[Usefulness of Doppler ultrasound imaging in monitoring of hypoxic-ischemic encephalopathy in preterm infants].

Cerebral blood flow disregulation could be one of the main causes of hypoxic-ischaemic encephalopathy (HIE). It is difficult to differentiate between sonographic appearance of immature periventricular white matter of premature neonate and changes of HIE type. Therefore the diagnostic and prognostic value of doppler ultrasound resistance index (RI) examination in anterior cerebral arteries of premature infants with early sonographic signs of periventricular white matter hyperechogenicity was the aim of the study. The study group consisted of 23 premature infants: birth weight 1550 +/- 570 g, gestational age 24-32 weeks, Apgar score 2-7 points, of which 19 were ventilated. Doppler ultrasound imaging was performed twice: during the first 24 hours of life and 3 weeks later. As not all infants survived to the time of control examination, the final study group consisted of 17 subjects. Doppler examination of premature infants having finally sonographic signs of HIE (n = 12) revealed that RI value in this group of infants was increased during initial as well as the next examination. In the group of premature infants having finally normal sonographic scan (n = 5), doppler examinations showed that RI value stayed in normal limits or was slightly decreased all the time. We conclude that doppler imaging of premature infants could be important diagnostic and prognostic tool in differentiating between the ultrasonographic view of immature periventricular white matter and real HIE. Doppler imaging is useful in identification of patients having increased risk of HIE and supplements routine transfontanellar ultrasound in estimation of HIE progression.