Fluid Accumulation in Mechanically Ventilated, Critically Ill Children: Retrospective Cohort Study of Prevalence and Outcome

OBJECTIVES: To describe the prevalence, patterns, explanatory variables, and outcomes associated with fluid accumulation (FA) in mechanically ventilated children. DESIGN: Retrospective cohort study. SETTING: Tertiary PICU. PATIENTS: Children mechanically ventilated for greater than or equal to 24 hours.None. MEASUREMENTS AND MAIN RESULTS: Between July 2016 and July 2021, 1,636 children met eligibility criteria. Median age was 5.5 months (interquartile range [IQR], 0.7-46.5 mo), and congenital heart disease was the most common diagnosis. Overall, by day 7 of admission, the median maximum cumulative FA, as a percentage of estimated admission weight, was 7.5% (IQR, 3.3-15.1) occurring at a median of 4 days after admission. Overall, higher FA was associated with greater duration of mechanical ventilation (MV) (mean difference, 1.17 [95% CI, 1.13-1.22]; p < 0.001]), longer intensive care length of stay (LOS) (mean difference, 1.16 [95% CI, 1.12-1.21]; p < 0.001]), longer hospital LOS (mean difference, 1.19 [95% CI, 1.13-1.26]; p < 0.001]), and increased mortality (odds ratio, 1.31 [95% CI, 1.08-1.59]; p = 0.005). However, these associations depended on the effects of children with extreme values, and there was no increase in risk up to 20% FA, overall, in children following cardiopulmonary bypass and in children in the general ICU. When excluding children with maximum FA of >10%, there was no association with duration of MV (mean difference, 0.99 [95% CI, 0.94-1.04]; p = 0.64) and intensive care or hospital LOS (mean difference, 1.01 [95% CI, 0.96-1.06]; p = 0.70 and 1.01 [95% CI, 0.95-1.08]; 0.79, respectively) but an association with reduced mortality 0.71 (95% CI, 0.53-0.97; p = 0.03). CONCLUSIONS: In mechanically ventilated critically ill children, greater maximum FA was associated with longer duration of MV, intensive care LOS, hospital LOS, and mortality. However, these findings were driven by extreme values of FA of greater than 20%, and up to 10%, there was reduced mortality and no signal of harm.