Which statement best describes normal pulmonary vascular resistance?

Which statement best describes normal pulmonary vascular resistance?

• A. Normal PVR is < 10 mmHg/L/min or 1000 Dynes
• B. Normal PVR is > 2.5 mmHg/L/min
• C. Normal PVR is < 0.5 mmHg/L/min or 50 Dynes
• D. Normal PVR is < 2.5 mmHg/L/min or 200 Dynes

Answer: (D)

Pulmonary vascular resistance is the pressure the right heart must overcome to push blood through the lungs. It’s calculated as (mean pulmonary artery pressure minus left atrial pressure) divided by cardiac output, in Wood units (mmHg per L/min). Normal PVR generally falls in about 1 to 2.5 Wood units, which corresponds to roughly 80 to 200 dynes·sec/cm^5. Therefore, stating that normal PVR is less than 2.5 mmHg/L/min (or about 200 dynes) matches the upper end of the normal range. Values well above this indicate increased resistance, as seen with pulmonary hypertension or vascular remodeling, while extremely low values are not typical for normal physiology.

Pulmonary vascular resistance is the pressure the right heart must overcome to push blood through the lungs. It’s calculated as (mean pulmonary artery pressure minus left atrial pressure) divided by cardiac output, in Wood units (mmHg per L/min). Normal PVR generally falls in about 1 to 2.5 Wood units, which corresponds to roughly 80 to 200 dynes·sec/cm^5. Therefore, stating that normal PVR is less than 2.5 mmHg/L/min (or about 200 dynes) matches the upper end of the normal range. Values well above this indicate increased resistance, as seen with pulmonary hypertension or vascular remodeling, while extremely low values are not typical for normal physiology.