Pleural Aspiration

Authors: Dr Angus Chew*
                            Dr Stuart Lyon *

What are the prerequisites for having a pleural aspiration done?

Pleural fluid may require aspiration as a therapeutic procedure (for relief of dyspnoea) or to help in making a diagnosis (to obtain material for microscopy and culture, biochemical or other analysis). Carrying out this procedure under imaging guidance reduces the likelihood of failure to remove any/sufficient fluid or to inadvertently injure other organs.

As with all invasive procedures:

Appropriate clinical examination and imaging investigations (e.g. chest X-ray, chest ultrasound or chest CT) should be carried out before the procedure. The choice of imaging will depend on the patient’s background clinical condition.

If there is any reason to suspect that platelet count or international normalised ratio (INR) may be abnormal (e.g. drug treatment, comorbidities, sepsis etc.), a full blood examination and coagulation profile should be carried out. It is prudent to check the usual practice of the facility/hospital where the procedure is to be carried out regarding their preferences for preprocedural tests for coagulation. These are likely to vary depending on the pretest probability of a clotting problem and this depends on the patient’s individual situation. It is therefore difficult to be prescriptive about who does and does not need testing before pleural aspiration.

It is usual for anticoagulation and antiplatelet therapy to be ceased before pleural aspiration. If the risks of ceasing these medications are considered too high, such as in patients with recently inserted stents or other cardiac intervention, this should be discussed with the radiologist before requesting the procedure.

The patient should be fasted for 4 hours before the procedure.

What are the absolute contraindications for a pleural aspiration?

There are no absolute contraindications.

What are the relative contraindications for a pleural aspiration?

• International normalised ratio (INR) greater than 1.3.
• Thrombocytopenia (less than 50,000 cells/mL).
• Anticoagulation or antiplatelet therapy.
• Underlying poor respiratory function or chronic lung disease.
• Loculated pleural fluid can limit the value of a pleural aspiration, particularly if it is for therapeutic purposes.
• The size of the pleural effusion is very small.
• Patient requiring mechanical ventilation.
• Anxiety precluding a procedure under local anaesthesia.

What are the adverse effects of a pleural aspiration?

• A pneumothorax can occur in up to 30% of patients undergoing a pleural aspiration. The risk is increased if the pleural effusion is small or the patient has a history of smoking or chronic lung disease, such as emphysema or chronic obstructive airways disease.
• Re-expansion pulmonary oedema is an uncommon complication. Its incidence is increased when the size of the effusion is large, but can be reduced by judicious removal of fluid (i.e. <500 mL/hour).
• There is a small risk of serious infection and haemorrhage.
• There is a very small risk of injury to the liver, spleen or heart. This is a very rare complication, particularly if ultrasound guidance is used.

Are there alternative imaging tests, interventions or surgical procedures to a pleural aspiration?

An alternative method of draining pleural fluid is via video assisted thoracoscopy. However, this is a more invasive surgical procedure, which is carried out by a thoracic surgeon and requires a general anaesthetic. It is usually reserved for pleural fluid that is loculated or focal pleural collections, such as an empyema.

*The author has no conflict of interest with this topic.

Page last modified on 26/7/2017.