Which statement best describes Systemic Vascular Resistance (SVR)?

Which statement best describes Systemic Vascular Resistance (SVR)?

• A. The resistance the blood must overcome to move within the systemic vasculature; typical value <20 mm Hg/L/min
• B. The pressure difference between systole and diastole
• C. The opposition encountered by the right ventricle
• D. The amount of blood the heart pumps per minute

Answer: (A)

Systemic Vascular Resistance is the load the left ventricle must overcome to push blood through the systemic circulation. It reflects the tone and impedance of the systemic arterioles and is calculated as SVR = (mean arterial pressure − right atrial pressure) / cardiac output. With typical values (MAP around 90 mmHg, low right atrial pressure, CO about 5 L/min), SVR falls in the vicinity of 18 mmHg/L/min, which is under 20 and considered normal. This makes the description “the resistance the blood must overcome to move within the systemic vasculature” the best match. The other statements refer to different concepts: one is the pulse pressure (difference between systolic and diastolic pressures), another to the right ventricle’s opposition (pulmonary vascular resistance), and another to the amount of blood the heart pumps per minute (cardiac output).

Systemic Vascular Resistance is the load the left ventricle must overcome to push blood through the systemic circulation. It reflects the tone and impedance of the systemic arterioles and is calculated as SVR = (mean arterial pressure − right atrial pressure) / cardiac output. With typical values (MAP around 90 mmHg, low right atrial pressure, CO about 5 L/min), SVR falls in the vicinity of 18 mmHg/L/min, which is under 20 and considered normal. This makes the description “the resistance the blood must overcome to move within the systemic vasculature” the best match. The other statements refer to different concepts: one is the pulse pressure (difference between systolic and diastolic pressures), another to the right ventricle’s opposition (pulmonary vascular resistance), and another to the amount of blood the heart pumps per minute (cardiac output).