Importance of volume factors in dialysis related hypertension.

In order to evaluate the influence of volume factors on blood pressure (BP) in 20 chronic hemodialysis patients, we studied the effect of total body water, interdialytic weight gain, hematocrit, erythropoietin, and blood viscosity on BP with predialysis and 24 h ambulatory measurements. There was a significant correlation between weight gain and mean BP before dialysis (r = .48, p = .02), but not with mean BP during the day before dialysis (r=0.08, p = .7). On the contrary there was no correlation between percentage of total body water (TBW %) and BP before dialysis (r = .08, p = .7), but a significant correlation with mean BP during the day before dialysis (r = .57, p = .01). The other variables had no influence on BP. The data suggest that BP before dialysis is more related to acute extracellular volume changes, and that chronic hypertension is more related to total body water. TBW measurements can possibly be used as a guideline in the treatment of dialysis patients with hypertension.