P2.E097: Should Initial Serum Creatinine Levels Influence Gentamicin Dosing Frequency In Neonatal Sepsis?

Background: Neonates with early-onset sepsis are typically treated with a combination of Gentamicin and Ampicillin. Current dosing regimen utilized at our institution is from Neofax, which is based on gestational age. Gentamicin troughs and peaks are monitored throughout the duration of therapy. Serum creatinine (SCr) levels in newborns are thought to be reflective of their mothers. However, neonates whose Gentamicin trough is elevated have been noticed to also have elevated baseline serum creatinine levels. Empirical Gentamicin dosing protocols based on baseline serum creatinine have been implemented at other institutions. The purpose of this study is to determine if the population in the Neonatal Intensive Care Unit (NICU) at this institution is comparable to literature published, and to determine if there is a need for an optimized empiric Gentamicin dosing protocol based on initial serum creatinine.

Methods: This eight year single-center retrospective cohort study includes data from neonates in the NICU at The Brooklyn Hospital Center. Data was collected from December 19, 2015 through October 19, 2023. Patients were included in the study if Gentamicin was administered in first 7 days of life, if a baseline serum creatinine was obtained within the first 24 hours of life and if a Gentamicin trough was obtained. Statistical analysis using Fisher Exact test, and Chi-Squared test was performed to evaluate if there was an association between elevated Gentamicin troughs to baseline serum creatinine and gestational age.

Results: Of the 425 patients reviewed during the study period, 356 were included in the study. When compared to normal SCr levels (≤0.7 mg/dL), elevated SCr (≥1.0 mg/dL) is associated with elevated Gentamicin troughs (p value = 0.047) regardless of gestational age. Further role of gestational age was evaluated, and elevated SCr was associated with elevated Gentamicin trough levels among neonates of gestational age ≥35 weeks (p = 0.046).

Conclusion: Neonates with gestational age of ≥35 weeks and elevated SCr of ≥1.0 mg/dL within the first 24 hours of life have a significant association with an elevated gentamicin trough level.