Pleural Effusion - Pleural Conditions

PLEURAL EFFUSION

Pleural effusion, a collection of fluid in the pleural space, is rarely a primary disease process but is usually secondary to other dis-eases. Normally, the pleural space contains a small amount of fluid (5 to 15 mL), which acts as a lubricant that allows the pleural surfaces to move without friction (Fig. 23-5). Pleural ef-fusion may be a complication of heart failure, TB, pneumonia, pulmonary infections (particularly viral infections), nephrotic syndrome, connective tissue disease, pulmonary embolism, and neoplastic tumors. Bronchogenic carcinoma is the most common malignancy associated with a pleural effusion.

Pathophysiology

In certain disorders, fluid may accumulate in the pleural space to a point where it becomes clinically evident. This almost always has pathologic significance. The effusion can be composed of a relatively clear fluid, or it can be bloody or purulent. 

An effusion of clear fluid may be a transudate or an exudate. A transudate (filtrates of plasma that move across intact capillary walls) occurs when factors influencing the formation and reabsorption of pleural fluid are altered, usually by imbalances in hydrostatic or oncotic pressures. The finding of a transudative effusion generally implies that the pleural membranes are not diseased. The most common cause of a transudative effusion is heart failure. An exu-date (extravasation of fluid into tissues or a cavity) usually results from inflammation by bacterial products or tumors involving the pleural surfaces.

Clinical Manifestations

Usually the clinical manifestations are those caused by the underly-ing disease. Pneumonia causes fever, chills, and pleuritic chest pain, whereas a malignant effusion may result in dyspnea and coughing. The size of the effusion and the patient’s underlying lung disease determine the severity of symptoms. A large pleural effusion causes shortness of breath. When a small to moderate pleural effusion is present, dyspnea may be absent or only minimal. The severity of the symptoms assessed depends on the time course of the develop-ment of the pleural effusion and the patient’s underlying disease.

Assessment and Diagnostic Findings

Assessment of the area of the pleural effusion reveals decreased or absent breath sounds, decreased fremitus, and a dull, flat sound when percussed. In an extremely large pleural effusion, the as-sessment reveals a patient in acute respiratory distress. Tracheal deviation away from the affected side may also be noted.

Physical examination, chest x-ray, chest CT scan, and thora-centesis confirm the presence of fluid. In some instances, a lateral decubitus x-ray is obtained. For this x-ray, the patient lies on the affected side in a side-lying position. A pleural effusion can be di-agnosed because this position allows for the “layering out” of the fluid, and an air–fluid line is visible.

Pleural fluid is analyzed by bacterial culture, Gram stain, acid-fast bacillus stain (for TB), red and white blood cell counts, chemistry studies (glucose, amylase, lactic dehydrogenase, pro-tein), cytologic analysis for malignant cells, and pH. A pleural biopsy also may be performed.

Medical Management

The objectives of treatment are to discover the underlying cause, to prevent reaccumulation of fluid, and to relieve discomfort, dyspnea, and respiratory compromise. Specific treatment is di-rected at the underlying cause (eg, heart failure, pneumonia, lung cancer, cirrhosis). If the pleural fluid is an exudate, more exten-sive diagnostic procedures are performed to determine the cause. Treatment for the primary cause is then instituted.

Thoracentesis is performed to remove fluid, to obtain a spec-imen for analysis, and to relieve dyspnea and respiratory com-promise. Thoracentesis may be performed under ultrasound guidance. Depending on the size of the pleural effu-sion, the patient may be treated by removing the fluid during the thoracentesis procedure or by inserting a chest tube connected to a water-seal drainage system or suction to evacuate the pleural space and re-expand the lung.

If the underlying cause is a malignancy, however, the effusion tends to recur within a few days or weeks. Repeated thoracenteses result in pain, depletion of protein and electrolytes, and some-times pneumothorax. Once the pleural space is adequately drained, a chemical pleurodesis may be performed to obliterate the pleural space and prevent reaccumulation of fluid. Pleurode-sis may be performed using a thoracoscopic approach or via a chest tube. Chemically irritating agents (eg., bleomycin or talc) are instilled in the pleural space. With the chest tube insertion approach, after the agent is instilled, the chest tube is clamped for 60 to 90 minutes and the patient is assisted to assume various po-sitions to promote uniform distribution of the agent and to max-imize its contact with the pleural surfaces. The tube is unclamped as prescribed, and chest drainage may be continued several days longer to prevent reaccumulation of fluid and to promote the for-mation of adhesions between the visceral and parietal pleurae.

Other treatments for malignant pleural effusions include sur-gical pleurectomy, insertion of a small catheter attached to a drainage bottle for outpatient management, or implantation of a pleuroperitoneal shunt. A pleuroperitoneal shunt consists of two catheters connected by a pump chamber containing two one-way valves. Fluid moves from the pleural space to the pump chamber and then to the peritoneal cavity. The patient manually pumps on the reservoir daily to move fluid from the pleural space to the peritoneal space (Taubert & Wright, 2000).

Nursing Management

The nurse’s role in the care of the patient with a pleural effusion includes implementing the medical regimen. The nurse prepares and positions the patient for thoracentesis and offers support throughout the procedure. Pain management is a priority, and the nurse assists the patient to assume positions that are the least painful. However, frequent turning and ambulation are impor-tant to facilitate drainage. The nurse administers analgesics as pre-scribed and as needed.

If a chest tube drainage and water-seal system is used, the nurse is responsible for monitoring the system’s function and recording the amount of drainage at prescribed intervals. Nurs-ing care related to the underlying cause of the pleural effusion is specific to the underlying condition.

If the patient is to be managed as an outpatient with a pleural catheter for drainage, the nurse is responsible for educating the pa-tient and family regarding management and care of the catheter and drainage system.