VExUS score: optimizing its use in perioperative and critical care management

The Venous Excess Ultrasound (VExUS) score has been developed to grade venous congestion and predict acute kidney injury in cardiac surgical setting by combining inferior vena cava diameter with hepatic, portal, and renal venous Doppler patterns. While initial studies demonstrated associations with acute kidney injury, subsequent non cardiac setting ICU studies yielded contradictory results, prompting reevaluation of what VExUS actually measures. Analysis of VExUS components reveals the score reflects complex interactions between cardiac function, filling pressures, and volume status rather than pure volume assessment. Each component-IVC diameter, hepatic vein flow, portal vein flow, and renal vein flow-is differently influenced by cardiac function and volume status. Observational studies demonstrate that patients with highest VExUS scores often have cardiogenic shock despite low fluid balance, while those with significant volume excess may have low scores when cardiac function is preserved. This evolving understanding necessitates a correction in clinical practice, returning to the original physiological framework where VExUS reflects the interaction of venous return and cardiac function rather than simple volume overload parameter.