Abstract 1248 Poster Session IV, Tuesday, 5/4 (poster 270)

Ibuprofen has been recently evaluated as an alternative to indomethacin for pharmacological closure of the ductus arteriosus in preterm infants. It shows clinical efficacy and, in contrast to indomethacin, is devoid of significant vasoconstrictor effect on the cerebral and splancnic vasculature. Aim of this study was to investigate the effect of ibuprofen on cerebral vasoreactivity to CO2 (CBVR), measured by near-infrared spectroscopy (NIRS), in premature infants.

Method Fourteen newborns, of 29 (25-31) weeks gestation, 890 (550-1640) grams birth weight, undergoing mechanical ventilation for RDS, who received ibuprofen (10 mg/kg) on their first day of life as prophylaxis against persistent patency of ductus arteriosus were studied. NIRS (NIRO 500, Hamamatsu Photonics), a technique based on the differential absorption of near-infrared light by hemoglobin, depending on its oxidation state, was used to assess changes in total cerebral hemoglobin (a direct index of cerebral blood volume). CBVR was estimated, before and after ibuprofen administration, by linear regression analysis of increases in total cerebral haemoglobin and corresponding increases in PaCO2, obtained introducing a 5 ml dead space in the ventilatory circuit. Pre-and post-treatment CBVR were compared by paired Student t test.

Results Increases in PaCO2 of 0.5 to 1.5 KPa were induced over 6 to 15 minutes. Total hemoglobin increased in all cases and the relation was always linear in the studied PaCO2 range. CBVR was not affected by ibuprofen (5.31±2.61 µol/L/KPa pre-treatment vs 5.18±2.69 µol/L/KPa post-treatment, N.S.). Regression analysis of the effects of MABP, gestational age and post-natal age on CBVR did not show any significant correlation.

Conclusions Preserved cerebral vasoreactivity to PaCO2 further differentiates ibuprofen from indomethacin. Whether this represents an advantage over indomethacin remains to be established.