Thoracentesis: Procedure to Drain Fluid Around the Lungs for Relief and Diagnosis

Thoracentesis is a minimally invasive procedure to remove excess fluid from the pleural space (between the lung and chest wall).

Indications

• Therapeutic: Relieve dyspnea, chest pain, cough from large effusions.
• Diagnostic: Analyze fluid (cell count, protein, LDH, glucose, pH, cytology, cultures, amylase) to determine cause (transudate vs. exudate, infection, malignancy).

Procedure Overview

1. Patient sits upright, leaning forward over a bedside table.
2. Ultrasound identifies optimal intercostal space (usually 7th–9th posteriorly).
3. Skin cleaned, local anesthetic infiltrated (1% lidocaine).
4. Needle/catheter advanced over superior rib margin (avoiding neurovascular bundle).
5. Fluid aspirated (typically ≤1.5 L per session to avoid re‑expansion pulmonary edema).
6. Catheter removed; pressure dressing applied.
7. Post‑procedure chest X‑ray to rule out pneumothorax.

Complications (Rare)

• Pneumothorax (1–5%, higher without ultrasound)
• Bleeding, infection, organ laceration
• Re‑expansion pulmonary edema (if >1.5 L removed rapidly)
• Vasovagal reaction

Fluid Analysis (Light’s Criteria)

Exudate if any: pleural fluid protein/serum protein >0.5, pleural fluid LDH/serum LDH >0.6, pleural fluid LDH >2/3 upper limit normal serum LDH.