Brent R. King
As is the case with adult patients, in children and adolescents trauma to the chest can either be blunt or penetrating, and injures can be restricted to the chest wall or may involve deeper structures.
Blunt trauma causes most injuries in all age groups, although adolescents may be victims of penetrating (1) chest trauma.
Because infants and young children have more compliant rib cages and less well developed thoracic musculature, blunt force to the chest wall is more easily transferred to deeper structures (2). Likewise, given the patient’s smaller body mass, missile injuries can be more devastating than might be the case in older patients.
CLINICAL PRESENTATION
Children who have sustained thoracic trauma may present along a spectrum of illness. At one end are those children who appear to have no or very minor injuries and on the other end are those who are critically ill or in extremis. However, because pediatric patients have immature cognitive and verbal skills, emergency physicians must use extra care and rely more heavily upon the results of the physical examination, laboratory, and imaging studies. Additionally, as in the evaluation of any trauma patient, frequent reassessment is required in order to identify evidence of clinical deterioration or occult injuries.
The emergency physician should be alert for signs of intrathoracic injuries, including tachypnea, tachycardia, abnormal movement of the chest wall, and diminished or abnormal breath sounds. Less specific signs such as hypotension and tachycardia are associated with significant injuries, including vascular injuries within the thoracic cavity (3). External signs of trauma like “seat-belt marks” and other bruises may indicate trauma to internal organs and should prompt further investigation. As is the case with adult patients, older children and adolescents who are conscious should be directly questioned and examined for the presence of chest wall pain or tenderness.
DIFFERENTIAL DIAGNOSIS
Blunt Chest Trauma
Blunt trauma, the most common mechanism of chest injury in the pediatric age group may cause injury to the chest wall musculature and ribs, as well as injury to the lungs, heart, great vessels, or diaphragm. Trauma involving both the chest and abdomen is more common than isolated thoracic trauma, making evaluation for the presence of associated intra-abdominal injuries mandatory.
Significant bruising of the chest wall, complaints of pleuritic chest pain, local tenderness to palpation, an unusual respiratory pattern, or abnormal excursion of the chest wall, all suggest rib fracture. Traditional wisdom has long held rib fractures uncommon in pediatric patients, but recent studies suggest that they are more common than was previously suspected (3,4). Rib fractures in very young children carry two important implications. First, rib fractures, especially lateral rib fractures in babies, are often associated with child abuse (fractures occur when the child’s chest wall is squeezed or compressed by an adult) (5); and second, due to the more compliant pediatric chest wall, rib fractures may indicate that there has been a significant blunt force and the patient may have sustained pulmonary, cardiac, or intrathoracic vascular injuries.
Abnormal or absent breath sounds suggest a pulmonary contusion, pneumothorax, or a hemothorax caused by intrathoracic vascular injury (3). Tachycardia and hypotension in the presence of unilaterally decreased breath sounds suggest tension pneumothorax. This injury can also be associated with other signs of elevated intrathoracic pressure (e.g., distended neck veins). Tension pneumothorax is a life-threatening emergency requiring prompt treatment with a needle or tube thoracostomy.
On the other hand, tachycardia and hypotension in the presence of normal breath sounds imply injury to the heart or to vascular structures within the mediastinum; pericardial tamponade is the most common injury associated with these symptoms. In rare cases, direct blunt trauma to the heart can cause cardiac contusion, with potential subsequent cardiac dysrrhythmias. Commodio cordis represents a specific direct blunt injury to the heart itself that causes immediate ventricular fibrillation and cardiac arrest. It occurs most commonly among young males after a direct blow to the precordial chest region (e.g., a thrown baseball or elbow to the chest) (6).
Finally, it must be remembered that the esophagus travels through the mediastinum, so injures to mediastinal structures can also injure the esophagus. The esophagus can also be directly injured by forceful emesis, as a result of an attempted Heimlich maneuver, or when certain objects or substances are swallowed.
Penetrating Trauma
The differential diagnosis of penetrating chest injury is necessarily broad and depends on the mechanism of injury and its location. Projectile weapons, especially firearms, deliver significant force at the point of impact and beyond and can injure organs that are remote from the point where the projectile entered the body. Projectiles can be deflected by bones or other structures, and knives or other devices can lacerate tissues deeper than originally suspected upon examination of the blade. Therefore, it is safest to assume a patient with penetrating trauma has sustained injuries to multiple intrathoracic structures until evaluation proves otherwise. All of the injuries described in the section on blunt trauma can also occur as a result of penetrating trauma. Some injuries, however, like pericardial tamponade or injuries to mediastinal structures are more common after penetrating trauma (7).
ED EVALUATION
The evaluation of the child with blunt or penetrating chest trauma begins with a process familiar to most emergency physicians (8). After a patent airway is assured, the patient’s chest is auscultated to note respiratory effort and the presence or absence of normal breath sounds in both hemithoraces. While normal bilateral breath sounds do not mean that no significant injury has occurred, they do suggest that the patient can tolerate a brief period of evaluation to determine the nature and location of specific injuries. Children who do not have adequate respiratory effort require immediate assisted ventilation, followed by placement of an artificial airway. Those who are hypoxemic but have a reasonably normal respiratory effort can be managed with supplemental oxygen, pending further investigation.
The patient’s circulatory status is then addressed and life threats identified and treated. Hypotension in the presence of unilaterally decreased breath sounds implies the presence of a tension pneumothorax or a massive hemothorax. Tension pneumothorax can be associated with air hunger and decreased oxygen saturation. Hypotension is an inconsistent finding, and distended neck veins, while frequently discussed, may be present but are uncommonly found (9). Resonance with percussion of the chest wall might also be noted. On the other hand, because hemothorax is associated with significant blood loss, hypotension tends to dominate the clinical picture, but signs of respiratory distress are typically also present (9). The neck veins may not be distended and the large amount of blood in the chest cavity can result in dullness to percussion. Both findings require urgent intervention. Tension pneumothorax can be managed by immediate placement of a thoracostomy tube or can be temporarily converted to an open pneumothorax by needle thoracostomy. In younger, smaller patients, this procedure can be performed by placement of an over-the-needle plastic catheter in the second intercostal space in the mid-clavicular line or in the fourth interspace in the mid-axillary line. In larger adolescents, the mid-axillary line is preferred as it avoids the musculature of the chest wall. Longer catheters may be required in obese children.
Massive hemothorax should be managed by tube thoracostomy and by transfusion to maintain circulatory function. In the past, emphasis was placed on autotransfusion of the blood evacuated from the thoracic cavity, but recent research has called this practice into question and it is currently considered controversial (10). Patients who have significant blood draining from the thoracostomy tube are candidates for urgent operative intervention.
Open pneumothorax is another potentially life-threatening injury. Also known as a “sucking chest wound,” this injury prevents the establishment of negative intrathoracic pressure during inspiration and renders effective respiration impossible. It can be definitively treated with placement of a tube thoracostomy and closure of the chest wall defect. In the emergency department (ED), however, it is sometimes treated by placement of an occlusive dressing over the wound which is left open on one side, creating a “flutter valve” that allows air to exit the thoracic cavity during expiration but prevents air from entering during inspiration.
Victims of trauma who have signs of life during transport but become moribund within minutes of arrival at a trauma center are potential candidates for ED thoracostomy. The indications for performing ED thoracostomy in children are identical to those in adult patients. Trauma centers that care for children should have available appropriate equipment to perform this procedure.
After the primary survey is complete and the patient is stabilized, a secondary survey should be performed. The secondary survey of the chest includes a careful external examination of the anterior, posterior, and lateral aspects of the chest to identify signs of injury, auscultation of the chest in several areas, and palpation of the soft tissues and bony structures of the chest wall. Any positive findings can then be used to guide further diagnostic testing.
Pneumothorax may be suspected on the basis of decreased breath sounds or the presence of air in subcutaneous tissues. Often, however, it is identified on routine chest imaging. Since pneumothorax can be difficult to detect by clinical examination, most victims of significant blunt chest trauma and all victims of penetrating trauma must undergo routine chest radiography unless a near-immediate chest CT is being performed (1). Recently, the FAST examination (focused abdominal sonography in trauma) has become the E-FAST examination (extended FAST) with the addition of ultrasound evaluation of the upper lung fields. The absence of the normal finding of the pleural linings moving against one another (so-called lung slide or lung sliding) is indicative of pneumothorax (11). Computed tomography (CT) of the head, chest, abdomen, and pelvis in victims of major trauma has made it possible to identify virtually every significant injury, and many insignificant injuries, in a matter of minutes. CT allows the detection of even the smallest pneumothorax. However, this enhanced imaging capability comes at the price of a substantial dose of radiation. A small percentage of patients who undergo comprehensive CT scanning will later develop one of a variety of cancers as a result of this radiation exposure (see Chapter 245). As children have longer life expectancies than older patients and therefore a longer period after exposure to radiation, they are thought to be at greater risk. Consequently, many authorities recommend more judicious use of CT scanning in the pediatric population (12).
Pulmonary contusion is a common injury that is caused by a direct blow transmitted to the lung, resulting in hemorrhage, interstitial edema, alveolar collapse, and consolidation (3,13). Although evidence of chest wall injury may be minimal or absent, a pulmonary contusion should be suspected when there is history of a likely mechanism and the presence of hypoxemia or rib fracture (1,3). Pulmonary contusion may not be visualized on the initial chest x-ray, but may be visible on subsequent films, usually within 6 hours of the injury. The radiographic appearance is that of an opacified lung segment (13). If a patient has unexplained respiratory distress after blunt trauma, a CT may be indicated since it is more sensitive than plain films for identification of pulmonary contusion (13).
Hemothorax is usually the result of injury to an intrathoracic blood vessel or to the lung tissue itself. Hemothorax is suspected when the patient has deceased breath sounds, evidence of hypovolemia, respiratory compromise, or dullness to percussion on the affected side (8,9). External evidence of injury to the chest wall should also raise clinical suspicion. In many cases, however, hemothorax will be identified on routine chest radiograph or will be seen when the diaphragm is visualized on E-FAST scanning. Most hemothoraces require evacuation with a thoracostomy tube. In the past, authorities have advocated the use of large-bore tubes to insure adequate drainage, but more recent literature suggests that this is not as important as was once thought (14). Persistent drainage of blood from the chest tube (>100 mL/hr or >20% of the child’s blood volume) is an indication for surgical intervention.
Direct injury to the heart and mediastinal structures can occur with either blunt or penetrating trauma. Missile injuries or stab wounds in any part of the thorax can involve the heart and much of the chest and abdomen as well. Blunt trauma to the anterior chest can also involve the heart and the great vessels. Bruising and tenderness of the anterior chest wall, distant or muffled heart sounds, especially when accompanied by unexplained hypotension, or diminished pulses should all raise suspicion for an injury to the heart (8). Although some cardiac injuries (e.g., pericardial effusion) might be suspected based upon the findings of a routine chest x-ray, the test of choice for the urgent evaluation of the heart is bedside ultrasonography. The four-chamber subxyphoid (sometimes called “subcostal”) view of the heart is a routine part of the E-FAST examination. This study can quickly identify the presence of a pericardial effusion with or without tamponade physiology and also allows for the rapid assessment of cardiac activity and the adequacy of ventricular function. Pericardial tamponade, which can be identified by the presence of right ventricular diastolic collapse on ultrasound, is a life-threatening emergency that requires urgent operative intervention or the performance of bedside emergency pericardiocentesis (15).
Cardiac contusion is a much rarer condition that can occur as a result of a forceful, direct blow to the anterior chest. Patients with myocardial contusion may present with dysrhythmias, unexplained hypotension, or elevation of cardiac-specific enzymes (8,16). Two-dimensional echocardiography is essential for inspection of the valves, the pericardial space, and ventricular wall motion (1,16). Treatment of children with serious myocardial contusion should follow the same guidelines as for acute myocardial infarction in adults (16). In most cases, injuries are not serious and management is usually supportive, including continuous monitoring for rhythm disturbance and hypotension (1,16).
Injury to other mediastinal structures, most notably the aorta and the esophagus, are uncommon in children and adolescents but can occur as a result of significant blunt trauma or penetrating injuries. Signs of aortic injury include paraplegia, upper extremity hypertension, diminished pulses in the lower extremities, or hypotension. A widened mediastinum, sternal fracture, or first-rib fracture may be noted on plain chest x-ray (1). Victims of significant blunt and penetrating trauma will, however, very often undergo CT scanning of their chests. Contrast-enhanced CT identifies almost all significant aortic injuries.
KEY TESTING
• Plain chest radiography for most patients
• Bedside ultrasound to identify the presence of pneumothorax or pericardial tamponade in patients with hypotension, decreased or abnormal breath sounds, muffled heart sounds, or cardiac arrhythmias
• Electrocardiogram performed and cardiac enzymes measured in patients with arrhythmias after blunt chest trauma
• CT should be considered in patients suspected of having significant intrathoracic injuries and should be considered the test of choice for suspected thoracic aortic injury
• Patients with significant blood loss and those requiring large-volume transfusion should have a prompt type and cross match for blood products and should have their coagulation parameters measured
ED MANAGEMENT
The ED management of children and adolescents who are victims of chest trauma largely depends upon the findings identified during the initial clinical evaluation and testing. Some patients will be found to have sustained only minor injuries and can be treated with analgesia and local wound care. Other patients will require near-immediate transfer to the operating room for life-saving interventions. However, many patients will require some intervention or observation by the emergency physician. Patients with life-threatening injuries resulting in respiratory compromise, tension pneumothorax, massive hemothorax, or pericardial tamponade require urgent management as previously described. Hypoxemic patients should receive supplemental oxygen but the routine administration of oxygen to all patients has recently been discouraged (17). Likewise, patients with hypotension should receive fluid resuscitation and, if needed, blood and blood products (8,18). Fluid administration is not a substitute for identification and treatment of injuries, however, nor is it appropriate for hemodynamically stable children.
Rarely, patients with blunt chest trauma may have potentially dangerous dysrhythmias which require antidysrhythmic agents or electrical cardioversion.
As previously noted, ED thoracostomy is only likely to be effective if it is performed in a setting where appropriate resources are available for definitive management of the patient’s injuries, and then only in selected patients.
Patients with isolated penetrating injuries, such as stab wounds, will require initial evaluation by chest x-ray, ultrasound, or CT. In the absence of pneumothorax or other significant injury, older patients can be observed for a period of 4 to 6 hours. If they remain clinically stable during observation and repeat chest imaging fails to identify the presence of a pneumothorax or other injury, they can often be discharged from the ED with precautions or transferred to an observation setting for continued monitoring (19). Younger children should most often be placed in an observation setting or admitted to the hospital after such injuries, and especially so if the mechanism is unclear or if abuse is suspected.
Patients with pneumothorax require one of three types of treatment. Those with minor pneumothorax may be initially managed with inspiration of 100% oxygen and observation, without placement of a thoracostomy tube. In some cases no other treatment is needed. Those with larger pneumothorax who are clinically stable may be good candidates for the placement of a small-bore thoracostomy tube attached to a Heimlich valve. The Heimlich valve allows gas from the chest cavity to exit but does not allow gas from the external environment to re-enter the chest. These devices offer several advantages. They are smaller and can be placed over a guide wire with less discomfort than might be experienced during the placement of a thoracostomy tube. They leave a much smaller scar, which may be important for cosmetic purposes. Stable patients can ambulate with the device in place. Finally, if suction is deemed to be necessary for complete evacuation of the pneumothorax, these catheters can accommodate standard thoracostomy suction devices (20). Many patients will not be appropriate candidates for either observation or placement of a Heimlich valve, and should be treated with an appropriate thoracostomy tube.
Pulmonary contusions should be addressed with great caution. Hypoxemic patients should receive supplemental oxygen in the ED. More importantly, however, the emergency physician should recognize that although a pulmonary contusion might appear relatively minor on initial presentation, these injuries can evolve over time and eventuate in respiratory compromise. Thus, most, if not all, of these patients should be admitted to a monitoring setting (1,4,13).
CRITICAL INTERVENTIONS
• Prompt recognition of the physiologically stable versus physiologically unstable patient.
• In patients with inadequate respiratory effort or who are hypoxemic despite the administration of supplemental oxygen, establish an artificial airway and insure adequate ventilation and oxygenation.
• Immediately treat tension pneumothorax with a needle or tube thoracostomy.
• In patients suspected of having a pneumothorax or pericardial tamponade perform a bedside ultrasound to evaluate the pleura and the pericardium.
• For patients with massive hemothorax and other causes of intrathoracic hemorrhage, employ balanced resuscitation using blood component therapy after one or two initial boluses of crystalloids.
DISPOSITION
Just as the nature and extent of the patient’s injuries dictate her or his ED management, these factors also determine the appropriate disposition. Children who have been found to have not been injured or to have sustained only minor injuries can be safely discharged with the usual caveat that they must remain under the care of reliable adults who can bring them back for further attention should they have an unexpected change in their condition.
Many injured children not require operative or other intervention but have findings that warrant admission to an inpatient unit or an observation setting. Examples include children with minor pneumothorax or pulmonary contusion. Adolescents with fractures of one or two ribs (except those with fractures of the first, second, or third rib) may be safely discharged in the absence of other findings, but patients with multiple rib fractures warrant observation. Rib fractures in younger children suggest that significant blunt trauma was delivered to the chest wall. Such patients should usually be placed in an observation setting or admitted to the hospital. Patients with a flail chest should be admitted to an intensive care unit for close monitoring. Likewise, all children whose injuries are more serious or whose condition has the potential to become worse should be admitted to a monitored setting.
Children with ongoing hemorrhage and those with serious pulmonary, cardiac, diaphragmatic, or mediastinal injuries may require operative intervention and if so, should be taken directly to the operating room or admitted to an intensive care unit pending surgery.
In many cases, an injured child requires resources that are not available at the treating facility. Such children should be transferred to a pediatric trauma center. Ideally, such transfers should occur once the patient has been stabilized, but even if it is not possible to completely stabilize the patient, the benefits of transfer often outweigh the risks. Once the referring center has reached the limits of its capability, transfer is in the patient’s best interest (8). When available, a dedicated pediatric transport team should be deployed to effect the transfer in a timely fashion. Referring physicians should also consider consultation with specialists at the trauma center (via telephone or telemedicine link) prior to transfer.
One special population of children bears mention. When the emergency physician suspects that a child’s injuries have been intentionally inflicted or are the result of caretaker neglect, he or she has a duty to report these suspicions to the appropriate authorities and should not discharge the patient until cleared to do so.
Common Pitfalls
• Failure to recognize that chest injury in children may occur with little or no external findings.
• Failure to understand that seemingly minor pulmonary contusions can worsen over time, leading to significant respiratory compromise.
• Failure to promptly recognize hemodynamic instability in children.
• Failure to recognize evidence of child abuse.
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