Brief summary

Acute kidney injury is a common complication after cardiac surgery with cardiopulmonary bypass and is associated with prolonged intensive care unit stay, increased morbidity, and mortality. Fluid overload and venous congestion are increasingly recognized as important contributors to postoperative organ dysfunction. The VExUS score is a bedside ultrasound tool that assesses systemic venous congestion through evaluation of the inferior vena cava and Doppler flow patterns in the hepatic, portal, and intrarenal veins. Although previous studies have suggested an association between VExUS-assessed venous congestion, AKI, and adverse outcomes, evidence regarding its relationship with advanced hemodynamic parameters remains limited. This prospective observational study will enroll adult patients undergoing cardiac surgery with cardiopulmonary bypass. All patients will undergo postoperative VExUS assessment and will be followed for the development of AKI and other postoperative complications. A predefined subgroup of patients undergoing clinically indicated PiCCO monitoring will additionally be evaluated to determine the association between VExUS score and PiCCO-derived hemodynamic parameters. The findings may support the use of VExUS as a noninvasive bedside tool for assessing venous congestion and identifying patients at increased risk of postoperative organ dysfunction after cardiac surgery.