Variability in splanchnic tissue oxygenation during preterm red blood cell transfusion given for symptomatic anaemia may reveal a potential mechanism of transfusion-related acute gut injury.

BACKGROUND

There is increasing evidence indicating an association between red blood cell (RBC) transfusions and necrotising enterocolitis (NEC) in preterm infants, especially late-onset NEC. This phenomenon is referred to as transfusion-related acute gut injury (TRAGI). One theory as to a pathophysiological mechanism is that transfusion may result in an ischemia-reperfusion injury to intestinal tissue. We tested the hypothesis that there is significantly greater variability during transfusion in splanchnic tissue oxygen saturation (SrSO2) than in cerebral tissue oxygen saturation (CrSO2).

MATERIALS AND METHODS

This was a prospective, observational study using near-infrared spectroscopy to monitor SrSO2 and CrSO2 in preterm neonates undergoing RBC transfusion for symptomatic anaemia. Mean, standard deviation, highest and lowest SrSO2 and CrSO2 values during each transfusion were determined. The greatest difference in SrSO2 and CrSO2 during each transfusion was calculated, along with the coefficient of variation.

RESULTS

We studied 37 subjects. Throughout all transfusions, the mean SrSO2 was 45.6% ±13.8 and the mean CrSO2 was 65.4% ±6.9 (p<0.001). The variability of SrSO2 was significantly greater than that of CrSO2. Averaging data from all subjects, the greatest difference in SrSO2 was 43.8% ±13.4 compared with 23.3% ±7.6 for CrSO2 (p<0.001). The mean coefficient of variation in all transfusions was 20.5% for SrSO2 and 6.0% for CrSO2 (p<0.001). Increasing post-conceptional age did not affect SrSO2 variability (R(2) =0.022; p=0.379), whereas CrSO2 variability during transfusion decreased with increasing post-conceptional age (R(2)=0.209; p=0.004).

DISCUSSION

In preterm infants, there is a large degree of tissue oxygenation variability in splanchnic tissue during RBC transfusion and this does not change with increasing maturity. We speculate that these findings, combined with lower average tissue oxygenation, may demonstrate susceptibility of the preterm gut to TRAGI.