PhD student University of Turku Turku, Varsinais-Suomi, Finland
Background: One of the problems in treating neonates with birth asphyxia is how to predict the severity of developing brain damage immediately after birth. Research on the connection between early-stage laboratory findings and later brain damage is scarce. Studies have shown that low umbilical artery pH value and base excess are related to poor prognosis. Hypocapnia and hypo- and hyperglycemia seem to relate to increased risk of brain damage. Objective: We aimed to study how early-stage hyponatremia is related to neurodevelopmental impairment and morbidity in patients with birth asphyxia. Design/Methods: In this retrospective study, we included infants born ≥36 weeks gestational age that received neonatal care in Turku University Central Hospital between Jan 1 2007 and Dec 31 2023 for birth asphyxia. From these patients we collected birth information and laboratory findings from patient records. For this analysis, we chose to focus on the infants’ lowest plasma sodium (P-Na) levels during the first 72 hours of life; below 125mmol/l, below 130mmol/l and below 135mmol/l. Neurodevelopmental impairment was defined as any occurrence of ICD-10 diagnoses in classes F70-79 (intellectual disability), F80-89 (psychological disorders), F90-98 (behavioral and emotional disorders), G40-41 (epileptical disorders), G80-83 (paralytical disorders), H47-49 (optic nerve disorders), H53-54 (visual disorders) or H90-91 (hearing disorders). Results: We identified a total of 381 infants who were diagnosed with birth asphyxia. Of these, 296 (78%) had recorded laboratory values for P-Na. Of these, 22 infants had P-Na below 125mmol/l, 84 below 130mmol/l, and 224 below 135mmol/l within the first 72 hours of life. Of the 296 infants with recorded P-Na values, 67 (23%) were diagnosed with NDI or died. In unadjusted analyses, hyponatremia was statistically significantly associated with death or NDI, irrespective of the selected threshold for hyponatremia (Table 1).
Conclusion(s): This study shows that hyponatremia within the first 72 hours of life is associated with adverse outcomes in infants with birth asphyxia. This finding could be due to the diluting effect of oliguria induced by kidney damage, inappropriate secretion of antidiuretic hormone or other reasons leading to fluid overload. This finding warrants further investigation of potential confounding effects e.g. cooling therapy and other components of electrolyte imbalance in this population.
.png)