title: Fluid distribution kinetics during cardiopulmonary bypass.
abstract: OBJECTIVE
  The purpose of this study was to examine the isovolumetric distribution kinetics of crystalloid fluid during cardiopulmonary bypass.
  
  
  METHODS
  Ten patients undergoing coronary artery bypass grafting participated in this prospective observational study. The blood hemoglobin and the serum albumin and sodium concentrations were measured repeatedly during the distribution of priming solution (Ringer's acetate 1470 ml and mannitol 15% 200 ml) and initial cardioplegia. The rate of crystalloid fluid distribution was calculated based on 3-min Hb changes. The preoperative blood volume was extrapolated from the marked hemodilution occurring during the onset of cardiopulmonary bypass. Clinicaltrials.gov: NCT01115166.
  
  
  RESULTS
  The distribution half-time of Ringer's acetate averaged 8 minutes, corresponding to a transcapillary escape rate of 0.38 ml/kg/min. The intravascular albumin mass increased by 5.4% according to mass balance calculations. The preoperative blood volume, as extrapolated from the drop in hemoglobin concentration by 32% (mean) at the beginning of cardiopulmonary bypass, was 0.6-1.2 L less than that estimated by anthropometric methods (p<0.02). The mass balance of sodium indicated a translocation from the intracellular to the extracellular fluid space in 8 of the 10 patients, with a median volume of 236 ml.
  
  
  CONCLUSIONS
  The distribution half-time of Ringer's solution during isovolumetric cardiopulmonary bypass was 8 minutes, which is the same as for crystalloid fluid infusions in healthy subjects. The intravascular albumin mass increased. Most patients were hypovolemic prior to the start of anesthesia. Intracellular edema did not occur.
authors.affiliation: Departments of Cardiovascular and Thoracic Anesthesia, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Törnudd
authors.affiliation: Department of Anesthesia and Intensive Care, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Hahn
authors.affiliation: Department of Anesthesia and Intensive Care, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
authors.forename: Joachim H
authors.initials: JH
authors.lastname: Zdolsek
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001810:Blood Volume / Q000187:drug effects / Q000502:physiology*; D001929:Brain Edema / Q000209:etiology; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D000077324:Crystalloid Solutions; D005110:Extracellular Space / Q000378:metabolism; D005260:Female; D018495:Fluid Shifts / Q000187:drug effects / Q000502:physiology; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007552:Isotonic Solutions / Q000493:pharmacokinetics*; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D008875:Middle Aged; D011446:Prospective Studies; D012709:Serum Albumin / Q000032:analysis; D012964:Sodium / Q000097:blood / Q000652:urine; D014882:Water-Electrolyte Balance / Q000502:physiology
chemical_list: D000077324:Crystalloid Solutions; D006454:Hemoglobins; D007552:Isotonic Solutions; C028570:Ringer's acetate; D012709:Serum Albumin; D008353:Mannitol; D012964:Sodium