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EM TopicsProcedural & diagnostic ED skills

EM · Procedural & diagnostic ED skills

Paracentesis and thoracentesis in the emergency department

Also known as Ascitic tap · Abdominal paracentesis · Large-volume paracentesis · Pleural tap · Thoracocentesis · Pleural fluid aspiration

Paracentesis and thoracentesis in the emergency department — who needs a tap, why coagulopathy is not a barrier in cirrhosis, ultrasound and site selection, drainage volumes and albumin, reading ascitic and pleural fluid, spontaneous bacterial peritonitis, and complications.

medium18 referencesUpdated 26 July 20265 min readSource-verified · Oct 2026

Checked against its sources on 23 Oct 2026

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Practise this topic8 MCQs with explanations

Target exams

ACEMFRCEMABEMFRCPCCCFPEMEBEEM

Red flags

  • An ascitic absolute neutrophil count of 250 cells/mm³ or more is diagnostic of spontaneous bacterial peritonitis
  • Do not routinely transfuse to correct coagulopathy before low-risk paracentesis or thoracentesis in cirrhosis
  • Real-time ultrasound was associated with a lower pneumothorax rate after thoracentesis in a meta-analysis
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Related topics

  • Pleural effusion (the emergency department workup and the Light criteria)
  • Lumbar puncture in the emergency department
  • Local anaesthesia and topical agents
  • Central and arterial line insertion in the emergency department
  • Procedural sedation in the emergency department
  • Focused Assessment with Sonography in Trauma (FAST and E-FAST)
  • Acute abdominal pain — the emergency department approach
Study tools

Your progress

Saved on this device.

Practise this topic8 MCQs with explanations

Target exams

ACEMFRCEMABEMFRCPCCCFPEMEBEEM

Red flags

  • An ascitic absolute neutrophil count of 250 cells/mm³ or more is diagnostic of spontaneous bacterial peritonitis
  • Do not routinely transfuse to correct coagulopathy before low-risk paracentesis or thoracentesis in cirrhosis
  • Real-time ultrasound was associated with a lower pneumothorax rate after thoracentesis in a meta-analysis
The one-line answer

Two bedside taps, each with an evidence-based decision at every step. Paracentesis is the diagnostic modality of choice for suspected spontaneous bacterial peritonitis, and an ascitic absolute neutrophil count of 250 cells/mm³ or more is diagnostic.[13] Real-time ultrasound was associated with a lower pneumothorax rate after thoracentesis in a meta-analysis, and routine correction of coagulopathy before low-risk paracentesis or thoracentesis is not recommended in patients with cirrhosis.[10][12]

Meet the patient

A man with known cirrhosis presents with increasing abdominal swelling, mild abdominal pain and new confusion. His INR is raised and his platelets are low. A second patient on the next bed has a large unilateral pleural effusion and is breathless.

Who needs a tap. Paracentesis should be performed in any patient with ascites and concern for spontaneous bacterial peritonitis or upper gastrointestinal bleeding, or who is being admitted for a complication of cirrhosis; the presentation may be abdominal pain, worsening ascites, fever or altered mental status, but some patients are asymptomatic or only mildly symptomatic.[13]

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References18ShowHide
  1. [1]Runyon BA, Montano AA, Akriviadis EA, Antillon MR, Irving MA, McHutchison JG. The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites Ann Intern Med, 1992.PMID 1616215
  2. [6]Feller-Kopman D, Berkowitz D, Boiselle P, Ernst A. Large-volume thoracentesis and the risk of reexpansion pulmonary edema Ann Thorac Surg, 2007.PMID 17954079
  3. [7]Sort P, Navasa M, Arroyo V, et al. Effect of intravenous albumin on renal impairment and mortality in patients with cirrhosis and spontaneous bacterial peritonitis N Engl J Med, 1999.PMID 10432325
  4. [8]Sperandeo M, Quarato CMI, Squatrito R, et al. Effectiveness and Safety of Real-Time Transthoracic Ultrasound-Guided Thoracentesis Diagnostics (Basel), 2022.PMID 35328278
  5. [9]Bernardi M, Caraceni P, Navickis RJ, et al. Albumin infusion in patients undergoing large-volume paracentesis: a meta-analysis of randomized trials. Hepatology (Baltimore, Md.), 2012.PMID 22095893
  6. [10]Gordon CE, Feller-Kopman D, Balk EM, et al. Pneumothorax following thoracentesis: a systematic review and meta-analysis. Archives of internal medicine, 2010.PMID 20177035
  7. [11]Lakkadghatwala R, Wilson A, Sabhaney V, et al. Ultrasound guidance compared to anatomic landmark approach for thoracentesis: A systematic review and meta-analysis. The American journal of emergency medicine, 2025.PMID 40738083
  8. [12]O'Leary JG, Greenberg CS, Patton HM, et al. AGA Clinical Practice Update: Coagulation in Cirrhosis. Gastroenterology, 2019.PMID 30986390
  9. [13]Long B, Gottlieb M Emergency medicine updates: Spontaneous bacterial peritonitis. The American journal of emergency medicine, 2023.PMID 37244043
  10. [14]Tarn AC, Lapworth R Biochemical analysis of pleural fluid: what should we measure? Annals of clinical biochemistry, 2001.PMID 11471871
  11. [15]Mohammed A, Hochfeld U, Hong S, et al. Thoracentesis techniques: A literature review. Medicine, 2024.PMID 38181250
  12. [16]Cantey EP, Walter JM, Corbridge T, et al. Complications of thoracentesis: incidence, risk factors, and strategies for prevention. Current opinion in pulmonary medicine, 2016.PMID 27093476
  13. [17]Brunet Mas E, Vives Moreno J, Solé Martí C, et al. Paracentesis-related bleeding complications and associated risk factors in patients with liver cirrhosis. Medicina clinica, 2026.PMID 41505936
  14. [18]MacIntosh T Emergency Management of Spontaneous Bacterial Peritonitis - A Clinical Review. Cureus, 2018.PMID 29721399
  15. [19]Tan HK, James PD, Wong F Albumin May Prevent the Morbidity of Paracentesis-Induced Circulatory Dysfunction in Cirrhosis and Refractory Ascites: A Pilot Study. Digestive diseases and sciences, 2016.PMID 27048451
  16. [20]Riggio O, Angeloni S Ascitic fluid analysis for diagnosis and monitoring of spontaneous bacterial peritonitis. World journal of gastroenterology, 2009.PMID 19701963
  17. [21]Wilcox ME, Chong CA, Stanbrook MB, et al. Does this patient have an exudative pleural effusion? The Rational Clinical Examination systematic review. JAMA, 2014.PMID 24938565
  18. [22]Torres E, Barros P, Calmet F Correlation between serum-ascites albumin concentration gradient and endoscopic parameters of portal hypertension. The American journal of gastroenterology, 1998.PMID 9820392

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Related topics

  • Pleural effusion (the emergency department workup and the Light criteria)
  • Lumbar puncture in the emergency department
  • Local anaesthesia and topical agents
  • Central and arterial line insertion in the emergency department
  • Procedural sedation in the emergency department
  • Focused Assessment with Sonography in Trauma (FAST and E-FAST)
  • Acute abdominal pain — the emergency department approach