Absolute blood volume and long-term survival in chronic hemodialysis patients

Current online hemodiafiltration devices can be used to determine the absolute blood volume in clinical practice using the dialysate bolus method. Most of publications on this method have focused on preventing intradialytic complications. The influence of absolute blood volume on long-term prognosis has not been reported yet. A total of 79 participants in a previous study about absolute blood volume were followed for 5 years. Patients with a specific blood volume above (n = 45) and below 75 ml/kg (n = 34) respectively were compared with regard to survival using Kaplan-Meier analysis. Patients with a specific blood volume below 75 ml/kg had a significantly higher overall 5-year survival rate than patients above 75 ml/kg (70% vs 39%, p = 0.0233). In patients without cardiac dysfunction, there were no significant differences in 5-year survival between a specific blood volume below or above 75 ml/kg (66% vs 51%). A specific blood volume above 75 ml/kg was associated with an increased mortality in patients with mildly impaired left-ventricular systolic ejection fraction of 40%-59%, whereas in patients with normal blood volume this cardiac impairment did not impact mortality (22% vs 90% 5-year survival, p = 0.0036). This demonstrates the significance of optimum volume control for long-term survival particularly in cases of reduced cardiac function.