PRESENTATION OF A CLINICAL HEMOVISCOMETER

A clinical hemoviscometer is presented. It is a Couette type viscomete r which is automatic and driven by a microcomputer. It was designed an d realized in the laboratory. The measurement of blood viscosity requi res 1 ml of anticoagulated blood adjusted at 45% of hematocrit. Experi ments are performed at a constant temperature (37-degrees-C) according to a well-established protocol : gentle mixing of the blood sample fo llowed by a 3 minute rest just before each of the following measuremen t modes begins. - Under steady state flow conditions, 12 viscosity mea surements are realized in a range of shear strers rate step of 1 s-1 i s applied. The elastothixotropic response of the blood sample is then obtained. Such a hemorheological test, called <<hemorheogram>>, requir es 15 minutes. Given to the clinician, the hemorheogram results includ e the absolute blood viscosities at the shear strers rates of 0.1 s-1, 1 s-1, 10 s-1, 70 s-1, the thixotropy index and the plasma viscosity. Finally, results to be kept in the laboratory files consist of the wh ole data issued from the patient hemorheogram including the relative b lood viscosities (blood viscosity/plasma viscosity) at the same shear strers rate values (J Mal Vasc, 1993, 18, pages 153-156.