RESUMO
Though often used in cardiac intensive monitoring set up, simultaneous evaluation of several variables like CVP, PCWP, SVV and hTEE for fluid volume resuscitation (especially when capillary permeability is major problem than cardiac performance) is a major challenge in many ICU setups. Therefore, repetitive determination of blood volume by trivalent chromium [51Cr (III)] as a direct single variable method may be a near ideal method during fluid volume resuscitation in cases where capillary permeability is a major problem (e.g. Burns). Hence, in the present article the repeatability and reliability of 51Cr (III) method in New Zealand white rabbits was explored. Mean blood volume values of initial measurement were 195.66 ± 47.30 ml or 89.81 ± 17.88 ml/kg body weight. Repeated mean blood volume values, measured after 1 h, was 181.98 ± 53.16 ml or 83.68 ± 22.09 ml/kg body weight. The average difference between the initial and repeated measurements was 10.93 ml (95% CI -3.33, 25.19 ml), which is not statistically significant (P = 0.128). The method using 51Cr (III) for repeat blood volume measurements after sixty minutes in rabbits is a reliable method. â¢Rapidâ¢Repeatableâ¢Reliable.
RESUMO
Serial injection into marginal vein and blood collection through auricular artery in New Zealand white Rabbit (Oryctolagus cuniculus) is an important procedure for various types of experimental studies. Limitations of the existing methods for serial injection and blood collection includes complex procedures, causes considerable discomfort to rabbits, whole blood samples obtained are highly prone to hemolysis and lastly detailed protocol is not available in the literature. Approximately 10 min before commencement of the experiment, a local anesthetic cream was applied over the right and left ear lobes. The skin at the site of sample collection and injection was prepared by shaving the area on both ears and wiping it with alcohol swab. Once prepared, a 26 GA (BD Neoflon) intravenous cannula was inserted into the marginal vein of the ear and secured with an adhesive plaster. In the other ear, a 24 GA (BD Neoflon) intravenous cannula was placed in the auricular/central artery and secured with an adhesive plaster. The novel and refined method described here has been standardized and found to be reliable. The samples obtained using this method is not susceptible to hemolysis and hence we recommend this method for serial injection and blood collection in rabbits. â¢Easy to performâ¢Not prone to hemolysisâ¢Detailed methodology described.
RESUMO
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.
