Trauma is usually separated into two distinct categories: penetrating and blunt trauma. Both can cause havoc on the body’s vascular, visceral, musculoskeletal, and nervous systems.

Penetrating injuries associated with thoracic trauma are typically associated with stabbings and gunshot wounds. The latter causes far more destruction because of the large amount of kinetic energy transferred to the thoracic cavity from the impact of the bullet. As a result, gunshot wounds to the thorax are diffuse and much more likely to be fatal when compared to stabbings.

Blunt injuries to the chest are far more common than penetrating injuries. The most common causes of blunt injuries are deceleration injuries (as a result of motor vehicle accidents) and crush injuries. These can range from relatively minor injuries such as rib fractures to more severe ones such as lung contusion, tracheobronchial tears, flail chest, pneumothorax, hemothorax, injuries to the great vessels, and traumatic ruptures of the esophagus or diaphragm.

Penetrating cardiac injuries often lead to immediate cardiovascular collapse, and patients rarely survive to reach the operating room. Injuries associated with penetrating cardiac trauma include pericardial tamponade, cardiac perforation, rupture of a chamber, and fistula formation.

Blunt cardiac trauma injuries include cardiac contusion (most common), pericardial ruptures, rupture of a chamber, valvular tears, coronary artery injuries, and ventricular aneurysms.

The primary complication of pericardial tamponade is a decrease in cardiac output secondary to pericardial pressure causing severe diastolic dysfunction. Unstable patients with acute pericardial tamponade present with hypotension, tachycardia, and tachypnea. The diagnosis can be made by the presence of Beck triad (hypotension, distended neck veins, and muffled heart sounds) and pulsus paradoxus; these signs can be easily missed on a hypovolemic trauma patient. Definitive diagnosis of cardiac tamponade can be made with transthoracic echocardiography. If the diagnosis of acute pericardial tamponade is made and the patient is unstable, immediate evacuation of the pericardium via a pericardiocentesis or a pericardial window is required (also see Chapter 12).

The anesthetic goal for treating acute cardiac tamponade is to maintain intrinsic sympathetic tone. These patients are extremely dependent on intrinsic sympathetic tone, and therefore, maintenance of heart rate and preload are of utmost importance. A preinduction intra-arterial catheter and large-bore intravenous access are essential. Ketamine and etomidate are considered appropriate agents for induction. A rapid sequence induction with succinylcholine or an awake intubation can be performed. If possible, preinduction sedation should be avoided. Inotropes such as epinephrine should be readily available and can be given in small doses to avoid bradycardia and hypotension. Induction should be delayed until after patient preparation and draping is completed. In the event the patient becomes hemodynamically unstable, the effusion can then be drained as quickly as possible (also see Chapter 12).

A systematic and organized approach to the assessment and management of the trauma patient has been developed by the American College of Surgeons and is taught as Advanced Trauma Life Support. Initial evaluation and management as stated by Advanced Trauma Life Support consists of five components:

The assessment of the trauma patient consists of the primary and secondary survey. The function of the primary survey is to identify and treat immediately life-threatening injuries. The life-threatening injuries associated with chest trauma are the following:

The secondary survey is a more detailed examination aimed at identifying other non-life-threatening injuries, planning further laboratory and radiographic studies, and forming a workable differential diagnosis. Examples of chest injuries identified on secondary survey are the following:

The signs and symptoms of a hemothorax include diminished breath sounds on the affected side, hemorrhagic shock, and mediastinal shift. A massive hemothorax is defined as a rapid accumulation of greater than 1,500 mL of blood in the thoracic cavity.

Hemothorax, if severe enough, can lead to hemorrhagic shock. Therefore, timely diagnosis and treatment are of utmost importance. After a chest tube is placed, if drainage of blood is greater than 1,200 mL or if drainage is greater than 200 mL per hour for over 4 hours, a thoracotomy is indicated. Alternatively, if the patient is older than 60 years, then if drainage is
greater than 100 mL per hour for over 4 hours, a thoracotomy is also indicated. If the patient does not meet these criteria but is still hemodynamically unstable or if ventilation is difficult, emergent surgery should be performed.

Pneumothoraces are categorized into three broad categories: open, closed, and tension pneumothorax. Pneumothoraces, like hemothoraces, can cause severe hypoxemia, impair venous return, and cause a severe mediastinal shift.

Open pneumothoraces are a result of penetrating wounds and allow intrathoracic pressure to equalize with atmospheric pressure. The result is introduction of outside air every time the patient takes a breath. Definitive treatment is to close the wound and placement of a chest tube.

Closed pneumothoraces can result from both blunt and penetrating trauma to the chest. It is defined as the presence of air in the pleural space. Diagnosis can be made radiographically, via a chest radiograph or computed tomography (CT), although in many trauma situations, the patients’ condition precludes obtaining a chest radiograph. In such cases, diagnosis can be made by physical examination, that is, by percussion or by diminished or absent breath sounds. In addition, a diagnosis can be made by ultrasound examination of the chest. Recent studies have suggested that using ultrasound detection of a pneumothorax can be a faster and more sensitive test than a supine chest radiograph. Treatment for a pneumothorax is the placement of a chest tube if the patient is unstable or if the pneumothorax is greater than 10% of the pleural cavity.

Tension pneumothorax is the progressive build-up of air within the pleural space that cannot escape. Essentially, it is a “one-way valve” that is exacerbated by positive pressure ventilation. This progressive build-up of air can cause a mediastinal shift, an acute rise in airway pressures, and obstruction of venous return. All of these factors can result in a sudden and dramatic cardiovascular collapse.

An occult pneumothorax is a pneumothorax that is diagnosed by CT but was not identified previously on the chest radiograph. In many cases, this type of pneumothorax is managed conservatively and resolves over time, without requiring placement of a chest tube. Frequently, a trauma patient with an occult pneumothorax will require general anesthesia and positive pressure ventilation. Whether these patients should have a chest tube placed preemptively is currently debated. For now, the decision should be made on a case-by-case basis.

When any trauma patient is placed on positive pressure ventilation, a history of a negative chest radiograph alone does not rule out the presence of an occult pneumothorax. As many as 50% of all pneumothoraces are occult, with an overall incidence of 5% in all trauma patients.

A chest radiograph revealing a widened mediastinum may indicate the presence of a thoracic aortic injury. These types of injuries are often life-threatening, necessitating immediate identification and intervention. Blunt aortic injury is associated with high-speed deceleration and
is the second leading cause of death in trauma patients, accounting for 16% of all traumarelated deaths. Open surgical repair requires a double-lumen tube, single-lung ventilation, and clamping of the proximal aorta while taking measures to protect the spinal cord. In patients with coexisting injuries, such as increased intracranial pressure, profound bleeding, or hypoxemia, this procedure may be contraindicated. These patients may be medically managed with blood pressure control until these other issues have resolved. They may also be candidates to undergo a less invasive endovascular repair, a technique that has been increasingly used over the last 20 years.

In blunt abdominal trauma, the most commonly injured organs are the spleen, liver, kidneys, and bowel. Generally, blunt abdominal trauma leads to higher mortality rates than penetrating trauma. The reason is multifactorial and includes greater difficulty in diagnosis and frequent association with other injuries, such as head injury, chest trauma, and fractures.

FAST is a rapid ultrasonography examination performed in the trauma resuscitation room. It has been used to determine the presence of fluid (blood) within the peritoneum, pericardium, and thorax. Currently, FAST is particularly helpful in the bedside examination of hemodynamically unstable blunt trauma patients. It may also have a role in some patients with penetrating trauma.

In penetrating trauma, diagnostic peritoneal lavage allows for rapid identification of a hemoperitoneum and, therefore, the discovery of an intraperitoneal injury. Peritoneal lavage is a procedure performed in the emergency room to help determine whether a patient has internal bleeding that requires an exploratory laparotomy. It is done by performing a minilaparotomy under local anesthesia. A catheter is then placed into the abdomen and is aspirated for gross blood. Aspiration of 10 mL of blood is considered a positive finding. A grossly bloody aspirate is indicative of solid or vascular injury. If less than 10 mL of blood is aspirated, then 1 L of lactated Ringer’s solution or normal saline is allowed to drain into the abdomen. The lavage fluid is then allowed to return by gravity and is sent to the laboratory for analysis. Criteria for a positive peritoneal lavage are an erythrocyte count of 100,000 per µL, a white blood cell count of 500 per µL, the presence of bile or food particles, and a fluid amylase concentration of 175 units per dL. The white blood cell level itself should not determine the need for laparotomy. The level of white blood cells also does not rise initially but requires several hours to rise. Alkaline phosphatase and amylase are contained in the small bowel and spill into the abdominal cavity after injury. These levels tend to rise early in injury. Amylase in lavage fluid has been seen as a more accurate marker than alkaline phosphatase. If the peritoneal lavage meets one or more of these criteria, the patient goes to the operating room for an exploratory laparotomy.

Peritoneal lavage was not done for two reasons. First, it is felt that all penetrating wounds to the abdomen need to be surgically explored. Second, this patient was exhibiting signs of shock and obviously needed to be sent to the operating room without delay.

Before CT and ultrasonography technologies, diagnostic peritoneal lavage was the only diagnostic test available to rapidly evaluate the abdomen for injury. Although diagnostic peritoneal lavage is highly sensitive, it can also result in false-positive results, leading to unnecessary exploratory laparotomies. CT now allows for evaluation of all intraperitoneal organs, the diaphragm, and the retroperitoneum (an area inaccessible to diagnostic peritoneal lavage) while also allowing for identification of the specific organ injured. CT should be used in the evaluation of hemodynamically stable trauma patients.

Shock is defined as the circumstance of insufficient oxygen delivery to sustain aerobic metabolism in vital cells of essential organs. Shock of all forms appears to be invariably related to inadequate tissue perfusion. The low-flow state in vital organs seems to be the final common denominator in all forms of shock.

For a working classification of shock, the following classification offered by Blalock in 1934 is still useful and functional:

Tachycardia, hypotension, cool extremities, pallor, oliguria, tachypnea, decreased capillary refill, anxiety, restlessness, and loss of consciousness are signs and symptoms of shock.

Classification of hemorrhage based on blood loss is as follows:

Class I: Blood loss of up to 15% of the blood volume: normal pulse and blood pressure

Class II: Blood loss of up to 30% of the blood volume: tachycardia, decreased urine output, and anxiety

Class III: Blood loss of up to 40% of the blood volume: marked tachycardia, hypotension, tachypnea, oliguria, and anxiety

Class IV: Blood loss of more than 40% of the blood volume: tachycardia and hypotension, tachypnea, anuria, confusion, and lethargy

The initial treatment of hemorrhagic shock is to attempt to stabilize hemodynamics by administering intravenous fluids and blood products as needed to maintain tissue perfusion and oxygen delivery. Recently, trauma centers have revised the standard approach to resuscitation for major traumatic hemorrhage requiring massive transfusion. Trauma centers have adapted the practice of initial resuscitation with hemostatic components such as plasma and platelets as well as packed red blood cells. This strategy for treating massive hemorrhage was pioneered from knowledge gained from combat hospitals in Iraq and Afghanistan. This approach involves limiting the total volume of crystalloid and replacing intravascular volume with packed red blood cells and fresh frozen plasma (FFP) in a ratio approaching 1:1. This strategy is geared to avoid the acute coagulopathy associated with major trauma and blood loss and has been shown to decrease mortality rates in combat and civilian injuries requiring massive transfusion.

Crystalloid solutions can sustain hemodynamics and deliver adequate oxygenation in healthy patients who have lost as much as 30% of their total blood volume. Still, controversy remains over the use of crystalloid versus colloid therapy for the initial therapy of hypovolemic shock.

Proponents of crystalloid therapy believe that both intravascular and interstitial fluid losses occur in hypovolemic shock and that these can be readily replaced with crystalloids. Another benefit of crystalloids is the decrease in blood viscosity, which may enhance perfusion. A particular advantage to lactated Ringer’s solution is that lactate is metabolized to bicarbonate, which may help to buffer the patient’s acidosis. Finally, in this age of medical economics, the cost of crystalloid is much less than that of colloid. Because crystalloid leaves the intravascular space and enters the interstitial space, large quantities are needed, and some fear that these quantities may lead to both pulmonary and peripheral edema, although studies have not confirmed this fear.

Proponents of colloid therapy, on the other hand, argue that much less volume of fluid is needed to counteract hypovolemic shock and that early colloid therapy can prevent the complications associated with large-volume crystalloid resuscitation such as dilutional coagulopathy, hyperchloremic acidosis, and edema. Colloids maintain the oncotic pressure and hold the interstitial fluids in the intravascular space, which is felt to possibly prevent pulmonary
edema. If leaky alveolar capillary membranes are seen within the lung, colloids may worsen pulmonary edema.

Dextran and hetastarch are synthetic polysaccharide solutions with varying mean molecular weights. Dextran 40, dextran 70, and hetastarch have all been used as volume expanders. Dextrans are relatively inexpensive, increase effective blood volume, and decrease blood viscosity. Nevertheless, their negative aspects are considerable. They impair coagulation by coating platelets, and they impair typing and crossmatching by coating red blood cells. In addition, anaphylactic reactions have been reported.