title: Determination of the critical absolute blood volume for intradialytic morbid events.
abstract: The reduction of blood volume below a critical threshold is assumed to trigger intradialytic morbid events (IME). Recently, we presented a simple method to determine the absolute blood volume during routine hemodialysis (HD) carried out without blood sampling and without injection of dyes or radiolabeled markers. Such information could be used to detect excessive volume reduction during HD and to prevent IME. Therefore, we performed a pilot study in IME-prone patients to identify the absolute blood volume at which they developed clinical symptoms. A volume of 240 mL of ultrapure dialysate was automatically infused into the extracorporeal circulation using the bolus function of a commercial online hemodiafiltration machine incorporating a blood volume monitor (BVM). The increase in relative blood volume (RBV) caused by the infusion was measured and used to determine the absolute blood volume at that time. The blood volume per kilogram body mass at the time of symptomatic IME was also determined. All IME-prone patients of a single-dialysis center were included in the study. Ten out of 12 patients became symptomatic at a specific blood volume between 65 and 56 mL/kg (mean 62 mL/kg) whereas RBV showed a wide scatter (82-97%). A specific blood volume of 65 mL/kg seems to represent the threshold for IME by this method. The technique could be completely automated without altering the hardware of the dialysis device. Present feedback systems for automated blood volume-controlled ultrafiltration could be adapted to maintain absolute blood volume above this critical volume to safely prevent volume-dependent IME.
authors.affiliation: Department of Nephrology, Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Kron
authors.affiliation: Institute of Physiology, Medical University of Graz, Graz, Austria.
authors.forename: Daniel
authors.initials: D
authors.lastname: Schneditz
authors.affiliation: KfH Kidney Center Berlin-Köpenick, Berlin, Germany.
authors.forename: Til
authors.initials: T
authors.lastname: Leimbach
authors.affiliation: KfH Kidney Center Berlin-Köpenick, Berlin, Germany.
authors.forename: Jutta
authors.initials: J
authors.lastname: Czerny
authors.affiliation: KfH Kidney Center Berlin-Köpenick, Berlin, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Aign
authors.affiliation: KfH Kidney Center Berlin-Köpenick, Berlin, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Kron
mesh_terms: D000368:Aged; D001810:Blood Volume / Q000502:physiology*; D015314:Dialysis Solutions / Q000009:adverse effects*; D005260:Female; D017583:Hemodiafiltration / Q000379:methods; D006801:Humans; D007022:Hypotension / Q000209:etiology*; D008297:Male; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods
chemical_list: D015314:Dialysis Solutions
keywords: Absolute blood volume; blood volume monitoring; hemodialysis; intradialytic morbid events; volume management