Mechanisms Affecting the Gut of Preterm Infants Receiving Blood Transfusion With Different Enteral Feed Interventions

MAGPIE-2 is a prospective observational study designed to investigate the physiological mechanisms linking blood transfusion and enteral feeding practices to gut perfusion and oxygenation in very preterm infants. The study is nested within the WHEAT International randomised controlled trial, which compares two standard care approaches: withholding versus continuing milk feeds during red blood cell transfusion. While WHEAT evaluates clinical outcomes such as necrotising enterocolitis (NEC), MAGPIE-2 focuses on the underlying physiological changes that may contribute to NEC development. NEC is a serious gastrointestinal condition affecting approximately 10% of extremely preterm infants and is associated with high mortality and long-term neurodevelopmental impairment. Previous observational studies have suggested a temporal link between blood transfusion and NEC onset, particularly when feeds are continued during transfusion. However, the mechanisms remain poorly understood. MAGPIE-2 will use non-invasive monitoring tools-near-infrared spectroscopy (NIRS) and Doppler ultrasound-to measure cerebral and splanchnic (gut) tissue oxygenation and superior mesenteric artery (SMA) blood flow. These measurements will be used to calculate the Splanchnic-Cerebral Oxygenation Ratio (SCOR), a validated marker of gut tissue perfusion and ischaemia. A reduction in SCOR may indicate compromised gut oxygenation, potentially contributing to NEC. The study will recruit 270 infants (135 per arm) already enrolled in the WHEAT trial. Weekly measurements will be taken until 34 weeks corrected gestational age or discharge. Peri-transfusion monitoring includes continuous NIRS from 4 hours before to 4 hours after transfusion, and additional 2-hour recordings at approximately 24 and 48 hours post-transfusion. SMA Doppler assessments will be performed weekly. Primary outcomes include changes in SCOR post-transfusion between the two feeding strategies. Secondary outcomes include changes in cerebral and splanchnic oxygenation, SMA blood flow velocities, and the impact of severe anaemia (pre-transfusion haemoglobin ≤80 g/L) on these parameters. The study also includes an assessment of inter-operator variability in Doppler measurements. MAGPIE-2 aims to provide mechanistic insights that could inform safer transfusion and feeding practices in neonatal care, potentially reducing the incidence of NEC in this vulnerable population.