Primer in Blunt Thoracic Trauma

Authors: Moriah Thompson, M.D., Rachel Lindor, M.D. and Meghana Helder, M.D.

Jobe et al. J Emerg Trauma Shock. 2013 Oct;6(4):296-7. [from i-Open]

Introduction

• A quarter of all injury related deaths are due to blunt thoracic injuries
• According to the NTDB, chest injuries occur in 13.8% of all blunt trauma
• Overall mortality of chest trauma is <10%
• Injury from blunt trauma is from direct trauma, compression, and acceleration/deceleration forces
  • MVAs most common cause, followed by falls
• Although these injuries can be serious, most can be treated with a few simple maneuvers in the ED

Early Interventions

• There are a few life threatening conditions which should be identified and treated during the primary survey
• Tension pneumothorax
  • Classic, although not typical findings: distended neck veins, hypotension, diminished or absent breath sounds, and tracheal deviation. Most commonly presents with signs of respiratory or hemodynamic compromise.
  • If suspected, immediate needle decompression is indicated
    • Rush of air can be heard and is diagnostic
    • Converts tension to open pneumothorax and requires prompt tube thoracostomy
    • If neck vein distention continues, consider pericardial tamponade

Case courtesy of Dr Frank Gaillard, Radiopaedia.org

• Massive hemothorax
  • Single hemithorax can hold about 40% of a patient’s blood volume
  • >1500 mL of blood immediately after thoracostomy or 200 mL/hr for 4 hrs
  • Findings: decreased/absent breath sounds, no chest movement with respiratory effort, dullness to percussion
  • Diagnosis can be made with CXR or bedside ultrasound
  • Tube thoracostomy is diagnostic and therapeutic
  • Indication for operative management

Case courtesy of  Dr Andrew Dixon, Radiopaedia.org

• Flail Chest
  • Free floating segment of ribs
  • Findings: segmental paradoxical chest wall motion, diminished breath sounds
  • Respiratory failure common, treat with early intubation and ventilator assistance.

Injuries of Interest

• Lung Injury
  • Pulmonary Contusion
    • Significant source of morbidity and mortality
    • Cause: compression-decompression injury such as MVC
    • Findings: chest pain, tachypnea, chest wall contusions, hypoxia, decreased or coarse breath sounds on the affected side
    • Patchy ground-glass opacities on CXR or CT or widespread consolidation in severe cases.
    • Treatment:
      • Maintenance of adequate ventilation
      • Pain control
      • Consider mechanical ventilation for contusion of greater than ¼ total lung volume
  • Hemothorax (see above)
  • Pneumothorax
    • Found in 1/5 of patients with chest trauma
    • Commonly caused by rib fractures in blunt trauma
    • If persists or there is a large air leak after chest tube, emergency bronchoscopy needed to rule out tracheobronchial tree injury
  • Pneumomediastinum
    • Findings: subcutaneous emphysema in the neck, crunching sound over the heart during systole (Hamman sign)
    • Can be seen on plain films or CT
    • 10% of these cases may have tracheobronchial injury
    • Findings: asymptomatic or chest pain, change in voice, cough, or stridor
    • Be on the lookout for other injuries: larynx, trachea, major bronchi, pharynx, esophagus
  • Pulmonary Hematomas
    • Usually resolve spontaneously over weeks
    • Can become infected and lead to abscess
  • Pulmonary Lacerations
    • Seen with displaced rib fractures from exposed bone ends
    • Also from shear forces on pleural adhesions with rapid deceleration injury
• Tracheobronchial Injury
  • Cause: shear forces on more mobile distal bronchi compared to fixed proximal portions
  • Findings: dyspnea, hemoptysis, subcutaneous emphysema, Hamman sign, sternal tenderness
  • Also be suspicious with large pneumothorax, pneumomediastinum, or deep cervical emphysema
  • Continuous massive air leak from after thoracostomy tube placement
  • Diagnosis made with fiberoptic bronchoscopy
  • High-frequency oscillation ventilator modality of choice
• Diaphragmatic Injury
  • Occurs less frequent than in penetrating trauma
  • Often masked by other injuries and discovered late unless large defect
  • Abdominal viscera can slowly migrate up through defect
    • Risk of obstruction or ischemia from torsion/strangulation
    • Compression of adjacent lung (tension enterothorax)
  • Diagnosis: Pass OG tube followed with xray, upper GI series, CCT chest/abdomen with contrast
    • Some diagnosed only in OR
  • Repair in the OR
  • Esophageal Injury
    • Less common in blunt trauma
    • High mortality from concurrent injury to other organs of the chest
    • Diagnosis with esophagogram and/or esophagoscopy
    • Significant morbidity and mortality
• Chest Wall Injury
  • Subcutaneous Emphysema
    • Suspect injury to pharynx, larynx, or esophagus
    • Presume underlying pneumothorax even if not visible on CXR
    • Insert chest tube if patient requires positive pressure ventilation
    • Suspect major bronchial injury and consider bronchoscopy
  • Clavicle Fracture
  • Rib fracture
    • Most common bony injury in chest trauma
    • Painful with increased mortality and morbidity
    • First 3 ribs indicate high-energy trauma
    • Lower rib fractures should raise suspicion for abdominal injury
  • Flail Chest
  • Sternal Fracture
    • Can be marker of serious life threatening injury such as cardiac
• Cardiac Injury
  • Most often involves right heart
  • Complex arrhythmias, cardiac-free wall rupture, or coronary artery laceration can lead to death
  • Many die at the scene
  • Distal end of heart swings like pendulum and pericardium can tear with rapid deceleration
  • Suspect valvular, septal, or papillary muscle injury with new-onset murmurs
  • Thin walled atria higher risk for rupture than thicker ventricles.
  • ECG findings consistent with MI raises suspicion for coronary artery dissection
  • Troponins may be elevated but not always
• Thoracic Great Vessels
  • Most patients die pre-hospital
  • Involves high speed deceleration such as MVC with chest impacting steering wheel
  • Findings: hypotension, unequal blood pressures in extremities, evidence of major chest trauma (seat belt sign), thoracic outlet expanding hematoma, intrascapular murmurs or bruits, palpable fractures of sternum/ribs, flail chest
  • Proximal descending aorta most commonly injured in blunt trauma because of shearing of mobile portions relative to tethered portions
  • CT angio diagnostic modality of choice
  • Patient needs prompt trauma or vascular surgery involvement

References

• Shayn, Martin, and Meredith Wayne. "Management of Acute Trauma." Sabiston Textbook of Surgery. 19th ed. Vol. 1. Philadelphia, PA: Saunders, an Imprint of Elsevier, 2012. 430-470. Print.
• Brunett, Patrick, Lalena Yarris, and Arif Alper Cevik. "Pulmonary Trauma." Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. Vol. 1. New York, NY: McGraw-Hill, 2011. 1744-1757. Print.
• Ross, Christopher, and Theresa Schwab. "Cardiac Trauma." Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. Vol. 1. New York, NY: McGraw-Hill, 2011. 1758-1764. Print.