What are common causes of hypoxemia in horses?

Hypoxemia in horses occurs when there is an inadequate level of oxygen in the blood, which can lead to serious physiological repercussions. The selection of hypoventilation, lung disease, and low cardiac output as common causes accurately reflects the primary mechanisms through which oxygenation is compromised.

Hypoventilation occurs when the respiratory rate or depth is insufficient to meet the body's oxygen demand, leading to carbon dioxide retention and reduced oxygen levels. This can stem from a variety of factors such as sedation, respiratory muscle weakness, or restrictive lung diseases.

Lung disease encompasses a range of conditions, including pneumonia, pulmonary edema, or other obstructive diseases that impair the lungs' ability to exchange gases effectively. These conditions can significantly interfere with oxygen transfer into the bloodstream.

Low cardiac output refers to the heart's inefficient pumping ability, which can occur due to heart disease or significant blood loss. When the heart doesn't pump effectively, tissues may not receive adequate oxygen delivery, contributing to hypoxemia.

In contrast, the other options present scenarios that do not typically lead to hypoxemia. For instance, high cardiac output combined with proper ventilation usually promotes effective gas exchange and oxygen delivery. Hypoventilation paired with increased tidal volume could seem plausible, but increasing tidal volume alone