Physiologic Approach to Sodium Supplementation in Premature Infants

Study Overview
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Brief Summary
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Postnatal growth failure occurs in up to 50% of very low birth weight (VLBW, <1500 grams at birth) infants as assessed by discharge weight. This study will evaluate if a sodium supplementation algorithm guided by spot urine sodium measurements can improve postnatal growth.

Detailed Description
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Postnatal growth failure is a significant morbidity in very low birth weight (VLBW, <1500 grams at birth) infants. Efforts to promote growth and optimize nutritional support have included earlier initiation of parenteral nutrition and increased caloric and protein administration. While these advances in nutritional practices have resulted in improved growth, up to 50% of VLBW infants continue to experience postnatal growth failure (defined as discharge weight <10th percentile by Fenton growth charts) and over 25% experience severe postnatal growth failure (<3rd percentile). Current nutritional recommendations for sodium provision to preterm infants is 3-5 mEq/kg/d and fails to take into account the degree of renal immaturity present in extremely preterm infants. The investigators hypothesize that the sodium supplementation algorithm will improve in-hospital somatic growth (weight, length, and head circumference) between 2 weeks of postnatal age and 36 weeks postmenstrual age over current sodium replacement practices. The algorithm will be evaluated in a prospective, pragmatic, randomized trial. Infants in the sodium supplementation algorithm group will have a spot urine sodium concentration determined every two weeks beginning on the 14th postnatal day and continuing until 36 weeks postmenstrual age with sodium supplementation provided according to the algorithm.

Official Title
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Physiologic Approach to Sodium Supplementation in Premature Infants

Conditions
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Postnatal Growth Disorder

Intervention / Treatment
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* Drug: Sodium supplementation guided by urine sodium concentration algorithm


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Infants with gestational age 25 0/7 - 29 6/7 at birth Birth weight ≥ 500 grams Admitted within the 1st week of life < 17 days of age at time of enrollment Exclusion Criteria: Infants admitted after the 1st week of life Major congenital anomalies Structural genitourinary abnormality Renal dysfunction (serum creatinine > 1.0 mg/dl or an increase of ≥ 0.3 mg/dl between the 2 most recent consecutive measurements) immediately prior to the initiation of study procedures. Diuretic use less than 48 hours prior to initiation of study procedures Infant with an ostomy (infants receiving an ostomy after study entry will be withdrawn) Infant with a diagnosis or suspicion of diabetes insipidus

Ages Eligible for Study
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Minimum Age: 7 Days
Maximum Age: 16 Days

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Control<br>Standard of care sodium supplementation as directed by the medical care team | |
| Active Comparator: Sodium supplementation algorithm<br>Beginning on the 14th -16th postnatal day and continuing until 36 weeks postmenstrual age, infants randomized to the algorithm will have a spot urine sodium concentration determined every two weeks and sodium supplementation provided according to the algorithm. | Drug: Sodium supplementation guided by urine sodium concentration algorithm<br>* 4 mEq/kg/d sodium added the first time urine [Na] below threshold; for each subsequent time urine [Na] below threshold, add additional 2 mEq/kg/d.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in somatic growth (weight) | evaluated by the change in Z-score | between 2 weeks of age and 36 weeks conceptual age | 
| Change in somatic growth (length) | evaluated by the change in Z-score | between 2 weeks of age and 36 weeks conceptual age | 
| Change in somatic growth (head circumference) | evaluated by the change in Z-score | between 2 weeks of age and 36 weeks conceptual age | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in somatic growth (weight) | evaluated by the change in Z-score | between 2 weeks of age and discharge or transfer from the NICU or 44 weeks corrected age (whichever occurs first) | 
| Change in somatic growth (length) | evaluated by the change in Z-score | between 2 weeks of age and discharge or transfer from the NICU or 44 weeks corrected age (whichever occurs first) | 
| Change in somatic growth (head circumference) | evaluated by the change in Z-score | between 2 weeks of age and discharge or transfer from the NICU or 44 weeks corrected age (whichever occurs first) | 
| Total body water | Measured by the doubly labeled water method | 32 weeks conceptual age | 
| Energy expenditure | Measured by the doubly labeled water method | 32 weeks conceptual age | 
| Incidence and severity of bronchopulmonary dysplasia (BPD) | as defined by the 2000 NICHD Workshop on BPD | 36 weeks conceptual age | 
| Duration of mechanical ventilation | days on assisted ventilation | 36 weeks conceptual age | 
| Need for supplemental oxygen | days on oxygen supplementation | 36 weeks conceptual age | 
| Use of diuretic therapy | frequency of use | 36 weeks conceptual age | 
| Retinopathy of prematurity | worst grade | 36 weeks conceptual age | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Postnatal Growth Disorder, Growth and development