Figure 1
From: Bench-to-bedside review: An approach to hemodynamic monitoring - Guyton at the bedside
Arthur Guyton's graphical approach to the factors regulating cardiac output. Upper left: venous return curve. At zero flow (cardiac output (Q)), the right atrial pressure (Pra) is equal to the mean circulatory filling pressure. (MCFP) The lower Pra, the greater Q up to a maximum (flat line), in which case the flow is limited. Upper right: cardiac function curve (Starling curve). The greater Pra, the greater Q up to a plateau, in which case flow is limited by cardiac function. Lower: Since both graphs have the same axes, they can be put together with the working cardiac output and working Pra (or central venous pressure (CVP)) given by the intersection.