Background
Trauma accounts for up to 720,000 annual admissions, and over 6 million attendances to the emergency department in the UK. Thoracic injuries directly account for 20–25% of deaths due to trauma and contribute to 25–50% of the remaining deaths. Figures from the USA suggest that there are over 17,000 deaths per year, directly attributable to chest trauma.
Unsurprisingly, there has been a steady increase in the number of penetrating injuries presenting to hospitals. Concurrently, however, there have also been significant improvements in pre-hospital and perioperative care facilities, meaning that there are now more opportunities to save patients who, previously, would have been declared unsalvageable.
The earliest written description of thoracic injuries dates back to the Edwin Smith Surgical Papyrus in 3000 BCE. Later, Galen reported attempts to treat gladiators with chest injuries and Labeza in 1635 reported surgical removal of an arrowhead from the chest wall of a Native American. In 1814 Napoleon’s military surgeon reported various injuries to the subclavian vessels. Until the late nineteenth century most agreed with the sayings of Boerhaave that ‘all penetrating cardiac trauma is fatal’, until the German physician Rehn in 1896 performed the first successful cardiorrhaphy for a right ventricular injury sustained during a fencing match.
Mechanisms of Cardiothoracic Trauma
Cardiothoracic trauma can be broadly divided into penetrating or blunt trauma (Table 35.1). Blunt trauma encompasses crush injuries, acceleration and deceleration, blast injuries and direct blunt trauma. Penetrating injuries include gunshot wounds, stabbing and shrapnel injuries (Figures 35.1–35.3). Only 10–15% of patients with blunt trauma and 15–30% of those with penetrating trauma require surgery.
Clinical Assessment and Resuscitation
As is usual management for any trauma patient, the ABC (airway, breathing, circulation) are established, although modification of the ABC may be required in order to diagnose the extent of the injury and resuscitate the patient simultaneously.
Any patient with a compromised airway should undergo endotracheal intubation; this may prove challenging, particularly in those with suspected cervical spine injury, as their neck must be immobilised. Immediate chest decompression for a tension pneumothorax is indicated, without requiring a chest radiograph, and a sucking chest wound requires cover to allow adequate ventilation. Presence of a haemothorax requires chest drainage. Control of ongoing haemorrhage and volume resuscitation are essential to maintain an adequate circulation.
On examination of the patient, it is essential to note the exact location of the injury and, in the case of a missile injury, the entry and exit points.
An entry wound below the nipples and inferior to the scapula should be considered to be a trajectory for an injury breaching the abdominal cavity. Gunshot wounds can penetrate any region of the body and in the absence of an exit point with a definitive entry point, a retained projectile has to be considered. Besides causing direct injury, this could also have the potential to embolise within the vasculature. Cardiac injury should be considered if entry points are present anywhere between the two midclavicular lines. The commonest chambers to be injured are the right ventricle and the left ventricle.
Table 35.1 Types of cardiothoracic trauma and subsequent effects
| Penetrating | Laceration of heart, great vessels, intercostal vessels, lung parenchyma, airways, oesophagus, diaphragm |
| Blunt |
|
| Crush | Ruptured bronchus, ruptured oesophagus, cardiac and pulmonary contusion |
| Deceleration | Aortic disruption, major airway injury, diaphragmatic rupture |
| Blast | Disruption of any intrathoracic organ |
Imaging
A chest radiograph may confirm the presence of a haemothorax or pneumothorax or a chest wall injury such as fractured ribs and flail chest as well as diaphragmatic injuries. Echocardiography can provide a quick means to assess for the presence of pericardial fluid; however this is an operator dependent imaging modality and clinical signs should override an apparently negative scan. CT scanning provides definitive and rapid imaging for more subtle injuries that cannot be diagnosed by clinical examination or simpler modalities alone. The clinical stability of the critically injured patient is paramount and no imaging should take priority over management.
Specific Injuries
Chest Wall
The function of the chest wall is twofold: firstly to to provide structural and functional assistance with respiration and secondly to provide a rigid structure comprising muscles and bony skeleton to protect the intrathoracic and upper abdominal organs from external forces.
In general, the majority of injuries to the chest wall can be managed conservatively, with effective pain control, pulmonary physiotherapy and early mobilisation. Specific patterns of injuries and the age of the patient are important factors to consider, and may require specialist care. For example, multiple rib fractures in the elderly may require early fixation to aid with respiratory mechanics and avoid prolonged ventilator assistance. Early epidural analgesia should be considered in those with multiple rib fractures and certain trauma guidelines suggest that thoracic epidurals should be used in patients over the age of 65 years with four or more rib fractures
Injuries to the first and second ribs indicate a high velocity injury with significant impact force, and other associated injuries must be sought and treated. Surgical management of flail chest segments (defined as at least two fractures per rib in two or more ribs, which are therefore unable to contribute to lung expansion) have been shown to have benefits, such as reduced duration of mechanical ventilation and ICU stay, as well as lower odds of pneumonia or death.
Lung Injuries
Blunt trauma can lead to significant pulmonary contusions, air leaks and haemothorax. Penetrating trauma leads to contusions from direct trauma as well as the dissipation of kinetic energy. In general, the management for pulmonary contusions is chest tube insertion, which itself although a commonly performed procedure, is not without complications and should be undertaken by individuals with adequate training and experience.
Lung lacerations can be minor, or major, resulting in bisection of a lobe, although even if a thoracotomy is required, the majority of injuries can be managed by simple stapling or over sewing. Major injuries requiring a pneumonectomy are rare (less than 3%).
Tracheobronchial Injuries
These injuries can frequently be immediately fatal due to loss of the airway. Autopsy reports indicate that over 3% of all trauma deaths have associated tracheobronchial injuries. For those patients surviving to make it to the hospital, early suspicion and recognition of signs is key. These injuries can present with subcutaneous emphysema, pneumothorax, massive air leak once a chest tube is in situ and haemoptysis. Urgent management of the unstable patient requires immediate securing of the airway followed by diagnostic flexible bronchoscopy. Surgical repair is the treatment of choice for major lacerations, and the technique of repair should be tension free to allow for optimal healing.
Cardiac Injuries
Blunt cardiac injury occurs due to an anterior force compressing the chest. The most common mechanism is compression of the heart between the sternum and the thoracic spine, although deceleration causes injury when the heart strikes the sternum freely. Cardiac contusions can lead to dysrhythmias, valvular disruptions, myocardial infarction, myocardial rupture and tamponade. Clinical evaluation includes an ECG and an echocardiogram. Common ECG findings are a sinus tachycardia or atrial fibrillation. Echocardiography can help rule out valvular insufficiency or tamponade.
Penetrating cardiac injuries are a highly lethal entity but urgent diagnosis and appropriate treatment can save patients. As a general rule, any wounds in the ‘cardiac box’ area bounded by the midclavicular lines laterally, the clavicles superiorly and the costal margins inferiorly should raise the suspicion of cardiac injury. Stab wounds fare better than gunshot wounds and outcomes for single chamber injuries are better than when two or more chambers are affected. Although the clinical signs of tamponade (Beck’s triad) are present in 30% of cases, they are easily missed in a busy emergency department setting.
Immediate surgical intervention is recommended for penetrating injuries to the anterior chest in a clinically unstable patient who cannot wait for diagnostic imaging. Occasionally an emergency room thoracotomy may have to be undertaken to salvage a dying patient. The American College of Surgeons guidelines on emergency department thoracotomy include the following:
Precordial wound in a patient with an out of hospital cardiac arrest.
A trauma patient with cardiac arrest after arrival into the emergency department.
Penetrating cardiac injuries with a short transport time and with witnessed physiological signs of life such as a pupillary response, spontaneous ventilation, measurable blood pressure and a palpable carotid pulse, extremity movement and electrical cardiac activity.
Victims of penetrating trauma usually fare better than those of blunt trauma, and of the victims of penetrating trauma, those with stab wounds fare better than those with gunshot wounds. A generous anterior thoracotomy or bilateral anterior thoracotomies (clam shell) should be performed. Once the chest is entered, evidence of tamponade is sought and relieved, if present. Immediate indications for a thoracotomy in a case of penetrating injury with cardiac arrest are shown in Table 35.2.
Table 35.2 Indications for immediate thoracotomy
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