Pulmonary vascular resistance is typically expressed in which units?

Pulmonary vascular resistance is typically expressed in which units?

• A. dynes-sec-cm-5
• B. mmHg/L/min
• C. Wood units
• D. L/min per m^2

Answer: (A)

Pulmonary vascular resistance is the pressure the right heart must overcome to push blood through the lungs, calculated as the difference between mean pulmonary arterial pressure and the left atrial (or wedge) pressure divided by cardiac output. Because the pressure is measured in mmHg and the flow is in L/min, the resulting unit is mmHg·min/L, which is known as a Wood unit. This is the most commonly used expression in clinical anesthesia and cardiopulmonary practice. Dynes·s·cm^-5 is the SI-equivalent form, with 1 Wood unit equaling about 80 dynes·s·cm^-5, so you can convert between them if needed. While dynes·s·cm^-5 is perfectly valid, Wood units are the typical unit used in practice, making them the standard choice for reporting PVR.

Pulmonary vascular resistance is the pressure the right heart must overcome to push blood through the lungs, calculated as the difference between mean pulmonary arterial pressure and the left atrial (or wedge) pressure divided by cardiac output. Because the pressure is measured in mmHg and the flow is in L/min, the resulting unit is mmHg·min/L, which is known as a Wood unit. This is the most commonly used expression in clinical anesthesia and cardiopulmonary practice. Dynes·s·cm^-5 is the SI-equivalent form, with 1 Wood unit equaling about 80 dynes·s·cm^-5, so you can convert between them if needed. While dynes·s·cm^-5 is perfectly valid, Wood units are the typical unit used in practice, making them the standard choice for reporting PVR.