title: A novel method for blood volume estimation using trivalent chromium in rabbit models.
abstract: BACKGROUND
  Blood volume measurement though important in management of critically ill-patients is not routinely estimated in clinical practice owing to labour intensive, intricate and time consuming nature of existing methods.
  
  
  OBJECTIVE
  The aim was to compare blood volume estimations using trivalent chromium [(51)Cr(III)] and standard Evans blue dye (EBD) method in New Zealand white rabbit models and establish correction-factor (CF).
  
  
  METHODS
  Blood volume estimation in 33 rabbits was carried out using EBD method and concentration determined using spectrophotometric assay followed by blood volume estimation using direct injection of (51)Cr(III). Twenty out of 33 rabbits were used to find CF by dividing blood volume estimation using EBD with blood volume estimation using (51)Cr(III). CF is validated in 13 rabbits by multiplying it with blood volume estimation values obtained using (51)Cr(III).
  
  
  RESULTS
  The mean circulating blood volume of 33 rabbits using EBD was 142.02 ± 22.77 ml or 65.76 ± 9.31 ml/kg and using (51)Cr(III) was estimated to be 195.66 ± 47.30 ml or 89.81 ± 17.88 ml/kg. The CF was found to be 0.77. The mean blood volume of 13 rabbits measured using EBD was 139.54 ± 27.19 ml or 66.33 ± 8.26 ml/kg and using (51)Cr(III) with CF was 152.73 ± 46.25 ml or 71.87 ± 13.81 ml/kg (P = 0.11).
  
  
  CONCLUSIONS
  The estimation of blood volume using (51)Cr(III) was comparable to standard EBD method using CF. With further research in this direction, we envisage human blood volume estimation using (51)Cr(III) to find its application in acute clinical settings.
authors.affiliation: Department of Physiology, Melaka Manipal Medical College, Manipal campus, Manipal University, Karnataka, India.
authors.forename: Prathap Moothamadathil
authors.initials: PM
authors.lastname: Baby
authors.affiliation: Department of Plastic Surgery, King Abdul Aziz Specialist Hospital, Al Jouf, Saudi Arabia.
authors.forename: Pramod
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Department of Nuclear Medicine, Kasturba Medical College, Manipal, Manipal University, Karnataka, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Department of Physiology, Kasturba Medical College, Manipal, Manipal University, Karnataka, India.
authors.forename: Sanu S
authors.initials: SS
authors.lastname: Jacob
authors.affiliation: Department of Nuclear Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Dinesh
authors.initials: D
authors.lastname: Rawat
authors.affiliation: Department of Statistics, Manipal Univeristy, Manipal, Karnataka, India.
authors.forename: V S
authors.initials: VS
authors.lastname: Binu
authors.affiliation: Department of Statistics, Manipal Univeristy, Manipal, Karnataka, India.
authors.forename: Kalesh M
authors.initials: KM
authors.lastname: Karun
keywords: Blood volume; Evans blue dye; measurement; trivalent chromium