From the Guidelines
Pleural effusions should be drained when they cause significant symptoms, are suspected to be infected, or require diagnostic evaluation, with specific indications including loculated pleural collections, large non-purulent effusions, and those with a pH <7.2. The decision to drain a pleural effusion is guided by the presence of symptoms, suspicion of infection, or the need for diagnostic evaluation. Indications for drainage include:
- Dyspnea
- Chest pain
- Hypoxemia
- Large effusions causing respiratory compromise
- Suspected empyema or parapneumonic effusions
- Malignant effusions
- Unknown etiology despite non-invasive testing
- Loculated pleural collections, as they are associated with a poorer outcome and may require earlier chest tube drainage 1
- Large non-purulent effusions, which can be drained by chest tube for symptomatic benefit 1
- Pleural fluid pH <7.2, which indicates the need for chest tube drainage 1
Therapeutic thoracentesis relieves symptoms by removing fluid, while diagnostic thoracentesis obtains fluid for analysis to determine the cause. The procedure involves inserting a needle or catheter into the pleural space, typically using ultrasound guidance for safety. For recurrent malignant effusions, placement of an indwelling pleural catheter or chemical pleurodesis may be considered. Contraindications include bleeding disorders, anticoagulation therapy, skin infection at the insertion site, and severe respiratory failure requiring positive pressure ventilation. Complications can include pneumothorax, bleeding, infection, and re-expansion pulmonary edema, particularly when large volumes (>1.5 liters) are removed rapidly. Drainage should be performed by experienced clinicians with appropriate monitoring to minimize these risks.
From the Research
Indications for Drainage of Pleural Effusion
The decision to drain a pleural effusion depends on various factors, including the underlying cause, symptoms, and patient's overall condition. The following are some indications for drainage of pleural effusion:
- Symptomatic patients with large or massive pleural effusions, especially those with dyspnea or chest pain 2, 3
- Malignant pleural effusions, which often require drainage to palliate symptoms and may need pleurodesis to prevent recurrence 2, 4, 5
- Empyemas, which require drainage and antibiotic treatment 2
- Refractory pleural effusions, which do not respond to treatment of the underlying medical disorder 2
- Patients with a high risk of complications, such as those with a history of lung disease or those who are immunocompromised 3
Diagnostic Evaluation
Before drainage, a diagnostic evaluation should be performed to determine the cause of the pleural effusion. This includes:
- Thoracocentesis to obtain a sample of the pleural fluid for laboratory testing 2
- Imaging studies, such as chest X-ray or ultrasonography, to evaluate the size and location of the effusion 3
- Cytological analysis and immunohistochemistry to help diagnose malignant pleural effusions 2
Drainage Procedures
Various drainage procedures are available, including:
- Thoracentesis, which involves removing fluid from the pleural space using a needle or catheter 2, 3
- Insertion of a small or large bore chest drain, which may be used for patients with a large or massive pleural effusion 3
- Pigtail chest tube, which is a type of chest drain that can be used for drainage and pleurodesis of malignant pleural effusions 4