pneumothorax|Tension pneumothorax]] is a [[medical emergency]] that requires needle decompression before a [[chest tube]] is placed.<ref>{{cite journal |last1=Harcke |first1=HT |last2=Mabry |first2=RL |last3=Mazuchowski |first3=EL |title=Needle thoracentesis decompression: observations from postmortem computed tomography and autopsy. |journal=Journal of Special Operations Medicine |date=2013 |volume=13 |issue=4 |pages=53–8 |doi=10.55460/FWAO-F36G |pmid=24227562 }}</ref><ref>{{cite journal |last1=Ball |first1=Chad G. |last2=Wyrzykowski |first2=Amy D. |last3=Kirkpatrick |first3=Andrew W. |last4=Dente |first4=Christopher J. |last5=Nicholas |first5=Jeffrey M. |last6=Salomone |first6=Jeffrey P. |last7=Rozycki |first7=Grace S. |last8=Kortbeek |first8=John B. |last9=Feliciano |first9=David V. |title=Thoracic needle decompression for tension pneumothorax: clinical correlation with catheter length |journal=Canadian Journal of Surgery |date=2010 |volume=53 |issue=3 |pages=184–188 |pmid=20507791 |pmc=2878990 }}</ref>

==Indications==
[[file:Thoracentesis.jpg|thumb|480px|The illustration shows a person having thoracentesis. The person sits upright and leans on a table. Excess fluid from the pleural space is drained into a bag.]]
[[File:Needle biopsy of the pleura.PNG|thumb|Instruments for thoracocentesis and needle biopsy of the pleura<ref name="Lyra">{{cite journal | author = de Menezes Lyra R | title = A modified outer cannula can help thoracentesis after pleural biopsy. | journal = Chest | volume = 112 | issue = 1 | pages = 296| year = 1997 | pmid = 9228404 | doi = 10.1378/chest.112.1.296}}</ref>]]
This procedure is indicated when unexplained fluid accumulates in the chest cavity outside the lung. In more than 90% of cases, analysis of pleural fluid yields clinically useful information. If a large amount of fluid is present, then this procedure can also be used therapeutically to remove that fluid and improve patient comfort and lung function.

The most common causes of pleural [[effusion]]s are [[cancer]], [[congestive heart failure]], [[pneumonia]], and recent [[surgery]]. In countries where [[tuberculosis]] is common, this is also a common cause of pleural effusions.

When cardiopulmonary status is compromised (i.e. when the fluid or air has its repercussions on the function of heart and lungs), due to air (significant [[pneumothorax]]), fluid ([[pleural effusion|pleural fluid]]) or [[blood]] ([[hemothorax]]) outside the lung, then this procedure is usually replaced with [[tube thoracostomy]], the placement of a large tube in the pleural space.

==Contraindications==
An uncooperative patient or a [[coagulation]] disorder that cannot be corrected are relative contraindications.<ref>{{cite web|title=Thoracentesis (section)|url=http://www.merckmanuals.com/professional/pulmonary_disorders/diagnostic_pulmonary_procedures/thoracentesis.html|website=Merck Manual|access-date=7 November 2014}}</ref> Routine measurement of coagulation profiles is generally not indicated, however; when performed by an experienced operator "hemorrhagic complications are infrequent after ultrasound-guided thoracentesis, and attempting to correct an abnormal INR or platelet level before the procedure is unlikely to confer any benefit".<ref>{{cite journal |last1=Hibbert |first1=Rebecca M. |last2=Atwell |first2=Thomas D. |last3=Lekah |first3=Alexander |last4=Patel |first4=Maitray D. |last5=Carter |first5=Rickey E. |last6=McDonald |first6=Jennifer S. |last7=Rabatin |first7=Jeffrey T. |title=Safety of Ultrasound-Guided Thoracentesis in Patients With Abnormal Preprocedural Coagulation Parameters |journal=Chest |date=August 2013 |volume=144 |issue=2 |pages=456–463 |doi=10.1378/chest.12-2374 |pmid=23493971 }}</ref>

Relative contraindications include cases in which the site of insertion has known [[bullous emphysema]], use of [[positive end-expiratory pressure]] (PEEP, see [[mechanical ventilation]]) and only one functioning [[lung]] (due to diminished reserve). Traditional expert opinion suggests that the aspiration should not exceed 1&nbsp;L to avoid the possible development of pulmonary edema, but this recommendation is uncertain as the volume removed does not correlate well with this complication.<ref name=":2" />

==Complications==
Major complications are [[pneumothorax]] (3–30%), [[hemopneumothorax]], [[hemothorax|hemorrhage]], hypotension (low blood pressure due to a vasovagal response) and reexpansion [[pulmonary edema]].

Minor complications include a dry tap (no fluid return), subcutaneous [[hematoma]] or [[seroma]], anxiety, [[dyspnea]] and cough (after removing large volume of fluid).

The use of [[Medical ultrasound|ultrasound]] for needle guidance can minimize the complication rate.<ref name=":0" /><ref name=":1" /><ref name=":2" />

=== Follow-up imaging ===
While chest X-ray has traditionally been performed to assess for pneumothorax following the procedure, it may no longer be necessary to do so in asymptomatic, non-ventilated persons given the widespread use of ultrasound to guide this procedure.<ref>{{cite journal |last1=Petersen |first1=William G. |last2=Zimmerman |first2=Robert |title=Limited Utility of Chest Radiograph After Thoracentesis |journal=Chest |date=April 2000 |volume=117 |issue=4 |pages=1038–1042 |doi=10.1378/chest.117.4.1038 |pmid=10767236 }}</ref>

==Interpretation of pleural fluid analysis==
Several diagnostic tools are available to determine the [[etiology]] of pleural fluid.

===Transudate versus exudate===
{{see also|Light's criteria}}
First the fluid is either [[transudate]] or [[exudate]].

An exudate is defined as pleural fluid to serum total protein ratio of more than 0.5, pleural fluid to serum LDH ratio > 0.6, and absolute pleural fluid LDH > 200 IU or > {{frac|2|3}} of the normal.

An exudate is defined as pleural fluid that filters from the circulatory system into lesions or areas of inflammation. Its composition varies but generally includes water and the dissolved solutes of the main circulatory fluid such as blood. In the case of blood it will contain some or all plasma proteins, white blood cells, platelets and (in the case of local vascular damage) red blood cells.

''Exudate '' 
* hemorrhage 
*[[Infection]]  
*[[Inflammation]]  
*[[Malignancy]] 
*[[Iatrogenic]]  
*[[Connective tissue disease]] 
*[[Endocrine disorders]] 
*Lymphatic disorders vs Constrictive [[pericarditis]]

''Transudate''
*[[Congestive heart failure]]
*[[Nephrotic syndrome]]
*[[Hypoalbuminemia]]
*[[Cirrhosis]]
*[[Atelectasis]] 
* Trapped lung
*Peritoneal [[Kidney dialysis|dialysis]]
*[[Superior vena cava syndrome|Superior vena cava obstruction]]

===Amylase===
A high amylase level (twice the serum level or the absolute value is greater than 160 Somogy units) in the pleural fluid is indicative of either acute or chronic [[pancreatitis]], pancreatic [[pseudocyst]] that has dissected or ruptured into the pleural space, [[cancer]] or esophageal rupture.

===Glucose===
[[Glucose]] is considered low if pleural fluid value is less than 50% of normal serum value. The [[differential diagnosis]] for this is:
*rheumatoid effusion. The levels are characteristically low (<15&nbsp;mg/dL).
*[[lupus erythematodes|lupus]] effusion
*bacterial [[empyema]]
*[[malignancy]]
*[[tuberculosis]]
*esophageal rupture ([[Boerhaave syndrome]])

===pH===
Normal pleural fluid pH is approximately 7.60.  A pleural fluid pH below 7.30 with normal arterial blood pH has the same differential diagnosis as low pleural fluid glucose.

===Triglyceride and cholesterol===
[[Chylothorax]] (fluid from [[lymph vessel]]s leaking into the pleural cavity) may be identified by determining [[triglyceride]] and [[cholesterol]] levels, which are relatively high in [[lymph]]. A triglyceride level over 110&nbsp;mg/dl and the presence of chylomicrons indicate a [[chylothorax|chylous effusion]]. The appearance is generally milky but can be [[serous]].

The main cause for chylothorax is rupture of the [[thoracic duct]], most frequently as a result of  trauma or malignancy (such as [[lymphoma]]).

===Cell count and differential===

The number of [[white blood cells]] can give an indication of infection. The specific subtypes can also give clues as to the type on infection. The amount of [[red blood cells]] are an obvious sign of bleeding.

===Cultures and stains===
If the effusion is caused by [[infection]], [[microbiological culture]] may yield the infectious organism responsible for the infection, sometimes before other cultures (e.g. blood cultures and sputum cultures) become positive. A [[Gram staining|Gram stain]] may give a rough indication of the causative organism. A [[Ziehl–Neelsen stain]] may identify [[tuberculosis]] or other mycobacterial diseases.

===Cytology===
[[Cytopathology|Cytology]] is an important tool in identifying effusions due to [[cancer|malignancy]]. The most common causes for pleural fluid are [[lung cancer]], [[metastasis]] from elsewhere and [[pleural|pleural mesothelioma]]. The latter often presents with an effusion. Normal cytology results do not reliably rule out malignancy, but make the diagnosis more unlikely.

==References==
<references/>

==External links==
*{{Commons category-inline}}
*A photo gallery of thoracentesis showing [http://note3.blogspot.com/2004/02/thoracentesis-procedure-guide.html the procedure step-by-step]. V. Dimov, B. Altaqi, Clinical Notes, 2005.

{{Respiratory system surgeries and other procedures}}

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[[Category:Interventional radiology]]
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