Thoracocentesis

Summary

Definition

The clinical technique whereby fluid or air is removed from the pleural cavity (see also Chest drain insertion Chapter).

Indications

Emergency: in the acute situation where removal of fluid or air may prevent the restriction of normal ventilation and/or tamponade of the heart.

Diagnostic: sampling of fluid in the thoracic cavity for microscopy, culture, serology and cytology. The appearance of the fluid can allude to a diagnosis, for example milky fluid (chyle) aspirated from a ‘chylothorax’ implies rupture of the thoracic duct, while aspiration of blood from a ‘haemothorax’ is usually the result from penetrating chest injuries.

Therapeutic: when fluid continually accumulates despite medical therapy, repeated aspiration can provide symptomatic relief.

Radiographic: improving radiographs in areas which may otherwise be obscured by radio-opaque fluid in order to further aid diagnosis.

Procedure

Pre-medication with an intravenous anxiolytic (e.g. midazolam 1.5 mg), which should be given immediately before the procedure, or an intramuscular opioid given one hour before, keeping an antidote at hand.

Collect all the correct equipment prior to procedure. The following are recommended: antiseptic preparation solution, sterile gloves, gauze, sterile towels/drapes, 1–2% lidocaine without epinephrine, 3–5 ml syringe and 18-gauge needle (for local anaesthesia), 22-gauge 3.5 cm needle, three-way stopcock, 50 ml syringe, 30 cm long large (16-gauge) catheter-through-needle intravenous placement system, appropriate containers for fluid for diagnostic tests, haemostat, adhesive dressing and an assistant as required.

Confirm the site of insertion both clinically and radiologically (unless in emergency when clinical suspicion is enough). Position of the patient depends on whether air or fluid is expected.