Splanchnic Oxygenation Patterns in Response to the First Enteral Feed in Preterm Infants: Prediction of Feeding Tolerance and Correlation With Abnormal Antenatal Doppler.

Enteral nutrition of preterm and intrauterine growth-restricted (IUGR) infants remains a major challenge for neonatologists. Early introduction of minimal enteral feeding (MEF) enhances gut hormones release, reduces the intestinal permeability and improves the motility of the intestinal tract, thus promoting gut functional maturation. Due to gastrointestinal immaturity, however, preterm infants are likely to develop clinical symptoms of feeding intolerance (FI), such as abdominal distention, vomiting, abundant and/or bilious gastric residuals, occult or gross bloody stools. FI could represent an early sign of necrotizing enterocolitis (NEC), the most feared gastrointestinal complication of prematurity. The occurrence of FI often prompts neonatologists to withhold, decrease or discontinue enteral feeds, thus hampering the establishment of an adequate early enteral nutrition.

Early identification of preterm infants at high risk of gastrointestinal complications could help clinical decisions on the introduction and the advancement of enteral feeding. The administration of the first feed in healthy preterm infants leads to a post-prandial increase of superior mesenteric artery (SMA) blood flow, detected by Doppler ultrasound. A significant correlation between early feeding tolerance and increased SMA blood flow velocity has been further observed one hour after the first feed.

Near-infrared spectroscopy (NIRS) provides a non-invasive monitoring of regional oxygen saturation (rSO2) and has been previously used to evaluate mesenteric perfusion in preterm infants at increased risk for intestinal complications. Abdominal rSO2 detected by NIRS has been shown to effectively reflect mesenteric blood flow changes. A significant correlation between lower abdominal rSO2 values in the first week of life and subsequent NEC development has been recently observed in a cohort of preterm infants, confirming previous data from animal models.

Current evidences on the role of NIRS monitoring in predicting FI development are still limited. To date, indeed, splanchnic oxygenation patterns in response to the first bolus feed and possible correlations with subsequent FI development have not been established yet.

The aim of this study is to assess abdominal rSO2 patterns in response to the first bolus feed and to evaluate possible correlations with the development of gastrointestinal complications.