Normovolemic hemodilution with Hb vesicle solution attenuates hypoxia in XXXX hamster flap tissue.

@entity1 @entity97 @entity26 @entity63
The aim of this study was to test whether oxygenation in acutely @entity63 , collateralized tissue may be improved by normovolemic hemodilution with a solution containing liposome-encapsulated @entity1 Hb ( @entity97 ). A skin flap model in anesthetized hamsters was used, which consisted of two parts receiving either anatomic or collateral perfusion. Microhemodynamics were investigated with intravital microscopy. Partial tissue @entity26 tension was measured with a Clark-type microprobe. Hemodilution was obtained by exchanging 50% of the total blood volume with @entity97 suspended in 8% human serum albumin (HSA8) or 6% Dextran 70 (Dx70). The size of the vesicles was 276 nm, the P(50) was 22 mmHg, and the Hb concentration of the solutions was 7.5 g/dl. Colloid osmotic pressure and viscosity were 49.9 mmHg and 8.7 cP for @entity97 -Dx70 and 40.0 mmHg and 2.9 cP for @entity97 -HSA8, respectively. Hemodilution with @entity97 -Dx70 led to an increase in microvascular blood flow in the @entity63 microvessels to maximally 158% (median, P < 0.01), whereas blood flow remained virtually unchanged after hemodilution with @entity97 -HSA8. In the @entity63 tissue, @entity26 tension was improved from 11.9 to 17.0 mmHg (P < 0.01) after hemodilution with @entity97 -Dx70 but remained virtually unchanged after hemodilution with @entity97 -HSA8. Our study suggests that the oxygenation in acutely @entity63 , collateralized tissue may be improved by normovolemic hemodilution with @entity97 suspended in Dx70. The effect was achieved by an increase in microcirculatory blood flow related to the rheological properties of the suspending medium.
