The influence of experimentally induced anemia on the patency of microvascular anastomoses

Anemia, secondary to blood loss or hemodilution, causes reduction of blood viscosity and has been assumed to favor the long-term patency of microvascular anastomoses. This assumption was tested by performing arterial and venous anastomoses on rat vessels measuring 0.3 to 0.8 mm. in external diameter. A group of rats rendered experimentally anemic (whose blood viscocity was lowered by 37 percent) showed no higher patency rates when the involved vessels were examined 3 weeks later than did a control group. The hypothesis that anemia favors higher patency rates was not substantiated.