The nurse notes increasing systemic vascular resistance readings on a patient in the intensive care unit. The nurse understands the effects of this change to include which of the following?

Choice A rationale Systemic vascular resistance (SVR) specifically measures the resistance the left ventricle must overcome to eject blood into the systemic circulation. It does not directly cause an increase in pulmonary vascular resistance (PVR), which is the resistance in the lung's blood vessels. While severe left sided heart failure can eventually lead to pulmonary backup, an increase in SVR itself is a systemic afterload issue. Respiratory rate changes are usually secondary to compensatory mechanisms or distress rather than a direct hemodynamic effect. Choice B rationale An increase in systemic vascular resistance usually results in an increase in arterial blood pressure, as pressure is the product of flow and resistance. If resistance increases and the heart maintains its output, the pressure will rise. Mean arterial pressure (MAP) typically increases with higher SVR unless the heart's pumping ability fails significantly. Therefore, decreasing blood pressure is generally the opposite of what is expected when SVR increases, provided the cardiac compensatory mechanisms are still functioning effectively. Choice C rationale Increasing systemic vascular resistance represents increased afterload. According to the Frank Starling law and basic hemodynamics, as afterload increases, it becomes harder for the heart to pump blood out, which typically leads to a decrease in stroke volume and subsequently a decrease in cardiac output. It would be highly unusual for cardiac output to increase in response to higher resistance unless there was a massive increase in contractility or heart rate to compensate for the added pressure work. Choice D rationale Increased systemic vascular resistance raises the afterload on the left ventricle, forcing the myocardium to work harder to eject blood. This increased workload directly leads to higher myocardial oxygen demands. Simultaneously, the higher resistance often leads to a reduction in stroke volume and cardiac output because the ventricle cannot empty as efficiently against the high pressure. Normal SVR ranges from 800 to 1200 dynes/sec/cm-5. High SVR can lead to heart strain and decreased systemic perfusion.