Continuing Education Activity

Chest injuries account for nearly one-fourth of all trauma-related mortality, second only to head and neck injuries. They often require rapid intervention and stabilization, whether they are from penetrating (i.e., gunshots, lacerations, punctures) or blunt (i.e., motor vehicle accidents, falls, crush injury, blasts, burns) trauma. In the setting of acute trauma, the aim of an emergency medical service (EMS) system is to minimize the time between injury and medical care. This activity reviews the pathophysiology of chest injuries and highlights the role of the interprofessional team in its management.

Objectives:

• Review the evaluation of a patient with chest injuries.
• Summarize the treatment of chest injuries.
• Describe the role of ultrasound in evaluating chest injuries.
• Explain the importance of improving care coordination among interprofessional team members to improve outcomes for patients affected by chest injuries.

Introduction

Chest injuries account for nearly one-fourth of all trauma-related mortality, second only to head and neck injuries. They often require rapid intervention and stabilization, whether they are from penetrating (i.e., gunshots, lacerations, punctures) or blunt (i.e., motor vehicle accidents, falls, crush injury, blasts, burns) trauma. In the setting of acute trauma, the aim of an emergency medical service (EMS) system is to minimize the time between injury and medical care. Specific actions vary slightly between different systems, but the overall approaches are similar and relate to the general principles of the advanced trauma life support (ATLS) protocol.[1][2]

Given the breadth and potential severity of chest trauma sequelae, rapid transport to a receiving hospital is of critical importance. Immediate interventions are occasionally necessary, but minimizing time on the scene should be a high priority of EMS providers as the evidence suggests better patient outcomes when invasive procedures are performed in-hospital as opposed to out-of-hospital.

Prehospital management often depends on the level of service of the transporting team; in the United States, this consists of basic life support (BLS) and advanced life support (ALS). Basic interventions include non-invasive airway management, cardiopulmonary resuscitation and defibrillation, hemorrhage control, spine immobilization, and splinting/stabilization of extremity fractures. More advanced techniques include advanced airway interventions (including endotracheal intubation), administration of select medications, cardiac monitoring, and needle decompression. Availability of transport services, as well as the capabilities of destination hospitals, vary greatly throughout different geographic settings, and special considerations must be taken based on local resources and facilities.[3]

Etiology

The primary mechanisms of traumatic chest injuries can be broken down into penetrating (i.e., gunshots, lacerations, punctures) or blunt (i.e., motor vehicle accidents, falls, crush injury, blasts, burns). The list of potential sequelae of penetrating or blunt trauma is extensive, including tension pneumothorax, open pneumothorax, hemothorax, flail chest, pericardial effusion, cardiac tamponade, aortic rupture, tracheal or bronchial tree injury, myocardial contusion, pulmonary contusion, diaphragmatic rupture, esophageal rupture, and more.[4]

Epidemiology

Chest wall injuries make up 14% of blunt trauma and 12% of penetrating trauma; however, they account for up to 25% of all trauma-related mortality.[4]

History and Physical

EMS providers may receive some information from dispatch about a 911 call prior to arriving on the scene, but this is often inaccurate or incomplete. A history and physical by providers is essential to determine appropriate treatment and transport destination. Many factors including severity of distress and scene safety will play a specific role in determining the depth into which EMS providers will be able to go, but ideally, a basic story of inciting events, overall timeline, and patient medical history are obtainable. If a patient is incapacitated, family members or other witnesses may be able to provide some third-party accounts. The physical exam is arguably more important than history, especially in cases where the victim is unable to speak to the providers themselves and will be discussed further in the following section. Specific things to note on scene that may be beneficial to in-hospital providers later on include amount of blood loss (in cases of gunshot wounds, stab wounds, amputations, etc.), extraction times (in cases of motor vehicle accidents or structural collapse), and any changes in patient mental status or vital signs while on route.

Evaluation

When caring for a trauma victim, EMS providers have three critical tasks: physical examination and recognition of injuries, stabilization, and transportation to a nearby trauma center or another hospital. The primary survey follows the “ABC” dogma: airway, breathing, and circulation. An issue with any of these categories requires resolution before progression to the secondary survey. These considerations remain the same regardless of whether the patient has an apparent or distracting traumatic injury.

Airway

Assessment and stabilization of the airway should always be a priority in the management of trauma patients. A preliminary impression is ascertainable from the patient’s appearance and verbalization. However, it can become more complicated if the patient has a decreased mental status or injury to the head or neck regions. Cervical spine precautions are imperative, and there should be a low threshold for immobilization and placement of a cervical spine collar. Necessary airway interventions include jaw thrust maneuvers, oropharyngeal or nasopharyngeal airways, suctioning, and supplemental oxygen via nasal cannula or non-rebreather facemask. Further airway control may involve temporizing measures (supraglottic airway) or more definitive ones (endotracheal intubation).

Breathing

The patient’s respiratory status is assessed immediately following (or often simultaneous with) the airway assessment. Fundamental evaluation of respiratory rate, chest wall movement, breath sounds, and oxygenation are useful in determining whether immediate intervention is necessary. In particular, providers may look for signs or symptoms of tension or open pneumothoraces, as well as, flail chest.

Circulation

An assessment of circulatory system status is of particular importance in cases of chest trauma, as hemodynamic compromise can be rapid and profound. Cardiac monitoring, examination for signs of internal or external bleeding, and application of direct pressure and/or tourniquet if indicated are all critical steps. IV or IO (intraosseous) access for fluid bolus may be obtained en route, but should not delay transport considerations. Similarly, cardiac monitoring and a 12-lead ECG may be helpful in cases of chest trauma, but should not come at the expense of timely delivery to the hospital.[5]

Other Considerations

There are several considerations unique to the prehospital setting for which EMS must take into account. One is an assessment for and establishment of scene safety. EMS providers practice in a diverse range of environments, from cramped personal living quarters to widespread disaster areas.  Each poses unique threats to both patient and EMS personnel safety. Although they have an innate inclination to help the victim, providers must recognize that their personal well-being is imperative to be able to help others. Precautions must be taken early to minimize the risk to providers during their treatment of victims. Additionally, environments often change rapidly, and recommendations are for periodic reassessment of scene safety whenever possible.[3]

EMS providers also encounter circumstances in which there are several injured individuals. Thus they must rely on their clinical assessment and knowledge of their system’s established set of triage criteria to distribute resources appropriately and provide each victim with the proper setting and in the appropriate order. Different systems have a variety of triage protocols available, and such protocols are continually being reviewed and refined. 

Ultrasound Use in Pre-Hospital Setting

Though far from universal, the use of ultrasound (US) devices imaging of trauma in the prehospital setting has been explored in Europe and parts of the United States. The benefits of US use include increased diagnostic accuracy and improved decision-making (i.e., triage, choice of transport modality, receiving facility). Regarding chest trauma specifically, US can aid in a quicker and more reliable diagnosis of pneumothorax, pericardial effusion, and more. However, additional research is necessary to determine if the prehospital US is truly helpful in decreasing morbidity and mortality in trauma patients.[6]

Treatment / Management

Numerous potential complicating diagnoses can result from chest trauma, and some require more emergent interventions than others. As addressed earlier, issues that arise while conducting the “ABC” evaluation require an immediate response in real-time before continuing with the remaining assessments. Some pathologies indicate a “load and go” approach, in which case the focus should be rapid non-invasive intervention and timely transport to a definitive health care facility.

Tension Pneumothorax is the progressive accumulation of air within the thoracic cavity, creating positive pressure within the pleural space. This pressure exerts itself on the mediastinal and intrathoracic structures. The creation of a one-way valve allows air to enter the thoracic cavity, but not to exit. An increase in the volume of air leads to increased thoracic pressure, causing the ipsilateral lung to collapse and the contralateral lung to be compressed. The mediastinum shifts away from the lung so affected and venous return to the heart decreases. If not corrected, this can progress to obstructive shock and ultimately may lead to death.

Signs and symptoms that might suggest tension pneumothorax include hypoxia, tachycardia, tachypnea, hypotension, tracheal deviation away from the injured side; reduced breath sounds on the injured side, hyper-resonance, hyper-expansion, and reduced thoracic wall movements.

Following the diagnosis, management by the EMS provider engages in needle decompression of the tension pneumothorax. Insertion of a 14-gauge needle, typically in the second intercostal space in the mid-clavicular line of the affected side, provides an escape route for the build-up of air and pressure. Although the success rate for this procedure varies, as the cannula can become obstructed by blood or tissue. It may become lodged within the muscle, and serve as a temporizing measure in an otherwise crashing patient; this can provide a stop-gap measure before more definitive management employing the insertion of an intercostal catheter (i.e., pigtail catheter, chest tube thoracostomy) can be performed in the hospital.[7][8]

Open Pneumothorax presents similar to and often precludes tension pneumothorax. It involves an open chest wound that communicates with the pleural space. Air rushes in through this “sucking” chest wound during inspiration but greatly limits the amount of air that can escape on expiration. Signs and symptoms are like that of a simple or tension pneumothorax. Interventions must take place to prevent rapid progression to more severe pathology. EMS providers can apply an occlusive dressing, consisting of a non-permeable cover that is sealed tightly on three out of four sides, which reduces air entry during inspiration and allows for more air to escape during expiration. Again, this is a temporary measure that buys the patient time until definitive hospital management becomes available.[9] 

Flail Chest occurs when adjacent ribs have two or more fractures, creating a portion of the rib cage that detaches from the rest of the chest wall. This detached segment depresses inward on inspiration (due to negative intrathoracic pressure) and is pushed outward on expiration (due to positive intrathoracic pressure).  This process is termed “paradoxical breathing,” since it is the opposite of normal chest wall motion. Blunt forces that are strong enough to cause multiple rib fractures often cause an underlying pulmonary contusion as well. But it typically does not manifest immediately and may only be detected subsequently, by radiographic studies. In the field, EMS providers can stabilize the "flail segment" by applying manual pressure to prevent hypoventilation on route to the hospital.[10]

Other diagnoses that result from chest trauma can range from completely simple and benign to truly emergent and life-threatening conditions. EMS protocols have not yet developed specific temporary protocols for addressing some of the more severe pathologies (eg., pericardial tamponade, massive hemothorax, aortic rupture, diaphragmatic tear, esophageal injury). Hence, it is sufficient for EMS providers to stabilize the patient’s “ABCs” and then “load and go.”[11][12]

Differential Diagnosis

• Tension pneumothorax
• Open pneumothorax
• Hemothorax
• Flail chest
• Pericardial effusion
• Cardiac tamponade
• Aortic rupture
• Tracheal or bronchial tree injury
• Myocardial contusion
• Pulmonary contusion
• Diaphragmatic rupture
• Esophageal rupture

Prognosis

Chest injuries carry a relatively high morbidity and mortality rate; however, with early on-scene evaluation and stabilization, as well as effective technical interventions when necessary, patients' chances of survival are significantly improved.

Complications

Chest injuries can lead to numerous complications involving all thoracic organs, many of which require formal radiographic imaging or operative exploration to diagnose and repair.

Consultations

Guidance from the online command is helpful and should be obtained particularly with severe injuries. 

Deterrence and Patient Education

Public education about preventative measures may help to reduce the incidence of chest injuries.

Pearls and Other Issues

Prompt recognition of injuries is critical; The interventions in the prehospital setting are based only upon clinical assessment.

In a  multi-system trauma patient, first, assess for potential life-threatening thoracic injuries to intervene immediately.

The administration of IV fluid should not delay transportation to the hospital; however, it merits consideration during transport to the hospital.

Enhancing Healthcare Team Outcomes

EMS providers are the first to arrive on the scene for most out-of-hospital emergency calls. They are the first to assess and treat the patient, and their initial impressions often have a significant influence on those of the physicians, nursing triage, and other providers at the hospital to which the patient is brought. A clean transition of care is imperative to minimize delays and promote positive outcomes. Physicians, nurses, and EMS officials work together to design and optimize field protocols that best utilize the resources and skillsets of providers in the field.

Chest injuries following blunt or penetrating trauma carry a high risk for morbidity and mortality. Potential complications of such injuries are diverse, ranging from completely benign to potentially fatal. EMS providers are typically the first trained medical professionals to encounter trauma victims on the scene.  Their early assessment and stabilization are critical in the survival and prognosis for each patient.