Accumulation of air in the pleural space is the most common indication for chest tube placement. Symptoms include tachy-pnea, dyspnea, and pleuritic pain, although some patients (in particular, those with a small spontaneous pneumothorax) may be asymptomatic. Physical findings include diminished breath sounds and hyperresonance to percussion on the affected side.

Diagnosis is often confirmed by chest radiography, demonstrating a thin opaque line beyond which exists a hyperlucent area without lung markings. Although the size of a pneumo-thorax may be estimated, this is at best a rough approximation of a three-dimensional space based on a two-dimensional view. Inspiratory and expiratory films may be helpful in equivocal situations, as may a lateral decubitus film with the suspected side up. Detection of an anterior pneumothorax in blunt trauma may be especially difficult and yet may be easily detected by chest computed tomographic (CT) scanning [4].

The decision to insert a chest tube for a pneumothorax is based on the patient’s overall clinical status and may be aided by serial chest radiographs. Tube decompression is indicated in those who are symptomatic, who have a large or expanding pneumothorax, or who are being mechanically ventilated (the latter of whom may present acutely with deteriorating oxygenation and an increase in airway pressures, necessitating immediate decompression).

A spontaneous pneumothorax occurs most commonly in tall, slender, young males secondary to rupture of apical alveoli and subsequent formation of subpleural blebs, which then rupture into the pleural space. An associated hemothorax from torn adhesions may occur in up to 5% of cases [5]. The risk of a recurrent ipsilateral spontaneous pneumothorax is as high as 50%, and the risk of a third episode is 60% to 80% [6].

A small, stable, asymptomatic pneumothorax can be followed with serial chest radiographs. Reexpansion occurs at the rate of approximately 1.25% of lung volume per day [7]. Definitive operative intervention beyond tube thoracostomy may include resection of apical blebs, pleurodesis, and/or pleurectomy via open thoracotomy or thoracoscopy. These procedures are often reserved for those with a persistent air leak or with recurrent spontaneous pneumothoraces.

Pneumothorax in trauma patients is often accompanied by bleeding (hemopneumothorax) and almost invariably requires tube decompression, especially if mechanical ventilation is planned, to avoid a life-threatening tension pneumothorax. Persistent leaking of air into the pleural space with no route of escape will ultimately collapse the affected lung, flatten the diaphragm, and eventually produce contralateral shift of the mediastinum. Compression of the contralateral lung and compromise of venous return result in progressive hypoxemia and hypotension. Emergency decompression with a 14- or 16-gauge catheter in the midclavicular line of the second intercostal space may be lifesaving while preparations for chest tube insertion are being made. In a hypotensive trauma patient, such pleural space decompression may be required before radiographic diagnosis of tension pneumothorax is confirmed.

Additional potential sources of pneumothorax are bullous disease, malignancies (particularly soft tissue sarcoma metastases), and necrotizing pneumonia. Iatrogenic causes include thoracentesis and central venous catheter insertion. The incidence of pneumothorax associated with attempts at subclavian vein access has been reported to be as high as 6%, and although the incidence is lower with an internal jugular approach, pneumo-thorax still may result (as the lung apices rise above the clavicles) [8]. Patients on mechanical ventilation, especially with elevated levels of positive end-expiratory pressure, are also at risk. In this setting, a tension pneumothorax may rapidly develop and require emergency measures as described above. Although prophylactic insertion of bilateral pleural tubes has been reported for patients on extremely high levels of positive end-expiratory pressure (greater than 40 cm H₂O), no controlled study has yet documented its benefit [9].

Accumulation of blood in the pleural space can be classified as spontaneous, iatrogenic, or traumatic. Attempted thoracentesis or tube placement may result in injury to the intercostal or internal mammary arteries or to the pulmonary parenchyma. Up to a third of patients with traumatic rib fractures may have an accompanying pneumothorax or hemothorax [10]. Pulmonary parenchymal bleeding from chest trauma is often self-limited due to the low pressure of the pulmonary vascular system. However, systemic sources (intercostal, internal mammary or subclavian arteries, aorta, or heart) may persist and become life threatening.

Indications for open thoracotomy in the setting of traumatic hemothorax include initial blood loss greater than 1,500 mL or continued blood loss exceeding 500 mL over the first hour, 200 mL per hour after 2 to 4 hours, or 100 mL per hour after 6 to 8 hours, or in an unstable patient who does not respond to volume resuscitation [11,12 and 13]. Placement of large-bore [36 to 40 French (Fr)] drainage tubes encourages evacuation of blood and helps determine the need for immediate thoracotomy. Although some have advocated clamping the tube in the face of significant intrathoracic hemorrhage, this practice should be discouraged, as it fails to prevent hypotension and instead hinders ventilation [14].

Incomplete drainage of a traumatic hemothorax due to poor tube positioning or tube “thrombosis” may result in a chronic fibrothorax. Subsequent significant reduction of pulmonary
reserve may occur as a result of restricted lung expansion. Early, aggressive evacuation of a retained hemothorax (via thoracoscopy or open thoracotomy) encourages full reexpansion and prevents empyema formation [15,16] in those who are able to tolerate the procedure. If the patient’s condition mandates nonoperative management, a waiting period of several weeks allows an organized “peel” to form, facilitating its removal (decortication).

Spontaneous pneumothoraces may result from necrotizing pulmonary infections, pulmonary arteriovenous malformations, pulmonary infarctions, primary and metastatic malignancies of the lung and pleura, and tearing of adhesions between the visceral and parietal pleurae.

Empyemas are pyogenic infections of the pleural space that may result from numerous clinical conditions, including necrotizing pneumonia, septic pulmonary emboli, spread of intraabdominal infections, or inadequate drainage of a traumatic hemothorax. Pyothorax as a complication of pneumonia is less common now than in the preantibiotic era, with the common organisms now being Staphylococcus aureus and anaerobic and Gram-negative microbes.

Definitive management includes evacuation of the collection and antibiotic therapy. Chest tube drainage is indicated for pleural collections with any of the following characteristics: pH less than 7.0, glucose less than 40 mg per dL, lactate dehydrogenase greater than 1,000 IU per L, frank purulence, or culture-positive specimens [17]. Large-bore drainage tubes (36 to 40 Fr) are used, and success is evidenced by resolving fever and leukocytosis, improving clinical status, and eventual resolution of drainage. The tube can then be removed slowly over several days, allowing a fibrous tract to form. If no improvement is seen, rib resection and open drainage may be indicated. Chronic empyema may require decortication or, in more debilitated patients, open flap drainage (Eloesser procedure). Fibrinolytic enzymes (urokinase or streptokinase) can also be instilled through the tube to facilitate drainage of persistent purulent collections or for hemothorax or malignant effusions [18,19, and 20].

A collection of lymphatic fluid in the pleural space is termed chylothorax. Due to the immunologic properties of lymph, the collection is almost always sterile. As much as 1,500 mL per day may accumulate and may result in hemodynamic compromise or adverse metabolic sequelae as a result of loss of protein, fat, and fat-soluble vitamins. The diagnosis is confirmed by a fluid triglyceride level greater than 110 mg per dL or a cholesterol-triglyceride ratio of less than 1 [21,22].

Primary causes of chylothorax include trauma, surgery, malignancy, and congenital abnormalities. Surgical procedures most often implicated are those involving mobilization of the distal aortic arch and isthmus (e.g., repair of aortic coarctation, liga-tion of a patent ductus arteriosus, or repair of vascular rings) and esophageal resections [23]. Its appearance in the pleural space may be delayed for 7 to 10 days if there are postoperative dietary restrictions; the fluid may also collect in the posterior mediastinum before rupturing into the pleural space (often on the right side) [22]. Traumatic causes include crush or blast injuries, those that cause sudden hyperextension of the spine or neck, or even a bout of violent vomiting or coughing.

In the absence of trauma, malignancy must always be suspected. Leak occurs secondary to direct invasion of the thoracic duct or from obstruction by external compression or tumor emboli. Lymphosarcoma, lymphoma, and primary lung carcinomas are those most frequently implicated [22].

Treatment involves tube drainage along with aggressive maintenance of volume and nutrition. With hyperalimentation and intestinal rest (to limit flow through the thoracic duct), approximately 50% will resolve without surgery [24]. Although no consensus exists as to the optimal time to intervene surgically, a minimum of 2 weeks of observation is usually appropriate unless the patient is already malnourished [25,26]. Open thoracotomy may be necessary to ligate the duct and close the fistula.