Effects of Human Serum Albumin Infusion on Microcirculation, Capillary Leakage, and Endothelial Function in Sepsis Patients: A Retrospective Cohort Study

BACKGROUND: Sepsis and its associated microcirculatory and endothelial dysfunction leading to organ failure remained the primary causes of morbidity and mortality in intensive care units. Fluid resuscitation served as the cornerstone of early supportive therapy. This study aimed to evaluate the impact of human albumin (HA) versus crystalloid-based resuscitation on microcirculation, capillary leakage, and endothelial function in sepsis patients with hypoalbuminemia who are not severely ill. METHODS: This retrospective cohort study included sepsis patients admitted to the same hospital between January 2022 and December 2024. Patients were divided into two groups based on the type of fluid resuscitation received: HA or crystalloids. Key parameters assessed included microcirculatory parameters, markers of capillary leakage, endothelial function, inflammatory markers, and albumin function within 72 hours, with organ support outcomes and clinical indicators evaluated at 4 weeks. RESULTS: The study included 223 patients (crystalloid group: n = 108; HA group: n = 115). The HA group showed superior microcirculatory perfusion at 72 hours (microvascular flow index: 2.87 vs. 2.73, P = 0.003; tissue oxygen saturation: 80.14% vs. 78.32%, P = 0.002), reduced capillary leakage (albumin leakage: 30.35% vs. 33.16%, P = 0.006), and improved endothelial function at 72 hours (nitric oxide: 25.83 vs . 24.56 μmol/L, P = 0.003). The incidence of acute kidney injury was lower (14.78% vs. 25.93%, P = 0.038), and intensive care unit stay duration was shorter (7.57 vs. 8.31 days, P = 0.006). Albumin treatment independently reduced the risk of microcirculatory deterioration ( P < 0.001). CONCLUSIONS: In hypoalbuminemic sepsis patients who are not severely ill, HA resuscitation provided multitarget benefits by improving microcirculation, endothelial integrity, and organ outcomes.