Cerebral oxygenation changes in response to post-hemodialysis standing

Few reports have examined the association between changes in cerebral oxygenation and clinical factors, including blood pressure (BP), upon standing after hemodialysis (HD). This study aimed to clarify the factors affecting the changes in cerebral regional oxygen saturation (rSO₂) upon standing after HD and monitor the differences in cerebral rSO₂ changes that occur upon standing after HD in patients with and without diabetes mellitus (DM). Changes in mean BP and cerebral rSO₂ were tracked in 43 HD patients during 120 s of standing after HD using an INVOS 5100c oxygen saturation monitor. The post-HD cerebral rSO₂ at rest was 55.8 ± 10.2%, while that at 120 s of standing decreased to 51.9 ± 9.6%; therefore, the percentage change in cerebral rSO₂ at 120 s of standing was - 6.8 ± 6.4%, which was significantly lower than before HD (p < 0.001). This change was significantly correlated with the presence of DM, HD duration, mean BP at 120 s of standing, and percentage change in mean BP at 120 s of standing. A multivariable linear regression analysis showed that percentage change in cerebral rSO₂ at 120 s of standing was independently associated with the percentage change in mean BP at 120 s of standing (standardized coefficient: 0.432; p = 0.004). Furthermore, there were significant decreases in percentage changes in cerebral rSO₂ throughout the standing period in HD patients with versus without DM. Therefore, cerebral oxygenation deterioration upon standing after HD should receive attention, particularly in HD patients with DM.