VASOACTIVE EFFECTS OF DEXTRAN-BENZENE-TET RACARBOXYLATE-HEMOGLOBIN, APOTENTIAL RED-CELL SUBSTITUTE, ASSESSED BY PULSED DOPPLER ULTRASONOGRAPHY

The effects of Dextran-Benzene-Tetracarboxylate-Hemoglobin (Dex-BTC-Hb ), a chemically-modified hemoglobin-based oxygen carrier, on the vascu lar tone were compared to those of standard solutions, i.e. the animal 's own blood and a 50 g/l albumin solution, by measuring the carotid b lood flow velocity, the mean arterial pressure, the heart rate and res piratory frequency, in anesthetized Hartley guinea pigs after a hemorr agic shock. Stroma-free hemoglobin induced 40 % hypertension and a 110 % rise in blood flow velocity immediately after injection. The veloci ty was still increased 38 %, 3 hours after injection. The calculations of the vascular resistances showed an increase in carotid vascular to ne. Dex-BTC-Hb brought about 35 % hypertension for two hours with no s ignificant modifications of the vascular tone. These effects are simil ar to those of the albumin solution. These results indicate that, unli ke stroma-free hemoglobin, Dex-BTC-Hb does not significantly affect th e vascular tone, probably because of its slight interaction with the f actors that regulate vascular tone.