Venous Congestion

Fluid resuscitation is generally considered a fundamental aspect in managing critically ill patients because it is intended to help optimize cardiac output and enhance tissue perfusion. However, determining the appropriate volume of fluids to administer can be challenging, as both under- and over-resuscitation can result in significant morbidity and mortality. Fluid responsiveness, defined as the ability of a patient's cardiac output to increase in response to a fluid bolus, has become an important concept in guiding fluid therapy, both in spontaneously breathing and mechanically ventilated patients. New concepts have emerged assessing venous congestion.

The concept of fluid tolerance refers to the capacity of patients to undergo fluid expansion without experiencing harmful effects of volume overload with organ dysfunction. It physiologically makes sense that systemic venous return can still increase even when some degree of venous congestion is already present. Markers of venous congestion frequently coexist with markers of fluid responsiveness — so even a fluid-responsive patient may not always benefit from more fluid. [Joseph et al., Critical Care 2024]

The Venous Excess Ultrasound (VExUS) score grades systemic venous congestion from the IVC together with hepatic-vein, portal-vein and intra-renal-vein Doppler. (Grading detail — IVC ≥2 cm plus severity of each Doppler pattern → grades 0–3 — to be added verbatim from the review.)

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CVP is the downstream pressure of systemic venous return and acts on organ perfusion and function. A CVP threshold of 12 mmHg has been used to define congestion in some studies; defining an optimal CVP threshold is challenging. Admission CVP has been associated with increased risk of acute kidney injury. [Joseph et al., Critical Care 2024]

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