The importance of fluid balance in critically ill patients: a retrospective observational study

BACKGROUND: Fluid therapy in critically ill patients remains one of the most demanding and difficult aspects of care. This is particularly important in patients admitted to the intensive care unit (ICU) due to cardiovascular disorders. AIMS: The aim of this study was to investigate whether a cumulative fluid balance (FB) affects mortality in critically ill patients hospitalized at the ICU. METHODS: Data were obtained from the medical records of the ICU at the Silesian Centre for Heart Diseases. All patients admitted to the ICU between 2012 and 2016 were evaluated. Patients who died or were discharged from the ICU within 48 hours from admission were excluded. Fluid balance and the type of fluids infused during the first 7 days were assessed. The primary outcome was ICU mortality. RESULTS: Overall, 495 patients were included in the study and 303 (61.2%) survived the ICU stay. Daily FB in the first 24, 48, and 72 hours after admission and the cumulative FB after 7 days were significantly lower in survivors. Fluid balance exceeding 1000 ml and the use of colloid solutions in the first 72 hours were independently associated with mortality, along with the diagnosis of stroke and shock on admission. CONCLUSIONS: A positive FB exceeding 1000 ml in the first 72 hours from admission to the ICU is independently associated with an increased risk of mortality in critically ill patients with cardiovascular disorders. The use of colloid solutions is associated with a higher positive FB.