Abstract: Objective:To explore the effects of different degrees of acute hypervolumic hemodilution on the blood coagulation function and systemic inflammatory response in elderly patients.Methods:The clinical data of 156 patients treated with acute hypervolumic hemodilution were retrospectively analyzed.According to the different degree of dilution,the patients were divided into the 30% Hct group(group A) and 25% Hct group(group B).The blood coagulation function and systemic inflammatory reaction between two groups before operation(T₀),after operation(T₁) and at the end of operation(T₂) were compared.Results:The hemoglobin level and platelet count in two groups at T₂ significantly decreased compared with at T₀(P<0.01),and the prothrombin time in two groups at T₁ was significantly higher than that at T₀ and T₂(P<0.05 to P<0.01).The hemoglobin level in group B at T₂ was significantly lower than that in group A(P<0.01),and the platelet count in group B at T₁ and T₂ were significantly lower than that in group A(P<0.01).The differences of prothrombin time and activated partial thromboplastin time between two groups at all time-points were not statistically significant(P>0.05).The levels of interleukin(IL)IL-1β,IL-6,atrial natriuretic polypeptide(ANP) in two groups at T₁ and T₂ were significantly higher than those at T₀(P<0.05 to P<0.01),and the pulmonary compliance(CL) at T₁ and T₂ were significantly lower than that at T₀(P<0.01).The levels of IL-1β and CL in group B at T₁ and T₂ were significantly lower than those in group A(P<0.01),and the level of ANP in group B at T₂ was higher than that in group A(P<0.05).Conclusions:The effects of different degrees of acute hypervolumic hemodilution on the blood coagulation function and systemic inflammatory response in elderly patients are different.The low degree of dilution may affect the oxygenation,reduce the blood coagulation function,and aggravate the systemic inflammatory response.