Early Sodium Intake in Preterm Newborns; Randomized Clinical Trial
Phase: PHASE4
Conditions: Hyponatremia, Premature
Sponsor: Hospital del Niño "Dr. Federico Gomez Santos"

 
 
“Early 
Sodium 
Intake 
in 
Preterm 
Newborns; Randomized Clinical Trial”  
 
 
NCT04035564 
 
January 2018 
 
 
 
 
 
 
 
 
 
 
 
 
 

Introduction 
Hyponatremia is a common complication among preterm infants, renal losses of sodium contribute 
to the development of hyponatremia in preterm newborns. Sodium imbalances impact in newborns 
outcome. There is controversy about the time of initiation and the requirements of sodium in 
premature infants. Hypothesis: early (24 hours of life) sodium supplementation (5mEq/kg/day) 
prevents the develop of hyponatremia in preterm infants. 
This study is a randomized controlled trial in infants less than 35 weeks gestation admitted to the 
Newborn Intensive Care Unit at Children Hospital in Saltillo Coahuila Mexico. 
Infants receive at 24 hours of life; sodium (5mEq/kg/day) versus less than 1mEq/kg/day. Weight, 
serum and urine sodium, serum chloride, serum and urine creatinine, serum chloride, bicarbonate and 
glucose are monitored daily during the first 3 days of life. Patients are assessed for hyponatremia, 
hypernatremia, weight change, sepsis, necrotizing enterocolitis and intraventricular hemorrhage. 
 
 Objectives: 
1. Compare the risk of hyponatremia in the first 72hrs of life, in preterm newborns with early 
sodium intake and late sodium intake.  
2. Compare the risk of hypernatremia in the first 72hrs of life, in preterm newborns with early 
sodium intake and late sodium intake.  
3. Assess the change in serum sodium in preterm newborns with early sodium intake and late 
sodium intake. 
4. Assess the weight change in preterm newborns with early sodium intake and late sodium 
intake. 
5. Assess the development of complications (sepsis, necrotizing enterocolitis, intraventricular 
hemorrhage, mortality) in preterm newborns with early sodium intake and late sodium intake. 
 
 
Study design and statistical analysis 
 
This study is a randomized controlled trial. 
Eligibility criteria: 
Preterm infants <35 weeks of gestation. 
Less than 24 hours of life. 
 
Exclusion criteria: 
Urinary malformations 
Congenital abdominal wall defect 
Intestinal atresia / obstruction 
Congenital heart defect 
 
The eligible patients will be simple randomized in two groups: 
1. Comparation: Sodium administration, enteral and/or parenteral less than 1mEq/kg/day 
starting on day of life one. 
2. Intervention: Sodium administration, enteral and/or parenteral of 5mEq/kg/day starting on 
day of life one. 

 
At admission, gestational age and sex and birth weight will be recorded. Weight will be evaluated 
every 24 hours for 3 days. 
Blood samples will be taken every 24 hours for 3 days to assess serum sodium, creatinine, glucose, 
sodium bicarbonate and serum chloride levels. 
Urine samples will be taken every 24 hours for 3 days to assess urine sodium and urine creatinine 
levels. 
The incidence of hyponatremia, hypernatremia, change of serum sodium and weight change will be 
evaluated and compared between groups during this time frame (72hrs). 
The patients will be following through hospital stay to record the development of sepsis, necrotizing 
enterocolitis, intraventricular hemorrhage and mortality. 
The distribution of variables will be assessed with Shaphiro Wilk test, normally distributed data will 
be compared with t test or Chi squared test and those with abnormal distribution with Mann-Whitney 
U test or Fisher exact test. The risk of hyponatremia and hypernatremia will be expressed using 
relative risk. 
The change of serum sodium, creatinine, chloride, sodium bicarbonate, glucose levels and weight will 
be evaluated using repeated measures ANOVA or Kruskal-Wallis test depending on data distribution. 
Exploratory analysis will include sodium balance (according to sodium intake and urinary 
excretion), urine output and total fluid administration.  
IBM SPSS Statistics (IBM Corp. Released in 2013. IBM Statistics for Windows, Version 21.0. 
Armonk NY: IBM Corp.) will be used for statistical analysis. A p-value <0.05 will be considered 
statistically significant. 
 
Definitions: 
Hyponatremia: Serum sodium <130mEq/L 
Hypernatremia: Serum sodium >150mEq/L 
Change in serum sodium: The difference between serum sodium (at 48 and 72hrs) and initial serum 
sodium. 
Weight change: The difference between weight (at 24, 48 and 72hrs) and birth weight. 
Sepsis: Positive blood culture and/or 5 days of continuous antimicrobial therapy. 
Necrotizing enterocolitis: Necrotizing enterocolitis according to Bell staging (II or grater). 
Intraventricular hemorrhage: Bleeding into the brain´s ventricular system (intracranial ultrasound). 
Mortality: Death during hospitalization. 
 
  

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