Comparison of venous overload ultrasound score with neutrophil gelatinase-associated lipocalin in the diagnosis and prognosis of sepsis-related acute kidney injury

Objective: This study aimed to evaluate the association of VEXUS scores and serum NGAL levels with the presence or development of acute kidney injury (AKI) and mortality among septic patients admitted to the intensive care unit (ICU). Materials and Methods: Following institutional ethics committee approval, this prospective cross-sectional study enrolled 98 septic patients requiring ICU management. Upon ICU admission, patients were stratified into two primary groups based on the presence or absence of AKI, as defined by KDIGO criteria. Over a 72-hour follow-up period, serum NGAL levels, VEXUS scores, and inferior vena cava (IVC)-related measurements were assessed on days 1 and 3. Demographic characteristics, laboratory findings, additional ultrasonographic parameters, and 28-day mortality outcomes were systematically recorded. Patients were re-evaluated for AKI status on day 3, and further subgroup analyses were performed accordingly. Results: On the first day of ICU admission, serum NGAL levels did not differ significantly between patients with and without AKI. However, by day 3, NGAL levels were significantly higher in patients without AKI (p<0.05). A temporal increase in serum NGAL concentrations was observed among patients initially free of AKI (p<0.05). VEXUS scores did not demonstrate significant variation between AKI and non-AKI groups on either day 1 or day 3 (p>0.05). Nevertheless, a statistically significant reduction in the IVC collapsibility index was noted among patients with AKI (p<0.05). Furthermore, in the AKI group, the proportion of patients with an IVC diameter below 2 cm increased, while those with a diameter greater than 2 cm decreased by the third measurement compared to baseline (p<0.05). Patients who developed AKI during the 72-hour observation period exhibited significantly higher VEXUS scores compared to those who did not (p<0.05). The overall 28-day mortality rate was approximately 30%. No significant differences were observed in serum NGAL levels or VEXUS scores between survivors ix and non-survivors on either day 1 or day 3. Logistic regression analysis identified third-day fluid responsiveness, presence of pleural effusion exceeding 500 mL, urinary microprotein levels, pulsatility index, and 72-hour cumulative fluid balance as independent predictors of mortality. Conclusion: This study suggests that, in patients with sepsis-induced AKI (SI-AKI), serum NGAL levels, VEXUS scores, and fluid responsiveness parameters may serve as prognostic markers—providing insights into recovery among patients with established AKI and predicting AKI development in initially unaffected patients—rather than serving as primary diagnostic tools for AKI. Keywords: Sepsis-induced acute kidney injury (SI-AKI); NGAL; VEXUS; mortality.