CVP And GI Pathology Exam 3 Practice

The key idea is that pulmonary artery pressure rises when the resistance to blood flow in the pulmonary circulation increases. Pulmonary pressure is shaped by how much blood the heart sends into the lungs and how hard the pulmonary vessels resist that flow. If the pulmonary vascular resistance goes up, the same amount of blood flow must push through stiffer or narrower vessels, leading to higher pressure in the pulmonary artery. Other factors like blood viscosity have some effect but are not the primary driver of a marked rise in pulmonary artery pressure. A slower heart rate lowers cardiac output, which tends to reduce the amount of blood entering the pulmonary circulation not increase its pressure. Decreased cardiac output can affect pressures elsewhere, but the direct cause of a higher pulmonary arterial pressure is increased resistance in the pulmonary vasculature.