Risk factors for the development of early hyponatraemia in the premature infant. A review of the practice of giving sodium in the first days of life

Abstract

IntroductionA retrospective study was conducted in the Neonatal Intensive Care Unit of a tertiary hospital to determine the incidence of early hyponatraemia (first 48h of life) in preterm infants. Risk and protection factors in this condition were also examined as a starting point for a change in the medical action when prescribing intravenous fluids. Material and methodsThe study included a sample of 256 premature babies (gestational age: 235–366) admitted to the Neonatal Intensive Care Unit of a tertiary hospital between January 2016 and June 2018. The number of patients receiving intravenous sodium in different intervals during the first 48h of life was determined, as well as the number of those with hyponatraemia of any type (<135mmol/l), and moderate-severe (<130mmol/l). An analysis was made of the relationship between early hyponatraemia and weight/gestational age, antenatal steroids exposure, respiratory pathology, early sepsis, and perinatal asphyxia. ResultsHyponatraemia occurred in 81 patients, 31.64% of the total (up to 50% in <30 weeks of gestational age), and was moderate-severe (<130mmol/l) in 17.3% of the cases. The period of time with the most cases of hyponatraemia was in the first 12h of life (22.64%). Weight (P=.034), gestational age (P<.001) and respiratory disease (P<.001) were found to be risk factors and, in a multivariate analysis, the latter was independently related to early hyponatremia (P<.01, OR=5.24, 95% CI: 2.79–9.84). Antenatal betamethasone exposure did not show to be a protection factor. ConclusionAccording to the results of this study, it is considered an advantage to provide sodium in the intravenous fluids prescribed during the first days of life, particularly in preterm infants of lower gestational age and with respiratory disease involvement.