Francesco Crispino

Background/Objectives: Preterm infants are particularly vulnerable to nutritional deficiencies and electrolyte imbalances during the early stages of extrauterine life. To ensure optimal metabolic support, they often require the early initiation of “aggressive” parenteral nutrition (PN), which is a known risk factor for Refeeding Syndrome (RS), a potentially serious metabolic condition characterized by fluid and electrolyte disturbances, the most significant of which is hypophosphatemia. Hypophosphatemia can impair the metabolism, survival, and function of red blood cells, leading to a reduction in key intracellular metabolites and the development of a metabolic block that alters their quality and decreases their stability. It is therefore hypothesized that RS may contribute to the development of anemia of prematurity (AOP). At the same time, early enteral nutrition (EN) may promote metabolic adaptation and reduce exposure to the complications of prolonged parenteral support, potentially protecting against AOP. The primary aim of this study was to determine whether preterm infants who develop RS are at increased risk of AOP. A secondary aim was to evaluate whether early EN may act as a protective factor against the development of AOP. Methods: This retrospective observational study was conducted on infants with a gestational age ≤ 34 weeks and/or birth weight ≤ 1500 g, admitted to the Neonatal Intensive Care Unit of Policlinico Umberto I—Sapienza University of Rome, between January 2015 and November 2022. Infants diagnosed with AOP were classified as cases, while those without AOP served as the control group. Results: A total of 412 preterm infants were enrolled (110 cases, 302 controls). Refeeding Syndrome was significantly more frequent in infants with AOP (30.9% vs. 11.6%, p < 0.001). In the logistic regression model adjusted for gestational age, RS was independently associated with AOP (OR = 2.81; 95% CI: 1.55–5.10; p < 0.001), along with gestational age ≤ 34 weeks (OR = 7.10; 95% CI: 2.13–24.0; p = 0.001). Early enteral nutrition during the first week of life was associated with a significantly lower risk of AOP (OR = 0.12; 95% CI: 0.029–0.52; p = 0.005). The association between RS and AOP was confirmed in the model adjusted for birth weight (OR = 2.06; 95% CI: 1.16–3.79; p = 0.021). Infants with AOP showed significantly higher parenteral nutrition intake, delayed initiation of enteral feeding, and later achievement of full enteral nutrition compared with controls (all p < 0.001). Conclusions: RS is significantly associated with AOP in preterm infants, likely through pathophysiological mechanisms related to hypophosphatemia. Importantly, early EN may be a protective factor against AOP, suggesting that timely initiation and advancement in enteral feeding may counteract the metabolic derangements associated with intensive parenteral support. These findings support a nutritional approach that prioritizes early and progressive enteral nutrition as a strategy to reduce the risk of both RS and AOP. Further prospective studies are needed to confirm these associations and to define optimal EN protocols for this population.

Background: Surfactant is a well-established therapy for preterm neonates affected by respiratory distress syndrome (RDS). The goals of different methods of surfactant administration are to reduce the duration of mechanical ventilation and the severity of bronchopulmonary dysplasia (BPD); however, the optimal administration method remains unknown. This study compares the effectiveness of the INtubate-RECruit-SURfactant-Extubate (IN-REC-SUR-E) technique with the less-invasive surfactant administration (LISA) technique, in increasing BPD-free survival of preterm infants. This is an international unblinded multicenter randomized controlled study in which preterm infants will be randomized into two groups to receive IN-REC-SUR-E or LISA surfactant administration. Methods: In this study, 382 infants born at 24⁺⁰–27⁺⁶ weeks’ gestation, not intubated in the delivery room and failing nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure ventilation (NIPPV) during the first 24 h of life, will be randomized 1:1 to receive IN-REC-SUR-E or LISA surfactant administration. The primary outcome is a composite outcome of death or BPD at 36 weeks’ postmenstrual age. The secondary outcomes are BPD at 36 weeks’ postmenstrual age; death; pulse oximetry/fraction of inspired oxygen; severe intraventricular hemorrhage; pneumothorax; duration of respiratory support and oxygen therapy; pulmonary hemorrhage; patent ductus arteriosus undergoing treatment; percentage of infants receiving more doses of surfactant; periventricular leukomalacia, severe retinopathy of prematurity, necrotizing enterocolitis, sepsis; total in-hospital stay; systemic postnatal steroids; neurodevelopmental outcomes; and respiratory function testing at 24 months of age. Randomization will be centrally provided using both stratification and permuted blocks with random block sizes and block order. Stratification factors will include center and gestational age (24⁺⁰ to 25⁺⁶ weeks or 26⁺⁰ to 27⁺⁶ weeks). Analyses will be conducted in both intention-to-treat and per-protocol populations, utilizing a log-binomial regression model that corrects for stratification factors to estimate the adjusted relative risk (RR). Discussion: This trial is designed to provide robust data on the best method of surfactant administration in spontaneously breathing preterm infants born at 24⁺⁰–27⁺⁶ weeks’ gestation affected by RDS and failing nCPAP or NIPPV during the first 24 h of life, comparing IN-REC-SUR-E to LISA technique, in increasing BPD-free survival at 36 weeks’ postmenstrual age of life. Trial registration: ClinicalTrials.gov NCT05711966. Registered on February 3, 2023.