Thoracentesis is a medical procedure performed to remove excess fluid that has accumulated in the chest cavity. It is usually carried out for diagnostic and therapeutic purposes. In the human body, there is a small space between the lungs and the inner chest wall. Normally, a very small amount of fluid is present in this space. This fluid reduces friction between the rib cage and lung tissue. However, an increase in the amount of this fluid can indicate a pathological condition. With thoracentesis, this excess fluid is carefully withdrawn to determine the cause of the disease and the appropriate treatment method.
| Definition | The procedure of draining fluid (pleural effusion) that has accumulated in the chest cavity with a needle for diagnostic or therapeutic purposes. |
| Indications | Pleural effusion, lung infections, malignancy, heart failure, post‑traumatic fluid accumulation. |
| Contraindications | Severe coagulopathy, infected skin area, small localized effusion, risk of respiratory distress. |
| Pre‑procedure Preparation | Blood tests (especially coagulation profile), imaging studies (ultrasound, X‑ray), patient information and consent, fasting requirement before procedure. |
| Procedure Duration | Usually 15–30 minutes. |
| Anesthesia Type | Local anesthesia. |
| Procedure Steps | 1. Positioning the patient (usually seated) 2. Cleaning the target area with antiseptic 3. Administering local anesthesia 4. Inserting needle or catheter into pleural space 5. Draining fluid and sending to laboratory 6. Removing needle or catheter and dressing the site |
| Complications | Pneumothorax, bleeding, infection, liver or spleen injury, pulmonary edema. |
| Recovery Time | Usually a few hours; post‑procedure observation required. |
| Success Rate | High; effective for diagnostic and symptomatic relief. |
| Alternative Treatments | Pleural catheter placement, surgical drainage, medical therapy (diuretics), chest tube insertion. |
Prof. Dr. Özgür KILIÇKESMEZ
Interventional Radiology / Interventional Neuroradiology
What Is Thoracentesis?
Thoracentesis is the procedure of removing fluid or air that has accumulated in the chest cavity. This procedure is performed under local anesthesia. During the procedure, a cannula or hollow needle is inserted into the chest wall. This method is especially important for:
- Abnormal fluid accumulation in the chest cavity,
- Conditions with trapped air,
Thoracentesis is also known as pleural tap or needle thoracostomy. The procedure is used both for diagnosis and treatment. Its implementation is carefully planned by the physician according to the patient’s condition. It is a method used in the management of intrathoracic pathologies.
Anatomy and Physiology of the Chest Cavity Dynamics
Between the right and left sides of the chest cavity, there is a space between the inner chest wall and the lungs. This space plays a vital role during normal respiratory activities. During breathing, this potential space provides a slippery surface necessary for the lungs to expand and contract freely. The small amount of fluid within also functions as part of the lymphatic drainage system. Functionally:
- During inhalation, this fluid assists lung expansion.
- During exhalation, it facilitates lung contraction.
The presence of this fluid not only provides a low‑friction environment between musculoskeletal structures and lung tissue but also contributes to lymphatic drainage. However, an increase in this fluid’s volume can indicate various health problems. Under normal conditions, the fluid volume is balanced; pathological accumulation can signal disease. Therefore, factors such as fluid volume, rate of accumulation, and chemical composition are evaluated as key data in disease diagnosis and treatment.
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Applications of Thoracentesis
Thoracentesis has a broad range of indications and is used for both diagnostic and therapeutic purposes. It is performed diagnostically when the cause of excess fluid is unknown. When fluid volume causes significant clinical symptoms, it is applied therapeutically. Whether diagnostic or therapeutic determines the volume of fluid removed and the precautions taken during the procedure.
Diagnostic Thoracentesis:
- Typically small volume.
- Uses a single 20–30 mL syringe.
- First sample is sent for laboratory and pathology analysis.
Therapeutic Thoracentesis:
- Large volume fluid removal.
- Several liters of fluid may be removed.
- If fluid cause is unclear or suspicion of change, a small sample is sent for analysis.
In cases where fluid may rapidly reaccumulate, a drainage system is usually placed. This can occur in various clinical scenarios:
- Hemothorax due to trauma,
- Malignant effusion in cancer,
- Post‑cardiothoracic surgery inflammation,
- Metabolic conditions such as cirrhosis or malabsorption syndromes.
Infected fluid collections should be drained to remove the source and reservoirs of infection. This is critical to prevent infection spread and improve patient outcomes.
Contraindications to Thoracentesis
Thoracentesis is a medical procedure that should not be performed under certain conditions. Although there are no absolute contraindications, there are relative contraindications. These include conditions that prevent the patient from safely positioning for the procedure. Certain coagulation disorders are also considered relative contraindications. Contraindications include:
- Conditions preventing the patient from safely assuming the required position.
- Uncontrolled coagulation disorders, which may include:
- Disorders due to medications or iatrogenic effects.
- Intrinsic disorders that cannot be controlled.
- When potential risks of the procedure outweigh expected benefits.
Pre‑procedure Preparations
Before starting thoracentesis, a detailed medical history should be obtained. This information allows the procedure to be performed safely. Next, a careful physical examination is conducted to accurately determine the intervention site. Obtaining informed consent from the patient is mandatory to fulfill legal requirements.
- Site marking: The side and location for the procedure should be marked according to hospital invasive procedure policies.
- Equipment assembly: All necessary medical instruments should be prepared before beginning.
- Patient monitoring:
- Apply pulse oximeter to the patient.
- Continuously monitor blood pressure and heart rate during the procedure.
Thoracentesis Technique and Procedure Steps
During thoracentesis, the patient is usually positioned supine or seated, depending on the target site. The affected side is chosen via the mid‑axillary or posterior mid‑scapular line. Bedside ultrasound is used to localize fluid, which is critical in patients with small effusions.
Sterilization of the procedure area is performed as follows:
- Prepare the patient under sterile conditions.
- Clean the skin with antiseptic solution.
- Use a 25‑gauge needle to create a small wheal for local anesthesia.
After local anesthesia, deeper tissues are anesthetized with a 20 or 22‑gauge needle placed just above the rib margin. Negative pressure is applied as the needle or catheter is advanced until fluid emerges.
Materials used during the procedure:
- Larger bore needle or prepackaged catheter.
- If using a catheter kit, a #11 scalpel is used to make a small skin nick.
The catheter is advanced into the thoracic cavity. Once the required fluid volume is collected, the needle is removed or the drainage system connected. For large‑volume removal:
- Gravity drainage,
- Serial syringe aspiration with a three‑way stopcock.
After catheter removal, pressure is applied to the entry site to minimize bleeding risk.
Complications During Thoracentesis
Various complications can occur during thoracentesis. Bleeding, pain, and infection at the procedure site are the most common issues. Inserting the needle too high between ribs can damage intercostal vessels and nerves. Rapid or excessive fluid removal increases the risk of pulmonary edema, which can severely impair lung function.
- Pneumothorax: The most frequent complication, occurring in 12–30% of cases.
- Empyema and other infections: If the needle passes through infected tissue, an abscess or empyema can develop in the chest cavity.
- Visceral injury: If the entry site is too low, the spleen or liver may be injured.
Chest tube placement is required for large or progressive pneumothoraces, especially in mechanically ventilated patients. Ultrasound signs such as lung sliding absence and B‑line disappearance are important for early pneumothorax detection. These assessments should be performed before starting the procedure.
Although rare, small catheter fragments may remain in the chest cavity, typically when catheters are retracted over a trocar. Careful technique is essential to maintain catheter integrity.
Clinical Significance of Thoracentesis
Thoracentesis alleviates symptoms by removing excess fluid from the pleural space surrounding the lungs. It is particularly effective for controlling pain and dyspnea, which impair lung function. Fluid obtained during the procedure undergoes detailed biochemical and microscopic examination. This analysis allows:
- Characterization of pleural fluid.
- Analysis of cellular composition and chemical content.
Health Team Approaches in Thoracentesis
Thoracentesis is performed by a multidisciplinary health team. The physician is responsible for applying the procedure using the most appropriate techniques to improve patient outcomes. Before the procedure, the patient is thoroughly informed of potential complications and benefits. The procedure environment is prepared meticulously to ensure safety, and adequate anesthesia is provided to ensure patient comfort. Post‑procedure, nurses play an active role. Their tasks include:
- Monitoring the patient’s overall condition,
- Encouraging light physical activities such as ambulation,
- Educating the patient on dressing changes.
A post‑procedure chest X‑ray is performed to assess for complications. Throughout this process, the patient is continuously informed and guided on when to seek medical attention. This comprehensive approach accelerates recovery and minimizes potential risks.
Frequently Asked Questions
Thoracentesis is performed by a pulmonologist. An anesthesiologist may assist as needed. In complex cases, interventional radiologists may be involved. In emergencies, emergency physicians can initiate the procedure. Thoracic surgeons may be consulted if necessary.
Fluid accumulation in the lung can often be detected on X‑ray. However, more detailed imaging methods may be required for confirmation. A chest X‑ray can show the presence of fluid, but CT scans and other advanced imaging techniques provide more precise information about fluid volume and location. Therefore, while X‑ray can suggest pleural effusion, additional tests are recommended for definitive diagnosis.
Thoracentesis usually takes 15–30 minutes. However, if performed for therapeutic drainage of large volumes, it may take longer. The patient must remain still during the procedure.
Thoracentesis is typically performed at an intercostal space located 5–10 cm lateral to the vertebral line, just above the upper border of the rib. If fluid is not obtained on the first attempt, the procedure may be repeated one intercostal space below. This increases the likelihood of successful fluid aspiration.
Thoracentesis is usually performed with the patient in a supine or upright seated position. In the upright position, the patient’s arms are supported. For patients unable to sit, the lateral decubitus position is used to allow fluid to accumulate dependent. Both positions ensure the procedure can be performed safely and effectively, always inserting the needle just above the upper border of the rib.
Prof. Dr. Özgür Kılıçkesmez graduated from Cerrahpaşa Medical Faculty in 1997. He completed his specialization at Istanbul Education and Research Hospital. He received training in interventional radiology and oncology in London. He founded the interventional radiology department at Istanbul Çam and Sakura City Hospital and became a professor in 2020. He holds many international awards and certificates, has over 150 scientific publications, and has been cited more than 1500 times. He is currently working at Medicana Ataköy Hospital.
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