Investigators enrolled 360 children aged 1 month to 18 years who stayed at least 24 hours in a tertiary paediatric intensive care unit. Early fluid accumulation (FA) was measured over the first 24 hours using the Goldstein formula and dichotomised at ≥5%. FA ≥5% occurred in 23.1% of patients. The cohort experienced AKI in 24.7% and PICU mortality of 19.4%.
Sequential adjusted models indicated FA predicted subsequent acute kidney injury (AKI). The study team reported an adjusted odds ratio of 4.45 for the FA–AKI association; propensity-score–matched analyses produced an attenuated but still positive estimate (OR 2.72). Short, clear effect sizes were reported. At the same time, FA did not independently predict PICU death once severity and AKI were included in models: the crude mortality association vanished after adjustment, the adjusted spline for mortality was flat, and the propensity-matched mortality estimate was null (OR 1.36).
The investigators modelled FA continuously using restricted cubic splines and observed a non-linear relationship with AKI. The dose–response curve showed an inflection roughly in the 2–5% FA range; risk increased more steeply past that region. The authors presented this as evidence that even modest early fluid gains may matter for renal risk, while larger accumulations carry proportionally greater AKI risk.
AKI itself showed strong, stagewise associations with death in this dataset: reported mortality rose across AKI stages, from 10.0% to 77.8% by stage. The study team tested interaction between FA and AKI and found the FA×AKI interaction to be sub-additive for mortality. Exploratory mediation analysis attributed most of FA’s small total association with mortality to the pathway through AKI rather than to a direct effect of FA on death. In short, data indicated FA increases AKI risk, and AKI—more than FA per se—drives mortality risk in this cohort.
Beyond renal and survival endpoints, the cohort showed clinically relevant downstream effects of early FA. FA was associated with longer mechanical ventilation duration and prolonged PICU stay. The authors reported these associations alongside the AKI findings, suggesting FA relates to morbidity signals even when it does not independently alter mortality prediction.
The study applied a sequence of convergent methods. Investigators adjusted all analyses for the PRISM III score to account for baseline severity. They used multivariable regression, restricted cubic splines for dose–response assessment, propensity-score matching to address measured confounding, and tests for additive and multiplicative interaction. Incremental discrimination analyses measured the change in predictive performance when FA was added to PRISM III (reported ΔAUC 0.007). Finally, exploratory mediation assessed whether AKI accounted for the FA–mortality relationship. These complementary approaches produced a consistent picture: FA is linked to AKI and morbidity but adds little to established mortality prediction.
The authors acknowledged limits inherent to observational cohorts. Causal claims require interventional confirmation; the report stated that whether limiting early FA prevents AKI remains to be tested in randomized trials. The abstract does not report some protocol details such as exact fluid types, management protocols, or timing of interventions, so those elements could not be evaluated from the source. The study received Institutional Ethics Committee approval (Ref. 388/MC/EC/2021) and obtained written informed consent from parents or guardians. The authors declared no competing interests.
Clinical takeaways from these data are practical but measured. Early fluid accumulation in the first 24 hours appears to be a modifiable risk marker for AKI and is associated with longer ventilation and PICU stay. However, after adjustment for severity and AKI, FA provided negligible incremental information for predicting PICU mortality compared with PRISM III. Whether active fluid-restriction strategies reduce AKI incidence or improve other outcomes will require prospective interventional trials to confirm the observational associations reported here.