Thoracentesis

See Also

Indications
Diagnostic Thoracentesis

Effusion >1 cm high on decubitus XRay in an undiagnosed patient
Effusion not explained by other cause
1. CHF not responding within 3 days to diuresis
2. Asymmetric Pleural Effusions
3. Fever
Effusion >5 cm high on lateral XRay in Pneumonia patient
1. Evaluate and treat for Parapneumonic Effusion, empyema
Avoid Thoracentesis for suspected transudative bilateral Pleural Effusions
1. Example: Congestive Heart Failure
2. Exception: Effusion not explained by other cause (see above)

Indications
Therapeutic Thoracentesis

Large Pleural Effusion (>50% of hemithorax) with Dyspnea and/or hemodynamic instability
Empyema (or other loculated fluid)
1. Directed Chest Tube or drain is typically performed instead

Contraindications
Relative

Mechanical Ventilation is NOT a contraindication to Thoracentesis
Conditions in which Chest Tube is indicated instead of Thoracentesis
1. Pneumothorax
2. Hemothorax
3. Empyema
4. Complicated Parapneumonic Effusion
5. Pleurodesis for malignant effusion
Small Pleural Fluid pocket
1. Ultrasound with Pleural Effusion <1.5 cm (or with intervening tissue such as liver)
2. Decubitus Chest XRay with <1 cm Pleural Effusion
3. CT Chest with <2 to 2.5 cm Pleural Effusion
Local cutaneous condition (esp. Cellulitis) interfering with percutaneous needle access
Severe Coagulopathy (perform under Ultrasound guidance for less severe coagulopathies)
1. Absolute contraindications
  1. INR >3 (on Warfarin)
  2. Partial Thromboplastin Time >2x normal
  3. Platelet Count <20,000
  4. Serum Creatinine > 6 mg/dl
2. Thoracentesis allowed if Ultrasound-guided by experienced clinician (without absolute contraindications above)
  1. Dual Antiplatelet Therapy (without reversal)
  2. Direct Oral Anticoagulant use (without reversal)
  3. Cirrhosis and Fibrinogen level >100-120
    1. If Fibrinogen<100, consider pre-procedure Cryoprecipitate (1 pack for weight <80 kg, 2 packs if >80kg)
Chest XRay with mediastinal shift toward effusion
1. Suggests negative pleural pressure
2. Suggests Bronchial obstruction
3. Bronchoscopy recommended in these cases

Precautions

Limit fluid removal to 1500 cc
1. Some experts recommend complete drainage
2. Removal of volumes >1000 to 1500 cc risk reexpansion Pulmonary Edema
Ultrasound-guided Thoracentesis is associated with fewer complications
1. Use low frequency probe
2. Ultrasound offers real-time guidance
  1. Identifies largest Pleural Fluid pocket
  2. Prevents Arterial Puncture
3. Clinical exam with chest percussion and auscultation is by contrast imperfect with increased risk
  1. Pneumothorax occurs in 10-39% of cases
  2. Dry tap (more than half of which are intraabdominal) occurs in up to 15% of patients
4. References
  1. Jones (2003) Chest 123:418-23 [PubMed]
  2. Soni (2015) J Hosp Med 10(12): 811-6 [PubMed]
Keep stopcock closed to patient at all times when not draining fluid
Coagulopathy correction prior to Thoracentesis is performed in some guidelines
1. Some guidelines recommend correcting to INR <2, holding Anticoagulation, Platelet Transfusion if <50k
2. Coagulopathy correction before Thoracentesis is not evidence based, but follow local expert opinion and guidelines

Preparation

Skin Preparation (e.g. Chlorhexidine)
Thoracentesis needle and catheter
Syringe 10 ml, 60 ml
Needles 18 gauge, 22 gauge
Lidocaine 1%
Collection bad
Manual aspiration tubing

Technique

Patient seated with arms and head supported
Ultrasound to localize best insertion site
1. Ultrasound Technique
  1. Convex array 3.5 to 5 MHz probe
  2. Probe indicator toward head (cephalad)
2. Insertion site restrictions
  1. Lateral to spine by at least 6 cm (medial locations are higher risk for intercostal artery injury)
  2. Superior to diaphragm by at least 6 cm
3. Best site is identified with a skin marker
  1. Often best site is posterior axillary (or mid-axillary line) at 5th intercostal space
  2. Do not use an insertion site below the 8th intercostal space in the mid-Scapular line
  3. Position insertion site above the rib
  4. Minimum pocket depth (visceral to parietal pleura) 1.5 cm for Thoracentesis
4. Precautions
  1. Perform procedure in same patient position as was used for Ultrasound
  2. In addition to marking skin, ideal to use Ultrasound during needle entry
    1. Lower complication rates with Ultrasound assume real-time needle guidance
Sterile preparation
1. Cleanse the insertion site (e.g. Chlorhexidine)
2. Consider encasing the Ultrasound probe in sterile cover for guidance during procedure
Local Anesthesia
1. Insert needle over top of rib and raise a skin wheel
2. Inject Lidocaine 1%, at the rib, over the top of the rib and at the pleura
3. Identify the depth at which Pleural Fluid is aspirated with Anesthetic needle
4. Remove the Anesthetic needle
Diagnostic Throacentesis needle insertion
1. Fluid may be aspirated with 18 to 21 gauge 1.5" needle with 60 cc syringe
Therapeutic Thoracentesis catheter insertion
1. Make a small incision at the insertion site with scalpel
2. Insert Thoracentesis needle, passing over the rib
3. Aspirate (back pressure on syringe) while inserting Thoracentesis needle
4. Once Pleural Fluid is aspirated
  1. Advance the needle another 2 cm to ensure the catheter is in the pleural space
  2. Advance the catheter over the needle into the pleural space until catheter hub is at skin or resistance
  3. Withdraw the needle
5. Cover catheter with a 3-way stop-cock and ensure it is closed to patient until use
Drain Pleural Fluid
1. Allow fluid to drain into container
2. Stop fluid flow at 1500 cc (or empty completely based on local guidelines)
  1. Larger volume removal is a risk for Reexpansion Pulmonary Edema
Remove the Thoracentesis catheter
1. Patient takes a deep breath or hums while the catheter is removed
2. Dress the insertion site with an Occlusive Dressing
Post-Thoracentesis Chest XRay Indications
1. Air is withdrawn in Thoracentesis catheter
2. Multiple Thoracentesis attempts are required
3. Significant symptoms during or after the procedure
  1. Chest Pain
  2. Dyspnea

Labs

See Pleural Fluid Examination
Process sample within 4 hours of fluid collection
Obtain 40 ml fluid divided over sterile tubes and culture bottles
1. Purple Top (with EDTA)
  1. Cell count with differential
2. Red Top (no additives)
  1. Protein
  2. Albumin
  3. Lactate Dehydrogenase (LDH)
  4. Glucose
3. Gram Stain and Culture
  1. Anaerobic and aerobic culture tubes
Special tubes
1. Anaerobic Heparinized tube on ice for pH
2. Cytology
3. CEA Level (for Lung Cancer)
4. Triglycerides
5. Acid Fast Bacteria testing (AFB RNA pcr, AFB culture, Adenosine deaminase)
6. Hematocrit

Complications

Pneumothorax (up to 20% in landmark-guided procedure)
1. Incidence with landmark guided Thoracentesis 5-20%
  1. Decreases to 1-2% risk in Ultrasound guided Thoracentesis
2. Requires Chest Tube in 2 to 33%
  1. Indicated in Pneumothorax >15% or symptomatic patients
3. Increased risk factors
  1. COPD
  2. Mechanical Ventilation
  3. Therapeutic procedures (esp. >1500 ml removed)
  4. Two or more attempts
4. Decreased risk factors
  1. Ultrasound guidance
  2. Experienced clinician
  3. Manual aspiration of fluid (in contrast to wall suction)
Reexpansion Pulmonary Edema (<1%)
1. Risk factors
  1. Higher risk if >1500 ml Pleural Fluid removed
  2. Lung collapse >72 hours
  3. Suction >20 cm H2O
  4. Rapid removal of fluid (esp. >1500 ml)
2. Mortality may be as high as 20%
Rare but important complications
1. Infection (2%)
2. Tumor seeding of needle tract
3. Hemothorax (<1%)
  1. Occurs with subcostal vascular puncture
  2. Higher risk in elderly, especially with Coagulopathy
4. Abdominal organ injury (avoid access sites below the 8th intercostal space in mid-Scapular line)
Peri-procedure symptoms that may predict Pneumothorax
1. Cough during procedure
2. Increased Dyspnea
3. Chest Pain
Other peri-procedure symptoms
1. Vasovagal Syncope

Follow-up
Post-procedure Chest XRay Indications

Not required unless otherwise indicated by symptoms or signs of complication
1. Typically performed in practice, however, to document no Pneumothorax, quantify residual fluid
Post-procedure symptoms (Chest Pain, Dyspnea)
Signs of Pneumothorax post-procedure
1. Voice transmission absent superior to Thoracentesis
2. Tactile fremitus absent superior to Thoracentesis

Interpretation

See Thoracentesis Interpretation
See Pleural Effusion Causes

References

Attum (2018) Crit Dec Emerg Med 32(2):18-9
Esherick (2025) Thoracentesis, Hospital Procedures Course
Natesan (2020) Crit Dec Emerg Med 34(7): 29-41
Sachdeva (2013) Clin Chest Med 34(1): 1-9 [PubMed]