Thoracentesis: The Procedure for Removing Pleural Fluid
The procedure in which pleural fluid is removed is called thoracentesis (option A).
Definition and Purpose
Thoracentesis is a commonly performed medical procedure used for both diagnostic and therapeutic purposes 1. It involves:
- The removal of pleural fluid from the pleural space between the lung and chest wall
- Use of a needle or catheter to access and withdraw the fluid
- Analysis of the fluid to determine its characteristics (diagnostic thoracentesis)
- Relief of symptoms by removing excess fluid (therapeutic thoracentesis)
Differentiating from Other Options
It's important to distinguish thoracentesis from the other options mentioned:
- Hemothorax (option B): This is a condition where blood accumulates in the pleural space, not a procedure 2
- Pneumothorax (option C): This refers to air in the pleural space and is actually a potential complication of thoracentesis, not the procedure itself 3
- Empyema (option D): This is a collection of pus in the pleural space, typically due to infection, not a procedure 4
Technical Aspects of Thoracentesis
The British Thoracic Society and American College of Chest Physicians recommend the following approach to thoracentesis 2:
- Ultrasound guidance is preferred, especially for small or loculated effusions (97% success rate)
- Small-gauge needles (21 or 22) are recommended for diagnostic thoracentesis to minimize complications 3
- For therapeutic thoracentesis, larger volumes are removed but with careful monitoring
Clinical Applications
Thoracentesis serves several important clinical functions:
- Diagnostic purposes: Differentiating between exudative and transudative effusions, identifying malignancy or infection 4, 1
- Therapeutic purposes: Relieving dyspnea and respiratory symptoms by removing excess fluid 5
- Combined with other procedures: Can be performed before thoracoscopy or pleurodesis in management of malignant effusions 4
Safety Considerations
When performing thoracentesis, several safety measures should be observed:
- Initial drainage should be limited to 1-1.5 liters per session to prevent re-expansion pulmonary edema 2
- Monitoring for symptoms like chest discomfort, persistent cough, or dyspnea during the procedure 5
- Patients with poor performance status (ECOG ≥3) who have large volumes (≥1.5L) removed are at higher risk for complications 5
- Post-procedure chest radiography is recommended to rule out pneumothorax 2
Complications
The most common complications of thoracentesis include:
- Pneumothorax (3-15% incidence, but only 0.28-1% requiring intervention) 4, 5
- Re-expansion pulmonary edema (rare, 0.08% incidence) 5
- Hemothorax (<2%) 4
- Vasovagal reactions (1-5%) 4
In summary, thoracentesis is the medical procedure specifically designed for removing pleural fluid, whether for diagnostic analysis or therapeutic relief of symptoms.