Effect of Cumulative Fluid Balance on Sepsis Outcome: A Retrospective Analysis

Background: Fluid resuscitation is a cornerstone of early management, yet excessive fluid administration leading to positive cumulative fluid balance (CFB) has been linked to adverse outcomes. This study aimed to evaluate the effect of 72-hour CFB on mortality and length of ICU stay in sepsis patients.Methods: This retrospective analysis included 80 adult sepsis patients (age 20-60 years) admitted to Tanta University Emergency Hospital between July and December 2020 who required fluid resuscitation. Patients with chronic renal failure, heart disease, liver failure, massive edema, on mechanical ventilation, or with ICU stays of less than 24 hours were excluded. CFB was calculated as total fluid input minus total fluid output over the first 72 hours. Results: The mean 72-hour CFB was 2393.07 ± 1241.11 mL. Non-survivors had a significantly higher mean 72-hour CFB (3497.47 mL) compared to survivors (2024.93 mL) (p < 0.001). A 72-hour CFB cutoff of 2650 mL predicted mortality with 80% sensitivity and 73.3% specificity (AUC 0.847, p < 0.001). Significant negative correlations were observed between CFB and urinary output (r=-0.739, p<0.001), HCO3 (r=-0.366, p=0.001), pH (r=-0.689, p=0.001), and WBC (r=-0.300, p=0.007). . Higher CFB was significantly associated with the development of ARDS (p = 0.005) and the need for mechanical ventilation (p < 0.001), but not with AKI or the length of ICU stay.Conclusion: Positive cumulative fluid balance within the first 72 hours of sepsis diagnosis is a significant predictor of mortality and is associated with increased risk of ARDS and the need for mechanical ventilation.