Serum chloride and sodium concentration as a predictor of acute kidney injury in premature newborns

Introduction/Objective. Hyperchloremia is often registered in adults’ studies after administration with 0.9% sodium chloride, which contributes to the development of acute kidney injury (AKI) as it leads to vasoconstriction of renal blood vessels. The aim of this study was to determine the correlation of sodium and chloride imbalance with the development of AKI, with consideration of other risk factors for this disorder. Methods. This retrospective study included 146 randomly selected preterm infants hospitalized at the Neonatal Intensive Care Unit from 2008 to 2015. Results. Among the patients registered for the study, 23.97% developed AKI, and they were of a significantly lower gestational age (26.3 ± 2.8 weeks vs. 31.7 ± 2.90 weeks, p < 0.05); birth weight (971.31 ± 412.1 g vs. 1,753.3 ± 750.3 g, p < 0.05); Apgar score in the first (3.2 ± 1.7 vs. 5.7 ± 2.4, p < 0.05) and fifth minute (5.3 ± 1.7 vs. 7.1 ± 1.8, p < 0.05) of life compared to those without AKI. The neonates with AKI had significantly higher maximum chloremia (Clmax: 114.1 ± 8.4 vs. 111.7 ± 4.6, p = 0.029) and maximum natremia (Namax: 147.9 ± 8.8 vs. 142.9 ± 4, p < 0.05). Each of these parameters is (independently) a statistically significant risk factor for the development of AKI, and gestational age is the strongest (OR = 1 / 0.643 = 1.55; 95% CI 1.24–1.94). Mortality in neonates with AKI was higher than in neonates without AKI (19.4% vs. 92.7%, p < 0.05). Conclusion. Hyperchloremia and hypernatremia are more common in the premature newborns with AKI compared to the premature newborns without AKI. Higher maximum sodium and chloride values are independent risk factors for AKI