This is an author produced version of a paper published in Intensive care medicine. This paper has been peerreviewed but does not include the final publisher proofcorrections or journal pagination.Citation for the published paper: Dubniks M, Persson J, Grände PO. "Effect of blood pressure on plasma volume loss in the rat under increased permeability" Intensive care medicine, 2007, Vol: 33, Issue: 12, pp. 2192 http://dx.doi.org/10.1007/s00134-007-0756-2Access to the published version may require journal subscription. Published with permission from: Springer Verlag Design: Prospective randomised laboratory study.Subject: Forty-five adult male Sprague-Dawley rats.Interventions: Permeability was increased via an anaphylactic reaction by injection of 0.5 ml dextran 70. One hour later, volume expansion with 15 ml/kg of 5% albumin was given for 15 min.Plasma volume was measured just before and 2.5 hours after the albumin infusion ( 125 I-albumin tracer technique). The study included a control group, a noradrenalin group and a metoprolol/clonidine group (n=10 in each group). The vasoactive treatment started after albumin infusion and continued throughout the experiment. Plasma volume was also measured in a separate group without albumin infusion, to evaluate the effect of noradrenalin-induced increase in blood pressure under hypovolemia (n=9). CVP was measured to estimate the venous pressure effect of noradrenalin (n=6). Results:The remaining increase in plasma volume 2.5 h after infusion of 15 ml/kg of albumin was 11.8 ± 3.6 ml/kg in the control group compared with 0.5 ± 6.3 ml/kg in the noradrenalin group (p < 0.001) and with 12.5 ± 4.9 ml/kg in the metoprolol/clonidine group (ns). The reduction in plasma volume by noradrenalin infusion was much smaller in the group not given albumin, or 3.5 ± 3.0 ml/kg. Conclusion:Noradrenalin infusion increases the loss of plasma volume during a state of increased permeability which, according to the 2-pore theory of transvascular fluid exchange, may be explained by increased hydrostatic capillary pressure. The loss was less pronounced in hypovolemia.3

After hemorrhage, the PV-expanding capacity of 6% dextran 70 was better than that of 5% albumin, which was in turn better than that of HES 130/0.4 given in equal volumes.

Objective: To compare the colloids 5% albumin, 4% gelatine, and 6% HES 130/0.4 with one another, and with saline, regarding their plasma expanding effects at increased permeability, and to compare the results with those from a previous study at normal permeability.Design: Prospective controlled randomised laboratory study.Setting: University research laboratory.Subjects: 48 adult male Sprague-Dawly rats.Interventions: Permeability was increased by an injection of 0.5 ml dextran 70 using the fact that dextran causes anaphylactic reaction in the rat. Plasma volume was determined ( 125 I albumin tracer technique) after anaesthesia, 1 h after the dextran injection (before infusion for 10-15 min of 20 ml/kg bw of each of the colloids or 80 ml/kg of saline), and 3 h later. Blood pressure, haematocrit, blood gases and electrolytes were measured. CVP was measured in 4 rats. Measurements and results:Plasma volume was 41.1±1.9 ml/kg at baseline (n=9), and 29.1±4.1 ml/kg (n=35) 1 h after the dextran injection (p<0.05). Three hours after infusion of the plasma expander, plasma volume had increased by 17.1±3.4 ml/kg in the albumin group, by 7.9±3.6 ml/kg in the gelatine group, by 7.4±4.4 ml/kg in the HES group, and by 12.2±3.1 ml/kg in the saline group. It was unchanged in a control group given no solution (n=7 for all groups) (Means ± SD). Conclusion:Albumin was a more effective plasma volume expander than gelatine or HES or saline (p<0.05), which were equally effective. All solutions showed a smaller plasma expanding effect than observed in a previous study with normal permeability.3