Fluid balance in sepsis and septic shock as a determining factor of mortality

Abstract

Objective: The objective was to assess whether fluid balance had a determinant impact on mortality rate in a cohort of critically ill patients with severe sepsis or septic shock.

Design: A prospective and observational study was carried out on an inception cohort.

Setting: The setting was an intensive care unit of a university hospital.

Patients: Patients admitted consecutively in the intensive care unit who were diagnosed with severe sepsis or septic shock were included.

Interventions: Demographic, laboratory, and clinical data were registered, as well as time of septic shock onset, illness severity (Simplified Acute Physiology Score II, Sepsis-related Organ Failure Assessment), and comorbidities. Daily and accumulated fluid balance was registered at 24, 48, 72, and 96 hours. Survival curves representing 28-day mortality were built according to the Kaplan-Meier method.

Results: A total of 42 patients were included in the analysis: men, 64.3%; mean age, 61.8±15.9 years. Septic shock was predominant in 69% of the cases. Positive blood cultures were obtained in 17 patients (40.5%). No age, sex, Sepsis-related Organ Failure Assessment, creatinine, lactate, venous saturation of O2, and troponin differences were observed upon admission between survivors and nonsurvivors. However, higher Simplified Acute Physiology Score II was observed in nonsurvivors, P=.016. Nonsurvivors also showed higher accumulated positive fluid balance at 48, 72, and 96 hours with statistically significant differences. Besides, significant differences (P=.02) were observed in the survival curve with the risk of mortality at 72 hours between patients with greater than 2.5 L and less than 2.5 L of accumulated fluid balance.

Conclusions: Fluid administration at the onset of severe sepsis or septic shock is the first line of hemodynamic treatment. However, the accumulated positive fluid balance in the first 48, 72, and 96 hours is associated with higher mortality in these critically ill patients.