FLuid Responsiveness Prediction Using EXtra Systoles

In this study, the investigators propose to investigate a novel technique for fluid responsiveness prediction. It is based on the occurrence of an extra systole, which induces a preload variation: Extra systoles are comprised by, first, the premature/ectopic beat with decreased cardiac preload, then, the post-ectopic beat with moderately increased preload.

Consequently, the post ectopic beat is associated with a Frank-Starling curve right shift but is otherwise a normal sinus beat. As such, the post-ectopic beat elucidates and predicts the hemodynamic effect of increasing preload, i.e. giving fluids