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. Aims: 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). Materials and 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.