Differences between Hepatic and Cerebral Regional Tissue Oxygen Saturation at the Onset of Intradialytic Hypotension

Background: Intradialytic hypotension (IDH) is a critical pathological condition associated with all-cause mortality in patients undergoing hemodialysis (HD). However, few studies have investigated IDH-related changes in hepatic and cerebral regional tissue oxygen saturation (rSO(2)). This study investigated IDH-induced changes in hepatic and cerebral rSO(2). Methods: Hepatic and cerebral rSO(2) during HD were measured using an INVOS 5100C oxygen saturation monitor, and their percentage (%) changes during the development of IDH were analyzed. Ninety-one patients undergoing HD were investigated, including twenty with IDH. Results: In patients with IDH, % changes in hepatic and cerebral rSO(2) decreased at the onset of IDH. Additionally, the % change in hepatic rSO(2) was significantly larger than that in cerebral rSO(2) (p < 0.001). In patients without IDH, no significant differences were found between the % changes in hepatic and cerebral rSO(2) at the time of the lowest systolic blood pressure during HD. Multivariable linear regression analysis showed that the difference between the % changes in cerebral and hepatic rSO(2) was significantly associated with the development of IDH (p < 0.001) and the ultrafiltration rate (p = 0.010). Conclusions: Hepatic and cerebral rSO(2) significantly decreased during the development of IDH, and hepatic rSO(2) was more significantly decreased than cerebral rSO(2) at the onset of IDH.