Patient-Specific Relationship Between Hydraulic Permeability of Microvasculature and the Extent of Burden of Excess Fluid in Hemodialysis Patients.

We have reported a significant correlation between hydraulic permeability of microvasculature adjusted with ultrafiltration rate (AdjLpst) and excess fluid divided by dry weight (ExF/DW) in a cross-sectional study of hemodialysis patients. We aimed to study longitudinally whether a similar relationship between them exists in each patient. Twelve hemodialysis (HD) patients in whom AdjLpst and ExF/DW had been measured more than four times (total of 85 measurements) were enrolled. AdjLpst was calculated by monitoring blood volume during HD. ExF was calculated from the fluid volume measured via bioimpedance spectroscopy. The borders of overhydration were 1.66 mL/mm Hg per min for AdjLpst and a positive value for ExF/DW. There was a significant correlation between AdjLpst and ExF/DW (r = 0.517). When the 85 measurements were classified into four quadrants according to ExF/DW and AdjLpst, the evaluations of fluid status agreed in 66 measurements. In six patients, significant positive correlations were found. In nine patients, equal to or more than 80.0% of evaluations by AdjLpst and those by ExF/DW agreed. In only one patient was there neither significant correlation nor agreement. AdjLpst of two patients suffering from chronic heart failure and microscopic polyangiitis was reduced compared with that of others loaded with the same extent of excess fluid. We concluded that there was a significant correlation between AdjLpst and ExF/DW and high agreement between evaluation by AdjLpst and evaluation by ExF/DW in the majority of patients. However, the relationship between them was patient-specific to some extent.