ABSTRACT
BACKGROUND: The optimal hematocrit (Hctopt) in hemodialysis (HD) patients has yet to be determined based on the etiology and complications of their endstage renal disease (ESRD). To investigate this problem, we compared regional cerebral oxygen supply (rCOS) in diabetic (DM group) and non-diabetic HD patients (non-DM group) with data from subjects without renal disease or DM (control group) METHODS: Regional cerebral blood flow (rCBF) was measured with single-photon emission computed tomography (SPECT) by the N-isopropyl-p-[(123)I]-iodoamphetamine ((123)I-IMP)-autoradiographic (ARG) method, and both the O2 content (O2CT) of arterial blood and hematocrit (Hct) were evaluated. Using the regression lines of rCBF vs Hct and O2CT vs Hct, we established a convex curve between rCOS and Hct. The peak of the curve indicates the maximum rCOS (rCOSmax) and Hctopt for rCOSmax RESULTS: The rCBF in both the DM and non-DM groups was lower than that of the control group at the same Hct level, and the DM group had the lowest values. The rCOSmax values in the DM and non-DM groups were nearly equal, but both were lower than in controls. The Hctopt in the DM group was lower than that in the non-DM group by 6.3%±3.3% CONCLUSIONS: Although the difference in Hctopt values in the DM and non-DM groups was 6.3%, the rCOSmax values in both groups were nearly equal. This suggests that differences in the Hctopt may depend on complications or causes of ESRD. The optimal Hct in the DM group was 22.6%±1.9%, and that for the non-DM group was 29.0%±1.8%
