Explanation of the use of Stroke Volume Variation (SVV) to determine fluid responsiveness based on Frank-Starling relationship. Fluid responsiveness is indicated when the variation in stroke volume is occurring on the steeper part of the curve (>12% variation indicates a fluid responsiveness).
Whilst it is important to identify when a patient is likely to respond to a fluid resuscitation, not every patient on the steeper part of the F-S curve requires fluid resuscitation. Think of your ARDS patient with normal Lactate and absent evidence of tissue hypoperfusion.