What causes atelectasis and hypoxia in drowning victims?

In drowning victims, the presence of water in the lungs is the primary factor that leads to atelectasis and hypoxia. When a person drowns, the inhalation of water causes the alveoli, the tiny air sacs in the lungs responsible for gas exchange, to fill with fluid instead of air. This fluid accumulation prevents the alveoli from expanding and leads to their collapse, a condition known as atelectasis.

As atelectasis occurs, the surface area available for gas exchange is significantly reduced, which directly contributes to hypoxia, a state where the body or a region of the body is deprived of adequate oxygen supply. With the alveoli unable to function correctly, the oxygen levels in the bloodstream drop, leading to hypoxemia and resulting in various physiological disturbances.

While other factors like oxygen deprivation and carbon monoxide exposure may have implications in different contexts, their roles are not as direct in the specific scenario of drowning victims as the presence of water in the lungs. The mismanagement of surfactant production can also be an indirect consequence of drowning but does not initiate atelectasis itself as directly as water in the lungs does.