Change over time in internal cerebral vein pulsation in premature infants at risk of intraventricular hemorrhage

Background: Prolonged continuation of augmented internal cerebral vein (ICV) pulsation may be related to the development of premature intraventricular hemorrhage (IVH). However, the characteristics of ICV flow patterns in premature infants are unclear.Aim: To investigate the changes over time in ICV pulsation in premature infants at risk of IVH.Study design: A 5-year retrospective observational study of a single-center trial.Subjects: In total, 112 very-low-birth-weight infants with gestational age of <= 32 weeks. Outcome measures: ICV flow was measured every 12 h until 96 h after birth and thereafter on days 7, 14, and 28. The ICV pulsation index (ICVPI), which is a ratio of the minimum/maximum speed of ICV flow, was calculated. We recorded longitudinal ICVPI change and compared ICVPI among three groups classified according to gestational age.Results: ICVPI started declining after day 1 and reached the minimum median value in 49-60 h after birth (1.0 during 0-36 h, 0.9 during 37-72 h, and 1.0 after 73-84 h). ICVPI was significantly lower during 25-96 h than during 0-24 h and on days 7, 14, and 28. ICVPI in the 23-25-week group was significantly lower between 13-24 h and day 14 than that in the 29-32-week group, and the same was observed for the 26-28-week group between 13-24 h and 49-60 h.Conclusions: ICV pulsation was affected by time after birth and gestational age, and this ICVPI fluctuation may reflect a postnatal circulatory adaptation.