TMC Respiratory Care Boards Practice Exam

During extreme dehydration, the body experiences a significant loss of fluids, leading to a reduction in blood volume. Hemodynamic pressures are primarily determined by the volume of blood that fills the cardiovascular system. When dehydration occurs, the decreased blood volume can result in lower blood pressure, particularly in the arterial system. This is because there is less fluid exerting pressure on the walls of the blood vessels.

In response to decreased blood volume, the body may attempt to compensate through mechanisms such as increased heart rate and vasoconstriction, but these compensatory mechanisms cannot fully counteract the effects of profound dehydration. The physiological response to dehydration thus typically results in decreased hemodynamic pressures, aligning with the answer provided.

Normal pressures can be expected when the body is well-hydrated, while highly variable pressures may occur in certain pathological conditions or acute blood loss scenarios, but they do not specifically represent the typical response seen in dehydration. Hence, decreased pressures accurately describe the physiological state during extreme dehydration.