Figure 3-11. Tension pneumothorax resulting from a closed chest injury.
b. Hemothorax. Hemothorax is a condition in which blood enters the pleural
cavity outside the lung and becomes trapped. As more and more blood becomes
trapped, the increased pressure causes the lung in the affected pleural cavity to
collapse (figure 3-12). Hemothorax can be caused by any chest injury. It can result
from lacerated blood vessels in the chest wall, lacerated major blood vessels within
the chest, or laceration of the lung. Signs and symptoms of tension pneumothorax
also apply to hemothorax. In addition, hemothorax may result in hypovolemic shock.
Tension pneumothorax and hemothorax may be present together. A hemothorax is
more likely to cause significant hypovolemia before tension could be built up. The left
and right lung spaces and the mediastinum can hold more than three liters of fluid
(over half of the circulating blood volume).
Figures 3-11 and 3-12 do not show a significant trachea deviation or
mediastinal shift. As the pressure increases and the injured (right) lung
collapses, the trachea and heart will be pushed more and more toward the
casualty's uninjured (left) side. The shift will compress the heart and the
uninjured (left) lung.