1. Indications for Thoracentesis

2. 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

3. Indications for thoracentesis
Symptom relief
Dyspnea
Unstable pulmonary mechanics, gas exchange
Diagnostic purposes
When the cause of the effusion is unclear

4. 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

5. 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

6. Etiology of a Pleural Effusion
Pleural 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.
Lymphatics have capacity absorb 20 times more fluid than is normally formed.

7. 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

8. 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
If criteria met for exudative yet clinically suspect transudative, measure difference between serum and pleural fluid albumin levels. If difference > 1.2 g/L, effusion is transudative. If measure fluid protein, a difference > 3.1 g/dl indicates transudate.

9. 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

10. 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

11. 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

12. 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

13. Resources
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 GW
Arch Intern Med ;170(4):332
Complications associated with thoracentesis.
Seneff MG, Corwin RW, Gold LH
Chest 1986; 90:97-100
Thoracentesis: complicatons, patient experience and diagnostic value.
Collins TR, Sahn SA.
Am Review Respiratory Disease 1983; 127:A114
Harrison’s Principles of Internal Medicine, 17th edition.
Fauci, Braunwald, Kasper, Hauser, Longo, Jameson, Loscalzo.
6. UpToDate online.