Chapter 38 Chest Trauma

Chest trauma, whether blunt or penetrating in nature, is a significant source of morbidity and mortality in the United States. Because the chest contains major organs responsible for ventilation, oxygenation, and circulation, traumatic injuries to the chest may disrupt the body’s most vital functions. Chest injuries can affect any one or all components of the chest wall and thoracic cavity. Direct injury to bony structures alters the mechanics of ventilation, and damage to the lung parenchyma interferes with gas exchange or oxygenation. Cardiac output is adversely affected because of primary cardiac damage or dysfunction, changes in intrathoracic pressure and diminished venous return, or disruption of major vessels and massive blood loss.

The most common cause of chest trauma is motor vehicle crashes (MVCs). Acts of violence, falls, blast injuries, and pedestrian versus automobile collisions are other etiologies of chest injuries. Chest or thoracic injuries can be categorized as immediately life-threatening, potentially life-threatening, or non–life-threatening (Table 38-1).

TABLE 38-1 CLASSIFICATION OF CHEST TRAUMA

IMMEDIATELY LIFE-THREATENING CHEST INJURIES	POTENTIALLY LIFE-THREATENING CHEST INJURIES	NON–LIFE-THREATENING CHEST INJURIES
Tension pneumothorax	Aortic disruption	Simple pneumothorax
Cardiac tamponade	Blunt cardiac trauma (cardiac contusion)	Rib fracture
Open pneumothorax	Pulmonary contusion	Sternal fracture
Massive hemothorax	Tracheobronchial disruption	Clavicular fracture
Flail chest	Diaphragmatic tear	Scapular fracture
	Esophageal disruption

In any trauma patient, rapid initial assessment and identification and treatment of life-threatening conditions are immediate priorities; many life-threatening conditions are a result of chest trauma. Table 38-2 lists some abnormal findings on initial assessment and the life-threatening conditions to be considered and ruled out. See Chapter 35, Assessment and Stabilization of the Trauma Patient, for a detailed discussion of the approach used with any trauma victim.

TABLE 38-2 ABNORMAL ASSESSMENT FINDINGS RELATED TO LIFE-THREATENING CHEST INJURIES

ASSESSMENT FINDING	POSSIBLE INJURY OR CAUSE
Breathing
Unequal breath sounds, unequal chest expansion	Pneumothorax
	Hemothorax
	Foreign body obstruction
	Misplacement of endotracheal tube
	Tension pneumothorax
Paradoxical chest movement	Flail chest
Chest wall wound	Open (“sucking”) chest wound
Subcutaneous air	Tracheobronchial disruption
Bowel sounds auscultated in chest	Ruptured diaphragm
Circulation
Signs of shock • Poor skin perfusion • Altered level of consciousness • Tachycardia • Hypotension	Massive hemothorax
	Tension pneumothorax
	Aortic disruption
	Cardiac tamponade
Muffled heart sounds	Cardiac tamponade
Jugular venous distension, elevated central venous pressure	Cardiac tamponade
Jugular venous distension, elevated central venous pressure	Tension pneumothorax
Difference in blood pressure in arms	Incomplete aortic transection

Immediately Life-Threatening Chest Injuries

Tension Pneumothorax

Tension pneumothorax occurs when air enters the pleural space during inspiration and is unable to escape during exhalation. Air accumulates in the thoracic cavity causing life-threatening hemodynamic compromise. The increasing intrathoracic pressure initially causes collapse of the lung on the injured side. As pressure from the accumulating air continues to rise, the opposite lung collapses and the mediastinum shifts, compressing the heart and great vessels. Venous return, and thus cardiac output, is markedly decreased. Immediate intervention is needed.

Tension pneumothorax is caused by blunt or penetrating trauma or is a complication of mechanical ventilation. A patient with a small pneumothorax may develop a tension pneumothorax shortly after positive pressure ventilation, with either bag-mask or mechanical ventilator, has been initiated.

Signs and Symptoms

• Severe respiratory distress: dyspnea, restlessness, and tachypnea

• Signs of decreasing cardiac output: tachycardia, hypotension, poor peripheral perfusion, cyanosis, and restlessness

• Jugular vein distension because of mediastinal shift and “kinking” of the great vessels

• Deviated trachea, away from the affected side (points to the “good” lung) and possible mediastinal deviation

• Hyperresonance with percussion of chest wall on affected side

• Distant heart sounds

• Symptoms such as jugular vein distension, tracheal shift and cyanosis will become increasingly worse as the condition worsens, and the patient may show signs of continued hypoxic deterioration such as decreasing levels of consciousness.

Diagnostic Procedures

• Clinical findings may indicate need for needle decompression (see “Therapeutic Interventions” below) of the affected lung before performing specific diagnostic procedures, such as a chest radiograph

• Chest radiograph: tracheal deviation and mediastinal shift may be evident (Fig. 38-1)

Fig. 38-1 Tension pneumothorax seen in intubated patient.

(From Marx, J., Hockberger, R., & Walls, R. [Eds.]. [2009]. Rosen’s emergency medicine [7th ed.]. St. Louis, MO: Mosby.)

Do not delay needle decompression of a clinically evident tension pneumothorax to obtain a confirming chest radiograph.

Therapeutic Interventions

• Support the patient’s airway, breathing, and circulation; administer supplemental oxygen.

• Perform immediate needle decompression if severe hemodynamic compromise is present.

• Use 14- or 16-gauge over-the-needle catheter, 3 to 6 cm in length (18- or 20-gauge for pediatric patient).

• Insert needle just above the third rib into the second intercostal space (ICS), midclavicular line, on the affected side.

• Air under pressure will be released. Remove needle stylet, leaving the catheter in place until chest tube can be inserted. Connect to Heimlich flutter valve if unable to insert chest tube immediately.

• Prepare for immediate chest tube insertion.

• Provide pain control.

Cardiac Tamponade

Cardiac tamponade is the collection of blood or blood clots in the pericardial sac; the accumulating blood exerts pressure on the heart, limiting ventricular filling and decreasing cardiac output. The decrease in cardiac function is directly related to both rate and amount of fluid accumulation. If accumulation is rapid, as little as 100 to 150 mL of blood in the pericardial sac can adversely affect cardiac output. The leading cause of cardiac tamponade is penetrating chest injuries (80% to 90%) such as stab wounds.¹

(From Davis, J. H., Foster, R. S., & Gamelli, R. L. [1991]. Essentials of clinical surgery. St. Louis, MO: Mosby.)

Open Pneumothorax

If a penetrating chest wound communicates with the plural space, room air enters the thorax and normal negative intrathoracic pressure is lost. As with a closed pneumothorax, the lung on the affected side collapses. Air continues to enter and exit the chest cavity through the wound as the patient breathes, producing a “sucking” sound. If the chest wound is approximately two thirds the diameter of the trachea, air may preferentially enter the plural space with inspiration rather than via the patient’s upper airways. This situation results in severe hypoxia and hypercapnea.³

Signs and Symptoms

• History of penetrating chest trauma; visible chest wound (may be as small as an ice pick hole)

• Signs of respiratory distress: dyspnea, tachypnea, restlessness, and cyanosis

• “Sucking” sound heard with respiration

• Asymmetric chest expansion (Fig. 38-3)

• Bubbling of blood around a chest wound with exhalation. Subcutaneous emphysema may also develop

Fig. 38-3 Open pneumothorax.

(From Marx, J. A., Hockberger, R. S., & Walls, R. M. [Eds]. [2006]. Rosen’s emergency medicine: Concepts and clinical practice [6th ed.]. St. Louis, MO: Mosby.)

Diagnostic Procedures

• Clinical assessment findings

• Chest radiograph will show evidence of a pneumothorax

Therapeutic Interventions

• Support airway, breathing, and circulation; administer supplemental oxygen.

• Immediately cover the wound with an occlusive dressing taped on three sides.

Taping the occlusive dressing on three sides creates a flutter valve effect with an open pneumothorax. As the patient breathes in, the dressing prevents air from entering the pleural space; on exhalation, air is allowed to escape through the open end of the dressing thus preventing the development of a tension pneumothorax.³

• Observe patient closely for development of tension pneumothorax (increasing respiratory distress, jugular venous distension, hypotension). If tension pneumothorax occurs, remove dressing immediately to relieve tension.

• Prepare for immediate chest tube insertion.

Hemothorax is the accumulation of blood in the pleural space and may result from either blunt or penetrating trauma (Fig. 38-4). Often accompanied by a pneumothorax, bleeding is the result of laceration of the intercostal vessels or internal mammary arteries, or from direct lung parenchymal damage. Massive hemothorax results from the rapid accumulation of more than 1500 mL of blood in the chest cavity and leads to respiratory and circulatory failure.