Analysis of prefrontal cerebral blood volume and flow changes in ESKD patients undergoing hemodialysis using functional near-infrared spectroscopy

End-stage kidney disease (ESKD) patients undergoing hemodialysis experience diverse neurological complications. This study investigated prefrontal cerebral blood volume (CBV) and cerebral blood flow (CBF) during hemodialysis using functional near-infrared spectroscopy (fNIRS) to analyze cerebral hemodynamic changes. ESKD patients undergoing maintenance hemodialysis without a history of neurological disorders were enrolled prospectively. The fNIRS data were collected using a NIRSIT Lite device. The fNIRS values were recorded three times for each patient: before the start of hemodialysis (pre-HD), 1 h after the start of hemodialysis (mid-HD), and after the end of hemodialysis (post-HD). The average changes in oxy-hemoglobin (HbO₂), deoxy-hemoglobin (HbR), total hemoglobin (HbT, calculated as HbO₂ + HbR) concentrations, and in hemoglobin concentration difference (HbD, calculated as HbO₂ − HbR) were analyzed. We then compared the differences in changes in HbO₂, HbR, HbT, and HbD according to the hemodialysis period. Thirty hemodialysis patients were analyzed. The change in HbO₂, HbT, and HbD levels showed significant differences according to the hemodialysis period. Between the pre-HD and post-HD periods, there were significant differences in changes in HbO₂ (0.005 ± 0.001 µM vs. 0.015 ± 0.004 µM, <i>p</i> = .046) and HbT (0.006 ± 0.001 µM vs. 0.016 ± 0.008 µM, <i>p</i> = .029). Additionally, between pre-HD and post-HD periods, HbD tended to increase (0.005 ± 0.001 µM vs. 0.014 ± 0.004 µM, <i>p</i> = .094). We demonstrated that during one hemodialysis session, the relative change in prefrontal CBV increased post-HD compared with pre-HD. These results are expected to help understanding the mechanisms underlying the effects of hemodialysis on brain function.