Volume responsiveness to guide fluid therapy

Frank-Starling relationship with corresponding respiratory variations in the arterial pressure waveform. Large respiratory variations in the arterial pressure or in the plethysmographic waveforms indicate that the patient is on the steep portion of the Frank-Starling relationship. Small variations indicate that the patient is on the plateau. Cardiac output maximization concepts aim at increasing cardiac output until it reaches the plateau of the Frank-Starling relationship. This goal, as demonstrated on this figure, could be achieved by minimizing respiratory variation in arterial pressure or plethysmographic waveform.