Effect of fluid balance situation within 7 days and early fluid intake after admission to the intensive care unit on in-hospital mortality and 1-year mortality in patients with cardiac arrest: a retrospective study from the MIMIC IV database.

Background: The objective of this study was to assess the associations between the mean daily fluid balance within 7 days and fluid intake within 24 h after admission to intensive care unit (ICU) and mortality for hospitalization and 1-year in cardiac arrest (CA) patients. Methods: Patients who experienced CA were enrolled from the Medical Information Mart for Intensive Care Database. CA patients were divided into <14, 14-37, 38-79 and >79 ml.kg-1 groups according to the interquartile range of the mean daily fluid balance. In addition, patients were divided into low (<147 ml.kg-1) fluid intake group and high (≥147 ml.kg-1) fluid intake group according to the median fluid intake within 24 h after admission to the ICU. Multivariate logistic regression models were constructed to determine the independent risk factors for in-hospital mortality and 1-year mortality. Results: The in-hospital mortality in the 38-79 ml.kg-1 and the >79 ml.kg-1 groups were higher than in the 14-37 ml.kg-1 and the <14 ml.kg-1 groups (P < 0.05). The 1-year mortality in the 38-79 ml.kg-1 and the >79 ml.kg-1 groups were higher than in the <14 ml.kg-1 group (P < 0.05). The 38-79 ml.kg-1 and >79 ml.kg-1 groups were associated with increased risk of in-hospital mortality [odds ratio (OR) 2.300, 95% confidence interval (CI) 1.381-3.831; P = 0.001; OR 2.691, 95% CI 1.515-4.779; P = 0.001] and 1-year mortality (OR 2.131, 95% CI 1.308-3.470; P = 0.002; OR 2.141, 95% CI 1.237-3.703; P = 0.006). The in-hospital mortality in the high-fluid intake group was higher than in the low-fluid intake group (P < 0.05). The 1-year mortality was not significantly different between the two groups (P = 0.055). A high fluid intake was not associated with an increased risk of in-hospital mortality (OR 0.841, 95% CI 0.587-1.204; P = 0.344). Conclusion: Mean daily fluid balance ≥38 ml.kg-1 within 7 days after admission to the ICU was associated with increased in-hospital mortality and 1-year mortality in cardiac arrest patients. Fluid intake ≥147 ml.kg-1 within 24 h after admission to the ICU was not associated with increased in-hospital mortality in cardiac arrest patients.