Twelve hours after sustaining chest trauma, a patient presents with a flail segment to the right, respiratory distress, and an oxygen saturation of 78%. Breath sounds are equal bilaterally and the jugular veins are normal. You should suspect:

• A. Traumatic asphyxia.
• B. Tension pneumothorax.
• C. Pulmonary contusion.
• D. Massive hemothorax.

Answer: (C)

Pulmonary contusion is the concept here. After blunt chest trauma, the lung tissue can be bruised and bleed, leading to edema and impaired gas exchange that may not be immediate. A patient can develop significant hypoxemia hours after injury even when breath sounds are relatively equal and there’s no evidence of a pleural space problem. The presence of a flail segment indicates severe chest wall injury and a risk for contusion, but it doesn’t by itself create unilateral breath sounds changes or neck vein distension.

In this scenario, the marked hypoxemia (oxygen saturation at 78%) with equal breath sounds and normal jugular venous pressure fits a parenchymal injury like pulmonary contusion rather than a space-occupying process. By contrast, tension pneumothorax would typically present with unilateral absent or diminished breath sounds, hyperresonance, possible tracheal deviation, and often hypotension with JVD. A massive hemothorax would produce reduced breath sounds on the affected side with dullness to percussion and often shock. Traumatic asphyxia would show facial cyanosis and edema with JVD following chest compression.