Vascular Refilling Is Not Reduced in Dialysis Sessions with Morbid Events

Abstract

Background: It is commonly believed that insufficient vascular refilling leads to hypovolemia during hemodialysis and contributes to intradialytic morbid events (IME). But data of refilling volumes at the time of IME are lacking. Methods: We compared the vascular refilling in 10 patients with IME with 14 stable patients with normal blood volume at the dialysis end (66-80 mL/kg). Results: The refilling characteristics in patients with IME did not differ from those in stable patients. The refilling fraction (refilling/ultrafiltration [UF] ratio) was 73.8 ± 9.4% in patients with IME, and 70.2 ± 6.4% in patients with normal blood volume at the end of the treatment. Refilling volume strongly correlated with UF volume in both patient groups (r2 = 0.93 and r2 = 0.81, respectively). Conclusion: IME are associated with a specific blood volume below 65 mL/kg. Vascular refilling is a constant fraction of UF in stable as well as in symptomatic dialysis sessions.