title: Atrial natriuretic peptide serum concentration decreases in donors undergoing discontinuous plasmapheresis involving a large extracorporeal blood volume.
abstract: BACKGROUND
  In donor plasmapheresis, circulatory reactions occur at a similar frequency as in whole-blood donation although the large extracorporeal blood volume (ECV) occurring during discontinuous plasmapheresis might predispose donors to hypovolemic reactions. The regulatory mechanisms compensating for this intradonation blood volume (BV) deficit are not well understood. It was the aim of this study to delineate whether atrial natriuretic peptide (ANP) is involved in the BV regulation of plasmapheresis donors. Because ANP regulates volume overload, it might decrease during BV decrease in plasmapheresis.
  
  
  METHODS
  ANP serum concentrations were determined in 60 donors undergoing discontinuous plasmapheresis. Samples were taken before the start of the procedure and when maximum ECV (ECV(max)) was reached at the end of the last withdrawal. Donors were randomly selected after stratification for sex and BV. In a control investigation, the same donors were kept in a reclined position for the duration of a plasmapheresis session without plasma withdrawal. ANP plasma concentration changes were correlated with changes of hemodynamic variables, which were recorded noninvasively with bioelectrical impedance cardiography.
  
  
  RESULTS
  Median ANP concentration decreased from 13.0 to 8.4 pg per mL during donation and from 11.6 to 10.5 pg per mL during the control session. The mean control-adjusted ANP change due to plasma withdrawal was -2.62 pg per mL (p = 0.006). This decrease was not attributable to a dilution effect. ANP change did not correlate with changes of recorded hemodynamic variables.
  
  
  CONCLUSIONS
  The decrease of the ANP serum concentration during plasmapheresis demonstrates that the ECV(max) constitutes a hypovolemic challenge of the donors, which elicits a neurohormonal regulatory mechanism aimed at maintaining cardiovascular homeostasis.
authors.affiliation: Institute for Transfusion Medicine and Hemostaseology, Philipps University, Marburg, Germany. karger@mailer.uni-marburg.de
authors.forename: Ralf
authors.initials: R
authors.lastname: Karger
authors.forename: Monika
authors.initials: M
authors.lastname: Halbe
authors.forename: Susanne
authors.initials: S
authors.lastname: Giffhorn-Katz
authors.forename: Norbert
authors.initials: N
authors.lastname: Katz
authors.forename: Volker
authors.initials: V
authors.lastname: Kretschmer
mesh_terms: D009320:Atrial Natriuretic Factor / Q000097:blood*; D001782:Blood Donors; D001810:Blood Volume; D005260:Female; D006801:Humans; D008297:Male; D010956:Plasmapheresis
chemical_list: D009320:Atrial Natriuretic Factor