Procedures

Thoracentesis and chest drain insertion

Reviewed Nov 2026·3 references
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Ultrasound-guided pleural aspiration, interpreting pleural fluid, intercostal drain insertion and drain management.

Definition
BTS 2023: use thoracic ultrasound for all pleural procedures for fluid; insert drains in the 'triangle of safety'; small-bore Seldinger drains are suitable for most effusions, pneumothorax and pleural infection.

At the bedside

  1. 1

    Image

    Ultrasound to mark or guide the site; note depth, diaphragm and organs; ICU patients often supine - lateral approach in mid- to posterior axillary line.

  2. 2

    Site

    Triangle of safety: anterior border of latissimus dorsi, lateral border of pectoralis major, line at the 5th intercostal space (nipple level); insert just above the rib.

  3. 3

    Diagnostic tap

    Send protein, LDH, pH (blood gas syringe), glucose, cell count, Gram stain and culture (blood-culture bottles), cytology, and ADA where TB is suspected.

  4. 4

    Therapeutic tap

    Stop if chest tightness, cough or vasovagal symptoms; limit volume at one sitting (commonly 1-1.5 L) to avoid re-expansion oedema.

  5. 5

    Chest drain

    Seldinger 12-14 Fr for most indications; larger bore for haemothorax or large air leaks; secure, connect to underwater seal.

  6. 6

    Pleural infection

    Drain if frank pus, pH < 7.2 or positive Gram stain/culture; antibiotics; consider intrapleural tPA + DNase if poor drainage; surgical referral if failing.

  7. 7

    Drain care

    Never clamp a bubbling drain; daily CXR/US and output; remove when lung re-expanded and air leak stops or fluid < ~200 mL/day (local protocol).

Local anaesthetic

Lidocaine (lignocaine)

Infiltration
Dose
1-2% lidocaine; stay under 4.5 mg/kg plain
Worked example
70 kg: max ~300 mg plain = 30 mL of 1% (10 mg/mL) or 15 mL of 2%.

Pleural infection with poor drainage

Intrapleural alteplase + dornase alfa

Intrapleural
Dose
Alteplase 10 mg + dornase 5 mg twice daily for 3 days

Light's criteria (exudate if any one present)

CriterionExudate
Pleural/serum protein> 0.5
Pleural/serum LDH> 0.6
Pleural LDH> 2/3 upper limit of normal serum LDH
Red flag · call your senior now
Sudden hypoxaemia and frothy sputum after draining a large effusion: re-expansion pulmonary oedema.
Red flag
Tension pneumothorax in a ventilated patient (hypotension, rising airway pressures, absent lung sliding): needle or finger decompression then drain.
Pitfall
Inserting a drain without ultrasound for a fluid collection.
Pitfall
Clamping a drain that is bubbling.
Pearl
Light's criteria misclassify about 25% of transudates in patients on diuretics as exudates - check serum-pleural albumin gradient (> 12 g/L favours transudate).

References

  1. 1

    Roberts ME, Rahman NM, Maskell NA, et al. British Thoracic Society Guideline for pleural disease. Thorax 2023;78(Suppl 3):s1-42.

  2. 2

    Rahman NM, Maskell NA, West A, et al. Intrapleural use of tissue plasminogen activator and DNase in pleural infection (MIST2). N Engl J Med 2011;365:518-26.

  3. 3

    Neal JM, Barrington MJ, Fettiplace MR, et al. The third American Society of Regional Anesthesia and Pain Medicine practice advisory on local anesthetic systemic toxicity: executive summary 2017. Reg Anesth Pain Med 2018;43:113-23.

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