Since 1987, red blood cell (RBC) transfusions have been proposed as a potential risk factor for necrotizing enterocolitis (NEC), which is one of the most severe gastrointestinal complications of prematurity.

Evidence from Doppler studies have shown a post-transfusion impairment of mesenteric blood flow in response to feeds, whereas NIRS studies have reported transient changes of splanchnic oxygenation after RBC transfusion; a possible role for these findings in increasing the risk for TANEC development has been hypothesized.

The aim of this study is to evaluate SrSO2 patterns in response to enteral feeding before and after transfusion.

Premature neonates are among the most transfused population, but the risks and benefits of this procedure remain unclear. Since 1987, red blood cell (RBC) transfusions have been proposed as a potential risk factor for necrotizing enterocolitis (NEC), which is one of the most common and feared gastrointestinal complications of prematurity. Several observational studies have tried to demonstrate this causal correlation, defining the so-called transfusion-associated NEC (TANEC), which occurs within 48 hours after RBC transfusion.

Evidence from Doppler studies have shown a post-transfusion impairment of mesenteric blood flow in response to feeds, whereas NIRS studies have reported transient changes of splanchnic oxygenation after RBC transfusion. This evidence, which has been hypothesized to play a role on the risk of TANEC development, has significantly raised the attention over the feeding plans during and after RBC transfusion.

To date, splanchnic oxygenation response to feeds before and after transfusion has not been investigated, but could bring useful information to understand the splanchnic hemodynamic changes associated to RBC transfusion.

Therefore, the aim of this study is to evaluate SrSO2 patterns in response to enteral feeding before and after transfusion.

Enrolled infants will undergo a 12-h monitoring of cerebral (CrSO2) and splanchnic (SrSO2) oxygenation, performed using an INVOS 5100 oxymeter (Medtronic, Boulder, CO), whose neonatal sensors will be placed in the central region of the forehead and the below the umbilicus, respectively.

The study monitoring includes the following phases:

• Phase 1 (0-3 hours): pre-transfusion feed and related post-prandial period
• Phase 2 (4-9 hours): RBC transfusion (10 ml/kg),administered over 3 hours, following which feeds are hold for 3 hours.
• Phase 3 (10-12 hours): post-transfusion feed and related post-prandial period.

CrSO2 and SrSO2 patterns before and after transfusion and the related changes from baseline values will be analyzed. SCOR (CrSO2/SrSO2 ratio) patterns will be also calculated and analyzed. IBM SPSS Statistics (Statistical Package for the Social Sciences, SPSS Inc., IBM, Armonk, NY) will be used for statistical analysis. If any infant develops TANEC after transfusion, the related patterns will be evaluated and analyzed separately.

Inclusion Criteria:

• gestational age <32 weeks or birth weight <1500 g
• need for red blood cell transfusion according to national guidelines

Exclusion Criteria:

• hemodynamic instability
• Prior occurrence of necrotizing or presence of symptoms and signs of feeding intolerance within one week before transfusion

Anemic preterm infants requiring red blood cell transfusion.