II. Indications: Diagnostic Thoracentesis
- Effusion >1 cm high on decubitus XRay in an undiagnosed patient
- Effusion not explained by other cause- CHF not responding within 3 days to diuresis
- Asymmetric Pleural Effusions
- Fever
 
- Effusion >5 cm high on lateral XRay in Pneumonia patient- Evaluate and treat for Parapneumonic Effusion, empyema
 
- Avoid Thoracentesis for suspected transudative bilateral Pleural Effusions- Example: Congestive Heart Failure
- Exception: Effusion not explained by other cause (see above)
 
III. Indications: Therapeutic Thoracentesis
- Large Pleural Effusion (>50% of hemithorax) with Dyspnea and/or hemodynamic instability
- Empyema (or other loculated fluid)- Directed Chest Tube or drain is typically performed instead
 
IV. Contraindications: Relative
- Mechanical Ventilation is NOT a contraindication to Thoracentesis
- Conditions in which Chest Tube is indicated instead of Thoracentesis- Pneumothorax
- Hemothorax
- Empyema
- Complicated Parapneumonic Effusion
- Pleurodesis for malignant effusion
 
- Small Pleural Fluid pocket- Ultrasound with Pleural Effusion <1.5 cm (or with intervening tissue such as liver)
- Decubitus Chest XRay with <1 cm Pleural Effusion
- 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)- Absolute contraindications- INR >3 (on Warfarin)
- Partial Thromboplastin Time >2x normal
- Platelet Count <20,000
- Serum Creatinine > 6 mg/dl
 
- Thoracentesis allowed if Ultrasound-guided by experienced clinician (without absolute contraindications above)- Dual Antiplatelet Therapy (without reversal)
- Direct Oral Anticoagulant use (without reversal)
- Cirrhosis and Fibrinogen level >100-120- If Fibrinogen<100, consider pre-procedure Cryoprecipitate (1 pack for weight <80 kg, 2 packs if >80kg)
 
 
 
- Absolute contraindications
- 
                          Chest XRay with mediastinal shift toward effusion- Suggests negative pleural pressure
- Suggests Bronchial obstruction
- Bronchoscopy recommended in these cases
 
V. Precautions
- Limit fluid removal to 1500 cc- Some experts recommend complete drainage
- Removal of volumes >1000 to 1500 cc risk reexpansion Pulmonary Edema
 
- 
                          Ultrasound-guided Thoracentesis is associated with fewer complications- Use low frequency probe
- Ultrasound offers real-time guidance- Identifies largest Pleural Fluid pocket
- Prevents Arterial Puncture
 
- Clinical exam with chest percussion and auscultation is by contrast imperfect with increased risk- Pneumothorax occurs in 10-39% of cases
- Dry tap (more than half of which are intraabdominal) occurs in up to 15% of patients
 
- References
 
- Keep stopcock closed to patient at all times when not draining fluid
- 
                          Coagulopathy correction prior to Thoracentesis is performed in some guidelines- Some guidelines recommend correcting to INR <2, holding Anticoagulation, Platelet Transfusion if <50k
- Coagulopathy correction before Thoracentesis is not evidence based, but follow local expert opinion and guidelines
 
VI. 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
VII. Technique
- Patient seated with arms and head supported
- 
                          Ultrasound to localize best insertion site- Ultrasound Technique- Convex array 3.5 to 5 MHz probe
- Probe indicator toward head (cephalad)
 
- Insertion site restrictions- Lateral to spine by at least 6 cm (medial locations are higher risk for intercostal artery injury)
- Superior to diaphragm by at least 6 cm
 
- Best site is identified with a skin marker- Often best site is posterior axillary (or mid-axillary line) at 5th intercostal space
- Do not use an insertion site below the 8th intercostal space in the mid-Scapular line
- Position insertion site above the rib
- Minimum pocket depth (visceral to parietal pleura) 1.5 cm for Thoracentesis
 
- Precautions- Perform procedure in same patient position as was used for Ultrasound
- In addition to marking skin, ideal to use Ultrasound during needle entry- Lower complication rates with Ultrasound assume real-time needle guidance
 
 
 
- Ultrasound Technique
- Sterile preparation- Cleanse the insertion site (e.g. Chlorhexidine)
- Consider encasing the Ultrasound probe in sterile cover for guidance during procedure
 
- 
                          Local Anesthesia
                          - Insert needle over top of rib and raise a skin wheel
- Inject Lidocaine 1%, at the rib, over the top of the rib and at the pleura
- Identify the depth at which Pleural Fluid is aspirated with Anesthetic needle
- Remove the Anesthetic needle
 
- Diagnostic Throacentesis needle insertion- Fluid may be aspirated with 18 to 21 gauge 1.5" needle with 60 cc syringe
 
- Therapeutic Thoracentesis catheter insertion- Make a small incision at the insertion site with scalpel
- Insert Thoracentesis needle, passing over the rib
- Aspirate (back pressure on syringe) while inserting Thoracentesis needle
- Once Pleural Fluid is aspirated- Advance the needle another 2 cm to ensure the catheter is in the pleural space
- Advance the catheter over the needle into the pleural space until catheter hub is at skin or resistance
- Withdraw the needle
 
- Cover catheter with a 3-way stop-cock and ensure it is closed to patient until use
 
- Drain Pleural Fluid- Allow fluid to drain into container
- Stop fluid flow at 1500 cc (or empty completely based on local guidelines)- Larger volume removal is a risk for Reexpansion Pulmonary Edema
 
 
- Remove the Thoracentesis catheter- Patient takes a deep breath or hums while the catheter is removed
- Dress the insertion site with an Occlusive Dressing
 
- Post-Thoracentesis Chest XRay Indications- Air is withdrawn in Thoracentesis catheter
- Multiple Thoracentesis attempts are required
- Significant symptoms during or after the procedure
 
VIII. Labs
- See Pleural Fluid Examination
- Process sample within 4 hours of fluid collection
- Obtain 40 ml fluid divided over sterile tubes and culture bottles- Purple Top (with EDTA)- Cell count with differential
 
- Red Top (no additives)- Protein
- Albumin
- Lactate Dehydrogenase (LDH)
- Glucose
 
- Gram Stain and Culture- Anaerobic and aerobic culture tubes
 
 
- Purple Top (with EDTA)
- Special tubes- Anaerobic Heparinized tube on ice for pH
- Cytology
- CEA Level (for Lung Cancer)
- Triglycerides
- Acid Fast Bacteria testing (AFB RNA pcr, AFB culture, Adenosine deaminase)
- Hematocrit
 
IX. Complications
- 
                          Pneumothorax (up to 20% in landmark-guided procedure)- Incidence with landmark guided Thoracentesis 5-20%- Decreases to 1-2% risk in Ultrasound guided Thoracentesis
 
- Requires Chest Tube in 2 to 33%- Indicated in Pneumothorax >15% or symptomatic patients
 
- Increased risk factors- COPD
- Mechanical Ventilation
- Therapeutic procedures (esp. >1500 ml removed)
- Two or more attempts
 
- Decreased risk factors- Ultrasound guidance
- Experienced clinician
- Manual aspiration of fluid (in contrast to wall suction)
 
 
- Incidence with landmark guided Thoracentesis 5-20%
- Reexpansion Pulmonary Edema (<1%)- Risk factors- Higher risk if >1500 ml Pleural Fluid removed
- Lung collapse >72 hours
- Suction >20 cm H2O
- Rapid removal of fluid (esp. >1500 ml)
 
- Mortality may be as high as 20%
 
- Risk factors
- Rare but important complications- Infection (2%)
- Tumor seeding of needle tract
- Hemothorax (<1%)- Occurs with subcostal vascular puncture
- Higher risk in elderly, especially with Coagulopathy
 
- Abdominal organ injury (avoid access sites below the 8th intercostal space in mid-Scapular line)
 
- Peri-procedure symptoms that may predict Pneumothorax- Cough during procedure
- Increased Dyspnea
- Chest Pain
 
- Other peri-procedure symptoms
X. Follow-up: Post-procedure Chest XRay Indications
- Not required unless otherwise indicated by symptoms or signs of complication- Typically performed in practice, however, to document no Pneumothorax, quantify residual fluid
 
- Post-procedure symptoms (Chest Pain, Dyspnea)
- Signs of Pneumothorax post-procedure- Voice transmission absent superior to Thoracentesis
- Tactile fremitus absent superior to Thoracentesis
 
XI. Interpretation
XII. 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]
