What factors are known to increase pulmonary vascular resistance (PVR)?

The correct answer is associated with excessive PEEP (positive end-expiratory pressure) and hypoxemia as factors that increase pulmonary vascular resistance (PVR). Excessive PEEP can lead to over-distension of the alveoli, which compresses the pulmonary capillaries and increases resistance to blood flow through the lungs. This can ultimately worsen gas exchange and increase the workload on the right side of the heart.

Hypoxemia, or low levels of oxygen in the blood, also contributes to increased PVR. When the body detects low oxygen levels, it responds by constricting pulmonary blood vessels in an effort to redirect blood flow to better-ventilated areas of the lungs. This vasoconstriction further elevates PVR.

Together, both excessive PEEP and hypoxemia create circumstances that elevate the resistance in pulmonary circulation, thereby making this choice the most accurate reflection of factors increasing PVR.

Factors like dehydration and exercise can have variable effects on vascular dynamics, but they are not primary causes of increased PVR. Increased cardiac output generally leads to decreased resistance due to the shear stress on vascular walls, and low PEEP typically promotes better lung expansion and improved blood flow in the pulmonary circuit, which supports lower PVR