ICU · Resuscitation & shock

Fluid Responsiveness — Static & Dynamic Indices, Passive Leg Raise, SVV/PPV & Fluid Challenge

Also known as Fluid responsiveness · Passive leg raise · PLR · Stroke volume variation · SVV · Pulse pressure variation · PPV · Fluid challenge · Dynamic indices · End-expiratory occlusion test · EEOT · IVC distensibility

Fluid responsiveness is the prediction of whether a patient will increase stroke volume (or cardiac output) by around 10 per cent in response to a fluid bolus — and only about half of ICU patients actually do. Static markers (CVP, PAOP) do NOT predict it; the curve is flat. Dynamic markers do: the passive leg raise (PLR) is the reference reversible self-test, valid in spontaneous breathing (a rise in CO, SV or LVOT VTI of at least 10 per cent is positive). Pulse pressure variation (PPV) above 12.5 per cent and stroke volume variation (SVV) above 11.6 per cent apply only in controlled mechanical ventilation with no spontaneous breathing and a tidal volume of at least 8 mL/kg. Fluid overload worsens outcome — the CLASSIC, FACTT and CLOVERS trials support a restrictive strategy once the patient is no longer responsive.