Microvascular pressure and functional capillary density in extreme hemodilution with low and high viscosity dextran and a low viscosity Hb-based O2 carrier.

Cabrales P, Tsai AG, Intaglietta M
Am J Physiol Heart Circ Physiol 2004 Feb 19 [Epub ahead of print].
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This is the first experimental proof that in conditions of extreme hemodilution (Hct 11%) high plasma viscosity preserves microcirculatory function by maintenance of hydraulic capillary pressure and as a consequence maintenance of functional capillary density. This effect of plasma viscosity appears independent of tissue oxygen pressure on a local basis.
Extreme hemodilution should therefore only be performed with high viscosity plasma substitutes but not with the conventional plasma expanders and/or crystalloids routinely used in limited normovolemic hemodilution.

– Konrad Messmer