Figure 1.

Functional hemodynamic monitoring for assessing the Frank-Starling relationship in patients with spontaneous breathing activity and/or cardiac arrhythmias and/or low tidal volume and/or low lung compliance. The same increase in cardiac preload (from A to B) induced by volume expansion can result in a significant (from a' to b') or to a negligible (from a to b) increase in stroke volume depending upon the shape of the curve. A static value of preload (A) does not predict to which extent stroke volume will respond to increased cardiac preload induced by fluid administration. Functional hemodynamic monitoring consists of observing the resulting effects of a preload variation, as can be induced by an end-expiratory occlusion test (EEO), a passive leg raising test (PLR) or by a 'mini' fluid challenge.