Ultrafiltration volume is associated with changes in blood pressure in chronically hemodialyzed patients.

INTRODUCTION: Volume overload is a main factor in development of hypertension in hemodialysis patients. In order to demonstrate impact of ultrafiltration volume on blood pressure during 15-months period in a group of patients undergoing chronic hemodialysis therapy, we conducted this study. We hypothesized that ultrafiltration volume different affects the pre/postdialysis systolic pressure, diastolic pressure, mean arterial pressure (MAP), and pulse pressure (PP) values. SUBJECTS AND METHODS: Study subjects were 23 anuric chronically hemodialyzed patients. The overall study time was 15 months, and 136 single hemodialysis treatments were analyzed. RESULTS: Ultrafiltration was negatively correlated with predialysis systolic blood pressure (r = -0.169, p = 0.025), postdialysis systolic blood pressure (r = -0.292, p < 0.001), postdialysis MAP (r = -0.186, p = 0.015), predialysis PP (r = -0.290, p < 0.001), and postdialysis PP (r = -0.370, p < 0.001). Ultrafiltration/dry body mass (UF/W) ratio was negatively correlated with predialysis PP (r = -0.222, p = 0.005), postdialysis PP (r = -0.340, p < 0.001), and postdialysis systolic blood pressure (r = -0.243, p = 0.002). We found significant difference in postdialysis PP between dialyses with UF/W ratio < or = 0.05 an dialyses with UF/W ratio > 0.05 (63.49 +/- 20.76 vs. 56.27 +/- 16.33 mmHg, p = 0.033). CONCLUSION: The ultrafiltration volume strongly affects postdialysis PP values. Evaluation of elevated blood pressure treatment in patients undergoing chronic hemodialysis therapy must be considered in respect of postdialysis PP values, not just depending on pre/postdialysis systolic and diastolic pressur or MAP values.

Metabolic acidosis of chronically hemodialyzed patients.

Metabolic acidosis is a condition that is commonly encountered in both chronic renal failure and in end-stage renal disease. Metabolic acidosis is associated with many adverse effects: negative nitrogen balance, increased protein decomposition, anorexia, fatigue, bone lesions, impaired function of the cardiovascular system, impaired function of the gastrointestinal system, hormonal disturbances, insulin resistance, hyperkalemia, altered gluconeogenesis and triglyceride metabolism, increased progression of chronic renal failure, and growth retardation in children. Even 'minor' degrees of metabolic acidosis are deleterious. Metabolic acidosis of end-stage renal patients could be successfully corrected with bicarbonate hemodialysis and with peroral bicarbonate-containing phosphate binders, i.e. calcium carbonate. Bicarbonate powder compared with bicarbonate solutions has some advantages and enables a stabile composition of electrolytes. 'High' dialysate bicarbonate (40- 42 mmol/l) is a safe, well-tolerated and useful tool for better correction of the metabolic acidosis and must become a standard of hemodialysis treatment. Measured postdialysis blood bicarbonate concentration should be obtained at least every month and correction of metabolic acidosis by maintaining serum bicarbonate >or=22 mmol/l should be a goal of the management of patients undergoing chronic hemodialysis.