Initial evaluation and management of blunt thoracic trauma in adults

INTRODUCTION — Multiple vital thoracic structures are at risk of injury from blunt chest trauma such as rapid deceleration and direct injury. Major concerns include chest wall injury (eg, rib fractures or flail chest), cardiovascular injury (eg, blunt aortic injury [BAI] or cardiac contusion), and pulmonary injury (eg, pneumothorax, contusions, or lacerations). BAI is the most lethal injury of the thorax if untreated.

This topic will review the epidemiology, diagnosis, and initial management of injuries sustained in adults from blunt thoracic trauma. Fundamentals of initial trauma management, thoracic trauma in children, and other injuries sustained from trauma are discussed separately.

●(See "Initial management of trauma in adults".)

●(See "Thoracic trauma in children: Initial stabilization and evaluation".)

●(See "Initial evaluation and management of rib fractures".)

●(See "Initial evaluation and management of chest wall trauma in adults".)

●(See "Initial evaluation and management of blunt cardiac injury".)

●(See "Initial evaluation and management of blunt abdominal trauma in adults".)

EPIDEMIOLOGY — Motor vehicle collisions (MVCs) are the most common cause of major thoracic injury in adult blunt trauma patients [1,2]. Risk factors for thoracic injury include:

●High speed

●Seatbelt non-use [3-5]

●Extensive vehicular damage

●Steering wheel deformity [6,7]

Patients with multiple rib fractures, older age, or higher injury severity scores have increased mortality and morbidity [1,8-11].

Epidemiology of specific injuries is presented below. In general, the trauma literature is biased towards more seriously injured patients because studies of chest trauma are often based upon registries that catalog admitted trauma patients. Patients with minor injuries or isolated rib fractures are often discharged and do not appear in these registries [10].

●Blunt aortic injury – Most blunt trauma patients who sustain a major aortic injury die immediately. Of those who reach the hospital alive, most either die during initial management or are unable to undergo aortic repair due to associated injuries, both intra- and extrathoracic [12].

Occupant-related risk factors for blunt aortic injury (BAI) include [3,13]:

•Age ≥60 (relative risk [RR] 3.6, 95% CI 2.5-5.2)

•Front-seat occupancy (RR 3.1, 95% CI 1.5-6.3)

•Seatbelt non-use (RR 3.0, 95% CI 2.2-4.3)

Collision-related risk factors for BAI include [3,13]:

•Front- or near-side MVC (RR 3.1, 95% CI 1.9-5.1 and RR 4.3, 95% CI 2.6-7.2, respectively)

•Abrupt deceleration ≥25 miles/hour (≥40 km/hour [RR 3.8, 95% CI 2.6-5.6])

•Intrusion ≥15 cm (RR 5.0, 95% CI 3.5-7.3)

•Car struck by a sports utility vehicle (RR 1.7, 95% CI 1.2-2.3)

(See "Clinical features and diagnosis of blunt thoracic aortic injury" and "Management of blunt thoracic aortic injury".)

●Blunt cardiac and pulmonary injury – Up to 20 percent of deaths from MVCs are attributable to blunt cardiac injuries, with most of these deaths occurring in the field [14,15]. While pneumothorax is a common injury, the incidence of occult pneumothorax (ie, diagnosed by computed tomography [CT] and not visible on chest radiograph [CXR]) is unclear, ranging between 2 to 55 percent [16]. The risk of pulmonary contusion appears to correlate with crash severity and the proximity of where the patient was sitting to where the car was impacted [17]. (See "Initial evaluation and management of blunt cardiac injury".)

●Rib fractures – Observational studies suggest that rib fractures occur in almost two-thirds of patients with chest trauma due to MVCs. However, most of these studies evaluated patients involved in high-energy trauma admitted to trauma centers. A cohort study of alert patients presenting to two emergency departments following blunt trauma and having a CXR found that multiple rib fractures (>2) was the most common serious thoracic injury and occurred in approximately 5 percent of patients [2]. Multiple rib fractures, particularly the first through third ribs, increases the risk of intrathoracic injury, especially in older adults. Sustaining even isolated, minor rib fractures portends a small increased risk of developing pneumonia; the risk is increased in older adults (≥65 years) and patients with pulmonary disease [18]. (See "Initial evaluation and management of rib fractures" and "Geriatric trauma: Initial evaluation and management".)

●Fractures of the sternum and scapula – The high-energy force needed to fracture the sternum or scapula is associated with an increased risk of internal injury. The epidemiology of these injuries is reviewed separately. (See "Initial evaluation and management of chest wall trauma in adults", section on 'Epidemiology'.)

ANATOMY AND INJURY PATTERNS — The chest wall protects against injuries to the intrathoracic structures (figure 1 and figure 2 and figure 3) and is commonly injured. The anatomy and physiology of the chest wall are discussed in detail separately. (See "Initial evaluation and management of chest wall trauma in adults", section on 'Anatomy and Injury Patterns'.)

The mediastinum is an anatomic division of the thorax extending from the diaphragm inferiorly to the thoracic inlet superiorly (figure 4 and figure 5 and figure 6). Its borders include the sternum anteriorly, the vertebral column posteriorly, and the parietal pleura laterally. Contained within the mediastinum are the heart, aorta, trachea, and esophagus. Injuries to any of these structures are potentially life threatening. One lung is located lateral to each side of the mediastinum.

With blunt trauma, the most common isolated mediastinal injury involves the aorta (figure 7). Hemorrhage from other nearby structures, such as venous lacerations or fractures of the ribs, sternum, or vertebra, can manifest as mediastinal blood, raising concern for aortic injury (algorithm 1). Aortic injuries are mainly transverse tears with relatively smooth margins. The underlying injury ranges from a simple subintimal hemorrhage, with or without intimal laceration, to complete aortic transection. (See "Clinical features and diagnosis of blunt thoracic aortic injury", section on 'Pathophysiology of injury'.)

The diaphragm constitutes the floor of the thoracic cavity (figure 8). The diaphragm exhibits substantial movement with inspiration and expiration, and thus, pain in the lower thorax may reflect intra-abdominal as well as intrathoracic injury.

PREHOSPITAL MANAGEMENT — Prehospital providers should treat patients with possible underlying pulmonary, cardiac, or major extrathoracic injuries according to the principles of Advanced Trauma Life Support (ATLS), paying special attention to the patient's airway, breathing, and circulation ("ABCs"). Rapid transport to the closest trauma center is crucial, and interventions causing unnecessary delay should be avoided. Basic interventions such as cervical spine immobilization are appropriate, as are high-flow oxygen and cardiac monitoring. Transport should not be delayed to place intravenous (IV) lines or perform endotracheal intubation unless the patient is in extremis and cannot be stabilized with bag-mask ventilation. More extensive intervention may be needed if prolonged transport time is expected. A detailed discussion of prehospital trauma care is found elsewhere.

If the patient shows no evidence of respiratory difficulty or underlying injury, no intervention may be necessary. Before leaving the scene of a vehicular accident, prehospital providers should quickly make note of important features associated with increased risk of injury and convey these findings to clinicians at the trauma center. Such findings include significant intrusion into the passenger compartment, deformed steering wheel, ejection of the patient from the vehicle, and fatality at the scene. Prehospital hypotension is an important indication of significant injury, and this finding must be communicated to the clinicians assuming care of the patient.

INITIAL EVALUATION AND MANAGEMENT

Primary survey — Initial resuscitation and management of the trauma patient is based upon principles from Advanced Trauma Life Support (ATLS) and is reviewed separately. Details pertaining to the initial assessment and management of a patient with blunt thoracic trauma are discussed below. In a patient with high-energy blunt trauma, initial evaluation should be performed in the trauma or critical care area within the emergency department. A basic algorithm for management is provided (algorithm 2). (See "Initial management of trauma in adults", section on 'Primary evaluation and management'.)

Clinicians first assess and stabilize the patient's airway, breathing, and circulation, in that order ("ABCs"; ie, primary survey). A caveat in patients with respiratory distress following chest trauma is that breathing may take priority over airway. If the patient is in respiratory distress due to a tension pneumothorax, the clinician should relieve the pneumothorax before performing endotracheal intubation, if needed. Positive-pressure ventilation following intubation can potentially exacerbate a pneumothorax. (See 'Breathing' below.)

Immediate life-threatening injuries from blunt chest trauma include:

●Tension pneumothorax (see 'Breathing' below)

●Cardiac tamponade from myocardial injury (see "Cardiac tamponade")

●Aortic injury (see 'Aortic injury' below and "Clinical features and diagnosis of blunt thoracic aortic injury")

●Hemothorax with severe, active bleeding (see 'Hemothorax' below)

●Tracheobronchial disruption (see 'Airway' below and "Identification and management of tracheobronchial injuries due to blunt or penetrating trauma")

Airway — Patients with respiratory distress, marked hemodynamic instability, or severe injury are intubated. Rapid sequence intubation is the preferred approach whenever possible, avoiding pretreatment and induction agents with the potential to cause hypotension. (See "Rapid sequence intubation in adults for emergency medicine and critical care" and "Initial management of trauma in adults", section on 'Airway'.)

Airway management may need modification if there are clinical or radiographic findings suggestive of a tracheobronchial injury (TBI), a rare but life-threatening complication of severe chest trauma, or in a patient with severe cardiac injury. Blunt-force injuries to the intrathoracic trachea, carina, or a mainstem bronchus can present with dyspnea and subcutaneous emphysema that may track into the mediastinum or neck, as well as bilateral pneumothoraces. Patients in extremis are intubated in standard fashion, but excessive manipulation during intubation and high airway pressures during mechanical ventilation can exacerbate an injury. Anatomic distortion can result in difficult airway management. Thus, in the stable patient without respiratory distress, bronchoscopy (if available) is the preferred approach to airway management because it allows for characterization of the lesion and safe placement of the tracheal tube. (See 'Tracheobronchial injury' below and "Identification and management of tracheobronchial injuries due to blunt or penetrating trauma".)

In a patient with severe cardiac injury (eg, ruptured valve, septum, or ventricular wall) planned for operative intervention, if possible, delay intubation until just before sternotomy because induction may precipitate hemodynamic collapse. (See "Initial evaluation and management of blunt cardiac injury", section on 'Valve, septum, or ventricular wall injury'.)

Breathing — Assess oxygenation, ventilation, and chest wall injuries, paying attention to breath sounds, chest wall deformity or asymmetric movement, wounds, and crepitus. (See "Initial management of trauma in adults", section on 'Breathing and ventilation'.)

Patients with a simple pneumothorax or tension pneumothorax may manifest tachypnea, chest pain, hypoxia, unilateral diminished or absent breath sounds, subcutaneous air, or unilateral hyperresonance to percussion, depending on the extent of the pneumothorax. Suspected tension pneumothorax is treated with immediate tube, needle, or finger thoracostomy (algorithm 2 and image 1 and image 2 and image 3). The needle and finger thoracostomy procedures are discussed in detail elsewhere. (See "Initial evaluation and management of penetrating thoracic trauma in adults", section on 'Role of needle/finger chest decompression'.)

A hemothorax can cause respiratory distress, diminished breath sounds, or signs of shock depending on the extent of bleeding. If thoracostomy is needed in an unstable patient, use a 24 to 28 French chest tube [19,20]. Studies have found similar efficacy, complication, and failure rates with smaller tubes (ie, 14 to 22 French), but these studies are biased by patient stability and may not be applicable for a patient in extremis from a traumatic hemothorax [21-23]. For example, a prospective trial comparing 14 French versus 28 to 32 French chest tubes for traumatic hemothorax and hemopneumothorax excluded patients requiring emergency tube placement [21]. Immediate bloody drainage of ≥20 mL/kg is generally considered an indication for thoracotomy in the operating room. (See 'Hemothorax' below.)

If needle or finger decompression is performed first, it is followed by tube thoracostomy soon afterwards. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children".)

Circulation — Assess for signs of shock by palpating central pulses, obtaining a blood pressure, and examining skin and mental status. Shock in the trauma patient is most often hemorrhagic but can also be obstructive (eg, tension pneumothorax, cardiac tamponade), distributive (eg, neurogenic shock), or unrelated to the trauma (table 1). (See "Approach to shock in the adult trauma patient", section on 'Causes of shock in the trauma patient'.)

The unstable, hypotensive, or pulseless trauma patient should be resuscitated following ATLS principles. In patients with signs of hemorrhagic shock, blood products should be given as soon as the need for transfusion is recognized in a 1:1:1 ratio of red blood cells, plasma, and platelets. Isotonic crystalloid in lieu of blood can be given initially, but unnecessary infusion of crystalloid should be avoided since it can dilute clotting factors, contribute to hypothermia, and disrupt thrombus. (See "Initial management of trauma in adults", section on 'Circulation' and "Approach to shock in the adult trauma patient", section on 'Diagnosis and Management' and "Initial management of moderate to severe hemorrhage in the adult trauma patient".)

Point-of-care emergency department ultrasound has become an integral part of trauma evaluation and is typically performed during the "C" part of the primary survey in the hemodynamically unstable patient. The focused assessment with sonography for trauma (FAST) exam is used primarily to assess for pericardial tamponade and hemoperitoneum, while the extended FAST (E-FAST) adds chest views to evaluate for pneumothorax (algorithm 2). Point-of-care ultrasound can also identify hemothorax, but this is not a routine part of the E-FAST exam. In the unstable, hypotensive, or pulseless trauma patient, abnormal ultrasound findings should be immediately addressed. (See "Emergency ultrasound in adults with abdominal and thoracic trauma" and "Initial management of trauma in adults", section on 'Ultrasound (FAST exam)'.)

Following blunt trauma, cardiac tamponade is most often caused by myocardial injury and detected by FAST exam (movie 1). Recognizing cardiac tamponade clinically can be challenging as Beck's triad (hypotension, jugular venous distension, muffled heart sounds) can be difficult to detect and is often not present. Due to the poor compliance of the pericardium, the acute accumulation of as little as 50 mL of blood can cause tamponade. If the rate of bleeding is slow or the pericardium periodically decompresses by emptying blood into the pleural space, the patient may initially appear stable. (See "Approach to shock in the adult trauma patient", section on 'Cardiac tamponade' and "Cardiac tamponade".)

Pericardiocentesis is performed immediately in patients with a pericardial effusion identified on ultrasound and significant hypotension or signs of shock. If bedside ultrasound is unavailable and the clinician strongly suspects tamponade, empiric pericardiocentesis should be performed if the patient is hemodynamically unstable and is an option to diagnose an effusion in a stable patient. (See "Emergency pericardiocentesis".)

If tamponade cannot be relieved by percutaneous drainage, or if the patient develops cardiac arrest, emergency department thoracotomy (EDT) may be necessary. In a patient with suspected myocardial rupture who is too unstable to be moved to the operating room, EDT rather than pericardiocentesis may be the best treatment to relieve tamponade. (See "Initial evaluation and management of blunt cardiac injury", section on 'Valve, septum, or ventricular wall injury'.)

Role of emergency department thoracotomy — In the setting of blunt trauma, EDT has narrow indications and rarely results in successful resuscitation [24-30]. A more complete discussion of EDT, including epidemiology, indications, and practice guidelines, is found separately. (See "Resuscitative thoracotomy: Technique", section on 'Preparation' and "Initial evaluation and management of penetrating thoracic trauma in adults", section on 'Role of emergency department thoracotomy'.)

Given the resources required and risks entailed in EDT, we recommend hospitals develop policies to determine the circumstances under which the procedure is to be performed. A trauma or thoracic surgeon should be readily available if EDT is performed since immediate surgical intervention may be necessary. Blunt trauma patients most likely to survive an EDT neurologically intact have no obvious nonsurvivable injury (eg, massive head trauma) and one of the following:

●Loss of vital signs in the emergency department

●Cardiac tamponade rapidly diagnosed by ultrasound

EDT in blunt trauma patients appears to be futile in any one or more of the following circumstances:

●Patient required over 15 minutes of prehospital cardiopulmonary resuscitation (CPR)

●Patient is apneic and pulseless and has no rhythm on cardiac monitor in the field

●Patient has nonsurvivable injuries

In blunt trauma patients, EDT results in neurologically intact survival in less than 5 percent of those in shock, 1 percent of those without vital signs upon arrival to the emergency department, and no patients without signs of life in the field [28,30,31]. A meta-analysis of 27 studies including 1369 blunt trauma patients who underwent EDT reported an overall neurologically intact survival rate of only 1.5 percent [31]. All 21 surviving patients had measurable vital signs at the scene or in the emergency department and a maximum duration of CPR of 15 minutes.

Secondary survey — After addressing the primary survey, the evaluation continues with the secondary survey, a careful, head-to-toe assessment that includes a detailed history (algorithm 2). The clinician needs to assess if the patient is at low or high risk for significant injury to cardiopulmonary and mediastinal structures based on vital signs, complaints, age, comorbidities, mechanism of injury, general clinical appearance, and external signs of injury [1,2,8-10]. This may be as simple as a thorough history and physical examination or may require multiple tests, including radiographs, computed tomography (CT) scans, and echocardiography.

●Mechanism of injury – Mechanism is less predictive of injury severity and ultimate disposition than abnormal vital signs in the setting of blunt trauma [32]. For example, a young, healthy patient involved in a rollover motor vehicle collision (MVC) may sustain no injuries, while a frail older adult patient who trips and falls may incur multiple rib fractures accompanied by a pulmonary contusion.

●Complaints and examination – The risk of serious injury is low among alert patients without discomfort, dyspnea, or tenderness [33-35]. A meta-analysis of studies of aortic injury from blunt trauma found that the presence of normal vital signs or hemodynamic stability does not rule out aortic injury [36]. Hypoxia and abnormal lung sounds are the most specific signs for pneumothorax or hemothorax, while chest pain and tenderness are most sensitive, albeit nonspecific [37]. Normal lung sounds showed a high negative predictive value for pneumothorax in one observational study, but the number of patients with abnormal findings was too low to draw definitive conclusions [34]. Patients with pain and tenderness of the lower ribs, especially with pleuritic complaints or abdominal pain and tenderness, are at higher risk for both intrathoracic and intra-abdominal injuries [38]. Even though studies suggest the history and physical examination are insensitive for detecting intrathoracic injury, most trauma studies are biased by a heterogeneous mix of patients and injuries, a low number of positive findings, and a lack of follow-up.

DIAGNOSTIC TESTING IN STABLE/STABILIZED PATIENT

Overview of testing — Testing is based on the patient's mechanism of injury and signs and symptoms (algorithm 2). A plain chest radiograph (CXR) is obtained for all hemodynamically stable patients who present with blunt chest trauma of any significance or who have any signs or symptoms (eg, chest pain, chest wall tenderness). The NEXUS guidelines can help determine which patients can safely forego any imaging (algorithm 3). (See "Emergency ultrasound in adults with abdominal and thoracic trauma", section on 'Focused Assessment with Sonography for Trauma' and 'When CXR is not needed (NEXUS)' below.)

When to obtain electrocardiogram — The electrocardiogram (ECG) is an important screening test for hemodynamically stable patients with potential blunt cardiac injury. Obtain an ECG on blunt trauma patients with any of the following (see "Initial evaluation and management of blunt cardiac injury"):

●Major mechanism of injury (eg, rollover, high speed, fatality at scene) in an older adult or a patient with known coronary artery disease

●Evidence of significant anterior chest wall trauma (eg, sternal fracture, manubrium fracture, retrosternal hematoma)

●Circumstances of trauma suggestive of heart disease (eg, accident preceded by syncope or shortness of breath)

●Active signs or symptoms consistent with heart disease, including chest pain suggestive of acute coronary syndrome (eg, pressure, heaviness, tightness, fullness, squeezing, radiation to one or both shoulders)

●Signs of heart failure (eg, pulmonary edema, distended jugular veins)

●Abnormal heart sounds (eg, muffled sounds, holosystolic or diastolic murmur)

●Unexplained tachycardia, bradycardia, or hypotension

●New dysrhythmia

Low-risk mechanism of injury: Obtain CXR — In a stable patient with only minimal findings (eg, minor abrasion, mild tenderness) without concern for major injury and with a low-risk mechanism of injury (eg, no rapid deceleration), we obtain a posterior-anterior (PA) and lateral CXR unless the patient is planned for computed tomography (CT) regardless [39]. The CXR is inexpensive and noninvasive, and it reveals useful information in many cases.

Aortic injury is unlikely in patients with a truly normal CXR, no sign of significant injury on examination, and a mechanism that does not involve rapid deceleration [40-43]. No further testing is needed in such patients.

Rib radiographs are rarely needed. They may provide more information about fractures but rarely change management. The clinician can treat patients likely to have sustained a rib fracture on the basis of symptoms and signs, despite the absence of radiographic evidence [44-46]. (See "Initial evaluation and management of rib fractures".)

When CXR is not needed (NEXUS) — A patient with minor trauma who has no chest discomfort and whose clinical evaluation reveals no signs of injury may not require a CXR. Imaging decisions should be based on institutional protocols and clinical judgement, while the NEXUS decision instrument (algorithm 3) can help determine which patients can safely forego imaging. This instrument is used most often to determine when chest CT is not needed, but it may also be used to help determine when CXR is not needed. Clinicians should not hesitate to obtain imaging studies if they have concerns based upon their clinical assessment, regardless of the decision instrument.

The NEXUS decision instrument (algorithm 3) is applied in a hemodynamically stable adult (older than 14 years) blunt trauma patient when the clinician initially believes chest imaging may be needed. If none of the NEXUS criteria are present, then imaging (CXR and chest CT) can be foregone safely without missing significant injury. Clinically significant intrathoracic injury is highly unlikely in the absence of all the following criteria:

●Age >60 years

●Mechanism involving rapid deceleration (eg, fall >20 feet [>6 meters], or MVC >40 mph [>65 km/hour])

●Chest pain

●Intoxication

●Abnormal alertness/mental status

●Distracting painful injury

●Tenderness to chest wall palpitation

The NEXUS research group developed and prospectively validated this decision instrument to help determine which adults with blunt thoracic trauma can safely forego imaging of the chest [47-49]. The first iteration of the NEXUS decision instrument (NEXUS Chest) included the above criteria. While the absence of all criteria indicates low risk for intrathoracic injury, the presence of any one criterion does not necessarily indicate high risk. A meta-analysis (five studies, 20,894 patients) found the NEXUS Chest criteria to have a high sensitivity (99 percent, 95% CI 98-99) and low negative likelihood ratio (0.04, 95% CI 0.03-0.06) but a low specificity (32 percent, 95% CI 17-52) [50]. These test characteristics only pertain to the NEXUS chest radiography rule. Subsequent iterations of the NEXUS decision instrument (Chest CT-All, Chest CT-Major) were developed to be applied after the CXR is obtained to determine which patients could safely forego chest CT (algorithm 3). The criteria age >60 years, chest pain, intoxication, and abnormal mental function were replaced with abnormal CXR and sternal, spine, and scapular tenderness, such that the updated criteria were the following [48]:

●Distracting injury

●Abnormal plain chest radiograph

●Sternal tenderness

●Thoracic spine tenderness

●Scapular tenderness

●Rapid deceleration mechanism (this criterion is excluded from Chest CT-Major)

While all the NEXUS decision instruments have demonstrated high sensitivity for major injury (approximately 99 percent), Chest CT-All had a specificity of 20.8 percent (95% CI 19.2-22.4) and an NPV of 99.8 percent (95% CI 98.9-100) for major injury, and a specificity of 25.5 percent (95% CI 23.5-27.5%) and an NPV of 93.9 percent (95% CI 91.5-95.8) for either major or minor injury. Chest CT-Major (which was created explicitly to detect major thoracic injury) had a specificity of 31.7 percent (95% CI 29.9-33.5) and an NPV of 99.9 percent (95% CI 99.3-100) for major injury. Major injuries included aortic or great vessel injury; diaphragm rupture; pneumothorax or hemothorax requiring thoracostomy; spine or other major fracture requiring surgical repair; esophageal, tracheal, or bronchial injury requiring surgical intervention; pulmonary contusion requiring ventilatory support; and several others.

An abnormal CXR is more suggestive of a major injury than any one criterion alone, highlighting the importance of carefully assessing any obtained CXR. A follow-up study of 269 patients found that the risk for major injury remained low in the presence of any one criterion except for an abnormal CXR, but the sensitivity and specificity of an abnormal CXR for major injury were relatively high (73.7 percent [95% CI 68.1-78.6] and 83.9 percent [95% CI 83.6-84.2], respectively) [51].

Abnormal CXR findings — The CXR can show evidence of hemothorax (image 4), pneumothorax (image 1 and image 2 and image 3), pulmonary contusion (image 5), fractures (image 6), and blunt aortic injury (BAI). The following findings on a plain CXR increase the likelihood of BAI and indicate a need for further investigation, usually contrast-enhanced CT of the chest (algorithm 1) [38,40,44-46]:

●Widened mediastinum (supine CXR >8 cm; upright CXR >6 cm)

●Obscured aortic knob; abnormal aortic contour

●Left "apical cap" (ie, pleural blood above apex of left lung)

●Large left hemothorax

●Deviation of nasogastric tube rightward

●Deviation of trachea rightward and/or left mainstem bronchus downward

●Wide left paravertebral stripe

Studies to determine CXR findings suggestive of BAI are limited by their observational design and the small number of injuries [52-54]. No single finding on CXR possesses high sensitivity or specificity for BAI. A widened mediastinum is the most sensitive (but nonspecific) sign of aortic injury (image 7). Mediastinal widening only correlates well with BAI when there is mediastinal bleeding from aortic rupture. Aortic injuries after blunt trauma account for only 20 percent of abnormal mediastinal widening on CXR [40].

High-energy mechanism of injury

Initial testing with CXR and FAST — Patients who have sustained high-energy blunt trauma with rapid deceleration are at risk for severe injury, and initial testing should be performed in the part of the emergency department where they can be closely monitored (ie, trauma or critical care area). Such patients include those with a more severe mechanism of injury, fatality in the vehicle, initial hemodynamic instability, significant tenderness, a seatbelt sign across the abdomen (picture 1 and picture 2), hypoxia, or clinical signs of multiple rib fractures. The CXR can demonstrate many findings that will need intervention. (See 'Abnormal CXR findings' above.)

●A portable anteroposterior (AP) CXR is obtained as part of the initial evaluation. The plain CXR may not have sufficient sensitivity to detect all injuries in these patients but can identify injuries (eg, hemothorax) that would benefit from intervention while awaiting CT. A normal mediastinum can appear enlarged with ill-defined borders on a portable supine CXR. In addition, a mediastinal hematoma does not necessarily reflect aortic injury.

●A PA and lateral CXR are subsequently obtained if the AP CXR is normal and no severe extrathoracic injury is identified. Clinicians often have difficulty obtaining an upright PA CXR in a trauma patient, and abnormalities may be missed on supine studies. However, if the patient meets appropriate criteria for CT or there are findings on the AP CXR that would warrant a CT scan, the patient should proceed directly to CT rather than imaging with additional plain radiographs.

●The focused assessment with sonography in trauma (FAST) examination should be performed as part of diagnostic testing unless it was already performed during the primary survey or the patient is hemodynamically stable and planned for CT imaging.

Chest computed tomography for most patients — We suggest obtaining a chest CT in patients with concerning clinical findings (eg, severe pain or marked chest tenderness, hypoxia, dyspnea, tachypnea, altered mental status, distracting injuries) even if the CXR is normal. In addition, we obtain a chest CT in patients with an abnormal CXR even if there are no obvious clinical signs of injury and in patients with a high-energy mechanism of injury. Among patients with abnormal CXR findings, chest CT identifies injuries that would not otherwise be found, resulting in significant changes in management between 20 and 30 percent of the time [41,55,56].

The diagnostic accuracy of CT is far greater than plain radiography for intrathoracic injury and allows for detailed evaluation of intrathoracic structures [41,57-59]. CT provides greater sensitivity for diagnosing small pneumothoraces, pneumomediastinum, and pulmonary contusions and lacerations. In addition, contemporary scanners allow for rapid three-dimensional imaging of the aorta and bony structures [16,41,60].

If an initially unstable patient stabilizes in the emergency department and does not require emergency surgery, chest CT with contrast is performed to define the extent of any thoracic injury and exclude aortic rupture (image 7 and image 8). If the patient is unable to undergo CT due to the need for immediate operation, transesophageal echocardiography can be performed in the operating room to assess the aorta and heart. (See 'Transesophageal echocardiography' below.)

The use of chest CT for trauma evaluation has increased dramatically; in many centers, patients involved in high-energy trauma are sent almost immediately for CT before a CXR can be performed. Patients with a low-risk mechanism, minor injuries by examination, and a normal CXR generally do not require CT imaging, which may be overused in these circumstances [41,43,61-63]. However, findings from some observational studies suggest that a substantial number of patients sustain clinically significant intrathoracic injuries that are identified by CT but do not manifest abnormal findings on plain CXR [58,64]. Conversely, abnormalities apparent on a plain radiograph strongly suggest the presence of a clinically significant injury [51].

Whether to obtain a CT purely on the basis of a high-risk mechanism remains controversial. Results of studies have been mixed but tend to favor performing a chest CT in patients with significant mechanisms of injury or severe concomitant injuries. As examples, one prospective study of 592 consecutive hemodynamically stable trauma patients with a significant mechanism of injury found that 20 percent of chest CT scans revealed clinically important abnormalities despite the absence of external signs of thoracic injury [65]. A prospective study of 609 blunt trauma patients imaged with CT noted that 11 percent of chest CT scans initially deemed unnecessary by emergency clinicians were reported to have clinically meaningful findings, including two that resulted in critical actions (spinal surgery for a T8 burst fracture and chest tube insertion for a lung laceration) [66].

Role of other studies to rule out aortic injury

Transesophageal echocardiography — Transesophageal echocardiography (TEE) is an excellent modality to assess for BAI in patients too unstable for chest CT. TEE has high sensitivity and specificity for BAI, can be performed in the emergency department or the operating room, requires no contrast, and provides information about cardiac injury and function. It should not be performed in patients with unstable cervical spine injuries or esophageal injuries. (See "Clinical features and diagnosis of blunt thoracic aortic injury", section on 'TEE findings'.)

TEE compares favorably with aortography or CT scan in the majority of cases and can identify some intimal tears not seen on corresponding aortography, although the clinical significance of these tears is unclear [67-69]. It can also identify valvular injuries and pericardial effusions. Unlike transesophageal imaging, transthoracic echocardiography cannot reliably diagnose or rule out BAI [67,68].

TEE is operator dependent and suffers in some studies from loss of sensitivity. The interposition of the air-filled trachea between the aorta and esophagus creates a blind spot, precluding adequate evaluation of the distal ascending aorta and proximal arch.

Aortography — Aortography should be reserved for patients with equivocal CT scans (typically with helical CT) who cannot have a TEE. Aortography was the traditional gold standard but has been supplanted by multidetector CT (MDCT) for identifying BAI. Aortography is more time consuming and invasive, and it may not detect a tear until the development of pseudoaneurysm. Test characteristics of aortography compared with MDCT and helical CT are discussed in detail separately. (See "Clinical features and diagnosis of blunt thoracic aortic injury", section on 'Approach to imaging'.)

Suspected blunt cardiac injury (echocardiography, cardiac biomarkers) — Blunt cardiac injury should be suspected in a patient with heart failure (eg, pulmonary edema, distended jugular veins); abnormal heart sounds (eg, muffled sounds, holosystolic or diastolic murmur); unexplained tachycardia, bradycardia, or shock out of proportion to apparent injuries or despite aggressive resuscitation; new dysrhythmia or conduction block (eg, bundle branch block); a FAST that is nondiagnostic for hemopericardium; or with other ECG abnormalities. Our approach to the evaluation of blunt cardiac injury, including the use of echocardiography and cardiac biomarkers, is discussed separately. (See "Initial evaluation and management of blunt cardiac injury", section on 'Evaluation and diagnosis of adult with blunt chest trauma'.)

SPECIFIC INJURIES

Aortic injury — Aortic tears usually occur from high-energy injuries to the thorax, often following rapid deceleration. Theories about the mechanism of aortic disruptions are discussed separately. (See "Clinical features and diagnosis of blunt thoracic aortic injury", section on 'Pathophysiology of injury'.)

Almost 80 percent of blunt aortic injuries (BAIs) cause immediate death from aortic transection. In a minority of patients, the adventitia and mediastinal structures contain the rupture, allowing the patient to survive transport to the hospital. If contained BAI goes undiagnosed, the patient is at risk for delayed aortic rupture [70]. Prompt emergency department diagnosis is crucial and may be lifesaving in some patients. There are no clinical signs or examination findings with sufficient sensitivity or specificity to detect or rule out BAI. High-energy trauma involving rapid deceleration with any associated injury or chest wall contusion or deformity should raise suspicion for BAI; the following algorithm provides a diagnostic approach (algorithm 1).

●Diagnostic evaluation – Computed tomography (CT) scan of the chest with intravenous (IV) contrast is the most commonly used imaging modality to definitively exclude BAI with near 100 percent sensitivity and specificity [53,71-76]. A diagnostic algorithm and testing options for evaluation of BAI are presented (algorithm 1 and table 2). Multidetector CT (MDCT) has improved spatial resolution, better image quality, and capability for multiplanar reformations. Aortic injuries can be categorized as minimal or significant on the basis of abnormalities of the external aortic wall, which helps surgeons determine the need for operative intervention [42,77]. Most patients with BAI have other thoracic injuries that CT will identify, including rib fractures, pneumothorax, hemothorax, and chest wall deformity [78]. (See "Clinical features and diagnosis of blunt thoracic aortic injury", section on 'Approach to imaging'.)

In a patient who cannot have a CT with IV contrast (eg, hemodynamically unstable, alternate indication for immediate surgery), a transesophageal echocardiography (TEE) is an appropriate next step and can be performed in the operating room.

An MDCT that is equivocal for BAI is rare but can occur with patient movement, mistiming of contrast injection (resulting in inadequate aorta visualization), rib fracture causing a small volume of mediastinal blood, a process obscuring the aorta, and potentially others. In a patient with an equivocal CT finding that has low suspicion for a BAI, a reasonable approach is to start anti-impulse therapy (ie, esmolol) to control blood pressure and heart rate, administer IV crystalloid to prevent contrast-induced nephropathy, and repeat the CT with IV contrast (preferably a CT angiogram) after one to two hours. (See "Prevention of contrast-induced acute kidney injury associated with computed tomography", section on 'Volume expansion'.)

A patient with equivocal CT findings that are suspicious for BAI should undergo TEE or aortography (while receiving anti-impulse therapy). Also, if significant delays to TEE or aortography are expected, repeating the CT (or CT angiogram) may be reasonable.

●Management – All patients with BAI require careful control of their blood pressure and heart rate to slow the expansion of the injury. The goal for systolic blood pressure and heart rate are approximately 100 mmHg and <100 beats per minute, respectively [79]. Esmolol, a rapidly acting IV beta-blocker with a short duration of action, is an ideal choice since its effects wear off quickly if the need arises to manage shock from an alternate etiology. (See "Management of blunt thoracic aortic injury", section on 'Anti-impulse therapy'.)

Further management decisions (eg, medical versus surgical management) are based on the extent of the BAI. A simplified aortic injury grading system is presented in the figure and discussed in detail separately (figure 9). (See "Clinical features and diagnosis of blunt thoracic aortic injury", section on 'Aortic injury grading' and "Management of blunt thoracic aortic injury", section on 'Approach to management'.)

•"Minimal" aortic injury – This does not require immediate surgical intervention and can often be managed solely with medical therapy, unlike "significant" aortic injuries (eg, active aortic bleeding, full-thickness aortic rupture, pseudoaneurysm). Minimal aortic injury (ie, grade I) is commonly defined as a subcentimeter intimal abnormality or localized intramural hematoma without external contour deformity (the exact definition is not well established) [80,81]. The incidence of minimal aortic injury is estimated to be 10 to 30 percent of all BAIs. (See "Management of blunt thoracic aortic injury", section on 'Nonoperative management of minimal injuries'.)

•"Non-minimal" aortic injury – Options for surgical treatment of grade II to IV aortic injury include open repair (via thoracotomy) or endovascular repair, but in some cases, emergency surgery is not feasible. The relative risks and benefits of immediate versus delayed repair are discussed separately. (See "Management of blunt thoracic aortic injury", section on 'Aortic repair' and "Surgical and endovascular repair of blunt thoracic aortic injury".)

Cardiac injury — Blunt cardiac injuries include myocardial contusion, cardiac (valve, septum, or ventricular wall) rupture, acute coronary syndrome/myocardial infarction, cardiac dysfunction, and dysrhythmias. These are discussed in detail elsewhere. (See "Initial evaluation and management of blunt cardiac injury".)

A patient with unexplained persistent tachycardia, new conduction block (eg, bundle branch block), or dysrhythmia may have a cardiac contusion, although identification of other injuries or ongoing hemorrhage, which may need specific intervention, should be prioritized. (See "Initial evaluation and management of blunt cardiac injury", section on 'Myocardial or cardiac contusion'.)

A patient with unexplained shock out of proportion to apparent injuries or despite aggressive resuscitation may have severe cardiac injury (eg, ruptured valve, septum, or ventricular wall). Signs of tamponade such as distended neck veins and muffled heart sounds are commonly absent. Immediate bedside cardiac ultrasound (ie, focused assessment with sonography in trauma [FAST]) can identify pericardial effusion and tamponade (movie 1), which often occur with severe cardiac injury. (See "Initial evaluation and management of blunt cardiac injury", section on 'Valve, septum, or ventricular wall injury'.)

Pulmonary injury — Major pulmonary injuries include pneumothorax, hemothorax, pulmonary contusion, pulmonary parenchymal injuries, and tracheobronchial injuries.

Pneumothorax

●Mechanism and clinical features – Pneumothorax is a common complication of blunt trauma, often sustained from a fractured rib [82]. Signs and symptoms include dyspnea, tachypnea, pleuritic chest pain, hypoxia, unilateral diminished or absent breath sounds, or unilateral hyperresonance to percussion, depending on the extent of the pneumothorax. Crepitus from subcutaneous emphysema may be present but is a less common finding.

●Diagnostic evaluation – Patients with signs or symptoms suggesting pneumothorax should be evaluated with an upright posterior-anterior (PA) chest radiograph (CXR) or a CT scan of the chest (image 1 and image 9 and image 10). The supine chest radiograph has high specificity for diagnosing a pneumothorax from blunt injury, but its sensitivity is variable. A CXR should be repeated in six hours in patients with a normal initial CXR, a high clinical suspicion for pneumothorax, and no other indication for chest CT. Ultrasound is also a sensitive initial screening tool. (See "Emergency ultrasound in adults with abdominal and thoracic trauma", section on 'Pneumothorax and hemothorax'.)

●Management – Traumatic pneumothorax has traditionally been managed with open tube thoracostomy. The Advanced Trauma Life Support (ATLS) curriculum suggests any traumatic pneumothorax visible on CXR should be treated with tube thoracostomy. We perform tube thoracostomy in spontaneously breathing patients with a traumatic pneumothorax identified on CXR in the following situations:

•Respiratory distress, hypoxia, or hemodynamic instability

•Anticipated prolonged transport time or transport by air ambulance

•Increased size of pneumothorax on serial imaging

•Pneumothorax size greater than 15 to 20 percent of lung field or 2.5 cm on CXR (can also use the 35-mm rule based on chest CT, discussed below) [83-86]

•Hemopneumothorax greater than 300 mL (see 'Hemothorax' below)

However, given known complications of chest tubes, other strategies such as needle aspiration, percutaneous pigtail placement, and observation of small pneumothoraces are reasonable. Management decisions must be made jointly with the admitting surgical service. There is scant literature on the optimal management of asymptomatic traumatic pneumothoraces that are small but visible on CXR, and evidence is extrapolated from small pneumothoraces seen on chest CT but not on CXR. (See 'Occult pneumothorax' below.)

•Percutaneous tube thoracostomy – Percutaneous pigtail placement is an option for treatment of traumatic pneumothorax under certain circumstances. A trial of 40 patients who had either a 14 French pigtail or 28 French chest tube placed for simple, uncomplicated traumatic pneumothorax showed less pain at site with the pigtail but no other important differences in outcomes [87]. A single-site, retrospective study found that use of a pigtail catheter was as safe and reliable as a regular-size chest tube for traumatic pneumothorax [88]. Choice of tube size is discussed elsewhere. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children", section on 'Pneumothorax'.)

•Observation – The "35-millimeter" rule for conservative management of traumatic pneumothorax has been proposed [89]. This rule suggests that observation of traumatic pneumothorax is safe when the radial distance between the parietal and visceral pleura or mediastinum in a line perpendicular to the chest wall on axial CT imaging of the largest air pocket is less than 35 mm. This rule can be extrapolated to CXR findings since a 35-mm pneumothorax would be expected to be visible on CXR, but we do not suggest obtaining a chest CT solely for the purpose of measuring a small pneumothorax to apply this rule. A CXR should be repeated after six hours to rule out increasing size of the pneumothorax if a chest tube is not placed immediately.

Antibiotics should be given to patients undergoing tube thoracostomy following chest trauma, although the benefit is questionable, and using sterile conditions is likely more important than antibiotics [23]. (See "Thoracostomy tubes and catheters: Placement techniques and complications", section on 'Antibiotic prophylaxis'.)

Occult pneumothorax — An occult pneumothorax is one not visible on a plain CXR but seen on cervical, chest, or abdominal CT; with the increased use of helical CT to evaluate trauma patients, the question of how to manage these arises frequently [90].

●Patients breathing spontaneously – Blunt trauma patients who are asymptomatic with small occult pneumothoraces, generally less than 8 mm in length (as determined by CT), can be managed with observation alone instead of chest tube placement [16,91-93]. In approximately 5 to 10 percent of patients, occult pneumothoraces expand and become clinically significant and rarely develop into a tension pneumothorax. If the pneumothorax enlarges or the patient becomes symptomatic, a chest tube should then be inserted, and placement will be easier and safer given the larger pleural cavity [92,93]. In all cases of occult pneumothorax not managed with tube thoracostomy, monitoring for signs of an expanding or tension pneumothorax is critical.

●Patients with positive-pressure ventilation – Patients can be managed with observation without prophylactic chest tube placement if they are expected to require only a short duration of positive-pressure ventilation, judged that they could tolerate a brief episode of hypotension or hypoxia, and do not have significant traumatic brain injury or severe multi-trauma [93]. If tube thoracostomy is not performed in patients requiring mechanical ventilation, careful monitoring for signs that the pneumothorax may be expanding is critical, and the patient should be in a setting where an experienced proceduralist is available to quickly insert a chest tube if needed. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children".)

Debate continues about the need for tube thoracostomy in patients with occult pneumothorax who require positive-pressure ventilation, reflecting the conflicting data [94-97]. The potential risk of an expanding pneumothorax is greater in patients receiving positive-pressure ventilation either during surgery or for long-term (more than four days) pulmonary support [98]. One trial found that such patients are at significant risk of developing a life-threatening tension pneumothorax [94]; subsequent trials reported that observation of such patients, without chest tube placement, was not associated with an increased incidence of pneumothorax progression or mortality [97,99]. However, 5 percent of observed patients required urgent rescue chest tube placement, highlighting need for presence of an experienced proceduralist if the plan is for observation [99]. Randomized trials assessing this circumstance are limited [93]; thus, it is difficult to draw meaningful conclusions. Practice guidelines from the Eastern Association for the Surgery of Trauma state that observation is an acceptable option [90].

There is insufficient literature to routinely recommend placing a pigtail catheter for traumatic pneumothorax in mechanically ventilated patients, although a retrospective study with a small number of patients found the pigtail as safe and reliable as a regular-size chest tube [88].

Hemothorax

●Mechanism of injury – Injuries leading to massive hemothorax include aortic rupture, myocardial rupture, and injuries to hilar structures. Other causes include injuries to the lung parenchyma and intercostal or mammary blood vessels. Disruption of the intercostal vessels, especially when multiple ribs are fractured, can cause a hemothorax, but massive hemothorax from intercostal vessel injury alone is rare. When present, significant hemothorax is more likely to be from direct lung parenchymal injury.

●Diagnostic imaging – A volume of 300 mL is needed for hemothorax to manifest on an upright CXR. Ultrasound can diagnose hemothorax accurately but is operator dependent. (See "Emergency ultrasound in adults with abdominal and thoracic trauma", section on 'Pneumothorax and hemothorax'.)

●Management – A hemothorax larger than 300 to 500 mL is treated with tube thoracostomy, traditionally using a tube 28 French or larger, but some studies have found that smaller tubes (14 to 22 French) have similar efficacy, complication, and failure rates [21-23,100,101]. However, the criteria in trauma patients for selecting a smaller versus larger tube are not established, and these studies tend to exclude hemodynamically unstable patients or those requiring emergency thoracostomy; thus, larger tube size may still be preferable in the patient with significant trauma. In the hemodynamically stable blunt trauma patient, it may be reasonable to place a smaller-size tube after consultation with the trauma or thoracic surgeon. Large hemothoraces that remain undrained can compromise ventilation and may not resorb, eventually causing infection and pulmonary fibrosis. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children" and "Thoracostomy tubes and catheters: Placement techniques and complications".)

Immediate bloody drainage of ≥20 mL/kg (approximately 1500 mL) is generally considered an indication for surgical thoracotomy, as are shock and persistent, substantial bleeding (generally 200 to 300 mL/hour). Vital signs, fluid resuscitation requirements, and concomitant injuries are considered when determining the need for thoracotomy.

Small, clinically insignificant collections (less than 300 mL) in patients not on positive-pressure ventilation may be treated with expectant management or needle aspiration and drainage, instead of tube thoracostomy, at the discretion of the trauma surgeon [102-104].

Pulmonary contusion

●Mechanism of injury and clinical features – Pulmonary contusion is a common consequence of blunt chest trauma, most often occurring from high-energy motor vehicle collisions (MVCs) [105,106]. Postulated mechanisms of injury include the implosion theory, where air expansion causes alveolar tearing; the "inertia effect," which occurs when lighter alveoli are stripped from the heavier bronchi; and the "spalling effect," which involves shearing at the gas-liquid interface. Lung damage results in ventilation-perfusion inequalities and decreased lung compliance [105,107]. Pulmonary contusions generally develop over the first 24 hours and resolve in about one week.

●Diagnostic imaging – Irregular, non-lobar opacification of the pulmonary parenchyma on CXR is the diagnostic hallmark (image 11 and image 5). About one-third of the time, the contusion is not evident on initial radiographs [106]. Chest CT provides better resolution but rarely alters management unless other injuries are found, which often occur concomitantly. Contusions visualized on CT but not plain radiograph have better outcomes [108].

●Management – Pain control and pulmonary toilet are the mainstays of treatment. Prophylactic endotracheal intubation is unnecessary, but patients with hypoxia or difficulty ventilating require airway management. Fluid resuscitation with crystalloid to achieve euvolemia appears appropriate despite varying opinions. Common complications include pneumonia and acute respiratory distress syndrome. (See "Acute respiratory distress syndrome: Clinical features, diagnosis, and complications in adults" and "Acute respiratory distress syndrome: Fluid management, pharmacotherapy, and supportive care in adults".)

Tracheobronchial injury

●Epidemiology and mechanism of injury – Tracheobronchial injuries (TBIs) occur in less than 1 percent of patients with blunt thoracic trauma [109]. Most patients who sustain such injuries die at the scene [109,110]. Injury of the cervical trachea is uncommon but can occur from a direct blow, which may be of low energy; injury of the intrathoracic trachea results from high-energy trauma (generally MVCs and sometimes crush injuries). Most tracheal or bronchial injuries occur in the setting of major trauma and are accompanied by additional injuries to the lungs and chest wall. (See "Identification and management of tracheobronchial injuries due to blunt or penetrating trauma", section on 'Mechanism and location of injury'.)

●Clinical features – The sine qua non of intrathoracic TBI is a pneumothorax or pneumomediastinum that reaccumulates despite tube thoracostomy (image 12) and significant air leak in the chest tube drainage system. Intrathoracic injury can be subtle and indolent, presenting with retained secretions, recurrent pneumothoraces, and airway obstruction. TBI is often difficult to diagnose [111]. A cervical injury may present without a significant air leak if the tear or rupture is contained by the adventitia. Signs of cervical tracheal injury include dyspnea, hoarseness, and subcutaneous emphysema. (See "Identification and management of tracheobronchial injuries due to blunt or penetrating trauma", section on 'Clinical features'.)

●Diagnostic imaging – Radiographs generally reveal marked air in local soft tissue (ie, subcutaneous emphysema). If tracheal disruption occurs, the larynx can rise and the hyoid bone can ascend above the level of the third cervical vertebra [111,112]. Other radiographic findings include persistent pneumothorax with a dependent lung (image 12), interstitial air in the wall of the trachea or mainstem bronchus, abnormal location of the endotracheal tube (ETT), and a distended ETT cuff due to protrusion of the trachea. However, an isolated CXR finding of pneumomediastinum resulting in air outlining the trachea or mainstem bronchus or occult pneumomediastinum seen on CT does not correlate significantly with TBI and does not require extensive evaluation for TBI [112,113].

●Diagnosis and management – Definitive diagnosis is made in the operating room or by bronchoscopy. CT enables diagnosis of some tracheal tears, but its sensitivity is unknown [112]. If TBI is suspected, obtain a CT of the neck and chest and consult a thoracic surgeon for evaluation and possible bronchoscopy. The management of TBI is discussed separately. (See "Identification and management of tracheobronchial injuries due to blunt or penetrating trauma", section on 'Approach to management'.)

Diaphragm rupture

●Epidemiology and mechanism of injury – Diaphragm rupture is reported to occur in approximately 1 percent of blunt thoracic trauma patients and has been reported in up to 8 percent of those requiring laparotomy. While case reports exist of diaphragm rupture following minor trauma [114,115], the great majority of cases result from high-energy injuries, most often MVCs [116]. Data from studies of highway MVCs suggest that significant intrusion (≥30 cm) into the passenger compartment following head-on or near-side collisions and rapid deceleration (≥40 km/hour) increase the risk of sustaining a diaphragmatic rupture [117].

Left-sided rupture occurs approximately twice as often as right-sided rupture in blunt trauma patients [116,118,119]. Anatomic differences account for this discrepancy: the posterolateral aspect of the left hemidiaphragm is relatively weak, and the bowel and stomach provide less protection than the liver. (See "Recognition and management of diaphragmatic injury in adults", section on 'Recognition of diaphragmatic injury'.)

●Associated injuries – Most cases of diaphragm rupture have associated injuries, including spleen and liver lacerations, hemothorax, pneumothorax, rib fractures, pelvic fractures, closed head injuries, and bowel and kidney injuries. Symptoms vary and generally reflect the severity of both the diaphragm injury (eg, tear versus rupture with herniation) and associated injuries. (See "Recognition and management of diaphragmatic injury in adults", section on 'Associated injuries'.)

●Clinical features – Diaphragm injury may be associated with epigastric and abdominal pain, referred shoulder pain, shortness of breath, vomiting, dysphagia, or shock. Some patients may have no symptoms or signs to suggest an injury to the diaphragm. Some diaphragm tears, especially if small, can present years after the initial injury; over time, the negative intrathoracic pressure and the positive intra-abdominal pressure ultimately lead to herniation of viscera into the chest. (See "Recognition and management of diaphragmatic injury in adults", section on 'Clinical evaluation'.)

●Diagnostic evaluation – The initial CXR is normal or nondiagnostic in up to 50 percent of patients or may reveal diagnostic findings such as abdominal viscera in the hemithorax, a nasogastric tube in the thorax, or a focal constriction of herniated viscera at the site of the tear producing circumferential compression (collar sign). MDCT has improved our ability to diagnose diaphragmatic injury and is the test used most often for diagnosis in hemodynamically stable patients. (See "Recognition and management of diaphragmatic injury in adults", section on 'Diagnostic evaluation'.)

●Diagnosis and management – Diagnosis is easiest in left-sided injuries when the bowel enters the thoracic cavity. If the CT imaging is inconclusive, diagnostic laparoscopy or thoracoscopy can confirm the diagnosis. Diaphragm injuries are often diagnosed incidentally during laparotomy or thoracotomy to treat coexistent injuries. All left-sided diaphragm injuries and some right-sided injuries require repair. Diagnosis and management of diaphragm injuries is discussed in detail elsewhere. (See "Recognition and management of diaphragmatic injury in adults", section on 'Diagnostic evaluation' and "Recognition and management of diaphragmatic injury in adults", section on 'Management approach'.)

Esophageal injury

●Mechanism of injury – Esophageal injuries occur most commonly from penetrating trauma, but esophageal rupture can rarely occur in the blunt trauma patient. Potential mechanisms include compression, traction from cervical hyperextension, and direct penetration from thoracic fractures [112].

●Clinical features and associated injuries – Esophageal injuries can present with blood in the nasogastric aspirate, subcutaneous cervical air, or a neck hematoma. However, esophageal injuries are often associated with severe concomitant injuries that mask findings, thus delaying diagnosis until mediastinitis or an empyema develops [112,120-124].

●Diagnostic evaluation – Plain radiograph may reveal pneumomediastinum, pleural effusion, mediastinal contour changes, or a gas bubble in the nasogastric tube or esophagus. CT may show subtle air leaks beside the site of perforation, although the sensitivity and specificity of such findings are unclear [112]. Diagnosis is made by endoscopy or esophagography using water-soluble contrast [112,125,126]. Diagnosis and management of esophageal rupture is discussed in greater detail elsewhere. (See "Overview of esophageal injury due to blunt or penetrating trauma in adults".)

Chest wall injury — The following chest wall injuries are discussed in more detail in other topics:

●Sternal fracture – These result from a high-energy direct blow to the anterior chest wall. Associated injuries include cranial injury (including intracranial hemorrhage), rib fracture, pulmonary contusion, spinal fracture, retrosternal hematoma, pneumothorax and hemothorax, extremity injuries, hemopericardium, cardiac contusion, and aortic tear [127]. We perform a contrast-enhanced CT of the chest and an ECG to rule out associated injuries if a sternal fracture is diagnosed on radiograph or ultrasound. (See "Initial evaluation and management of chest wall trauma in adults", section on 'Sternal fractures'.)

●Scapula fractures – Significant force is needed to fracture a scapula; such fractures are therefore often associated with other injuries such as clavicle fractures, rib fractures, spine fractures, spleen and liver injuries, and tibial fractures (usually in pedestrians struck by motor vehicles) [128]. Scapula fracture may also be associated with BAI, although the incidence is probably lower than historically described [129]. We obtain a contrast-enhanced chest CT in most patients with a scapula fracture following significant blunt chest trauma because of the forces involved and the risk of concomitant injury [130]. (See "Initial evaluation and management of chest wall trauma in adults", section on 'Scapula fracture'.)

●Rib fractures – Rib fractures can be diagnosed by ultrasound, plain radiographs, or CT scan. However, the main goal of obtaining chest radiographs is to look for a pneumothorax, hemothorax, or other signs of intrathoracic injury since nondisplaced rib fractures are often not visualized. Patients, particularly older adults, with multiple rib fractures or displaced rib fractures may need admission due to the increased risk of potentially dangerous complications (eg, pulmonary contusion). The diagnosis, management, and disposition of patients with isolated rib fractures are discussed in greater detail separately. (See "Initial evaluation and management of rib fractures" and "Inpatient management of traumatic rib fractures and flail chest in adults".)

●Flail chest – When three or more adjacent ribs are each fractured in two places, the result is an unstable section of chest wall. This floating segment moves in the opposite direction of the uninjured, normal-functioning chest wall with breathing (ie, exhibits paradoxical motion) (figure 10). This injury is associated with significant morbidity from pulmonary contusion. Management involves support of oxygenation and ventilation as needed. Flail chest and its management is discussed in greater detail elsewhere. (See "Initial evaluation and management of chest wall trauma in adults", section on 'Flail chest' and "Inpatient management of traumatic rib fractures and flail chest in adults".)

●Sternoclavicular dislocation – Although uncommon, posterior sternoclavicular joint dislocations can cause significant internal injury such as tracheal compression, subclavian or brachiocephalic vessel laceration or occlusion, pneumothorax, or laryngeal nerve injury (which may present as hoarseness). Therefore, a contrast-enhanced CT of the chest is performed to look for associated injuries [131,132]. The management of sternoclavicular dislocation is discussed in greater detail elsewhere. (See "Initial evaluation and management of chest wall trauma in adults", section on 'Sternoclavicular dislocation'.)

●Thoracic spine fractures – Thoracic spine fractures most commonly occur after an MVC, a fall from a height, or penetrating trauma, including gunshot wounds. Clinical features include back pain, midline back tenderness or step-off, and lower extremity neurologic dysfunction. Evaluation and management of these is discussed in detail elsewhere. (See "Thoracic and lumbar spinal column injury in adults: Evaluation".)

DISPOSITION — Patients without evidence of injury after appropriate evaluation may be discharged (algorithm 2). This includes patients with minimal symptoms, no apparent injury, low-risk mechanism, and no abnormal findings on posterior-anterior (PA) and lateral chest radiograph (CXR) and ECG (if either performed). In a patient with continued symptoms but negative initial evaluation, it is reasonable to observe for six to eight hours and repeat an exam or CXR.

Patients with evidence of relatively minor injuries such as contusions, strains, or some fractures may still be appropriate for discharge. Inform patients of the possibility of delayed complications (eg, pneumothorax, hemothorax), which can infrequently develop hours to days after the injury. Such patients should return to the emergency department immediately for symptoms of new or severe pain, difficulty breathing, worsening cough, generalized weakness, pallor, fever, and lightheadedness [133-136]. Prospective studies found that 10 to 12 percent of patients with thoracic injuries not warranting admission (eg, rib fractures, sternal fractures) develop a delayed complication [137-139]. It is therefore reasonable to encourage follow-up with a primary care doctor or surgeon within approximately one week. We often provide discharged patients with an incentive spirometer, educate on its proper use, and strongly encourage frequent use to prevent atelectasis and pneumonia.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General issues of trauma management in adults" and "Society guideline links: Thoracic and lumbar spine injury in adults".)

SUMMARY AND RECOMMENDATIONS

●Epidemiology – Motor vehicle collisions (MVCs) are the most common cause of major thoracic injury among emergency department patients. Direct trauma and rapid deceleration cause injury to thoracic structures. (See 'Epidemiology' above.)

●Initial management – Initial resuscitation and management follows Advanced Trauma Life Support (ATLS) principles. (See 'Initial evaluation and management' above and "Initial management of trauma in adults".)

•Airway, breathing, and circulation ("ABCs") – Assess and stabilize the patient's ABCs. If a tension pneumothorax is present, breathing may take priority over airway, and the pneumothorax should be relieved before performing tracheal intubation. (See 'Primary survey' above and 'Breathing' above.)

•Point-of-care ultrasound – As part of the primary survey, the extended focused assessment with sonography for trauma (E-FAST) assesses for pericardial tamponade, hemoperitoneum, and pneumothorax. In the unstable, hypotensive, or pulseless trauma patient, abnormal ultrasound findings should be immediately addressed. (See "Initial management of trauma in adults", section on 'Circulation' and "Emergency ultrasound in adults with abdominal and thoracic trauma", section on 'Focused Assessment with Sonography for Trauma'.)

•Cardiac tamponade – Pericardiocentesis is performed immediately in a patient with significant hypotension or signs of shock and a pericardial effusion detected by FAST ultrasound exam. (See 'Circulation' above and "Emergency pericardiocentesis", section on 'Technique overview'.)

•Role of emergency department thoracotomy – In the pulseless blunt trauma patient, emergency department thoracotomy rarely results in successful resuscitation, except in the following subset when neurologically intact survival is a possibility (see 'Role of emergency department thoracotomy' above and "Resuscitative thoracotomy: Technique", section on 'Techniques'):

-Patients who lose vital signs in the emergency department and appear to have no obvious nonsurvivable injury (eg, massive head trauma, multiple severe injuries)

-Patients with cardiac tamponade rapidly diagnosed by ultrasound, with no obvious nonsurvivable injury

●Diagnostic evaluation – A basic algorithm for the evaluation and management of blunt thoracic trauma is provided (algorithm 2).

•Decision to NOT image – The NEXUS guideline can help determine which patients can safely forego imaging (algorithm 3). (See 'When CXR is not needed (NEXUS)' above.)

•Chest radiograph (CXR) – A CXR should be obtained in all patients who have sustained blunt thoracic trauma of any significance unless the patient requires immediate surgery or warrants immediate chest computed tomography (CT). Hemodynamically stable patients with concerning abnormalities identified on CXR generally undergo chest CT. Concerning CXR findings for aortic injury include the following (see 'Abnormal CXR findings' above):

-Wide mediastinum (supine CXR >8 cm; upright CXR >6 cm)

-Obscured aortic knob; abnormal aortic contour

-Left "apical cap" (ie, pleural blood above apex of left lung)

-Large left hemothorax

-Deviation of nasogastric tube rightward

-Deviation of trachea rightward and/or left mainstem bronchus downward

-Wide left paravertebral stripe

•Chest CT – It is reasonable to obtain a chest CT in patients with concerning clinical findings (eg, severe pain or marked chest tenderness, hypoxia, dyspnea, tachypnea, altered mental status, distracting injuries) even if plain CXR is unremarkable, in patients with an abnormal plain CXR even if no obvious clinical signs of injury, in patients with high-risk mechanism, and following institutional trauma protocols. The diagnostic accuracy of CT is far greater than plain radiography for intrathoracic injury and allows for detailed evaluation of intrathoracic structures. (See 'Chest computed tomography for most patients' above.)

●Specific injuries – Common and important injuries include the following:

•Aortic injury – While 80 percent of patients who sustain blunt aortic injury (BAI) die immediately, those surviving to the hospital with contained aortic rupture require prompt diagnosis and treatment. Most patients with BAI have sustained other thoracic injuries (eg, rib fracture, pneumothorax). Multidetector CT (MDCT) of the chest with intravenous (IV) contrast has near 100 percent sensitivity and specificity for BAI. Initial management is control of blood pressure and heart rate to slow the expansion of the injury, typically with IV esmolol, and goals are approximately 100 mmHg and <100 beats per minute, respectively. Definitive management is based on the grade of BAI, the hemodynamic status of the patient, and the presence of other injuries and medical comorbidities and discussed in detail elsewhere. (See 'Aortic injury' above and "Management of blunt thoracic aortic injury".)

•Cardiac injury – Cardiac contusion, myocardial rupture, and myocardial infarction can occur and are diagnosed by ECG and echocardiography. (See 'Cardiac injury' above and "Initial evaluation and management of blunt cardiac injury".)

•Pulmonary injury – Major pulmonary injuries that require treatment include pneumothorax, hemothorax, pulmonary contusion, pulmonary parenchymal injuries, and tracheobronchial injuries. Pneumothorax is a common complication of blunt trauma, often sustained from a fractured rib, and managed with observation or tube thoracostomy based on size and symptoms. (See 'Pulmonary injury' above.)

•Diaphragm rupture – Diaphragm injuries occur less commonly in blunt than penetrating trauma and require high-injury mechanism. Diaphragm injuries are often diagnosed incidentally during laparotomy or thoracotomy to treat coexistent injuries. (See 'Diaphragm rupture' above.)

•Esophageal rupture – These occur rarely in blunt trauma; can present with bloody nasogastric aspirate, subcutaneous cervical air, and neck hematoma; and are diagnosed by endoscopy or esophagography using water-soluble contrast. (See 'Esophageal injury' above.)

•Chest wall injury – Common chest wall injuries include sternal, rib, and scapular fractures; flail chest; and sternoclavicular dislocation. Chest CT provides the most accurate diagnosis. Stabilization of the flail chest segment with manual or object pressure restricts chest wall expansion, thereby interfering with proper respiratory mechanics, and is no longer used. (See 'Chest wall injury' above.)