How does pulmonary contusion interfere with oxygenation?

Pulmonary contusion significantly impairs oxygenation primarily due to the accumulation of blood and fluid in the alveoli and interstitial spaces of the lung. This condition leads to a disruption in the normal gas exchange process, as the alveoli, which are essential for facilitating the transfer of oxygen into the bloodstream and the removal of carbon dioxide, become filled with fluid and blood instead of air.

As a result, the functional surface area for gas exchange is reduced, leading to shunting of blood away from areas of properly ventilated lung tissue and ultimately causing hypoxemia. The presence of these fluids not only hampers adequate oxygen transport but also promotes increased surface tension and inflammation, further complicating the overall respiratory function.

The other options, while related to lung function and injury, do not encompass the specific mechanism through which pulmonary contusion affects oxygenation like the accumulation of blood and fluid does.