May 25th, 2015

Primer in Blunt Thoracic Trauma

By Daniel Cabrera, M.D.

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

chest

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
tension-pneumothorax-3
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
mutli-trauma-chest-x-ray
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.

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