Drainage of fluid from the pleural space using needle, cannula, or fl exible
small-bore drain. Increasingly being performed under ultrasound guidance.
Blood/pus often requires large-bore drain insertion.
Indications
Improvement of blood gases.
Symptomatic improvement of dyspnoea.
Diagnostic ‘tap’.
Contraindications/cautions
Coagulopathy.
Technique
Confi rm presence of effusion by CXR or ultrasound.
Select drainage site either by maximum area of stony dullness under
percussion or under ultrasound guidance.
Use aseptic technique. Clean area with antiseptic and infi ltrate local
skin and subcutaneous tissues with 1% lidocaine. Advance into deeper
tissues, aspirating to confi rm absence of blood, then infi ltrate with
local anaesthetic until pleura is pierced and fl uid can be aspirated.
Advance drainage needle/cannula/drain slowly through chest wall and
intercostal space (above upper border of rib to avoid neurovascular
bundle). Apply gentle suction until fl uid is aspirated.
Withdraw 50mL for microbiological (M, C & S, TB stain, etc.),
biochemical (protein, glucose, etc.) and histological/cytological
(pneumocystis, malignant cells, etc.) analysis, as indicated.
Either leave drain in situ connected to a drainage bag or connect
needle/cannula by a three-way tap to a drainage apparatus.
Continue aspiration/drainage until no further fl uid can be withdrawn
or if patient becomes symptomatic (pain/dyspnoea). Dyspnoea or
haemodynamic changes may occur due to removal of large volumes
of fl uid (>1–2L) and subsequent fl uid shifts; if this is considered to be
a possibility, remove no more than 1L at a time, either by clamping/
declamping drain or repeating needle aspiration after an equilibration
interval (e.g. 4–6h).
Remove needle/drain. Cover puncture site with fi rmly applied gauze
dressing.
Complications
Puncture of lung or subdiaphragmatic viscera.
Bleeding.
Fluid protein level
Protein >30g/L (NB. This should be viewed in the context of the plasma
protein level) is an exudates; caused by: infl ammatory, e.g. pneumonia,
pulmonary embolus, neoplasm, collagen vascular diseases.
Protein <30g/L is a transudate caused by: (i) raised venous pressure
(e.g. heart failure, fl uid overload), (ii) decreased colloid osmotic pressure
(e.g. critical illness leading to reduced [plasma protein] from capillary
leak and hepatic dysfunction, hepatic failure, nephrotic syndrome).