What is the common hemodynamic abnormality in ARDS?

In Acute Respiratory Distress Syndrome (ARDS), a hallmark hemodynamic abnormality is the increase in pulmonary artery pressure. This elevation occurs as a result of several physiological changes in the lungs and the overall hemodynamic response to hypoxemia and reduced lung compliance.

In ARDS, the lung injury leads to inflammatory processes that cause increased permeability of the pulmonary capillaries, resulting in pulmonary edema. This fluid accumulation in the alveolar spaces and interstitial tissue creates a significant increase in the resistance within the pulmonary circulation, thus elevating pulmonary artery pressure. The right ventricle must work harder to pump blood through the lungs, leading to this increase in pressure.

Moreover, the combination of hypoxemia and decreased lung compliance often results in changes in the hemodynamic status, where the body's compensatory mechanisms aim to maintain oxygen delivery despite compromised gas exchange. As pulmonary vascular resistance rises due to the pathological changes in the lung vasculature, it also contributes to the overall increase in pulmonary artery pressure.

In summary, the increased pulmonary artery pressure in ARDS reflects the underlying pathophysiological changes occurring in the pulmonary circulation as a response to severe lung injury and the resultant functional impairment.