Related Subjects: Asthma
|Pleural effusion
|Pleural tap (thoracentesis)
|Pulmonary Embolism
|Cardiogenic Pulmonary Oedema
|Pneumothorax
💉 Pleural Aspiration (Thoracocentesis)
💡 Key Point (BTS 2023): Pleural aspiration is performed for diagnosis or symptom relief.
Always use thoracic ultrasound guidance (mandatory to reduce complications). Limit removal to ≤1.5 L per session to prevent re-expansion pulmonary oedema (RPE). Only trained or supervised personnel should perform.
🎯 Indications
- 🔍 Diagnostic: To determine the cause of a pleural effusion (infection, malignancy, heart failure, parapneumonic, etc.).
- 💨 Therapeutic: To relieve dyspnoea or chest discomfort caused by moderate/large effusions.
- 🕊️ Palliative: Symptom control in recurrent malignant or end-stage effusions (recurrence common without pleurodesis or indwelling catheter).
⚠️ Precautions
- 👩⚕️ Only trained staff or supervised trainees should perform the procedure (BTS recommends simulation training + supervision).
- 📡 Thoracic ultrasound guidance is mandatory for all pleural fluid procedures - reduces pneumothorax risk substantially (strong BTS recommendation).
- Use full aseptic technique in an appropriate clinical setting.
🚫 Cautions & Relative Contraindications
- 🩸 Coagulopathy / Anticoagulants: Aim for INR <1.5, platelets >50×10⁹/L; hold Warfarin, Heparin, or DOACs per local policy if safe.
- 💨 Mechanically ventilated patients: Higher risk of tension pneumothorax or bronchopleural fistula - requires senior involvement.
- 🦠 Local skin infection: Avoid insertion through cellulitic or infected skin.
- Other: Very small or unsafe fluid pocket on ultrasound; uncooperative patient.
🧰 Required Equipment
- Thoracic ultrasound machine + sterile probe cover (mandatory).
- 1% or 2% Lidocaine (local anaesthetic).
- Basic dressing pack, sterile towels, sterile gloves, gown.
- Iodine / Chlorhexidine solution for skin prep.
- Sterile sample pots (universal for M,C&S; plain/FDA for cytology ≥25–50 mL; biochemistry tubes; pH syringe if needed).
- Needles: 25–27G (fine) for skin, 21G (green) for deeper infiltration.
- Aspiration: 16–18G cannula/needle + 3-way tap, 10–50 mL syringes, extension tubing, drainage bag for therapeutic volumes.
- Monitoring: pulse oximetry, BP cuff; emergency equipment nearby.
🩺 Procedure Steps (Ultrasound-Guided)
- 🗣️ Consent and Preparation: Explain risks/benefits, obtain written consent. Position patient sitting upright, leaning forward with arms supported. Monitor oxygen saturation continuously.
- 📍 Site Selection: Use real-time thoracic ultrasound to identify a safe fluid pocket (avoiding lung, diaphragm, liver/spleen, vessels). Mark in the mid-scapular line (posterior) or posterior axillary line (lateral), typically in the 6th–8th intercostal space, 1–2 ribs below the upper border of dullness/fluid level. Insert the needle/cannula immediately above the superior border of the rib to avoid the intercostal neurovascular bundle (artery, vein, nerve) that runs along the inferior rib margin.
- 🧴 Aseptic Prep: Clean skin widely and apply sterile drapes.
- 💉 Local Anaesthetic: Infiltrate 5–10 mL Lidocaine superficially, then deeper to pleura (aspirate before injecting to avoid vessels). Confirm fluid entry.
- 💧 Aspiration: Advance needle/cannula under ultrasound guidance. Collect diagnostic samples first. For therapeutic drainage, use cannula + 3-way tap/syringe or gravity system. Monitor closely for cough, chest pain, or dyspnoea.
- 🚫 Drainage Limit: Do not remove >1.5 L per session (BTS consensus to prevent RPE; stop earlier if symptoms develop).
- 🩹 Completion: Withdraw device, apply firm pressure for 1–2 minutes, and dress with sterile occlusive dressing.
🧪 Laboratory Analysis of Pleural Fluid
| Test | Purpose / Interpretation |
| Microscopy, Culture & Sensitivity (MCS) | Identifies bacterial, fungal, or mycobacterial infection (use blood culture bottles if low volume). |
| Cytology | Detects malignant cells; send ≥25–50 mL for optimal yield (BTS 2023). |
| Protein & LDH | Apply Light’s criteria to classify exudate vs transudate. |
| pH | pH <7.2 suggests empyema or complicated parapneumonic effusion. |
| Glucose / Complement | Low in rheumatoid, lupus, or empyema. |
| Amylase | Raised in pancreatitis or oesophageal rupture. |
| Triglyceride / Cholesterol | Confirms chylothorax if milky and triglyceride >1.24 mmol/L. |
| AFB Stain / Culture / TB PCR | For tuberculosis if clinically suspected. |
🩻 Post-Procedure Care
- 🗑️ Dispose of sharps and contaminated materials safely.
- 📸 Chest X-ray: Routine if symptoms, air aspirated, multiple attempts, or high risk; otherwise selective to exclude pneumothorax.
- 🖋️ Documentation: Record side, site, volume drained, fluid appearance, complications, and samples sent.
- Monitor for immediate complications (pain, dyspnoea, cough suggesting RPE).
⚠️ Complications
- 😣 Pain: During insertion or drainage - ensure adequate local anaesthetic; consider additional analgesia.
- 💨 Pneumothorax: Risk reduced with ultrasound; most small and asymptomatic (observe); large/symptomatic → chest drain.
- 🩸 Bleeding: Intercostal vessel injury or coagulopathy-related.
- 🦠 Infection: Empyema risk; strict asepsis essential.
- ⚕️ Organ Injury: Rare (liver/spleen) if site too low - ultrasound prevents this.
- 🌫️ Re-expansion Pulmonary Oedema: Rare but serious; prevent by limiting volume and stopping if cough/chest tightness occurs.
📚 References
