title: Evaluation of hydration status calculated from differences in venous and capillary plasma dilution during stepwise crystalloid infusions: A randomized crossover study in healthy volunteers.
abstract: OBJECTIVE
  A mini volume loading test (mVLT) was proposed for estimating hydration status and interstitial fluid accumulation during stepwise infusion of crystalloids. The method is based on both the transcapillary reflux model and the hypothesis that when subjects are dehydrated, venous plasma dilution induced by a fluid challenge is higher than in the capillaries, and that difference is diminished when the fluid challenge is given to more hydrated individuals. Our objective was to test that hypothesis by evaluating the veno-capillary dilution difference during mVLT in subjects with different hydration status.
  
  
  METHODS
  In a prospective randomized crossover study, three mini fluid challenges were given to 12 healthy volunteers on two occasions. The subjects were either dehydrated or hydrated before the experiments.
  
  
  RESULTS
  In dehydrated subjects only, capillary plasma dilution was significantly lower than venous (P=0.015, 0.005 and 0.006) after each mini fluid challenge.
  
  
  CONCLUSIONS
  Veno-capillary dilution difference during mVLT depends on the hydration status. The mVLT method could possibly discriminate between the different states of hydration.
authors.affiliation: Section of Anaesthesiology and Intensive Care, Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden. Electronic address: christer.svensen@sodersjukhuset.se.
authors.forename: Christer H
authors.initials: CH
authors.lastname: Svensen
authors.affiliation: Institute of Physiology and Pharmacology, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania.
authors.forename: Edgaras
authors.initials: E
authors.lastname: Stankevičius
authors.affiliation: Section of Anaesthesiology and Intensive Care, Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Jacob
authors.initials: J
authors.lastname: Broms
authors.affiliation: Department of Electronics Engineering, Kaunas University of Technology, Kaunas, Lithuania.
authors.forename: Vytautas
authors.initials: V
authors.lastname: Markevičius
authors.affiliation: Clinic of Anaesthesiology and Intensive Care, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
authors.forename: Audrius
authors.initials: A
authors.lastname: Andrijauskas
mesh_terms: D002196:Capillaries; D018592:Cross-Over Studies; D000077324:Crystalloid Solutions; D003681:Dehydration / Q000097:blood / Q000628:therapy*; D064368:Healthy Volunteers; D006801:Humans; D007262:Infusions, Intravenous; D007552:Isotonic Solutions / Q000008:administration & dosage*; D010949:Plasma; D014680:Veins
chemical_list: D000077324:Crystalloid Solutions; D007552:Isotonic Solutions
keywords: Crystalloid; Hydration status; Interstitial fluid; Mini volume loading test; Noninvasive hemoglobin