Problems with the Pleura

Pleural Problems

1. Pleural Effusions
1. Clinical Manifestations
• most common symptom is dyspnea
• many patients are asymptomatic


2. Diagnosis
1. Chest X-ray
• upright chest x-ray is the initial diagnostic tool
• effusions < 300 cc may not be apparent on the upright chest x-ray
• lateral decubitus films can detect smaller effusions and confirm that the fluid is free-flowing



2. Thoracentesis
• mainstay of diagnosis
• distinguishes between transudative and exudative effusions
• positive cytology is diagnostic of malignancy
• positive cultures are diagnostic of empyema
• milky-colored fluid is diagnostic of chylothorax
• elevated amylase levels are suggestive of a sympathetic effusion from pancreatitis, pancreatic pseudocyst, or pancreatic ascites
• pleural pH < 7.20 strongly suggests bacterial infection


3. Video-Assisted Thoracoscopy
• provides excellent visualization of the thoracic cavity
• valuable tool when a biopsy of the pleura or lung is required


3. Types of Effusions
1. Transudates
• ultrafiltrates of plasma low in total protein (<3.0 g/dL)
• common causes include congestive heart failure, cirrhosis, sepsis


2. Exudates
• protein-rich effusions with pleural fluid protein/serum protein > 0.5 or pleural fluid LDH/serum LDH > 0.6
• more likely to be associated with a diseased pleura
• common causes include malignancy, infection, sympathetic effusions from pancreatitis or a subphrenic abscess


4. Treatment
1. Transudative Effusions
• treatment is directed at the underlying condition
• repeat thoracenteses may be required
• occasionally, chest tube placement with or without pleurodesis may be necessary


2. Malignant Pleural Effusions
• lung, breast, ovarian, and gastrointestinal cancers are the most common primary tumors responsible for pleural effusions
• fluid is exudative in character and frequently bloody
• treatment is palliative since median survival is only 3 – 6 months


1. Initial Management
• therapeutic thoracentesis determines the symptomatic response to drainage, the ability of the lung to reexpand completely, and the subsequent rate of reaccumulation
• for some chemoresponsive tumors (breast, ovarian, lymphoma), treatment of the underlying malignancy may prevent effusion recurrence


2. Recurrent Malignant Effusions
1. Pleurodesis
• eliminates the pleural space by creating an inflammatory fusion between the visceral and parietal pleura
• as the first step, the pleural fluid must be completely evacuated and the lung re-expanded
• talc is now the most common agent used and may be administered at bedside through a chest tube or at the time of thoracoscopy
• following talc pleurodesis the chest tube is left in place until the output is minimal
• besides talc, other sclerosing agents in use include doxycycline (painful) or bleomycin (expensive)
• the inflammatory response may cause severe pain in some patients
• success rate is 80% to 90%


2. Indwelling Pleural Catheter
• allows for intermittent outpatient drainage
• catheters are typically left in place for 2 – 6 weeks
• spontaneous pleurodesis may occur in ~ 40% of patients
• may also be combined with talc pleurodesis
• serious complications include tract infection, empyema, catheter blockage, and catheter fracture during removal
  
• only option for patients with a lung that cannot be reexpanded


2. Spontaneous Pneumothorax
1. Etiology
• nontraumatic pneumothorax most commonly results from rupture of a pulmonary bleb or bulla
• large leaks can produce a life-threatening tension pneumothorax
• 80% occur in young, tall, thin males without significant pulmonary disease
• in patients over 40, primary pulmonary disease (COPD, emphysema) is usually present


2. Clinical Manifestations
• chest pain and dyspnea are the most common findings
• on physical exam, decreased breath sounds and hyperresonance to percussion may be present


3. Diagnosis
• characteristic x-ray finding is absence of lung markings and a faintly visible line defining the edge of the lung
• CT scan may identify the cause of the spontaneous pneumothorax



4. Treatment
1. Nonoperative Treatment
• most spontaneous pneumothoraces can initially be managed with anterior placement of a small-bore drainage catheter
• progression in size mandates a chest tube


1. Tube Thoracostomy
• 20 Fr tube is appropriate for most cases
• tube is placed in the 4th or 5th intercostal space in the midaxillary line and is directed towards the apex
• most common chest drainage system is the pleur-evac
• tube may also be attached to a one-way Heimlich valve (useful for outpatient management)
• if the air leak is large, more than one chest tube may be necessary to expand the lung


2. Operative Treatment
• indicated for a massive air leak with failure of lung reexpansion or for a smaller leak that has persisted for more than one week
• other indications include recurrent pneumothorax or a first episode in a patient with an occupational hazard (airplane pilot, diver)


1. Video-Assisted Thoracic Surgery (VATS)
• most common operative procedure
• less pain and less postoperative respiratory dysfunction than thoracotomy
• apical blebs are resected with staplers
• pleurodesis is accomplished mechanically by pleural abrasion or chemically by talc


2. Thoracotomy
• rarely necessary
• may be done through an axillary incision


3. Chylothorax
1. Etiology
• results from leakage of lymphatic fluid (chyle) from the thoracic duct into the pleural space
• the thoracic duct traverses the mediastinum and enters the venous system at the confluence of the left internal jugular and subclavian veins
• most chylothoraces are unilateral and on the left side
• most common cause is operative injury (esophagectomy, mediastinal node dissection, neck dissection)
• traumatic chylothorax usually results from penetrating injuries
• most common noninjury cause is malignancy (lymphoma)



2. Diagnosis
• aspiration of milky white, odorless fluid is virtually diagnostic
• lymphocyte count, triglyceride level, and the presence of chylomicrons in the fluid can help in ambiguous cases


3. Management
1. Nonoperative Management
• goals are to decrease chyle production and keep the lung expanded
• a medium chain triglyceride diet or NPO/TPN are used to reduce chyle production
• a chest tube is required to keep the lung expanded
• nonoperative management should not be tried for more than 7 to 10 days because significant immunosuppression results from long-term thoracic duct drainage


2. Operative Management
• ligation of the thoracic duct at the site of injury is the procedure of choice
• if the site of injury cannot be identified, then the thoracic duct may be ligated at the diaphragmatic hiatus via a right thoracoscopy or thoracotomy


4. Empyema
• infection of the pleural space


1. Etiology
• most frequently caused by pneumonia
• other causes include trauma, postoperative, bronchopleural fistula, esophageal perforation or anastomotic leak, or spread from an intraabdominal source (subphrenic abscess, intrahepatic abscess)
• most common organisms isolated are Staphylococcus, Streptococcus, gram-negative rods (Pseudomonas, Klebsiella, E. coli), and anaerobes


2. Clinical Manifestations and Diagnosis
• patients are febrile and have a pleural effusion on chest x-ray or CT scan
• thoracentesis with Gram stain and culture of the fluid confirms the diagnosis
• pleural fluid with a pH < 7.20 and glucose < 40 mg/dL also strongly suggests the diagnosis
• CT scan may be necessary to rule out other pathology such as a lung abscess



3. Treatment
• principles are appropriate antibiotics, obliteration of the empyema space by lung reexpansion, and complete dependent drainage


1. Thoracentesis
• may be used to make the diagnosis, but is insufficient treatment because the empyema space is not obliterated


2. Thoracostomy Tube
• usually the first treatment chosen
• must use a large tube in order to evacuate the thick, viscous material
• fibrinolytics and DNase may be used to break up loculations
• should be placed in the most dependent part of the empyema cavity
• if a small space persists after closed-tube drainage, the drainage can be converted to open drainage by cutting the tube off at the skin and allowing it to drain into dressings


3. Open Drainage with Rib Resection
• allows for evacuation of pus and adequate breakup of loculations and adhesions
• if the cavity is mature it can be marsupialized – this facilitates dressing changes and irrigation


4. Decortication
• requires a thoracoscopy or formal thoracotomy
• empyema space is evacuated under direct vision and the inflammatory peel is completely removed from the visceral pleura
• goal is to allow lung reexpansion
• chest tubes are placed in the most dependent position


5. Chest Tube Mechanics
• the tube is connected to a collection device that consists of 3 separate but interconnected bottles or chambers
• must be placed below the level of the chest for gravity drainage


1. Bottle #1
• connects directly to the chest tube
• used for fluid collection
• air flows into the next bottle


2. Bottle #2
• air flows into the water at the bottom of the bottle
• bubbles indicate an air leak
• functions as a one-way valve: air can escape the chest on exhalation but cannot get back in during inhalation
• the water seal chamber must be filled to 2 cm


3. Bottle #3
• manometer allows you to set a defined amount of suction through the chest tube