Q: Calculation of Pulmonary vascular resistance requires all of the followings except?

A) Central Venous Pressure (CVP)
B) Mean Pulmonary Artery Pressure (mean Pap)
C) Pulmonary capillary wedge pressure (PCWP)
D) Cardiac Output (CO)
E) Constant 80


Answer: A

Formulae for Systemic vascular resistance (SVR) and Pulmonary vascular resistance (PVR) is almost same except as SVR represent systemic circulation, it takes into account of CVP and MAP (Mean arterial Pressure). And, as PVR represents only pulmonary circulation, it takes into account of PCWP and mean-Pap instead of CVP and MAP respectively.

SVR = 80x [MAP – CVP]/CO)

PVR = 80 x [mean Pap – PCWP]/CO)