The hemodynamic effect of different ultrafiltration rates in patients with cardiac failure and patients without cardiac failure: comparison between isolated ultrafiltration and ultrafiltration with dialysis.

OBJECTIVE

The increasing number of dialysis patients with cardiovascular diseases will lead to an increase in the incidence of intradialytic hypotension. Intradialytic hypotension is determined by changes in plasma volume, changes in vascular reactivity and structural cardiovascular changes. In this study the effect of two different ultrafiltration rates (UF-rate), i. e. 500 and 1000 ml/h, on plasma volume, extracellular volume and arterial blood pressure was studied during different treatments of 2 hours combined ultrafiltration + hemodialysis (UF+HD) and 2 hours isolated ultrafiltration (i-UF).

PATIENTS AND METHODS

15 Patients, 8 patients with cardiac failure, CFpts (NYHA classification III and IV) and 7 patients without cardiac failure (NCFpts) were investigated during a standardized dialysis treatment.

RESULTS

The decrease in plasma volume and decrease in extracellular volume was comparable both between i-UF and UF+HD and comparable between CFpts and NCFpts and was only dependent on the UF-rate. i-UF resulted in minor blood pressure changes in both CFpts and NCFpts. In CFpts UF+HD resulted in a significant decrease in systolic blood pressure (SBP) at both UF-rates while in NCFpts SBP decreased significantly only at the higher UF-rate during UF-HD. Although there were no significant differences in hemodynamic stability during the different treatment modalities between CFpts and NCFpts, the decrease in SBP in CFpts at the higher UF-rate during UF+HD was much more pronounced.

CONCLUSION

From this clinical study we conclude that differences in hemodynamic stability between i-UF and UF+HD and between CFpts and NCFpts are not related to differences in plasma volume preservation. Other factors like different changes in vascular reactivity and in CFpts structural cardiovascular changes might be responsible for the observed differences.