Neutrophil gelatinase-associated lipocalin and albuminuria as predictors of acute kidney injury in patients treated with goal-directed haemodynamic therapy after major abdominal surgery

Abstract

Neutrophil gelatinase-associated lipocalin (NGAL) is emerging as a new biomarker for the early identification of acute kidney injury (AKI). There is also increasing evidence of an association between urinary albumin/creatinine ratio (ACR) and AKI. The primary aim of this study was to evaluate the clinical utility of these biomarkers to predict AKI in a population of perioperative patients treated with goal-directed haemodynamic therapy (GDHT). Secondary aims were to examine NGAL and ACR as sensitive biomarkers to detect the effects of GDHT and to investigate the association of these biomarkers with secondary outcomes. Urine was obtained from 109 patients admitted to a critical care unit following major abdominal surgery. Patients were treated with intravenous fluid, GDHT with intravenous fluid or GDHT with intravenous fluid and dopexamine. Urine was collected preoperatively, and at times 0, 8 and 24 h postoperatively and outcome monitored for 28 days. There were no significant differences in NGAL or ACR concentrations between the cohorts treated with GDHT compared to standard care. However, both biomarker concentrations rose significantly in all cohorts over the time points. There were no significant differences in NGAL observed between patients who developed AKI and those who did not. However, there were significantly higher ACR preoperatively in patients who developed AKI. There were higher NGAL concentrations in patients who developed an infection and who died. NGAL has a poor predictive role in evaluating AKI in this clinical setting. Preoperative ACR may have a role as an AKI marker.