Methods and instrumentation used in practice of clinical haemorheology

Abstract

The aim of practice of clinical haemorheology is to study patients who might present themselves with or without any clinical symptoms but who might suffer from silent or overt cardiovascular disorders, some forms of cancer, anxiety, etc. A presence and a prognosis of these disorders are linked to an increase and/or abnormality of one or more of the blood viscosity factors: blood viscosity, plasma viscosity, red cell aggregation and rigidity, platelet aggregation, ability for formation of thrombi, flow instability, etc. Hyperviscosaemia might be present in spite of normal or low viscosity of the whole blood. Different disorders can be described by ‘profiles of viscosity factors’ which form a rheological fingerprint specific to a particular disease or a group of disorders. Determination of viscosity factors is carried out utilizing a series of instruments: (a) rotational viscometers, (b) capillary viscometers, (c) erythrocyte sedimentation tubes in 20C and 37C water tanks, (d) variable frequency thrombo-viscometer, (e) slit-capillary photo-viscometer, etc. One known factor which is not measured routinely is ‘inversion phenomenon’, and this is due to complexity and expense of measurements. Biochemical studies, including fibrinogen assay and estimation of AB0 blood groups, are carried out. Effect of drugs on blood viscosity factors can be studied in vitro or in vivo.