Difference in cerebral blood flow velocity in neonates with and without hyperbilirubinemia

Purpose: To evaluate the difference in cerebral blood flow velocity (CBFV) in neonates with and without hyperbilirubinemia. Methods: CBFV of 70 healthy late-preterm and term newborns with unconjugated hyperbilirubinemia (UCH) reaching the threshold of phototherapy requirement was compared with 70 gestational- and postnatal age-matched controls without hyperbilirubinemia. Resistance index (RI), pulsatility index (PI), peak systolic velocity (PSV) and vascular diameter were measured in internal carotid, vertebral and middle cerebral arteries by transcranial color Doppler ultrasound at the beginning of phototherapy, after 48–72 h of starting phototherapy and at 5–7 days after its stoppage. In controls CBFV was assessed once at inclusion. Results: Both the groups were comparable. An increase in CBFV (decreased RI and PI, increased PSV and vasodilation) was observed in the UCH group. A further increase in CBFV was noticed after 48 h of phototherapy. After 5–7 days of stoppage of phototherapy, though there was a significant reduction in CBFV in mild-to-moderate UCH (serum bilirubin ⩽25 mg/dL), in severe UCH (serum bilirubin >25 mg/dL), CBFV remained increased. Four neonates developed features of acute bilirubin encephalopathy and had significantly higher CBFV compared to those with normal outcome. Conclusions: An increase in CBFV was observed in neonates with UCH compared to those without hyperbilirubinemia.