Current Respiratory Medicine Reviews - Volume 11, Issue 1, 2015

Traumatic injury varies so widely between patients that it becomes critical to have a basis for standardizing care and quality outcome efforts. Methods to describe severity of traumatic injuries have been in evolution over the past 60 years, and have led the development of other scoring systems which now are used across all medical specialties. A variety of scoring systems have been developed, based on anatomic and/or physiologic grading. Anatomic grading has been found useful in helping determine management of abdominal injuries, but are not discrete enough to manage chest injuries on a real-time basis. However, they are vital for assessing treatment outcomes, and are the basis for quality improvement programs.

Point-of-care ultrasound is an increasingly utilized technology in the management of the acutely injured patient. Ultrasonography has demonstrated utility and improved outcomes in rapidly detecting pnemothorax, intrapericardial blood and assessing cardiac function in the hemodynamically unstable patient. Examination of the thorax incorporated into the FAST exam (termed E-FAST, or extended FAST exam) enables rapid recognition of pathology within the trauma bay, permitting earlier intervention.

Major traumatic injuries to the thorax can present significant challenges at even the most modern and well-equipped trauma centers. Additional significant challenges regarding the evaluation and management of these injuries arise in more resource-constrained environment such as the rural setting or on the battlefield during combat operations. The recent prolonged combat operations in Iraq and Afghanistan have resulted in a large body of experience and lessons learned related to combat thoracic trauma, and much of this can be applied to the civilian setting. Although advances in protective equipment and vehicles, as well as changes in the common mechanisms of wounding on the modern battlefield have impacted the incidence and severity of these injuries, they remain relatively common and carry a high morbidity and mortality. Initial evaluation and interventions should focus on identification and control of ongoing hemorrhage, rapidly determining the need for operative intervention, and then appropriate surgical decision-making including the need for an abbreviated initial damage-control procedure with more definitive repairs/reconstruction delayed until after the patient is stabilized and adequately resuscitated. Additional operational factors that must be considered and can alter management decisions include the tactical situation, the local supply and personnel situation, the need for evacuation to the next higher level of care, and the needs of other casualties in a mass casualty scenario.

Lung injury resulting from inhaled toxins continues to be associated with significant morbidity and mortality. Inhalation injury, when combined with epidermal burns, increases fluid resuscitation requirements. While cutaneous burns can be excised and grafted, pulmonary mucosa must be protected from secondary injury caused by mechanical ventilation, resuscitation, and infections to allow for host repair mechanisms. Many of the consequences of smoke inhalation result from activation of an inflammatory response with immune mediators which are not completely understood. Morbidity from smoke inhalation results from thermal injury and inhaled toxins.

Injuries to lung parenchyma are common, but in the majority of cases supportive management is sufficient. In the setting of blunt trauma, primary concerns are acute or delayed respiratory compromise including pneumonia or adult respiratory distress syndrome (ARDS). In the setting of penetrating injury, the most common indication for surgery is active hemorrhage and, less commonly, significant air leak. If surgery is required, the primary goal is to preserve as much parenchyma as possible, which is associated with improved survival.

Tracheobronchial injuries are uncommon, occuring in as few as 0.5% of patients following injury. The incidence is highest following penetrating neck and the lowest as 2% following blunt chest injury. While commonly presenting as immediately life threatening injuries, they may present in a more occult fashion with late onset of hemoptysis, recurrent pneumonia and/or “asthma.” Management must be immediately directed to securing the airway, which may require advanced bronchoscopic skills. Subsequent repair must take into account the severity of associated injuries and exact location and degree of airway disruption.

Esophageal injuries are rare after chest trauma, but trauma surgeons are often called upon to manage acute esophageal injuries. Because of the unique anatomy and in particular its posterior thoracic position, esophageal injuries whether from traumatic or non-traumatic etiologies, pose an immediate risk to survival. Operatively, for the same reasons, they are very difficult to manage. Principles include early diagnosis, aggressive drainage, preferably primary repair if possible, and a coherent plan to manage the underlying pathology.

Traumatic Diaphragmatic Injury although rare, results in high rates of mortality and morbidity if missed. Despite advances in imaging, diagnosis without the presence of a hernia remains difficult and a high index of suspicion must be maintained particularly in penetrating mechanisms of injury. Chest X-ray remains an important tool in early diagnosis. Multi-Detector Computed Tomography improves preoperative diagnosis but is not adequate to rule out smaller injuries or those without the presence of a hernia. Minimally invasive modalities allow for both the diagnosis and repair of suspected injuries in hemodynamically stable patients while avoiding the morbidity and mortality of an open approach. All diaphragmatic injuries require surgical repair. The principles of diaphragmatic injury repair are complete reduction of all abdominal contents and watertight, tension-free closure. Most injuries can be closed primarily, but more complex defects may require the use of prosthetic material or local flaps to achieve closure. Mortality remains primarily dependent on the mechanism of injury and the presence and severity of associated injuries, with little to no additional morbidity if the diaphragm injury is promptly diagnosed and treated. Missed injuries that progress to become chronic diaphragmatic hernias have the potential for high morbidity and mortality.

The most common surgical intervention following chest injury is simply tube thoracostomy. Despite the fact that it is uncommon for more complex interventions to be required acutely, the overall mortality and complication rate following chest injury is as high as 25%. Complications in the post resuscitation phase not uncommon, and surgeons managing these patients must be facile with a number of exposures and techniques, the choice of which will be affected by the patients injury mechanism, stability and the setting in which the patient is initially resuscitated.