Normal values of blood flow velocity in the terminal vein of preterm infants

Aim: Evaluation of blood flow velocity in terminal veins of both cerebral hemispheres by Doppler-sonographic measurement. The examinations were done in clinically stable, non-ventilated preterm infants between gestational weeks 29 and 36. Method: Terminal veins were localised by colour duplex sonography, then the maximal blood flow velocity was measured by PW Doppler. Every measurement was repeated for accuracy. Results: From the averaged data, percentiles were calculated for both cerebral hemispheres. A linear correlation between gestational age and maximal blood flow velocity in the terminal vein was seen. The maximal blood flow velocity increased from 3.2 cm/sec at 29 weeks to 4.6 cm/sec at 36 weeks. No difference could be seen between both cerebral hemispheres. Conclusion: Percentiles could be calculated for the blood flow velocity in the terminal vein of both cerebral hemispheres. Maximal blood flow velocity increases from 29 to 36 weeks of gestational age. Serial examination during the first days of life are a feasible tool for detecting preterm infants at risk for intracerebral haemorrhage or infarction.