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 [51Cr(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 51Cr(III). Twenty out of 33 rabbits were used to find CF by dividing blood volume estimation using EBD with blood volume estimation using 51Cr(III). CF is validated in 13 rabbits by multiplying it with blood volume estimation values obtained using 51Cr(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 51Cr(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 51Cr(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 51Cr(III) was comparable to standard EBD method using CF. With further research in this direction, we envisage human blood volume estimation using 51Cr(III) to find its application in acute clinical settings.

Preclinical evaluation of efficacy and pharmacokinetics of gentamicin containing extracellular‐matrix envelope

“…These findings align with previous clinical studies, in which gentamicin delivered via collagen ECM or directly to the surgical site reached concentrations in local tissues that exceeded 300 mg/L, whereas systemic exposure was limited to approximately 1‐2 mg/L 36,49 . It is worth noting that the blood volume of a rabbit is approximately 3% of the blood volume of a human (∼0.15 L in rabbits and 5 L in humans) 50,51 . Therefore, the concentration of gentamicin expected in the systemic circulation of a patient implanted with one gentamicin containing ECM envelope would be much lower than the levels observed in this rabbit study, and probably undetectable.…”

“…36,49 It is worth noting that the blood volume of a rabbit is approximately 3% of the blood volume of a human (∼0.15 L in rabbits and 5 L in humans). 50,51 Therefore, the concentration of gentamicin expected in the systemic circulation of a patient implanted with one gentamicin containing ECM envelope would be much lower than the levels observed in this rabbit study, and probably undetectable. However, low systemic exposure to gentamicin may be more relevant in older patients and those with pre-existing renal failure.…”

A Modified Carbon Monoxide Breath Test for Measuring Erythrocyte Lifespan in Small Animals

“…The EBD dilution test was used to estimate blood volume [ 12 , 13 ]. It was conducted on the same day of the CO breath test after breath sampling.…”

“…Blood volume is a parameter in the equation used to calculate RBC lifespan based on CO breath test results. The EBD dilution test was performed as described elsewhere with slight modifications [ 12 , 13 ]. Briefly, for each animal, an initial (blank) 1 mL blood sample was withdrawn from the auricular artery and 1 mL of 0.2% EBD solution in normal saline was injected into the marginal vein.…”

An innovative approach for serial injection in marginal vein and blood collection from auricular artery in New Zealand white Rabbit

“…The blood volume of New Zealand white rabbits was estimated using this procedure, by injection of Evan’s blue dye into the marginal vein and serial blood samples were obtained from the auricular artery to estimate the concentration of the dye [8] . It has been observed that the mean blood volume values using this procedure (65.76 ml/kg) falls within the normal physiological range (45–70 ml/kg) in New Zealand white rabbits [5] .…”