Ross J. Fleischman
EPIDEMIOLOGY
Blunt chest trauma accounts for 25% of civilian trauma deaths.
CLINICAL FEATURES
Follow the Advanced Trauma Life Support primary survey for the initial assessment and management of airway, breathing, circulation, and disability.
Patients in respiratory distress need endotracheal intubation. Maintaining good oxygenation is especially important in head-injured patients.
Recognize tension pneumothorax and treat with needle thoracostomy (decompression) during the primary survey without waiting for radiologic confirmation.
Subclavian venous catheterization should be done on the side of suspected injury if needed.
In patients with cardiac arrest due to chest trauma, closed chest compressions are generally ineffective and may cause further damage, so it should only be undertaken while preparing for ED thoracotomy. An exception would be the patient whose cardiac arrest might be due to a direct blow to the heart with resulting arrhythmia (commotio cordis).
Evaluate for tension pneumothorax in any patient who suddenly decompensates while on mechanical ventilation.
Administer IV crystalloid fluids judiciously to avoid causing pulmonary edema. Consider early administration of blood products for patients needing resuscitation.
CHEST WALL INJURIES
CLINICAL FEATURES AND DIAGNOSIS
Examine for tracheal deviation, unequal chest rise, unequal breath sounds, and subcutaneous emphysema (suggestive of pneumothorax).
Flail chest occurs when multiple fractures of a section of ribs allow them to move paradoxically to the motion of breathing.
Fractures of the first and second ribs require a large force and raise high suspicion for other major injuries.
Multiple lower rib fractures raise suspicion for hepatic or splenic injuries.
Up to 50% of simple rib fractures are not seen on chest radiograph. The goal of diagnostic imaging is to exclude other significant thoracic injuries.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Assume that patients with subcutaneous emphysema have a pneumothorax even if not seen on chest radiograph. Insert a chest tube prior to endotracheal intubation or aeromedical transport.
Penetrating wounds should never be probed deeply.
Mark puncture wound sites with a paper clip prior to chest radiograph.
Cover open chest wounds with sterile petroleum gauze taped on three sides to allow air to exit but not enter. Place a chest tube at another site and not through the wound.
Even simple rib fractures may lead to splinting, ven-tilatory compromise, and pneumonia. Patients being discharged should receive nonsteroidal as well as opioid analgesics. Teach them to breathe deeply and perform incentive spirometry exercises.
Consider admitting patients with multiple rib fractures, medical comorbidities, or older age until they are stabilized on a regimen of pain control and pulmonary toilet. Intercostal nerve blocks and epidural anesthesia may be considered. Attempts to stabilize the chest wall with tape or binding are not recommended.
Intubation and positive pressure ventilation will stabilize a flail segment, so patients with respiratory compromise should be intubated, as should those with shock, severe head injury, preexisting pulmonary disease, fracture of eight or more ribs, other associated injuries, and age >65 years. Surgical fixation should be considered.
Assess patients with sternal fractures for cardiac injury, as described in the section on blunt cardiac trauma.
LUNG INJURIES
CLINICAL FEATURES AND DIAGNOSIS
Patients with a tension pneumothorax may have dyspnea, tachycardia, hypotension, distended neck veins, and tracheal deviation along with unequal chest rise, percussion, and breath sounds.
Supine chest radiograph is an insensitive screening tool (52%) for pneumothorax and for hemothoraces of less than 200 mL; up to 1000 mL may appear as only diffuse haziness. Lung collapse from intubation of a mainstem bronchus can have a similar appearance. Upright and expiratory views are more sensitive.
A small stab wound may develop a delayed pneumothorax. Repeat a chest radiograph after 4 to 6 hours of observation before discharging an asymptomatic patient.
Ultrasound is very sensitive for detecting pneumothorax and may be useful for diagnosing pneumothorax, hemothorax, cardiac tamponade, and intra-abdominal hemorrhage in a patient with chest trauma. Use a high-frequency linear probe to look for loss of the sliding pleura sign and absence of comet tail artifacts. A hemothorax will show fluid in the dependent portion of the pleural cavity.
CT is highly sensitive for hemothorax and pneumothorax in the stable patient.
Pulmonary contusions are direct injuries to the lung parenchyma without laceration. Hypoxia ensues as bruised lung tissue is compromised by bleeding and edema.
Seventy percent of pulmonary contusions are not visible on initial radiograph, but may appear as patchy opacities over the first 6 hours. Radiographic findings of fat embolism and aspiration pneumonia are similar, but usually appear 12 to 24 hours after injury. CT is more sensitive than radiographs.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Recognize and treat tension pneumothorax immediately without waiting for radiographs. Insert a 14-gauge, 4.5-cm over-the-needle catheter in the second intercostal space at the midclavicular line. A rush of air is confirmatory. Leave the catheter in until a chest tube is inserted.
A small pneumothorax may be treated with observation without a chest tube.
For larger pneumothoraces without hemopneumotho-rax, a 24- to 28-F (8.0- to 9.3-mm) chest tube should be inserted. If blood is suspected in the chest, a 32- to 40-F (10.7- to 13.4-mm) tube should be inserted.
Insert a chest tube in all patients with pneumothorax or presumed pneumothorax (subcutaneous emphysema) who will be intubated or transported by air.
Treat patients with hemothoraces larger than 200 to 300 mL or with ongoing bleeding with tube thoracos-tomy. Surgical exploration should be strongly considered for an immediate return of 1000 mL of blood or ongoing bleeding of 150 to 200 mL/h for 2 to 4 hours. A large blood return can be collected in a heparinized autotransfusion device.
Always confirm chest tube placement with a chest radiograph.
Initial management of pulmonary contusions includes pain control to prevent hypoventilation, avoidance of unnecessary fluids to prevent pulmonary edema, and pulmonary toilet. Positive pressure ventilation by mask may be used in a patient with normal mental status who requires limited respiratory support.
Patients with a contusion of greater than 25% of lung tissue will likely require intubation, but should not be intubated obligatorily. If intubated, positive end expiratory pressure should be used.
Diuretics can be used for pulmonary contusion if the patient is thought to be volume overloaded from excessive IV fluids. Steroids are not recommended. Admit patients to a setting where they can be closely monitored for expected deterioration.
TRACHEOBRONCHIAL INJURIES
CLINICAL FEATURES AND DIAGNOSIS
Major deceleration injuries can result in injuries to the trachea and large airways, usually within 2 cm of the carina or at the origin of lobar bronchi.
Signs of tracheobronchial injury include hemoptysis, subcutaneous emphysema in the neck, a crunching sound with the cardiac cycle (Hamman’s sign), and a massive continued air leak through a chest tube.
Mediastinal air, large pneumothorax, and a round appearance of the endotracheal tube balloon on plain radiograph or CT suggest tracheobronchial injuries.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Obtain bronchoscopy in a major trauma patient with mediastinal air or other signs of tracheobronchial injury.
DIAPHRAGMATIC INJURIES
CLINICAL FEATURES AND DIAGNOSIS
All penetrating injuries between the nipples and the umbilicus may injure the diaphragm. Left-sided injuries are more commonly diagnosed because the liver may prevent herniation of abdominal contents into the chest.
Small lacerations can be asymptomatic and allow herniation of abdominal contents into the chest weeks to months later.
Auscultate for bowel sounds in the chest.
The diagnosis is obvious if the chest radiograph reveals abdominal contents or coiling of a gastric tube within the chest.
A normal chest radiograph, CT, or upper GI series with contrast does not exclude diaphragmatic injury.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Laparotomy or laparoscopy remain the gold standards to exclude diaphragmatic injuries.
All diaphragmatic lacerations require surgical repair.
PENETRATING INJURIES TO THE HEART
CLINICAL FEATURES AND DIAGNOSIS
Suspect cardiac injury in any patient with penetrating trauma to the “cardiac box” bordered by the clavicles, xiphoid process, and nipples.
The right ventricle is the most commonly injured portion of the heart.
Accumulation of blood in the pericardium compresses the heart, preventing filling during diastole. Beck’s triad of hypotension, distended neck veins, and muffled heart tones may be seen. The diagnosis of cardiac tamponade is confirmed by bedside ultrasound.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Cardiac tamponade can be temporized in the ED by pericardiocentesis prior to definitive operative management. Pericardiocentesis is technically difficult and may result in further injury; therefore, it should only be attempted for a patient in shock with confirmed cardiac tamponade. Stable patients should have a pericardial window or thoracotomy in the operating room.
Patients in shock who do not respond to adequate fluid resuscitation and who are suspected of having a cardiac injury should undergo emergent thoracotomy.
Patients with penetrating injuries who showed signs of life in the field but subsequently became pulseless may be candidates for ED thoracotomy. ED thora-cotomy is a high-risk procedure for bloodborne pathogen exposure to staff. Potential interventions include open cardiac massage, relieving cardiac tamponade, cross-clamping the descending aorta, or repairing a myocardial laceration with staples or sutures.
BLUNT INJURIES TO THE HEART
CLINICAL FEATURES AND DIAGNOSIS
Blunt cardiac injury can lead to death from damage to cardiac structures, coronary artery injury and thrombosis, and contusion of the myocardium resulting in impaired contractility and arrhythmias.
A patient with cardiac injury may present with chest pain, tachycardia unexplained by hemorrhage, or arrhythmias.
If a patient with myocardial rupture survives to ED arrival, a “splashing mill wheel” murmur may be heard. The diagnosis is confirmed by echocardiogram and treated surgically.
ECG changes consistent with ischemia suggest coronary artery dissection or thrombosis, which are evaluated and treated by cardiac catheterization and stenting. A direct blow to the chest such as when a young athlete is struck by a hard ball can induce ventricular fibrillation cardiac arrest even without myocardial injury (commotio cordis).
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Antiarrhythmic and inotropic medications should be administered, according to Advanced Cardiac Life Support algorithms.
Bedside echocardiogram by the emergency provider should be performed as a first screen for cardiac tamponade and grossly impaired contractility.
Patients with hypotension not explained by another cause, arrhythmias, and impaired contractility should undergo further evaluation by formal echocardiography and cardiac enzymes. Transesophageal echocardiogram is three times more sensitive than transthoracic echo for blunt myocardial injury.
A normal initial echocardiogram does not rule out subsequent development of complications.
Admit patients with arrhythmias, abnormal ECG, or cardiac markers for serial cardiac enzymes and ECGs.
Admit patients with an abnormal initial ECG but no other findings of myocardial injury to a monitored setting.
Patients with normal vital signs, normal ECG, no underlying cardiac disease, and age under 55 years may be discharged home after 4 to 6 hours of normal cardiac monitoring.
PERICARDIAL INFLAMMATION SYNDROME
Patients may develop chest pain, fever, and a friction rub 2 to 4 weeks after cardiac trauma or surgery. ECG may show the diffuse ST-segment elevation of pericarditis. Pericardial and pleural effusions may be seen on echocardiography and chest radiograph.
Treat with nonsteroidal anti-inflammatory medications, such as indomethacin 25 to 50 milligrams by mouth every 6 hours.
TRAUMA TO THE GREAT VESSELS
CLINICAL FEATURES AND DIAGNOSIS
Injury to the great vessels may be caused by penetrating trauma or rapid deceleration injury.
Trauma to the major thoracic vessels is usually lethal, with 90% of those sustaining blunt aortic injury dying at the scene.
The most common site of blunt aortic injury is between the left subclavian artery and the ligamentum arteriosum. Injury to the subclavian and innominate arteries can be related to shoulder belts and fractures of the first and second ribs and proximal clavicle and can cause a unilateral radial pulse deficit.
Assess patients for subtle findings, including unequal bilateral blood pressures, diminished lower extremity pulses, chest bruits, and new murmurs.
Descending aortic injuries may cause paraplegia, mesenteric ischemia, anuria, and lower extremity ischemia if they affect flow to the relevant arteries.
Table 166-1 lists radiographic findings of great vessel injury. Chest radiograph has poor sensitivity for injury to the great vessels.
All stable patients with a mechanism concerning for great vessel injury should undergo CT angiogram with IV contrast. Conventional aortography may be used to assess injuries and guide operative planning.
Transesophageal echocardiogram is highly sensitive for aortic intimal lesions and can be done at the bedside of an unstable patient. It is contraindicated in airway compromise or suspected cervical spine injury.
With gunshot wounds, a discrepancy between the number of presumed entrance and exit wounds and bullets seen on imaging should make the provider consider entry into a vessel with embolization to another part of the body. Fuzzy appearance of a projectile on radiograph suggests an intravascular missile vibrating with blood flow.
TABLE 166-1 Radiographic Findings Suggestive of a Great Vessel Injury
EMERGENCY DEPARTMENT CARE AND DISPOSITION
A patient with no signs of life in the field requires no further resuscitative efforts. If the patient lost vital signs immediately prior to hospital arrival, then consider ED thoracotomy.
Patients with severe shock, radiographic evidence of a rapidly expanding hematoma, or large chest tube output should have emergent surgery or intravascular stenting.
Patients with multiple injuries, advanced age, or uncontrolled medical comorbidities may require stabilization before delayed repair.
Administer narcotic pain medications and sedatives to control hypertension in order to decrease shear stress on the vessel wall.
A short-acting beta-blocker, such as esmolol 50 to 300 micrograms/kg/min, may be titrated to a systolic blood pressure of 100 to 120 mm Hg and a heart rate above 60 beats/min. If bradycardia prevents further dosing of a beta-blocker, an arterial dilator such as sodium nitroprusside 0.25 to 10 micrograms/kg/min IV may be infused.
ESOPHAGEAL AND THORACIC DUCT INJURIES
CLINICAL FEATURES AND DIAGNOSIS
Penetrating, and occasionally blunt, trauma may cause injury to the thoracic esophagus.
If suspected, evaluate the patient by esophagram with water-soluble contrast. While water-soluble contrast is less likely to cause mediastinitis, a negative study should be followed by the use of barium contrast, which has a higher sensitivity for injury.
Flexible esophagoscopy is an alternative modality.
Injuries to the area of the left proximal subclavian vein may result in chylothorax, which usually is discovered as a delayed right-sided pleural effusion.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Esophageal injuries require emergent surgical repair in order to prevent mediastinitis.
Initial treatment of chylothorax is with chest tube drainage and observation.
For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed., see Chapter 258, “Pulmonary Trauma,” by Patrick H. Brunett, Lalena M. Yarris, and Arif Alper Cevik, and Chapter 259, “Cardiac Trauma,” by Christopher Ross and Theresa M. Schwab.