Clinical Hemorheology and Microcirculation 18 (1998) 265–272 265 IOS Press Hemorheological, coagulative and fibrinolytic changes during autologous blood donation X. Clivillé a,* , C. Bofill a , J. Joven a , J. Monasterio b , G. Viscor c , M. Vernis a , A. Angles b and T. Sans a a Hospital Universitari de Sant Joan de Reus b Unitat de Recerca en Trombosis i Hemostasia del Hospital General de la Vall d’Hebron c Departament de Fisiologia de la Universitat de Barcelona Abstract. Background. Clinical data suggest that autologous blood donation may prevent postsurgical venous thrombosis. If confirmed, this is probably due to beneficial effects in rheologic and hematologic variables which may be changed in patients as a result of repeated bleeding. Study design and methods. To ascertain this point, we studied variations in hematological, hemorheological, coagulative and fibrinolytic parameters in 30 patients undergoing autologous blood donation. Results. Whole blood viscosity (WBV), plasma viscosity and blood viscosity adjusted to 40% hematocrit, progressively and substantially decreased throughout the successive bleeding at all the shear rates considered. WBV was further reduced by presurgical hemodilution with autologous plasma which decreased the platelet and leukocyte count. The hemostasis and fibrinolysis variables, however, underwent no clinically significative changes. Conclusion. Repeated bleedings change most hemorheological variables. By decreasing cytocrit and viscosity, reducing aggregability and increasing blood cell deformability an optimal milieu to help prevent thrombosis is artificially created. Keywords: Autologous blood transfusion, coagulation, fibrinolysis, hemorheology, venous thrombosis, viscosity 1. Introduction In surgical practice, predeposited autologous blood transfusion programs (PABTPs) are widely ac- cepted as an effective measure for reducing the need for allogeneic blood [34,28] and preventing its infectious and/or immunologic complications [33]. Deep-vein thrombosis and pulmonary embolism, however, are still frequent and serious complications during the surgical process [13]. In the immediate postoperative period, immobilization and therefore stasis, as well as hyperviscosity and blood hyperco- agulability are concurrent [10], and these perturbations probably explain most of the thromboembolic complications. In primary proliferative polycythemia, the risk of venous thrombosis increases markedly with the in- crease in hematocrit [27] and is reduced by normalizing the hematocrit prior to surgery [35]. There is also evidence that hemodilution of patients with normal circulating red cell mass is beneficial in relation to improved rheology [14,19] and, conversely, thrombosis is uncommon in patients with low circulating red cell mass [25]. Finally, there is also experimental evidence suggesting that hemodilution may delay * All correspondence and requests for reprints should be addressed to: Dr. X. Clivillé, Centre de Recerca Biomèdica, Hospital Universitari de Sant Joan, Carrer Sant Joan s/n, 43201, Reus, Spain. Tel.: +3477310300, ext. 303; Fax: +3477312569; E-mail: ala@fmcs.urv.es. 1386-0291/98/$8.00  1998 – IOS Press. All rights reserved