Indications for Thoracentesis

Objectives

• Know when to consider a thoracentesis• Know how to evaluate if safe to perform

thoracentesis• Know when to consult specialists• Quick review of pathophysiology of effusions • Know how to analyze the fluid obtained• Know when pleural fluid results suggest a need

for a chest tube• Summary

Indications for thoracentesis

• Symptom relief• Dyspnea• Unstable pulmonary mechanics, gas exchange

• Diagnostic purposes• When the cause of the effusion is unclear

Pre-procedure check list• Normal hemostasis• Effusions with thickness > 1 cm on lateral

decubitus film• Ultrasound evaluation of the pleural space• Weigh risks and benefits of procedure

• 4 studies between 1983 and 1994 looking at complications of thoracentesis reported rates of pneumothorax between 11 to 19%.

• 2 studies in 2009 and 2010 specifically addressing use of ultrasound for fluid location show risk of pneumothorax declines to 0.6 to 1.1%. Good training and experience matter.

• Risks for complications: large volume thoracentesis, COPD

When to consult with specialists

• Consult Pulmonary Team when:• If overall clinical situation warrants pulmonary specialty

assist• If pre-procedure evaluation indicates may be difficult

thoracentesis to perform• If medical team lacking a member who feels confident

performing the procedure

• Pulmonary team strongly encourages consults with them prior to requesting Intervention Radiology to perform the procedure

Etiology of a Pleural EffusionPleural fluid accumulates when formation exceeds

absorption

Normally: Fluid enters pleural space from parietal pleura capillaries and is drained via the lymphatics in parietal pleura.

Fluid can also come from: interstitial spaces of lung via visceral pleura peritoneal cavity via small holes in diaphragm.

Diagnostic Approach to Pleural Effusions

• Transudative effusions occur with either increased mean capillary pressure or decreased oncotic pressure

• Cirrhosis Left ventricular failure Nephrotic syndrome• SVC obstruction Myxedema Peritoneal dialysis PE

• Exudative effusions occur with damage or disruption of the normal pleural membranes or vasculature occurs, leading to increased capillary permeability or decreased lymphatic drainage. • Infectious diseases• Malignancy• Pulmonary embolism• Collagen vascular diseases: RA, SLE, Wegener’s g.,Sjogren’s• Drug-induced: nitrofurantoin, amiodarone, bromocriptine

Differentiation between exudative and transudative

Exudative effusions meet at least one of the following criteria, transudative meet none:

Light’s criteria:• Pleural fluid protein/serum protein>0.5• Pleural fluid LDH/serum LDH>0.6• Pleural fluid LDH more than 2/3 normal upper limit for serum

2 Test Rule:• Pleural fluid cholesterol > 45 mg/dL• Pleural fluid LDH > .45 upper limit normal serum LDH

3 Test Rule: as above 2 Test, but add:• Pleural fluid protein > 2.9 g/dL

– Note if fluid exudative, need description of fluid, pH, glucose level, differential cell count, microbiologic studies, and cytology

Other diagnostic pleural fluid tests• Glucose < 60 mg/dL

• Malignancy• Bacterial infections• Rheumatoid pleuritis

• Amylase• Acute pancreatitis• Esophageal rupture• Lung carcinoma

• Triglycerides > 110 mg/dL, milky appearance• Chylothorax , usually from trauma or mediastinal tumors

• Cell count predominantly neutrophils in febrile pt with normal pulmonary parenchyma

• Intraabdominal abscess

Other diagnostic pleural fluid tests• Bloody pleural fluid

• Pleural hematocrit/serum hematocrit > 0.5 = hemothorax

» Usually result of trauma or tumor, or infarction

• Tuberculous effusions• Exudative with predominantly small lymphocytes• Adenosine deaminase > 40 IU/L• Interferon gamma > 140 pg/mL, positive PCR for TB DNA• Fluid culture, needle biopsy of pleura

• pH < 7.3• Empyema malignancy esophageal rupture• Collagen vascular disease TB

Factors suggestive of need for chest tube

(placed in increasing order of importance)

• Loculated pleural fluid• Pleural fluid pH < 7.20• Pleural fluid glucose < 60 mg/dL• Chylothorax• Hemothorax• Positive Gram stain or culture of pleural fluid• Presence of gross pus in pleural space

Summary

• Indications: symptom relief, stabilization, and diagnostic• Weigh risks and benefits• Pre-procedure, double check safety: hemostasis, fluid

quantity and location• Call Pulmonary consult if:

• Need pulmonary input in the case• Pre-procedure check indicates a difficult thoracentesis• Team lacking a member with good experience and confidence in

performing the thoracentesis

• Recommend calling Pulmonary prior Interventional Radiology

Resources1. Reducing iatrogenic risk in thoracentesis: establishing best practice via

experiential training in a zero-risk environment. Duncan DR, Morgenthaler TI, Ryu JH, Daniels Chest. 2009;135(5): 1315 2. Pneumothorax following thoracentesis: a systematic review and meta-

analysis.Gordon CE, Feller-Kopman D, Balk EM, Smetana GWArch Intern Med. 2010;170(4):332

3. Complications associated with thoracentesis.Seneff MG, Corwin RW, Gold LHChest 1986; 90:97-100

4. Thoracentesis: complicatons, patient experience and diagnostic value.Collins TR, Sahn SA.Am Review Respiratory Disease 1983; 127:A114

5. Harrison’s Principles of Internal Medicine, 17th edition. Fauci, Braunwald, Kasper, Hauser, Longo, Jameson, Loscalzo.

6. UpToDate online. www.uptodate.com.