Perioperative fluid balance and acute kidney injury

Positive fluid balance (FB) has been linked to adverse clinical outcomes. We performed this study to explore the relationship between perioperative fluid balance and acute kidney injury (AKI). The relationships between FB and AKI were explored using a prospective, observational design. Patients were divided into quartiles based on FB status in the first 24 h from initiation of surgery in order to further explore this relationship. One hundred adult patients undergoing cardiovascular surgery were included in the analysis. The major finding of the study was that positive FB occurred early in the intraoperative period and progressed into the postoperative period and that fluid administration was not clearly associated with any identifiable volume-sensitive event. The evolution of positive FB preceded the rise in serum creatinine. Progressive severity of positive FB was associated with increased incidence of AKI. The highest quartile FB group had a five-fold increased risk for AKI (adjusted odds ratio 4.98, 95 % confidence interval 1.38-24.10, p = 0.046) compared to the lowest quartile group, higher postoperative peak serum creatinine values (p < 0.001), surgery-related complications (p < 0.001) and intensive care unit (p < 0.001) and hospital length of stay (p = 0.048). Positive FB was associated with increased incidence of AKI.