(13) Acute Kidney Injury in Extreme Preterm Infants: Impact of Renal Solute Load

Sarah Furqan, Southern illinois university, Springfield, IL, United States; Mohamed Ahamed, Southern Illinois University, United States; Venkata S. Majjiga, Southern Illinois University, Chatham, IL, United States; Beau Batton, Southern Illinois University School of Medicine, IL, United States; Albert Botchway, Southern Illinois University School of Medicine, IL, United States; Blaine A. Traylor, Southern Illinois University School of Medicine, Springfield, IL, United States

Background: Extremely preterm infants are at high risk of developing acute kidney injury (AKI) which is associated with increased mortality and prolonged length of stay. Restriction of fluids and solutes such as proteins and electrolytes is common once AKI is diagnosed. However, the extent to which solute and fluid administration contribute to the development of AKI has not been well investigated.

Objectives: To explore factors associated with development of AKI and the impact of sodium, protein and fluid administered in the first 14 postnatal days on the development of AKI in infants born under 27 weeks of gestation.

Design/Methods: Retrospective study of all inborn infants (230/7 – 270/7 weeks GA) cared for at a level III NICU (ADC: 40, >700 annual admissions) over a 5 year period (1/2016-2/2021). Infants with and without AKI were analyzed based on the neonatal modified KDIGO (Kidney Diseases: Improving Global Outcomes) AKI definition. Data included demographics, clinical variables, in-hospital outcomes and sodium, protein and fluid administration through the first 14 days. Data was analyzed with independent t-test for continuous variables and Chi square for categorical variables. To assess the impact of fluid, sodium, and protein intake on the development of AKI, survival analysis using Weibull regression was performed on both groups using longitudinal time to event format with AKI as the outcome variable and sodium, protein and fluid intake as the independent variables with results reported as hazard ratios. P< 0.05 was considered significant.

Results: 35 (27.5%) infants with AKI were compared to 92 infants without AKI. As shown in Table 1, when compared to controls AKI infants were less mature, had higher CRIB II scores, and were more likely to develop NEC and IVH. Other clinical variables were similar. Average daily sodium, protein and fluid intake for the two groups were similar (Table 2). The amount of fluid administered in the first 14 days was associated with a lower occurrence of AKI (HR-0.98, p-0.03). Amount of sodium and protein administered were not associated with the development of AKI (Table 3).

Conclusion: Infants who develop AKI are less mature and sicker at birth and have higher rates of NEC and IVH. Amount of sodium and protein in the first 14 days do not seem to affect the occurrence of AKI. Higher rate of fluid administration during the first 14 days is associated with lower hazards of development of AKI in preterm infants. However, a larger prospective study is required to confirm this and its clinical significance.