Abstract
BACKGROUND: Albumin is widely used for volume replacement therapy during cardiopulmonary bypass (CPB) including priming fluid, despite significant controversy over its benefits. This study aimed to examine how 20% exogenous albumin affects kidney function in patients with varying preoperative albumin levels. METHODS: We conducted this single-center, retrospective study in 28,298 adult patients undergoing on-pump cardiac surgery between 2018 and 2023. Patients were stratified according to preoperative albumin values (g/L): ≤35 (N = 1,525), 35.1-37.5 (N = 4,115), 37.6-40 (N = 7,894), and >40 (N = 14,764). Multivariate logistic regression, propensity score matching (PSM), and an inverse probability-weighting (IPW) model were applied to evaluated the impact of 20% albumin infusion on cardiac surgery-associated acute kidney injury (CSA-AKI). RESULTS: A total of 2,541 pairs were created after PSM: ≤ 35 g/L (307 pairs), 35.1-37.5 g/L (518 pairs), 37.6-40 g/L (743 pairs), and > 40 g/L (973 pairs). Patients with intraoperative 20% albumin infusion had a statistically higher risk of CSA-AKI in the group with preoperative albumin above 40 g/L (OR, 1.29; 95% CI, 1.07-1.57; p = 0.007) in the PSM model. This result remained significant after adjusting for the effects of potential confounding variables (OR, 1.38; 95% CI, 1.19-1.61; p < 0.001 for multivariate logistic regression; OR, 1.63; 95% CI, 1.55-1.72; p < 0.001 for IPW model). However, there was no significant association with Stage 2 and 3 CSA-AKI both for multivariable logistic regression and PSM. CONCLUSIONS: This analysis highlights that 20% albumin infusion during on-pump cardiac surgery may increase the risk of all stages CSA-AKI in patients with preoperative albumin above 40 g/L.