O-029 Neonatal Circulation Measured Using Near-infrared Spectroscopy (nirs) Differs Between Preterm And Term Born Intrauterine Growth Restricted (iugr) Infants

Abstract

<h3>Background and aim</h3> IUGR fetuses display redistribution of fetal blood flow to vital organs. This can be different in preterm and term IUGR fetuses. It is not known whether the distribution of the neonatal circulation is still affected by IUGR, and if it differs between these groups. Our aim was to compare the neonatal circulation in preterm and term IUGR infants, measured by NIRS. <h3>Methods</h3> Preterm and term infants were prospectively included between May 2012 and April 2014 when IUGR was diagnosed. Cerebral, renal and abdominal regional tissue oxygen saturations (rSO₂) were measured for 2 h continuously using NIRS on days 1 to 3 after birth. Fractional tissue oxygen extraction (FTOE) was calculated using rSO₂ and arterial oxygen saturation (SaO₂) values: (SaO₂–rSO₂)/SaO₂. <h3>Results</h3> We included 42 IUGR infants (21 preterm/21 term), gestational age median 31.3 weeks (IQR 28.5–33.2), and 38.6 weeks (37.7–39.1), respectively; birth weight 1100 grams (770–1510), and 2420 grams (2027–2645). Results are shown in Table 1. <h3>Conclusion</h3> In the first 2 days after birth, preterm IUGR infants showed lower renal and abdominal rSO₂ (higher FTOE) when compared with term IUGR infants, indicating altered neonatal circulation. Furthermore, cerebral rSO₂was higher and cerebral FTOE was lower indicating increased cerebral perfusion. This may be interpreted as brain sparing continuing after birth. However, the difference with term IUGR (higher cerebral FTOE indicating no brain sparing) vanishes. We conclude that preterm IUGR infants experience brain sparing in the first 2 days, whereas term IUGR infants do not.