Abstract 37

Background/Aim: Previous studies have shown increased generation of oxidation products in the plasma of hypoxic newborns at birth. The present study tests the hypothesis that hypoxic preterm newborns are at increased risk for free radical damage in the following days. Subjects: Heparinized blood samples of 29 hypoxic (BW = 1910 ± 499 g, GA 33.0 ± 2.3 wks) and 16 control (BW = 1966 ± 622 g, GA 32.8 ± 2.2 wks) preterm newborns were obtained at birth and on the 7th day of life. Neonates were considered hypoxic according to the following criteria: pH in the umbilical vein ≤ 7.2, Apgar score at 5 min ≤ 6 and FiO2 ≥ 0.4 at birth. Measurements: Plasma levels of TH, AOPP and hypoxanthine (Hx) were detected by spectrophotometric assay (TH and AOPP), and by high-pressure liquid chromatography (Hx). Results: Hx, TH and AOPP were significantly higher in cord and 7h-day blood samples of hypoxic newborn than controls (cord: p = 0.0001, p = 0.0001, p = 0.003; 7th-day p = 0.007, p = 0.005, p = 0.007 respectively). Statistically significant correlations were observed between AOPP and Hx plasma levels (r = 0.63, p = 0.005, n = 18) on day 7. AOPP and TH plasma levels significantly increased from cord to 7th day blood in neonates without hypoxia (p = 0.006 and p = 0.01 respectively). Conclusions: Hypoxic preterm newborns are at increased risk of free radical damage in the days following birth. This risk is lower but still exists in preterm neonates without hypoxia.

Supported by a grant from the Italian Ministry of Education (MURST 60%)