问题详情

A 65-year-old slightly cyanotic man presents to his physician complaining of ruritus and nose bleeds. A blood test reveals a hematocrit of 62%, leading to the diagnosis of polycythemia vera. Treatment includes aspirin to prevent thrombosis and periodic phlebotomy to reduce the hematocrit. The reduction in hematocrit is beneficial because it does which of the following？

A、Decreases cardiac output

B、Reduces blood viscosity

C、Reduces blood velocity

D、Increases arterial oxygen saturation