Nonlinear cardiovascular regulation consequent to changes in blood viscosity
Issue title: Selected Proceedings of the 16th Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM), 18–21 June, 2011, Munich, Germany
Affiliations: Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA | Faculty of Medicine, Universidad Juárez del Estado de Durango, Victoria de Durango, Durango, Mexico, Mexico
Note: [] Corresponding author: Marcos Intaglietta, PhD, Department of Bioengineering, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093 0412, USA. Tel.: +1 858 534 4275; E-mail: mintagli@ucsd.edu
Abstract: Increasing blood and plasma viscosity is generally associated with pathological conditions, and increased cardiovascular risk, a perception based in part on studies where blood viscosity is increased to extreme values attained by hemoconcentration. Present studies, supported by epidemiological studies in humans, show that moderate increases in Hct improve cardiovascular function and vice versa. This result is due to the nonlinear regulation of peripheral vascular resistance arising from the increased production of nitric oxide following the increase of shear stress on the vascular wall due to increasing blood viscosity. Similar effects are found in when plasma viscosity is increased in the extremely hemodiluted circulation. In both cases there is an effect at the arteriolar/capillary level, leading to a condition of improved microvascular function and supra perfusion that facilitates clearance of metabolic waste products, while maintaining oxygen delivery. Application of these findings to the design of viscogenic plasma expanders suggests a new approach for the treatment of hemorrhage that in part replaces the use of blood transfusions, making it feasible to lower the transfusion trigger to levels below than normally considered safe.
