Sodium Values During the First 10 Postnatal Days in Extremely Low Birth Weight Infants and Long Term Neurocognitive Outcomes: A Systematic Review

Purpose: To synthesize all existing literature on the association between sodium disturbances during the first 10 days of life in Extremely Low Birth Weight (ELBW) infants and the risk of developing severe intraventricular hemorrhage (IVH> grade 1) or long-term neurodevelopmental impairment. Methods: Applying systematic review (ID CDR42024622933) principles, five major databases were explored. Any study was included if reporting on ELBW infants, on serum sodium values within the first 10 postnatal days and related these to neurocognitive or neurodevelopmental outcomes. Results: Ten studies (13,276 infants) met inclusion criteria. Six studies evaluated the association between hypernatremia (>145 or >150mmol/L) and severe IVH, two reported a significant association. Among two studies studying hyponatremia (ranging <130 or <120mmol/L), one found a significant association with severe IVH. Evidence regarding sodium fluctuations (difference between the maximum and minimum serum sodium values) identified fluctuations >13 mmol/L as a strong risk factor for severe IVH, while another showed that glucose-corrected sodium fluctuations were independently associated with severe IVH. Long-term neurodevelopmental outcomes were reported in four studies; hyponatremia was significantly associated with hearing loss in one study (OR 5.6 (95% CI 1.1–27.8)), while another study reported that glucose-corrected sodium fluctuations were associated with neurodevelopmental impairment at 18–21 months, although significance disappeared after adjustment for confounding factors. Conclusion: This systematic review suggests a possible association between early sodium disturbances and adverse neurodevelopmental outcomes in ELBW infants, emphasizing the need for further high-quality, prospective studies, especially since sodium management can be modulated.