title: Kinetics of plasma refilling during hemodialysis sessions with different initial fluid status.
abstract: Removal of fluid excess from the plasma volume by ultrafiltration during hemodialysis (HD) is balanced by plasma refilling from the interstitium, driven mainly by the increase in plasma oncotic pressure. We calculated the plasma refilling coefficient (Kr, a parameter expressing the ratio of refilling rate to the increase in oncotic pressure) for nine patients, each undergoing two HD sessions differing by pretreatment fluid status and session time (shorter session, SH, 3.5 h, and longer session, LH, 4.5h). Relative blood volume change was measured online, and solute concentrations were measured regularly during the sessions. The volume of body compartments was measured by bioimpedance. The patients were more volume expanded before LH session (higher initial body mass and total body water). Oncotic pressure was similar for both sessions. The refilling rate, despite higher fluid overload in the LH sessions, was similar for both sessions. The final Kr values stabilized on similar levels (SH: 136.6 ± 55.6 ml/mm Hg/h and LH: 150.7 ± 73.6 ml/mm Hg/h) at similar times, notwithstanding the difference in initial fluid overload between the two groups, suggesting that Kr at dry weight is relatively insensitive to the initial fluid status of the patient.
authors.affiliation: From the *Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland; †Baxter Novum and Renal Medicine, Karolinska Institutet, and Karolinska University Hospital, Stockholm, Sweden; ‡Diaverum, Stockholm, Sweden; and §Institute of Physiology, Medical University of Graz, Graz, Austria.
authors.forename: Mauro
authors.initials: M
authors.lastname: Pietribiasi
authors.forename: Krassimir
authors.initials: K
authors.lastname: Katzarski
authors.forename: Magda
authors.initials: M
authors.lastname: Galach
authors.forename: Joanna
authors.initials: J
authors.lastname: Stachowska-Piętka
authors.forename: Daniel
authors.initials: D
authors.lastname: Schneditz
authors.forename: Bengt
authors.initials: B
authors.lastname: Lindholm
authors.forename: Jacek
authors.initials: J
authors.lastname: Waniewski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001810:Blood Volume / Q000502:physiology*; D005260:Female; D017583:Hemodiafiltration; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D014462:Ultrafiltration