Splanchnic Oxygenation and Perfusion Response to Enteral Feeds in Preterm Infants With Abnormal Antenatal Doppler: Pattern Assessment and Correlation With Feeding Intolerance

Intrauterine growth restriction (IUGR) is a major cause of perinatal morbidity and mortality. Severe IUGR is often due to impaired placental circulation, with absent or reversed end-diastolic flow (AREDF) velocity through the umbilical arteries. Fetuses with AREDF adapt to chronic hypoxia by undergoing a blood flow redistribution, which favors cerebral perfusion at the expense of the mesenteric district. The resulting hypoxic-ischemic injury of the intestinal mucosa represents a major risk factor for the post-natal development of gastrointestinal complications, such as necrotizing enterocolitis (NEC), spontaneous intestinal perforation (SIP) and feeding intolerance (FI). Due to the fear of the aforementioned conditions, the establishment of adequate enteral feeding in AREDF preterm infants is often difficult; hence, the identification of infants at highest risk for GI complications could aid their delicate nutritional management.

Postnatal Doppler studies have shown a decreased blood flow velocity in the superior mesenteric artery in response to the first enteral feed in AREDF preterm infants who later developed feeding intolerance. A similar Doppler impairment and lower values of splanchnic oxygenation at feeding introduction have been described in non-IUGR preterm infants with later GI complications. To date, however, it is not known whether the impaired mesenteric blood flow observed after the first feed in high-risk AREDF infants persists over time, or if it correlates with reduced splanchnic oxygenation and perfusion.

This observational prospective study aims:

• to assess the patterns of abdominal oxygenation and perfusion in response to enteral feeds in AREDF preterm infants at different phases of enteral feeding establishment;
• to evaluate a possible correlation with the development of gastrointestinal complications.

Infants admitted to the Neonatal Intensive Care Unit (NICU) are consecutively enrolled in the study if fulfilling the following criteria: gestational age ≤34 weeks, stable clinical conditions, documented evidence of antenatal umbilical Doppler impairment.