Background and aims Increased cerebral haemoglobin oxygen saturation (rSO₂) and decreased cerebral fractional tissue oxygen extraction (FTOE) 24 h after birth in infants have reported to be associated with adverse outcomes. Near-infraredtime-resolved spectroscopy (TRS) device enables the simultaneous assessment of quantitative hemodynamics, and absolute values of (rSO₂) and cerebral bloodvolume (CBV). The purpose of our study was to determine the usefulness of both rSO₂ and CBV measured by TRS in infants with asphyxia after birth.

Methods Twenty-six infants with asphyxia (Apgar score < 7 at 1 min after birth) were divided into 2 groups: those with hypoxic-ischaemic encephalopathy (HIE; HIE group, n = 5) and those without hypoxic-ischaemic encephalopathy (non-HIE group, n = 21). rSO₂ and FTOE were measured by TRS at 12, 24, 48, and 72 h after birth.

Results rSO₂ was significantly higher and FTOE was significantly lower in the HIE group (n = 5) than in the non-HIE group (n = 21) at 12, 24, 48, and 72 h after birth. CBV was significantly higher in the HIE group (n = 5) than in the non-HIE (n = 21) from 3–6 h after birth through all measurement time points.

Conclusions Changes in CBV occurred earlier than those in rSO₂. Thus, CBV may be an early predictive parameterfor adverse outcomes in infants with asphyxia after birth.