Thoracocentesis is the insertion of a needle or catheter into the pleural space to remove fluid or air.
Classification
| Classification | Description |
|---|---|
| Diagnostic thoracocentesis | Performed to determine the cause of pleural effusion and exclude infection |
| Therapeutic thoracocentesis | Performed to relieve symptomatic effusions |
Common causes of pleural effusion
| Category | Causes |
|---|---|
| Transudative | Heart failure, cirrhosis (hepatic hydrothorax), and nephrotic syndrome |
| Exudative | Infection (parapneumonic effusion), malignancy, TB, pulmonary embolism, autoimmune disease, and chylothorax |
Stages of a parapneumonic effusion
| Stage | Features |
|---|---|
| Simple/exudative stage | Free-flowing. Consider drainage when thickness is >10 mm |
| Complicated or fibropurulent stage | pH < 7.20, glucose < 3.3 mmol/L, ↑ LDH, may be loculated, cultures can be negative, and antibiotics alone are insufficient and drainage required |
| Empyema | Pus in pleural space OR Positive Gram stain/culture |
- Indications
- Diagnostic thoracocentesis (20 – 30 mL for analysis)
- Unexplained pleural effusion
- Suspected pleural infection or empyema or TB
- Suspected malignancy
- Differentiating cardiac from non-cardiac causes
- Therapeutic thoracocentesis (1 – 1.5 L per session)
- Large symptomatic effusion causing dyspnoea or lung compression
- Empyema
- Hemothorax
- Before pleurodesis
- Drain placement when rapid reaccumulation is expected
- Diagnostic thoracocentesis (20 – 30 mL for analysis)
- Contraindications
- Significant coagulopathy or thrombocytopaenia
- Infection or cellulitis at the insertion site
- Haemodynamic instability
- Pleural adhesions
- Mechanical ventilation (relative contraindication)
- Procedure
- Review Chest X-ray, CT scan or Ultrasound
- Informed consent
- Positioning
- Sitting and leaning forward with the arms supported by pillows or overbed table
- Site
- Posterior mid-scapular line at the 6th – 8th intercostal space, depending on fluid location
- Ultrasound can be used to identify the safest pocket and reduce complications
- Sterile preparation with chlorhexidine/povidone iodine and draping
- Local anaesthesia up to the pleura with 1% plain lidocaine
- Insert the needle just above the superior border of the rib to avoid the neurovascular bundle
- Aspirate while advancing
- Advance catheter once pleural fluid is obtained
- Drain slowly
- Remove the catheter and apply pressure
- Send fluid for analysis if diagnostic evaluation is required
- Pleural fluid analysis
- Protein
- LDH
- pH
- pH < 7.2 in parapnemonic effusions
- Glucose
- < 3.3 mmol/L in parapneumonic effusion, empyema, malignancy, rheumatoid pleuritis or TB
- Cell count/differential
- Gram stain and culture
- Cytology
- TB testing (AFB, GeneXpert, culture or ADA)
- Light’s criteria
- A pleural fluid is an exudate if any one of the following is present:
- Pleural protein/serum protein >0.5
- Pleural LDH/serum LDH > 0.6
- Pleural LDH > 2/3 upper limit of normal serum LDH
- A pleural fluid is an exudate if any one of the following is present:
- Complications
- Pneumothorax (most common)
- Vascular injury → bleeding → haemothorax
- Pain
- Infection
- Intercostal nerve injury
- Liver or spleen puncture if inserted to low
- Re-expansion pulmonary oedema
- Vasovagal symptoms