Fluid Overload at 48 Hours Is Associated With Respiratory Morbidity but Not Mortality in a General PICU: Retrospective Cohort Study

Objective: Recent evidence suggests that fluid overload may be deleterious to critically ill children. The purpose of this study was to investigate the association of early fluid overload with respiratory morbidity and mortality in patients admitted to a general PICU. Design: Retrospective cohort study. Setting: Single, tertiary referral PICU. Patients: Six hundred thirty-six patients aged 0-16 years invasively ventilated at 48 hours post admission, admitted between April 1, 2009, and March 31, 2013. Measurements and Main Results: Data collected included demographics, diagnosis, Pediatric Index of Mortality 2 score, and fluid overload percent at 48 hours from admission. Fluid overload percent was calculated as (cumulative fluid in - cumulative fluid out (L))/hospital admission weight (kg) x 100%. Outcome measures were oxygenation index at 48 hours from admission, death, and invasive ventilation days in survivors. Data are reported as median (interquartile range) and were analyzed using nonparametric tests. The median age was 1.05 years (0.3-4.2 yr). Fifty-three patients (8%) died. Median duration of ventilation in survivors was 5 days (3-8 d). Fluid overload percent correlated significantly with oxygenation index (Spearman., 0.318; p < 0.0001) and with invasive ventilation days in survivors (Spearman., 0.274; p < 0.0001). There was no significant difference in fluid overload percent between survivors and nonsurvivors. Regression analysis demonstrated that fluid overload percent was a significant predictor of both oxygenation index at 48 hours (p < 0.001) and invasive ventilation days (p = 0.002). Conclusions: Fluid overload at 48 hours was associated with oxygenation index at 48 hours and invasive ventilation days in survivors in a general PICU population. There was no association of fluid overload at 48 hours with mortality.