Chest Trauma - EMBR 2nd Edition

Educational Objectives

The Audio-Digest Emergency Medicine Board Review — Second Edition

The lecture you’ve selected is part of the Audio Digest Emergency Board Review Course. Our overall Board Review Course is designed to match the defined learning objectives of the American Board of Emergency Medicine, and it is intended to provide a source of review material for those who are preparing for the ABEM's Continuous Certification Examination and for those preparing for the ABEM’s Initial Certification Examination. The goal is to provide a comprehensive update in many aspects of emergency medicine practice that will enhance the lifelong learning experience.

Course Objectives

Upon completing this educational activity, participants will be able to:

1. Rapidly diagnose and medically respond to a wide variety of critical issues presenting in the emergency department.
2. Triage the need for medical care (as appropriate) and initiate therapeutic procedures where needed.
3. Manage patients who require continuing respiratory and cardiovascular support until stable or transitioned to other hospital care centers.
4. Determine circumstances in which hospital care beyond the emergency department is required, and initiate procedures to obtain such care.
5. Prescribe drugs as appropriate for the short term management of presenting medical problems.

After listening to this lecture and reading the accompanying summary, the clinician will be better able to:

1. Identify and treat injuries that affect airway and breathing during the primary evaluation.
2. Identify and treat cardiothoracic-related injuries during the secondary evaluation.
3. Describe indications, contraindications, and steps to emergency thoracotomy.

Summary

Thoracic trauma: 10% or less of blunt chest trauma patients require surgery; 15% to 30% of penetrating chest trauma patients require surgery; the majority require a simple intervention to secure the airway, reexpand the lungs, possibly drain the pleural space, and improve respiratory mechanics; time is of the essence; chest injuries are responsible for 1 in 4 trauma deaths, second only to head injury; the patient’s chances of survival diminish after a short period of time; thoracic trauma is significantly associated with early mortality; specific life-threatening injuries include aortic injury, cardiac injury, tamponade, or tension pneumothorax; it is also important to consider abdominal injuries associated with lower thoracic trauma; prehospital treatment can include needle decompression for a patient who has a tension pneumothorax and may be in obstructive shock, three-sided occlusive dressing for someone with an open pneumothorax, or even potentially a finger thoracostomy; start to consider which level of trauma has been sustained (eg, level 1 trauma as opposed to level 2) (eg, is there tachycardia greater than 120 bpm or blood pressure less than 80 mm Hg?; what is the mechanism of injury?; is a secure airway needed?); perform a primary survey and resuscitate essential vital signs; if patient has received fluid and needs blood, resuscitation with blood products should be started

Adjuncts to primary survey: include chest x-ray, pelvic x-ray, and potentially a focused assessment with sonography (FAST); reevaluate the patient; if the issues addressed in the primary survey are stable, move along to the secondary survey, a head-to-toe examination of the patient; perform further imaging and reevaluate; decide whether the patient needs definitive care

Primary Survey

The ABCs of trauma: A — airway with breathing protection; B — breathing and ventilation; C — circulation with hemorrhage control; D — disability and assessing the Glasgow Coma Score and neurologic status; E — exposure, with mindset to environmental control

Breathing and ventilation: most life-threatening injuries that need attention are found during the primary survey; the lungs oxygenate and ventilate; respiratory rate — tachypnea; chest movement — look for flail chest, paradoxical chest rise and fall, air entry, tracheal trauma, and laryngeal trauma; oxygen saturation — comes into play in patients who have a pneumothorax or pulmonary contusions

Identifying life-threatening thoracic injuries: must be done immediately; respiratory rate — tachypnea, respiratory distress, hypoxia, or evidence of tracheal deviation; breath sounds — when patient arrives in the trauma bay, ask for a name; if the patient can answer, the airway is patent and ventilation and oxygenation are sufficient to perfuse the brain and lungs; listen to the patient’s lungs for abnormalities; consider percussing the lungs; if lung sounds are diminished on one side relative to the other, consider whether it is dull on that side; consider the possibility of massive hemothorax; look for chest wall deformity; do not move to the next step of the primary survey until all issues requiring attention have been addressed, the first of which is airway obstruction; if airway is obstructed via neck trauma or facial trauma, manage it immediately; continue on to “B” and consider a tension or open pneumothorax; if patient has a flail chest, a chest tube or some type of splinting measure may be required; evaluate for massive hemorrhage, massive hemothorax, and cardiac tamponade; tension pneumothorax and cardiac tamponade cause obstructive shock that can lead to cardiac arrest, and therefore need to be addressed within the primary survey

Laryngotracheal injury: rare, but needs to be recognized within the primary survey; consider in a patient with a hanging or clothesline-type injury; can present with hoarseness; patient may have subcutaneous emphysema and need to be managed in the primary survey as soon as possible; patients need to be intubated cautiously and may require tracheostomy or cricothyroidotomy; the neck and the zones of the neck extend into the chest and so are relevant to chest discussion

Tension pneumothorax: clinical diagnosis; because of the mediastinal shift and collapsed lung, the heart is unable to fill and the patient goes into obstructive shock; look for respiratory distress, shock, distended neck veins, absent breath sounds, and hyperresonance; cyanosis and cardiac arrest are late signs (early recognition is crucial); treated with needle thoracotomy and a chest tube; develops when a one-way valve causes air to be forced into the pleural space, compressing the heart and lungs; important to differentiate from cardiac tamponade; more likely to result from blunt injury (whereas penetrating trauma is more likely to cause cardiac tamponade); both cause obstructive shock and both need to be addressed in a trauma patient with pulseless electrical activity (PEA); if a patient has dyspnea, hypotension, jugular venous distention or distended neck veins, and tachycardia along with absent breath sounds and tracheal deviation, an immediate decompression should be performed with needle thoracostomy in the second intercostal space at the midclavicular line

Open pneumothorax (“sucking chest wound”): caused by a defect in the chest wall greater than two-thirds the diameter of the trachea; air preferentially moves through the chest wall instead of the trachea, causing ineffective ventilation and hypoxia; treat by closing the defect with an occlusive dressing taped on three of the four sides, allowing air to escape but not enter the chest preferentially through the wound; a chest tube is then placed remote to the open injury as soon as possible (above or lateral to the wound rather than through the injury); immediate surgical consultation is indicated, as surgical repair is almost always required

Flail chest: another injury that should be recognized in the primary survey; occurs when a segment of the chest wall lacks bony continuity with the remainder of the thoracic cage, resulting in a disruption of the rise and fall and movement of the chest; the chest is unable to create negative pressure for ventilation; the patient cannot take in air through the trachea; it is usually combined with injury to the underlying lung tissue (pulmonary contusion); presentation — asymmetric chest wall movement and paradoxic breathing; palpation can reveal crepitus; perform chest x-ray or CT after clinical diagnosis is made; can be missed in the ED, especially if located in the posterior chest wall (be sure to examine the posterior wall when the trauma patient is turned over during the primary survey); treatment — consider stabilization of the segment if achievable with splinting; often, patients need to be intubated for positive-pressure ventilation; oxygen is required, and the patient may need a chest tube; consider judicious fluids; consider an intercostal nerve block; good analgesia and pain control is necessary

Massive hemothorax: diagnosis should be made during the primary survey; defined as >1500 mL of blood in the thoracic cavity immediately after chest tube placement, or 200 mL or more per hour for four hours after tube thoracostomy; clinical presentation — diagnosis based on diminished breath sounds and dullness to percussion on the involved side; consider in a patient who presents in shock; diagnostic evaluation — chest x-ray to look for effusion (more easily seen on an upright x-ray); ultrasonography is effective for diagnosis; tension pneumothorax and massive hemothorax are associated with decreased breath sounds on auscultation, but hyperresonance (versus percussion examination) can help make the diagnosis (ie, dullness suggests a massive hemothorax and hyperresonance likely represents a tension pneumothorax); treatment — chest tube (typically, 36-40-French large-bore); surgical intervention necessary because otherwise hemorrhage will continue; consider heparinized cell saver for autotransfusion, if available

Hemothorax: <1500 mL of blood within the thoracic cavity (differentiated from massive hemothorax based on the amount of blood and rate of bleeding); chest wall injury is the cause, usually a lung laceration or laceration to an intercostal vessel or the internal mammary artery secondary to penetrating or blunt trauma; treatment — tube thoracostomy, typically with a 36- or 40-French chest tube; needs to be diagnosed primarily on the primary survey (or on the chest x-ray, which is an adjunct to the primary survey)

Cardiac tamponade: cardiac injuries common in penetrating trauma to the chest; penetrating trauma can result in exsanguinating hemorrhage or tamponade; ventricles are more susceptible to injury because their location; anatomy of the chest — cardiac box is bounded by the sternal notch, the xiphoid process, and the nipples; if patient presents with a stab wound or penetrating trauma to that area of the chest, one must think about the heart as a cause of the trauma; pericardial tamponade is more common with penetrating injuries; in patients with blunt chest trauma and shock, consider tension pneumothorax; pericardial tamponade is more common with penetrating injuries; about 80% of stab wounds can develop tamponade; patients may present with PEA

Underlying causes of PEA: can include “Hs and Ts”; Hs — hypotension; hypoxia; hydrogen anions (acidosis); hypoxia and acidosis commonly resolve when the patient is intubated; often, the patient is hypoxic and becomes acidotic; can also become acidotic because of hypovolemia; start infusion of fluids and then switch to blood; Ts — tamponade; tension pneumothorax; presentation — Beck triad, which includes hypotension, distended neck veins, and muffled heart tones (when diagnosing on the basis of these signs, intervention is often late); can also look for pulsus paradoxus, which is decrease in systolic pressure >10 mm Hg with inspiration; patients may have decreased pulse pressure and Kussmaul sign (distended neck veins with inspiration); signs are difficult to appreciate in the trauma bay, especially in hypovolemic patients, but they provide cues to an obstructive etiology of shock

Diagnosis and treatment: ultrasonography can be tremendously helpful, with extended FAST (eFAST) or FAST examination to look for fluid in the pericardial sac; patients need IV fluids and/or blood, followed by pericardiocentesis; as little as 15 to 20 mL of removal of acute blood can result in immediate hemodynamic improvement; consider an emergency department thoracotomy

Aortic dissection or disruption: many patients do not undergo a primary survey because they expire before reaching the emergency department (ED); caused by a deceleration injury; often tearing or dissection at the ligamentum arteriosum, where part of the aorta is fixed and the other part is freely mobile; in about 50%, there is no evidence of chest trauma (a high index of suspicion is necessary in these patients); patients are treated by surgical repair after prevention of hypertension and tachycardia, just as one would manage an aortic dissection in a medical patient; consider titratable β-blockers (eg, esmolol), or an agent that reduces blood pressure, such as nitroprusside (not typical for treatment of trauma patients); a prompt clinical diagnosis is necessary; presentation — chest or back pain; harsh systolic murmur over the pericardium; changes in the voice in the absence of laryngeal trauma; pulse deficits or upper extremity hypertension possible; imaging — on chest x-ray, look for a widened mediastinum (>8 cm), fractures of the first and second ribs, an indistinct aortic nob, presence of an apical cap, deviation of the trachea or an NG tube (if placed), depression of the left mainstem bronchus, or loss of space between the pulmonary artery and aorta

Additional considerations: consider aortic dissection or disruption in a patient who sustained a rapid deceleration or acceleration injury (eg, fall from a high height, ejected passenger from a motorcycle or motor vehicle; surgical consultation is necessary and adjuncts to the primary survey are key, including a chest x-ray and, if patient is sufficiently stable, helical CT or aortography; helical CT is quickly becoming the optimal diagnostic evaluation for a patient who is able to undergo CT

Secondary Survey

Introduction: a complete examination of the patient, during which an ample history is obtained to determine the next steps to be taken to make the diagnosis; important in thoracic trauma; identifies potentially life-threatening injuries; injuries that must be detected in the secondary survey include tracheobronchial tree disruption, simple pneumothorax, pulmonary contusion, hemothorax, blunt cardiac injury, blunt esophageal trauma or rupture, and traumatic diaphragmatic injury

Simple pneumothorax: can occur after blunt or penetrating injury; may not be apparent on physical examination; look for ventilation or perfusion defect, hyperresonance or decreased breath sounds, and subcutaneous emphysema (often not considered); treatment — tube thoracostomy, which should be performed when the condition is recognized

Tracheobronchial tree injury: difficult to diagnose; present in only 1% to 2% of blunt trauma; requires a strong index of suspicion; consider in cases in which the lung does not properly inflate after the insertion of a chest tube, or if there is a persistent air leak after tube thoracostomy; consider also in patients with rapid deceleration injuries, much like aortic injury; 80% occur at the carina, distal trachea, or at the origin of the mainstem bronchi; often missed; can result from penetrating or blunt trauma; bronchoscopy can be a helpful adjunct but often cannot be performed in the ED; treatment — airway and ventilation, intubation if needed, insertion of a chest tube, and ultimately, surgery; presentation — look for dyspnea, dysphonia, hoarseness or subcutaneous air; consider when there is a persistent pneumothorax or an air leak despite a well-placed chest tube; additional management tips — selective intubation of the uninvolved lung may be necessary; operative repair needed for lacerations of the bronchi that involve more than one-third of the circumference

Pulmonary contusions: can occur without rib fractures or flail chest, especially in young patients without completely ossified ribs; in adults, most commonly seen with associated rib fractures; the most common potentially lethal chest injury, in part because of delays in making the diagnosis; respiratory failure is often delayed; greater than 20% contusion creates risk for deterioration; chest x-ray may be initially negative; CT is more sensitive; hypoxic patients may require intubation; a common injury; consider in patients who are hypoxic and not oxygenating well; intubation is often necessary; consider serial x-rays to help with diagnosis; most increase in size and severity after fluid resuscitation; therefore, the current trend is to avoid overly aggressive fluid resuscitation in trauma patients in favor of more judicious fluid treatment

Blunt cardiac injury: rare and difficult to diagnose; patients can present with a spectrum of injury, from asymptomatic to in cardiogenic shock; abnormal ECG and monitor changes usually occur within about 24 hours; echocardiography is necessary if the patient is hemodynamically compromised; diagnosis — requires serial troponin testing and ECG; if both are negative, cardiac contusion is unlikely; if only one is positive, the patient needs to be observed and consideration given to a structural or electrical injury; can result in myocardial muscle contusion, cardiac chamber rupture, coronary artery dissection or thrombus, or valvular disruption; patients with cardiac rupture typically present with cardiac tamponade, which would likely be diagnosed during the primary survey

Diaphragmatic injury: a significant transmission of force is required to rupture the diaphragm; consider in high-velocity, large mechanism injuries; more often left-sided; blunt injuries can cause large tears, whereas penetrating injuries can cause small perforations; frequently misinterpreted on x-rays; important to consider other imaging; elevated diaphragm on x-ray should raise suspicion for a rupture; at times, an elevated hemidiaphragm can resemble a hemothorax; if the patient is stable, obtain CT; even CT can fail to identify this injury, so a high index of suspicion is important; 1% to 6% of major thoracic trauma involve diaphragmatic injury; treatment — surgery

Rib fractures: fracture of ribs 1 to 3 requires severe force (mortality risk high with associated injuries); with ribs 4 to 9, consider pulmonary contusion and pneumothorax; in the lower ribs, (10-12), suspect intra-abdominal injury; the key to treating rib fractures is pain control; inadequate control of pain can interfere with ventilation and clearing of secretions, which can lead to atelectasis and pneumonia; in the elderly, consider admission for pain control (a single isolated rib fracture in an elderly patient may be reason for admission because of the risk for atelectasis and pneumonia); with fracture of ribs 1 or 2, consider myocardial injury, major vessel injury, and bronchial tears (with sternal fractures, there is a low risk of associated cardiac injury)

Sternal and scapular injuries: usually the result of a direct blow; pulmonary contusion and blunt cardiac injury should be considered with all of these fractures; intraoperative repair may be indicated; rarely, posterior sternoclavicular dislocation can result in a mediastinal injury and mediastinal displacement of the clavicular heads, causing superior vena cava obstruction; with severe chest injury causing posterior displacement of the heads of the clavicles, immediate reduction is required; isolated sternal fractures rarely cause injury to the underlying structures (typically do not require surgical repair); rarely diagnosed on the initial chest x-ray (more likely to be seen on CT); if a patient has a sternal injury, look for associated rib fractures, pulmonary contusion, pneumothorax, and hemothorax (sternal injury is a surrogate marker for severe force to the chest)

Traumatic asphyxia: caused by compression of the chest secondary to pressure; signs are petechiae, swelling, plethora, and cerebral edema; treatment — airway management (if needed) and oxygen

Subcutaneous emphysema: consider if a patient has crepitus, or swelling of the face or around the eyes; look for pneumothorax, tracheal injury, airway injury, and pneumomediastinum; consider in cases of blast injury or barotrauma; if positive-pressure ventilation is required, a chest tube may need to be placed on the side of the subcutaneous emphysema to ensure that a tension pneumothorax does not develop

Esophageal injury: uncommon and difficult to diagnose; can be a cause of unexplained pain or shock; radiographs may demonstrate mediastinal air; signs and symptoms can include pneumomediastinum, shock, left hemothorax, or effusion; patients require further work-up, often with contrast studies or endoscopy; early diagnosis is the key to successful treatment, as well as antibiotics and surgery; mechanism is typically a severe epigastric blow; patients should be admitted for gastrografin swallows and/or endoscopy; injury can be penetrating and present like a postemetic rupture or Boerhaave syndrome; fever is a late finding; diagnosis is very important; treatment — surgical drainage and repair

Adjuncts to the Secondary Survey

Pearls on chest trauma: with penetrating chest trauma, crystalloid fluids promote coagulopathy and should be used judiciously; administer blood products if the patient is bleeding (after 1 L of fluid, switch to blood or blood products); in patients with gunshot wounds, consider bullet trajectory; x-rays can identify injuries in unexpected locations but may also miss injuries; consider ordering x-rays of areas that do not have a bullet hole; perform right-sided thoracostomy in patients receiving left-sided thoracotomy

Imaging: eFAST is necessary; order chest x-ray and pelvic films as needed; CT of the head and cervical spine; lateral cross-film cervical spine x-rays are no longer recommended because of their low yield; consider CT of chest, abdomen, and pelvis, with spinal reconstructions for polysystem trauma; however, consider risks associated with radiation and contrast

Laboratory testing: blood type and screen are among the most important tests; if transfusion of blood is indicated, it needs to be administered quickly; O-negative blood can be given to any patient, and O-positive blood to male trauma patients; consider CBC, UA, urine toxicology screen, and blood alcohol level; in patients with possible blunt cardiac injury or elderly patients, consider ECG and chest x-ray, as well as cardiac enzymes; in cases of blunt cardiac injury or cardiac contusion, look for ECG changes and troponin “bumps”; consider LFTs, lipase, and abdominal laboratory tests for patients with lower thoracic trauma; in patients with fractures of ribs 10 to 12, incidence of associated abdominal injury is high

Resuscitative thoracotomy: consider in patients with a penetrating injury and PEA, especially when loss of signs of life are recent (5 minutes out from ED); a qualified surgeon must be present at the time of the patient’s arrival to determine the need for, and potential success of, thoracotomy; once the chest is open, the bleeding must be controlled

Blunt trauma with PEA: resuscitative thoracotomy not typically indicated; instead, perform assessment of the Hs and Ts (hypotension or hemorrhage, hypoxemia and acidosis need to be evaluated with large-bore IVs, fluid and blood, airway protection, and ventilation; tamponade and tension pneumothorax can be addressed with finger thoracotomy, needle decompression, chest tubes, and consideration of pericardiocentesis

Role of resuscitative thoracotomy: a life-saving measure for patients with arrest or who are in extremis (about to arrest), and who cannot be brought to the OR immediately

Survival rates: about 8.8% for penetrating trauma, which includes 16.8% for stab wounds and 4.3% for gunshot wounds; 10.7% in cases of thoracic injury; 19% if injury is isolated to the heart; very low in patients with multiple injuries; not performed in patients with blunt trauma because the survival rate is only about 1.4%

Goals: hemorrhage control, release of cardiac tamponade, open or internal cardiac massage, aortic cross-clamping, and repair of cardiac or pulmonary injury; extend to clamshell bilateral thoracotomy, if needed; Foley balloon tamponade can be used, as well as staples or sutures, to repair a ventricular rupture; equipment includes a chest trauma set and internal cardiac paddles, which should be available in the trauma bay

Advantages and disadvantages: pros — about 9% of patients with penetrating trauma survive; assures family, EMS, and hospital staff that everything possible was done; cons — futility (ie, survival [and meaningful survival] are questionable); possibility of injury to health-care provider (procedure often performed “frantically” under suboptimal conditions, which increases risk for, eg, needle sticks); literature indicates that about $100,000 are spent per life saved; loss of dignity at the end of the life

Readings

Disclosures

Nothing to disclose

Acknowledgements

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

EMBR170134

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.