Chapter 25: Lung, Trachea, and Esophagus

Injuries to the chest are common following both blunt and penetrating trauma. Blunt thoracic injuries are responsible for approximately 8% of all trauma admissions in the United States, with motor vehicle crashes being the most common mechanism.^1,2,3 In one report, penetrating chest trauma accounted for 7% of all trauma admissions and 16% of penetrating trauma admissions overall.⁴

Despite the prevalence of thoracic injury following trauma, the majority of patients can be successfully managed nonoperatively. Between 18% and 40% of patients sustaining thoracic trauma can be treated with tube thoracostomy alone, and thoracotomy will be required for between 3% and 9% of patients. Even among those with penetrating chest trauma, only 14% of stab wounds and between 15% and 20% of gunshot wounds require thoracotomy.⁴

Operative mortality varies between 5% and 45%; approximately 30% of patients undergoing thoracotomy requiring a pulmonary resection.³ This wide variability is related to differences in mechanism of injury, inclusion of cardiac and major thoracic vascular injury in some of the datasets, the extent of pulmonary resection performed, and concomitant extrathoracic injuries.^3,5,6,7

Technological and imaging advances, particularly the expanded role of CT scanning, have allowed clinicians to characterize thoracic injury rapidly and accurately. Some injuries are minor, such as small pneumothoraces, which require no treatment. However, major injuries require rapid and definitive care. In an era of nonoperative management for many injuries, clinicians caring for trauma patients must appreciate the indications for operation and understand the treatment options in the emergency department as well as in the operating room. Sophisticated judgment is essential when evaluating the patient with multiple and often competing injuries.

While physiologically complicated, the lungs are anatomically simple, consisting primarily of alveoli and blood vessels. The paired large pulmonary artery and vein are high volume, low pressure circuits. The bronchial vascular bed is characterized by a higher systemic pressure but relatively small caliber vessels. Injury to the protective bony thorax serves as a marker for pulmonary injury following blunt trauma in adults. In contrast, the greater chest wall elasticity in children may result in significant pulmonary injury without associated thoracic wall injury.

The anatomic simplicity of the lungs suggests a limited parenchymal response to trauma regardless of the severity and mechanism of injury. The alveoli can rupture, causing a pneumothorax. Larger injuries can result in a continued air leak. The lung parenchyma can bleed causing a hemothorax or the architecture can be disrupted as with a pulmonary contusion. The chest wall, especially the intercostal and mammary arteries, may bleed when injured, as there is limited tissue to provide tamponade. Any of these injuries can range from relatively trivial to life-threatening.

Very large pneumothoraces produce tension by shifting the mediastinal structures toward the contralateral side with resulting anatomic distortion. Increased intrathoracic pressure causes decreased venous return, decreased cardiac output and, if untreated, cardiac arrest. In contrast, large hemothoraces generally produce symptoms through the effects of hypovolemia, although a massive hemothorax may also produce tension physiology.

Presentation and Evaluation

Any patient with blunt or penetrating chest trauma is at risk for lung injury. The mechanism of injury, time from injury, vital signs, and neurologic status at the scene and any changes during transport are critical components of an adequate history.

Physical examination alone may confirm the diagnosis of intrathoracic injury. The presence of distended neck veins, tracheal deviation, subcutaneous emphysema, chest wall instability, absent breath sounds, or muffled heart sounds may provide crucial information. Vital signs should be frequently monitored with careful attention to the work of breathing and arterial saturation. Hypoxia and increased work of breathing may be manifested by anxiety, confusion, combative behavior, dyspnea, or the use of accessory muscles. Any of these findings should prompt rapid evaluation for serious thoracic injury. Findings of subcutaneous air or decreased breath sounds should alert the clinician to the possibility of pneumothorax and/or hemothorax. Prompt placement of a tube thoracostomy in an unstable patient is wise, as radiographic confirmation may delay treatment.

Penetrating thoracic trauma in a hemodynamically unstable patient is virtually always an indication for operative exploration. Conversely, hemodynamically stable patients with penetrating thoracic injury may benefit from additional imaging, especially chest computed tomography. This modality provides high resolution, detailed and organ-specific information, including the vascular anatomy.^8,9,10

Following blunt trauma, stable patients require a rapid, yet thorough, evaluation for associated injuries. An arterial blood gas is essential and should be sent with the initial laboratory studies. It will yield critical information about oxygenation, ventilation, the presence and depth of shock. An electrocardiogram should be obtained, and a focused abdominal sonography for trauma (FAST), including the precordium, should be performed. A portable chest radiograph (CXR) is routinely obtained (Fig. 25-1) to examine for pneumothorax or hemothorax, although some authors question the utility of this study in stable patients with a normal chest examination.¹⁵ FAST may be as sensitive as CXR for diagnosing a pneumothorax.¹¹ CT scan is extremely useful in the multiply injured patient to evaluate for additional cavitary injuries. If indicated, thoracic ultrasound, esophagoscopy, bronchoscopy and, echocardiography should be obtained.

The modern, widespread utilization of CT imaging, with three-dimensional reconstruction, provides a more precise evaluation of the aorta and great vessels.^8,10 Pneumothoraces or hemothoraces not visualized on chest x-ray are often seen on CT. If they are small and patients are asymptomatic, observation is typically all that is required. For those patients undergoing operation for an associated injury, or intubation for positive pressure ventilation, the chances that these small pneumothoraces will become clinically significant is relatively low.¹²

In general, large pneumothoraces seen on CT, but not detected on CXR, are most often anterior. Treatment is tube thoracostomy. While it is possible that these can be treated without drainage, our experience has been that these patients may become symptomatic and we prefer to treat preemptively.

In general, hemothoraces are treated similarly to pneumothoraces. If they are small, observation is generally successful, monitoring with serial chest x-rays to document resolution. However, any moderate or large hemothorax should be drained with a tube thoracostomy. Blood left within the pleural cavity will clot and will not be evacuated with a chest tube. A retained hemothorax may progress to fibrothorax with lung entrapment or become infected resulting in an empyema.

Patients with significant lung lacerations will often have large air leaks or, less commonly, hemoptysis. Bronchoscopy is the modality of choice to diagnose a tracheobronchial injury. Blood and secretions must be suctioned clear, allowing unimpaired visualization of the entire airway. Large air leaks resulting in respiratory compromise generally require thoracotomy. While rare, significant hemoptysis can result in profound respiratory compromise, and bronchoscopy may localize the bleeding lobe or segment. Control of airway is essential; options include a double lumen endotracheal tube, selective mainstem intubation, bronchial blocker, lateral decubitus position, catheter-based therapy and surgery.

If the patient is stable, CT scanning can also be quite helpful in patients with hemoptysis (Fig. 25-2). CT scanning with intravenous contrast will define the pulmonary anatomy and may localize the site of parenchymal hemorrhage. The pulmonary vascular tree is a low-pressure system and radiographic vascular injuries do not carry the same prognosis as do arterial vascular injuries identified within solid viscera in the abdomen. If symptomatic, operative exploration is the preferred strategy. In a selective group of patients, including those who are a poor operative risk, transcatheter embolization offers an alternative to thoracotomy.

The majority of patients with a lung injury can be managed nonoperatively. Simple tube thoracostomy evacuates accumulated air and blood, allowing complete lung re-expansion with apposition to the chest wall. A number of patients, however, will require thoracotomy for pulmonary and/or chest wall injury. Intercostal or internal mammary artery hemorrhage following penetrating or blunt trauma can continue even after evacuation of the associated hemothorax. Additional bleeding sources that may require intervention include chest wall musculature and lung lacerations.

Rib fractures are the most common thoracic injury following blunt trauma and may be associated with an underlying pulmonary contusion. Treatment is supportive, the goal being prevention of the known sequelae. Pain with respiration and splinting can lead to atelectasis, hypoventilation, inability to clear secretion and pneumonia. The presence of a pulmonary contusion can exacerbate hypoxia and shunting. While upright positioning, incentive spirometry and analgesia are all important, the latter is essential. Multiple treatment options are available to achieve adequate analgesia. Some reports have demonstrated the superiority of an epidural analgesia, while others have shown similar efficacy among the various modalities.¹³ While it is well known that morbidity is increased among the elderly with rib fractures, it is important to note that morbidity is also higher in those older the 45 with multiple rib fractures.¹⁴

A flail chest occurs when three or more adjacent ribs are segmentally fractured leading to paradoxical chest wall motion. These patients often require mechanical ventilation, especially when there is an associated pulmonary contusion.¹⁵ In a recent review of flail chest injuries, over half the patients had a pulmonary contusion, and the same percentage required mechanical ventilation. Infections complications were common; mortality was 16% and related to concomitant head injury.¹⁶ With the advances in technology, materials, and operative techniques, rib stabilization has been performed with increasing frequency. The precise indications and patient population to benefit from the procedure are still not fully defined.¹⁷

Pulmonary contusions are common and range from clinically silent to causing severe respiratory distress. Although they can occur with any chest injury they are highly associated with rib fractures, especially flail chest. The clinical symptoms include respiratory distress, increase work of breathing, hypoxia and, less commonly hypercarbia. One of the hallmarks is that clinical symptoms and radiographic findings increase over time, generally over 3 days, and resolve in 1 week. Supportive treatment is typically all that is necessary including judicious volume administration, pulmonary toilet and supplemental oxygen. Mechanical ventilation is indicated for respiratory failure refractory to less invasive therapies.¹⁸

Indications for Operation

Massive hemothorax, defined as 1500 cc or more of blood in the pleural cavity or persistent chest tube output of 200 to 250 cc per hour for 3 consecutive hours, is generally considered an indication for thoracotomy. Thoracic trauma resulting in persistent hemodynamic instability, without another obvious source, should prompt emergent thoracic exploration. Delaying emergent thoracic exploration may result in increases in morbidity and/or mortality.¹⁹

Care must be exercised when evaluating chest tube output. While a dramatic decrease in output may signify a cessation of intrathoracic bleeding, it may be the result of clotted chest drains. There may be ongoing hemorrhage but the lack of chest tube output may give the clinician a false sense of security. Chest tubes may become clotted and, if poorly positioned, may not completely evacuate blood or air. An increasing hemothorax will be seen on subsequent CXR or chest CT. While a second chest tube may be helpful, patients with a large retained hemothorax should generally be explored and drained. A thoracoscopic approach is often successful, particularly if performed early within the first few days following injury, before the clot becomes organized, and loculations and adhesions form. We do not utilize video-assisted thoracoscopic surgery (VATS) for emergent exploration but perform a thoracotomy or sternotomy as indicated.

Delayed operative intervention may be indicated for a variety of traumatic complications, including retained hemothorax, persistent air leak, missed injury, and empyema. Early evacuation of retained hemothorax prevents the clot from becoming fibrotic and trapping the lung, and decreases the chance of empyema. Post-traumatic empyema is almost always best treated with operation. Many of these other non-emergent procedures can be performed using noninvasive methods, such as video-assisted thoracic surgery (VATS).^20,21

Surgical Exposure

There are a number of operative approaches to the thorax, each with advantages and disadvantages. Unlike an elective thoracotomy, in which the posterolateral approach is most commonly used, several important factors influence the choice of the incision for a traumatic injury. Foremost is whether the operation is performed for exploration, as for a patient in hemorrhagic shock, or alternately to repair a specific, defined injury, such as a tracheobronchial disruption. Regardless of the operative indication or approach, the incision must provide excellent exposure and versatility. The overall clinical condition, hemodynamic instability, results of the imaging studies and presence of concomitant injuries will influence the operative approach.

As a general rule, a median sternotomy or anterolateral thoracotomy, which can be extended as a clamshell, are the preferred incisions for exploring the hemodynamically unstable patient. Both of these incisions afford exceptional exposure to all but the posterior structures. Additionally, they can be extended for a laparotomy. Hemodynamically unstable patients may not tolerate the lateral position without further hemodynamic or respiratory compromise.

Commonly employed operative approaches include anterolateral, posterolateral, bilateral anterior thoracotomies (“clamshell”), and median sternotomy. The anterolateral approach is rapid and can be easily extended across the midline as a clamshell thoracotomy. This affords excellent exposure to both pleural spaces and the anterior mediastinum. Likewise, an anterolateral thoracotomy can be continued as a laparotomy for abdominal exploration, and is the preferred approach in the patient in shock. The main disadvantage of the anterolateral approach is the inability to provide adequate exposure of posterior structures. By extending the ipsilateral arm and placing a bump to elevate the thorax approximately 20°, the incision can be carried to the axilla improving posterior exposure (Fig. 25-3).

The posterolateral thoracotomy affords optimal exposure of the hemithorax, especially the posterior structures, and is the standard incision for most elective operations. Its lack of versatility limits the usefulness in unstable trauma, but is the preferred approach to repair intrathoracic tracheal and esophageal injuries.

Median sternotomy provides excellent access to the heart, great vessels, and anterior mediastinum. It is versatile and can be extended as an abdominal, periclavicular, or neck incision (Fig. 25-4). Widely incising the pleura provides access to either hemithorax, however, exposure of the posterior structure is quite limited. The “trapdoor” incision is rarely used since left-sided thoracic vessels can be approached via sternotomy with extension.^10,22

Operative Techniques

A double-lumen endotracheal tube dramatically improves operative exposure, and while it is widely used in elective thoracic operations, it is rarely used in trauma, especially for emergency thoracotomies. Lung isolation should be avoided in hemodynamically comprised patients. Single lung ventilation may not be tolerated and the time spent ensuring proper tube placement is not warranted in an emergency. One exception is massive hemoptysis where lung isolation may indeed be lifesaving. In the hemodynamically stable patient placing a double-lumen tube should be considered as it improves exposure and facilitates pulmonary resection. If a single lumen tube is used, intermittently holding ventilation is advantageous during pulmonary repair or resection.

However, if the patient’s respiratory status is tenuous, any extended interruption of ventilation and oxygenation may precipitate decompensation. In this case, manual compression of the adjacent lung tissue may provide sufficient exposure to facilitate operative repair or resection.

Upon entering the chest, blood and clot should be evacuated allowing a thorough examination and exploration of the hemithorax. The lung is mobilized by incising the inferior pulmonary ligament and lysing any adhesions. Exsanguinating hemorrhage demands immediate attention and initial control is achieved with digital pressure. This allows time for ongoing volume resuscitation and an improved assessment of the injury. Hilar bleeding is a particularly significant challenge. The low pressure pulmonary artery bleeds more like a major systemic vein than an artery. There are a several techniques for hilar compression including finger occlusion, and placing a Penrose drain around the hilum twice; tightening the drain will provide temporary vascular control. More definitive and secure control is achieved by placing a hilar vascular clamp. Finally, the lung can be twisted on itself at the level of the hilum. This latter maneuver occludes the pulmonary artery and vein, as well as the main stem bronchus. The hilar twist or clamping the hilar vessels may result in further decompensation in hemodynamically compromised patients. The rapid increase in pulmonary artery pressure can cause acute right heart dysfunction or failure, with catastrophic consequences.

There are a number of techniques for lung repair. The decision regarding the technique chosen will be influenced by the type and severity of the parenchymal injury, concomitant injuries and the patient’s physiologic status. Pneumonorrhaphy is the simplest technique and is generally used to treat superficial pulmonary lacerations. The laceration is closed with either a running simple or mattress suture. More extensive injuries require resection including simple wedge resection, tractotomy, nonanatomic and formal anatomic resections. Peripheral lacerations not amenable to simple repair can be treated by wedge resection using any of the commercially available staplers. It is crucial to determine the location of major pulmonary artery branches prior to firing the stapler. This is generally not a concern when resecting peripherally located injuries but is vitally important with more central lesions.

More significant lung injuries, particularly those from gunshot wounds, are often best treated with tractotomy^23,24,25 (Fig. 25-5). This is performed by placing the jaws of the stapler through the injury tract and firing it, similar to the technique used to expose and repair liver injuries. The resulting opening exposes the bleeding vessels and injured airways for individual ligation. The staple line can be oversewn with a running suture to achieve adequate hemostasis and an air tight seal. In general, peripheral injuries are treated with tractotomy but this method is not utilized for long central missile tracts.

Significant lobar injuries not amenable to tractotomy can be treated by nonanatomic resection or formal lobectomy. For the latter, the arterial and venous lobar branches must be dissected and either ligated or stapled. Similarly, the lobar bronchus is identified and generally divided using a stapler. Prior to firing the stapler, and with the bronchus occluded by the stapling device, the lung is inflated. The lobe to be resected will not inflate, ensuring the appropriate bronchus is transected.

Hilar injuries pose special challenges as hemorrhagic shock is almost always present and the anatomic challenges are significant. In very proximal hilar injuries, inflow occlusion is virtually always necessary in order to assess the extent of injury. Opening the pericardium and controlling the intra-pericardial pulmonary artery and vein is a useful maneuver. Hilar injuries are rarely amenable to direct repair and may require pneumonectomy. Unfortunately, mortality after pneumonectomy for patients in shock approaches 100%, with patients dying from either uncontrolled hemorrhage or acute right heart failure.^26,27 If pneumonectomy is considered, it should be performed early, and rapid treatment of right heart dysfunction and support with extracorporeal membrane oxygenation may improve survival in these devastating injuries.²⁸

As a bronchial stump dehiscence is a devastating complication following lobectomy, and especially pneumonectomy, our practice is to reinforce the bronchial stump with viable tissue, preferably muscle. An intercostal muscle flap that preserved the blood supply is an ideal choice. Less commonly we have utilized a diaphragmatic flap. Other options include a pedicled pericardial flap, pericardial fat pad, and mediastinal pleura. If the bronchial stump dehiscence occurs later in the postoperative period, typically related to a pleural infection, covering the stump with omentum and/or latissimus dorsi flap are excellent options.

The concept of damage control, originally described for penetrating abdominal trauma, has been expanded to include chest injury as well. The well-established principles of hemorrhage control, resuscitation in the intensive care unit and a planned, delayed definitive repair are applicable to thoracic trauma patients with severely impaired physiology. Hemorrhage from named vessels and structures are controlled, the pleural cavity or cavities are packed and the chest is left open. Thoracic packing does not interfere with cardiac or pulmonary function. Once normal physiology is restored, the packs are removed, and the chest closed. In a series of 44 patients with a mean pH 7.07 and a median ISS 29 on admission, the mortality was 23%. All patients were physiologically normal at the time of chest closure, which on average was 2–3 days after the index operation.²⁹

Video-Assisted Thoracoscopic Surgery

Increasing experience with minimally invasive techniques has contributed to enthusiasm for video-assisted thoracoscopic surgery (VATS) for a variety of sequela of trauma.^20,21 As a diagnostic tool, VATS remains an acceptable alternative to laparoscopy to identify and repair penetrating diaphragmatic injuries. Persistent air leak, retained hemothorax and, in selected cases, decortication for empyema are recognized indications for VATS. Emergent exploration for hemorrhage or severe parenchymal trauma should be performed using an open operative approach.

VATS is performed in the operating room under general anesthesia, with lung isolation achieved with a double-lumen endotracheal tube. Lung isolation provides superior exposure and an operative field with good visualization. The procedure is performed with the patient in the full lateral decubitus position with the affected side up. The operative field should be widely prepped and draped to facilitate conversion to a thoracotomy if indicated.

On single lung ventilation, the first port is placed in the fourth or fifth intercostal space in the mid or anterior axillary line. The tip of the scapula serves as a convenient landmark to facilitate appropriate positioning (Fig. 25-6). An angled thoracoscope is preferred for initial use, as it improves visualization of the pleural space recesses. An aspiration catheter can be placed coaxially to the optical port to facilitate the lavage and evacuation required for initial visualization. Additional ports can then be developed under direct visualization to address the pathology encountered.

The instruments used for VATS are similar to those for laparoscopic procedures. Conventional open surgery forceps can also be used. Cautery, however, should be utilized cautiously and in close coordination with anesthesia, as oxygen-rich air leaks and cautery may interact to create a fire hazard with catastrophic results. On completion, the chest is irrigated with normal saline or sterile water. Utilizing the existing port sites, chest tubes are positioned under direct visualization, and the lung re-expanded prior to closure. Following the procedure a chest x-ray should be obtained, and the thoracostomy tubes managed as they would for a thoracotomy.

Outcomes

There is wide variability in reported mortality after thoracic injury. Blunt trauma results in mortality as high as 68%.^1,2 This is probably related to higher ISS, lower GSC, and more associated nonthoracic injuries than those with penetrating injuries.^3,6 There is also variation in the reported mortality with penetrating trauma. Cardiac and major vascular injuries and the percentage of major pulmonary resections all contribute to poorer outcomes.^3,6 A relationship between the magnitude of the pulmonary resection and subsequent mortality has been demonstrated.³ This finding may reflect the degree of the parenchymal injury that necessities a more extensive resection.

Complications of Lung Injury

Pneumonia

Pneumonia is the most common significant complication following pulmonary injury, and the relative risk is closely associated with the need for mechanical ventilation. Following thoracic injury patients requiring intubation are approximately seven times more likely to develop pneumonia than those who do not.¹ Of all patients admitted with the diagnosis of pulmonary contusion (Fig. 25-5), nearly 50% will develop pneumonia, barotrauma, and/or major atelectasis, and one-fourth will go on to develop acute respiratory distress syndrome (ARDS).¹

Retained Hemothorax

It has been estimated that tube thoracostomy fails to completely evacuate hemothorax in over 5% of cases.³⁰ Typically, small hemothoraces will be reabsorbed, however, post-traumatic empyema and, less commonly, fibrothorax with entrapped lung are known sequelae of a retained hemothorax.^31,32

The diagnosis of retained hemothorax requires a chest CT, as plain radiography has been shown to be inadequate.³³ There is wide variability, even among United States trauma centers, regarding the treatment of retained hemothoraces. Many patients require more than one procedure to evacuate the pleural space. In general, CT estimated retained hemothorax volumes less than 300 cc can be safely observed in the absence of infection, while those greater than 300 cc will likely require evacuation.³¹ The timing of VATS has been somewhat controversial, with early studies reporting optimal results when the retained hemothorax was evacuated within the first few days following injury.^21,34 A more recent multi-center study found no significant impact of the timing of VATS and successful evacuation of the pleural space.³¹

Empyema

Empyema is diagnosed by positive pleural cultures or frank purulence in the pleural space. Overwhelmingly, the most common cause of post traumatic empyema is a retained hemothorax, with both postpulmonary resection and post-pneumonic etiologies much less common. A recent large multicenter study reported empyema developed in 26.8% of patients with a retained traumatic hemothorax.³²

Empyema has been characterized by three often overlapping stages; exudative, fibrinopurulent and, organizing. While most early stage postpneumonic empyemas can be successfully treated by chest tube drainage and antibiotics, this is not the case for post-traumatic empyema. Delay in evacuating a retained hemothorax, an appreciable inflammatory response with resultant loculations, renders simple tube thoracostomy inadequate treatment. Both VATS and thoracotomy are acceptable modalities; VATS is more successful in the earlier stages, while thoracotomy is performed for later stage empyema or failed initial therapy. A large, single institution series of 125 consecutive patients with post-traumatic empyema VATS and thoracotomy were performed 20% and 80%, respectively. Mortality was 4% and associated with ruptured lung abscesses.³⁴ It is important to note that failure of the first intervention to treat empyema is an independent predictor of mortality.³⁵ Therefore, it is essential that thoughtful judgment is exercised when considering treatment options.

Persistent Air Leak and Bronchopleural Fistula

A true bronchopleural fistula is a centrally located communication between a lobar or segmental bronchi and the pleural cavity. This specific communication is uncommon following trauma, but may occur with an injury to a major bronchus or following pulmonary resection for a lung injury. Most post-traumatic air leaks are actually communications from the lung parenchyma to the pleural space, and are more accurately termed parenchymal–pleural or alveolar–pleural fistula. Traditionally, bronchopleural fistula refers to any air leak from the lung to the thoracic cavity.

While there is no agreed on definition of a persistent air leak, in general it is a leak which continues beyond 5 to 7 days.³⁶ They can be challenging to manage, especially in the ventilated patient in whom large leaks may result in loss of effective tidal volume and, consequently, hypoxia and/or hypercarbia. The diagnosis is usually not subtle, with persistent, vigorous air bubbling through the water-seal chamber of the thoracostomy tube collection system. Bronchoscopy should be performed if there is concern for a major airway injury.

Although the vast majority of air leaks will resolve within 7 days, those which persist will require treatment. The management of the air leak is complicated if the patient is on mechanical ventilation, in which case safely minimizing the mean and end-inspiratory plateau pressure is a useful strategy. Autologous blood pleurodesis, various commercially available sealants, endobronchial one-way valves, Heimlich valves and operative therapy are among the management options to treat a persistent air leak.³⁷

Chylothorax

Primary traumatic chylothorax, characterized by milky chest tube output, is uncommon after traumatic injury or surgery. The diagnosis is established by analyzing the content of the effusion and documenting the presence of fat (triglyceride levels > 110 mg/dL) with or without predominant lymphocytes in the effusion. The primary complications of chylothorax are nutritional depletion, electrolyte abnormalities and, compromised immune function. Nonoperative management includes lung expansion to promote tamponade, total parenteral nutrition, enteral medium-chain triglycerides, and octreotide. Persistent chylous drainage for 5–7 days is a failure of nonoperative management. While there are a few reports of successful embolization of the thoracic duct, direct ligation following lymphangiographic localization is the preferred approach.^38,39

Tracheobronchial injuries are infrequent, but potentially life-threatening consequences of trauma. They can occur in the neck or thorax, resulting from either blunt or penetrating mechanisms. While these injuries occur more commonly in the neck, and may be the result of either mechanism, intra-thoracic airway trauma generally is related to blunt injuries from high-speed motor vehicle crashes.^{40,41,42,43,44} Most penetrating injuries to the cervical trachea, while straightforward to repair, may be associated with injury to vessels, esophagus, thoracic duct, and nerves.

Presentation and Evaluation

Cervical tracheal injuries are often obvious on physical examination.⁴⁵ A large volume of subcutaneous air and/or air exiting from the missile tract may be observed. Patients often present in respiratory distress requiring urgent intubation. Extreme care must be taken when intubating these patients, as a partial tracheal injury can be converted to total circumferential disruption. The resultant loss of airway can lead to respiratory arrest and, if the airway cannot be secured, death. Direct laryngoscopy, video laryngoscopy, fiberoptic intubation, and a surgical airway are all methods to establish a secure airway. The choice of technique depends on the specific injury, impending loss of airway and the skill of the providers. The classic presentation of a distal tracheal or proximal bronchial injury is a very large pneumothorax, a large air leak and/or persistent pneumothorax following chest tube insertion.

Patients with suspected tracheal or major airway injury should undergo emergent bronchoscopy (Fig. 25-7). Flexible fiberoptic bronchoscopy is the technique most often used. To achieve an unobstructed view of the mucosa and perform a thorough bronchoscopic examination it is essential to clear the airway of blood and secretions. Over three-quarters of blunt tracheobronchial injuries occur within 2 cm of the carina.⁴¹

The entire circumference of the trachea must be examined. If the cervical trachea is at risk and the patient is intubated, the endotracheal tube may have been inserted distal to the area of suspected injury. In these cases, the endotracheal tube should be carefully withdrawn using the bronchoscope as a guide. When the examination is complete, the endotracheal tube can be advanced distally over the bronchoscope and secured.

As CT scanning has evolved, it is now sometimes used in the evaluation of potential trachea injuries. In the case of penetrating injury, a trajectory that is clearly remote from the trachea should effectively rule out the possibility of a tracheal injury. Three-dimensional reformatting of the images can sometimes demonstrate a tracheal injury, though a negative study does not effectively rule out the presence of an injury.⁴⁶

Operative Techniques

The management of a tracheobronchial injury begins with establishing a secure airway.^45,47 Endotracheal intubation, performing a surgical airway, and directly intubating the tracheal laceration are all acceptable techniques. The location and extent of the airway injury must then be completely characterized and associated injuries evaluated.

During intraoperative management, cooperation between the anesthesiologist and the surgeon is paramount. With an injury to the cervical trachea the airway can be managed with a single-lumen endotracheal tube. If necessary, the airway can be intubated over the operative field (Fig. 25-4). The surgical repair is facilitated by keeping the mean airway pressure as low as possible while consistent with adequate oxygenation and ventilation. Brief periods of apnea afford improved visualization of the operative site.

Although operative repair is the mainstay of treatment for tracheobronchial injuries, in highly selected patients there is limited role for both stent placement and nonoperative management.⁴⁸ Conservative management is reserved, on a case-by case basis for small (<2 cm), nontransmural tears; especially in those who are severely injured.⁴⁹ Most tracheobronchial injuries are amenable to primary repair.

Appropriate tracheal exposure is determined by the anatomic location of the airway injury. Arterial blood supply to the trachea is segmental arising from the inferior thyroid and bronchial vessels. The proximal half of the trachea can be exposed through a collar incision and blunt dissection in the pretracheal plane will facilitate mobilization.

The distal half of the trachea, the right main stem, and proximal left main stem bronchus are best approached through a right posterolateral thoracotomy. A double lumen endotracheal tube will greatly enhance operative exposure. Widely opening the mediastinal pleura, and doubly ligating and dividing the azygous vein will provide the desired exposure (Fig. 25-8). If an esophageal injury has been excluded, placing an esophageal bougie or nasogastric tube will facilitate dissection in the plane between the esophagus and trachea. The distal left main stem bronchus is best approached through a left posterolateral thoracotomy (Fig. 25-9). This approach, while necessary, is complicated by the aortic arch.

Tracheal repair is accomplished with interrupted absorbable sutures. Simple lacerations are closed primarily while more extensive injuries may require debridement to healthy tissue prior to repair. Extensive circumferential injures necessitate end-to-end anastomosis preserving the blood supply to avoid suture line ischemia (Fig. 25-6). If necessary, additional length can be achieved by mobilizing the trachea by blunt dissection in the avascular pretracheal plane. Other maneuvers such as laryngeal release are rarely needed. In extreme circumstances approximately half of the trachea can be resected and a primary repair performed. Care must be exercised when placing the sutures avoiding the endotracheal tube and its cuff. Lower tidal volume ventilation and brief periods of apnea will allow precise suture placement. After the trachea repair is completed, and before the thorax is closed, it is wise to have the anesthesiologist ensure the endotracheal tube is movable, confirming the endotracheal tube has not been inadvertently caught by a suture.

If there is a concomitant vascular or esophageal injury each should be primarily repaired. The presence of suture lines in opposition increases the possibility of fistula formation. The risk of this dreaded complication is reduced by interposing a vascularized muscle between the suture lines. In the thorax the intercostal muscle is ideal; in the neck the sternocleidomastoid and strap muscles are excellent choices.

Outcomes

Due to the scarcity of series in the literature, reported outcomes vary.^45,47,48,49 In studies where over half of the patients had associated injuries, the mortality was as high as 21%, with almost all deaths secondary to the concomitant injury, especially vascular trauma.^45,47,48,49

Complications of Tracheobronchial Injuries

Tracheal Stenosis

Postoperative tracheal or bronchial stenosis is an uncommon but potentially devastating complication. Initial symptoms may be missed. Wheezing from the attempt to move air through the narrowed airway may be attributed to reactive airway diseases, such as asthma or chronic obstructive pulmonary disease. Once identified by bronchoscopy or CT, initial treatment consists of controlling the airway in patients with high-grade lesions. Subsequent therapy is rigid or balloon dilation, which should be performed under direct visualization. Surgical treatment for postrepair airway obstruction is typically reserved for severe and relatively short-segment lesions. The surgical treatment for post-traumatic stenosis varies by location of the stenosis, but most commonly consists of end-to-end anastomosis or tracheal sleeve resection.

Esophageal injuries, while rare are nonetheless serious, especially when they occur in the intra-thoracic esophagus. Due to the protection of the bony thorax, esophageal injuries are more common in the neck than the thorax. Blunt esophageal injuries are extremely rare, but may occur as the result of a direct blow against a hyperextended neck or less commonly due to rupture secondary to overpressure of the esophagus.¹ Overwhelmingly, esophageal injuries are the result of penetrating trauma.^1,50 To date the largest multicenter study of penetrating esophageal injuries was conducted by the American Association for the Surgery of Trauma and involved 34 trauma centers in the United States. Only 405 penetrating esophageal injuries were identified over a span of 10.5 years and fully 88% had associated injuries.⁵⁰

Presentation and Evaluation

Patients with an injury pattern or trajectory adjacent to the esophagus require evaluation. While physical examination may be helpful in diagnosing a cervical esophageal injury, it is rarely useful for an intra-thoracic injury. Saliva exiting a neck wound would seem to confirm the diagnosis of esophageal injury. Unfortunately, physical findings are often nonspecific, occurring in less than one-quarter of patients with a penetrating neck injury. Patients with thoracic esophageal injury may present with concomitant pneumothorax or hemothorax from associated injury to the lung and/or vascular structures. Tube thoracostomy drainage with obvious saliva or food particles warrants urgent esophageal evaluation.^{34,35,36,50,51,52,53}

CT scanning has become more widely utilized in the evaluation of penetrating thoracic injury, as it will define the missile trajectory to determine if the esophagus is at risk. If oral contrast has been administered, CT may identify contrast outside of the esophagus. The ability to obtain three-dimensional imaging of the mediastinum potentially makes CT more attractive than a simple contrast study. However, CT is a static examination and cannot assess the passage of contrast moving through the esophagus, as with an esophagram.

Contrast esophagography has traditionally been used to evaluate both the cervical and the thoracic esophagus. If performed with good technique, the entire esophagus can be evaluated. In intubated patients contrast can be instilled via a nasogastric tube that is pulled back so the tip rests in the proximal esophagus. Contrast studies may, however, miss esophageal injuries. Obtaining high-quality contrast studies may be difficult, particularly in off-hours. Esophagoscopy is certainly an alternative and flexible esophagoscopy is most often used, with a demonstrated negative predictive value of 100% but a positive predictive value of only approximately 33%.^54,55

Operative Treatment

Because esophageal injury is uncommon, most studies include only a small numbers of trauma patients for analysis.^56,57,58,59 Although commonly described as a heterogeneous group, iatrogenic esophageal injuries are quite different than those due to external trauma. Iatrogenic injuries are commonly successfully managed nonoperatively, while surgical repair remains the mainstay of for external trauma.

Exposure of the cervical esophagus is achieved through the left neck with the incision placed along the anterior border of the sternocleidomastoid muscle. Lateral retraction of this muscle and blunt dissection in the avascular prevertebral plane will allow a Penrose drain to encircle the esophagus achieving 360° exposure. As opposed to the trachea, the blood supply to the esophagus courses longitudinally in the submucosa allowing for full mobilization. During dissection care must be exercised to avoid injuring the recurrent laryngeal nerves that lie in the tracheoesophageal grove.

It is important to remember the esophagus lacks a serosal layer and therefore is more prone to a postoperative leak. If this occurs in the neck it is easily treated, however, mediastinal leaks can cause significant morbidity and mortality. A fundamental principle in repairing esophageal injuries is visualizing the entire extent of the mucosal injury. The defect in the muscular layer is almost always less extensive than that in the mucosa. The extent of the mucosal defect is exposed by incising the muscular layer until both ends of the mucosal tear are visualized. Esophageal repair is performed in two layers and must be tension free. The mucosa is approximated with interrupted sutures, either absorbable or nonabsorbable, and the muscular layer is closed with interrupted nonabsorbable sutures (Fig. 25-10). The repair can be facilitated by placing a nasogastric tube. Drains are recommended.

Intrathoracic esophageal injuries are associated with more serious sequelae and require more extensive exposure. The operative principles are preservation of esophageal length, primary repair, buttressing the repair, wide drainage, antibiotics and enteral feeding access. Preoperative localization of the site of injury is imperative, as it will influence the surgical approach. With the exception of its most distal segment, the intra-thoracic esophagus is approached through a right posterolateral thoracotomy. The azygous vein is divided and the lung is retracted. The mediastinal pleura widely opened exposing the esophagus which is mobilized by blunt dissection. Devitalized mediastinal and esophageal tissues are debrided. A pedicled intercostal muscle is ideal to buttress the repair, it is robust and easily harvested.^34,50,51 (Fig. 25-11). Wide mediastinal drainage is mandatory and enteral feeding access placed. A contrast study is performed approximately 1 week postoperatively, and if no leak is noted, oral feedings are started.

There are several surgical approaches to the distal esophagus or esophagogastric junction including a left sixth or seventh interspace posterolateral thoracotomy, laparotomy, or a thoracoabdominal approach. Injuries to the distal intrathoracic esophagus are best approached via thoracotomy. The choice of incision to expose the esophagogastric junction is influenced by the exact location of the injury and associated injuries. If there are concomitant abdominal injuries, laparotomy alone may be sufficient, while associated intrathoracic injuries may be approached by thoracotomy or thoracoabdominal incision. Distal esophageal injuries lend themselves to reinforcement with a fundal wrap.

Regardless of the location, a primary buttressed repair and adequate mediastinal drainage is the optimal treatment. Esophageal excision and resection with diversion should be avoided, and every effort made to preserve esophageal length. In rare circumstances, the magnitude of the esophageal injury or the patient’s clinical condition precludes definitive repair. In these instances a damage control procedure may be lifesaving. Creating a controlled esophageal fistula by using a T-tube is an effective procedure.⁶⁰ This technique, combined with wide drainage, controls mediastinal contamination and preserves esophageal length. Devastating injury to the stomach and esophagogastric junction presents a unique challenge. These are not amenable to T-tube drainage; however, retrograde esophageal drainage may prove useful. Continuity is reestablished by an esophagojejunostomy performed several months later.⁶¹

Outcomes

Esophageal trauma results in significant morbidity and mortality. Mortality ranges from 0% to 22%.^50,51 In the large AAST series, the mortality was 19%.⁵⁰ Complications are common with esophageal related complications ranging between 38% and 66%.^50,51,52 Independent risk factors for esophageal related complications included delay in operative treatment, higher grade esophageal injury and resection and diversion.⁵⁰ Prompt diagnosis and operation, a precise technical repair and consideration of a damage control procedure in dire circumstances are essential for a satisfactory outcome.

Complications of Esophageal Injury

Missed/Delayed Diagnosis

In the largest study to date of penetrating esophageal injuries, Asensio and colleagues found that patients subjected to lengthy evaluations had higher complication rates overall and esophageal related complications specifically, compared to counterparts who proceeded directly to operation for diagnosis and received operative treatment in an expedited fashion.⁵⁰

Tracheoesophageal Fistula

Acquired, nonmalignant tracheoesophageal fistula, is a dreaded complication, which fortunately is exceptionally rare. Contemporary endotracheal tubes with high volume, low pressure cuffs have virtually eliminated this complex problem among ventilated patients. Combined airway and esophageal injuries, repaired without muscle interposition, are at risk to develop a tracheoesophageal fistula. The clinical presentation initially may be subtle, with symptoms ascribed to other conditions, especially respiratory. Recurrent pneumonia and persistent cough with unidentified cause alone warrants evaluation in the appropriate patient. Once diagnosed, treatment commonly requires surgical intervention, with fistula ligation, repair of the respective tracheal and esophageal defects and muscle interposition. Ideally this is accomplished once the patient is liberated from mechanical ventilation, as the operative repair is more complex on mechanical support. The use of covered tracheal or esophageal stents has been described for those who are not operative candidates, as has operative diversion.^62,63 Avoiding rather than treating this complication is the preferred strategy. As described earlier, with a combined airway and esophageal injury, a precise technical repair of each individual structure and muscle interposition will greatly reduce the change of this complication.⁶⁴