Isovolemic hemodilution as a functional therapy of decompensated arteriosclerotic stenoses of the femoral, cerebral and ophthalmic artery.
Isovolemic hemodilution, i.e. an intentionally induced anemia with strict replacement of red cell volume, represents a simple, effective and safe procedure to improve the fluidity of blood, especially under conditions of local or generalized low flow. After a short historical note on phlebotomy, the precursor therapy to hemodilution, the hemorheological theory proposed to explain the effects of hemodilution in the treatment of obliterative vascular diseases, is outlined. It is stressed that this procedure is not intended to reduce the 'viscosity' of blood in the conventional sense, but to counteract or abolish the thixotropic and pseudoplastic properties of human blood. These exist only at low shear stresses and only at normal or elevated hematocrit levels. Thence, hemodilution is induced to ensure maintenance of residual blood flow even if the shear stresses fall below subcritical levels in the poststenotic areas of the vascular beds. Compensatory mechanisms for the induced anemia, the effect of hemodilution on oxygen delivery to various organs is reviewed, and a short summary of the presently available clinical experience is given.
D000818:Animals; D001157:Arterial Occlusive Diseases / Q000628:therapy*; D001162:Arteriosclerosis Obliterans / Q000628:therapy; D001794:Blood Pressure; D001809:Blood Viscosity; D002199:Capillary Permeability; D002560:Cerebrovascular Circulation; D005260:Female; D005263:Femoral Artery; D005528:Foot / Q000098:blood supply; D006225:Hand / Q000098:blood supply; D006400:Hematocrit; D006438:Hemodilution; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000628:therapy*; D008433:Mathematics; D008833:Microcirculation; D008875:Middle Aged; D009880:Ophthalmic Artery; D010101:Oxygen Consumption; D012039:Regional Blood Flow; D012212:Rheology; D013817:Thermography; D013919:Thromboangiitis Obliterans / Q000628:therapy; D014664:Vasodilation